second revision no. 5-nfpa 820-2014 [ section no. 2.3.1 ] · second revision no. 17-nfpa 820-2014 [...
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Second Revision No. 5-NFPA 820-2014 [ Section No. 2.3.1 ]
2.3.1 ASTM Publications.
ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959.
ASTM E 84 E84 , Standard Test Method for Surface Burning Characteristics of Building Materials, 2013a 2014 .
ASTM E 108, Standard Test Methods for Fire Tests of Roof Coverings , 2011.
ASTM E 136 E136 , Standard Test Method for Behavior of Materials in a Vertical Tube Furnace at 750°C, 2012.
ASTM E 2652 E2652 , Standard Test Method for Behavior of Materials in a Tube Furnace with a Cone-shaped AirflowStabilizer, at 750°C, 2012.
IEEE/ASTM SI 10, Use of the International System of Units (SI): the Modern Metric System, 1997 2010 .
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Submittal Date: Tue Oct 07 11:14:11 EDT 2014
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Committee Statement: Update year dates
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Public Comment No. 6-NFPA 820-2014 [Section No. 2.3.1]
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Second Revision No. 17-NFPA 820-2014 [ Section No. 3.3.22 ]
3.3.22* Flame Spread Index.
A number obtained according to ASTM E 84, Standard Test Method for Surface Burning Characteristics of BuildingMaterials , or ANSI/UL 723, Standard for Test for Surface Burning Characteristics of Building Materials . [ 220,2015] See 8.2.3.4 .
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Submittal Date: Thu Oct 16 11:23:37 EDT 2014
Committee Statement
CommitteeStatement:
The definition of flame spread index was moved into Chapter 8 along with definitions of limited and noncombustible so that all the definitions applicable to Chapter 8 were in one the same location in the document.
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Second Revision No. 16-NFPA 820-2014 [ Section No. 3.3.23 ]
3.3.23 Flammable Limits. Lower Explosive Limit (LEL).
See Lower Flammable Limit (LFL) 3.3.24 .
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CommitteeStatement:
While the preferred term for NFPA use is lower flammable limit, the industry still uses the term LEL andmanufacturers of combustible gas detectors continue to use the LEL acronym on monitors and meters. A crossreference to LFL has been provided.
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Second Revision No. 2-NFPA 820-2014 [ Section No. 4.2 ]
4.2* Design and Construction.
The design and construction of collection system facilities shall conform to Table 4.2.1 , which summarizes thevarious components associated with wastewater collection and transport systems.
4.2.1
The design and construction of buildings and structures containing wastewater collection and transport systems shallcomply with the applicable building code and the additional requirements in Chapters 7 through 9 .
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4.2.2
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The design and construction of the components associated with the wastewater collection and transportation systemsshall conform to Table 4.2.1 Table 4.2.2 .
Table 4.2.2 Collection Systems
Rowa Linea
Location
and
Function
Fire andExplosion
Hazard Ventilationb
Extent ofClassified
Area
NEC -Area NECArea ElectricalClassification
(All Class I,Group D)
Materials ofConstruction
forBuildings or
Structures c
FireProtectionMeasures
1 MATERIALS USEDIN REHABILITATION,RECONSTRUCTION,OR SLIP-LINING OFSEWERS
NA N/A NA N/A NA N/A NA N/A In accordancewith8.3.1 8.3.5
NA N/A
2 INDUSTRIALSEWER Sewertransporting industrialwastewater only (nosanitary wastewater)
Not included within the scope of this standard
3 STORM SEWERSewer transportingstorm water only (nosanitary wastewater)
Possibleignition offlammablegases andfloatingflammableliquids
NNV Inside ofsewer
Division 2 In accordancewith8.3.1 8.3.5
NR
4 STORM WATERPUMPING STATIONWET WELLS
Liquid side ofpumping stationserving only a stormsewer system
Possibleignition offlammablegases andfloatingflammableliquids
NNV Entire roomor space
Division 2 NC, LC, orLFS
NR
5 a STORM WATERPUMPING STATIONDRY WELLS
Dry side of apumping stationserving only a stormsewer system andphysically separatedfrom wet well
Buildup ofvapors fromflammableorcombustibleliquids
D Entire drywell
Division 2 NC, LC, orLFS
FE
b C Entire drywell
Unclassified NC, LC, orLFS
FE
6 PRESSURE SEWER(Force main) Sewerunder pressure(flooded dischargepipe from pump ortank)
Not included within the scope of this standard
7 BUILDING SEWER(Lateral sewer ordrain) Sewer servinga house or singlebuilding (plumbing)
Not included within the scope of this standard
8 INDIVIDUALRESIDENTIALSEWER
Sewer serving one ormore individualresidences with atotal flow of not morethan 1500 gallons perday (gpd)
NA N/A NNV Withinenclosedspace
Unclassified NR NR
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Rowa Linea
Location
and
Function
Fire andExplosion
Hazard Ventilationb
Extent ofClassified
Area
NEC -Area NECArea Electrical
Classification (AllClass I, Group D)
Materials ofConstruction
forBuildings or
Structures c
FireProtectionMeasures
9 INDIVIDUALRESIDENTIALPUMPING UNITS
Pumping unitsserving one or moreindividual residenceswith a total flow of notmore than 1500gallons per day (gpd)(e.g., grinder pumps,septic tank effluentpumps, ejectorpumps)
NA N/A NNV Withinenclosedspace
Unclassified NR NR
10 a RESIDENTIALSEWER
Sewer transportingprimarily residentialwastewater
Possibleignition offlammablegases andfloatingflammableliquids
NNV Withinenclosedspace
Division 2 In accordancewith8.3.1 8.3.5
NR
b B Withinenclosedspace
Unclassified In accordancewith8.3.1 8.3.5
NR
11 a RESIDENTIALWASTEWATERPUMPING STATIONWET WELL
Pumping stationtransporting primarilyresidentialwastewater
Possibleignition offlammablegases andfloatingflammableliquids
A Entire roomor space
Division 2 NC, LC, orLFS
CGD
b B Entire roomor space
Unclassified NC, LC, orLFS
CGD
12 a RESIDENTIALWASTEWATERPUMPING STATIONDRY WELL
Dry side of apumping stationtransporting primarilyresidentialwastewater
Buildup ofvapors fromflammableorcombustibleliquids
D Entire roomor space
Division 2 NC, LC, orLFS
FE
b C Entire roomor space
Unclassified NC, LC, orLFS
FE
13 OUTFALL SEWERFinal discharge pipefrom a treatmentplant, transportingtreated wastewater
NA N/A NNV NA N/A Unclassified NR NR
14 a SANITARY SEWERSewer transportingdomestic,commercial, andindustrial wastewater
Possibleignition offlammablegases andfloatingflammableliquids
NNV Inside ofsewer
Division 1 In accordancewith8.3.1 8.3.5
NR
b B Inside ofsewer
Division 2 In accordancewith8.3.1 8.3.5
NR
15 a COMBINED SEWERSewer transportingdomestic,commercial, andindustrial wastewaterand storm water
Possibleignition offlammablegases andfloatingflammableliquids
NNV Inside ofsewer
Division 1 In accordancewith8.3.1 8.3.5
NR
b B Inside ofsewer
Division 2 In accordancewith8.3.1 8.3.5
NR
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Rowa Linea
Location
and
Function
Fire andExplosion
Hazard Ventilationb
Extent ofClassified
Area
NEC -Area NECArea Electrical
Classification (AllClass I, Group D)
Materials ofConstruction
forBuildings or
Structures c
FireProtectionMeasures
16 a WASTEWATERPUMPING STATIONWET WELLS
Liquid side of apumping stationserving a sanitarysewer or combinedsystem
Possibleignition offlammablegases andfloatingflammableliquids
A Entire roomor space
Division 1 NC, LC, orLFS
CGDrequired ifmechanicallyventilated oropens into abuildinginterior
b B Entire roomor space
Division 2 NC, LC, orLFS
CGD
17 a BELOWGRADE ORPARTIALLYBELOWGRADEWASTEWATERPUMPING STATIONDRY WELL
Pump roomphysically separatedfrom wet well;pumping ofwastewater from asanitary or combinedsewer systemthrough closedpumps and pipes
Buildup ofvapors fromflammableorcombustibleliquids
C Entire spaceor room
Unclassified NC, LC, orLFS
FE
b D Entire spaceor room
Division 2 NC, LC, orLFS
FE
18 ABOVEGRADEWASTEWATERPUMPING STATIONPump roomphysically separatedwith no personnelaccess to wet well;pumping ofwastewater from asanitary or combinedsewer systemthrough closedpumps and pipes
NA N/A NR NA N/A Unclassified NC, LC, orLFS
FE
19 a ABOVEGRADEWASTEWATERPUMPING STATIONPump room notphysically separatedfrom wet well;pumping ofwastewater from asanitary or combinedsewer systemthrough closedpumps and pipes
Possibleignition offlammablegases andfloatingflammableliquids
A Entire spaceor room
Division 1 NC FE
b B Entire spaceor room
Division 2 NC, LC, orLFS
FE
20 a ODOR-CONTROLAND VENTILATIONSYSTEMS SERVINGCLASSIFIED AREAS
Leakageand ignitionofflammablegases andvapors
D Entire areaif enclosed
Division 2 NC, LC, orLFS
CGD andFDS
b C Areas within0.9 m (3 ft)of leakagesourcessuch asfans,dampers,flexible
Division 2 NC, LC, orLFS
CGD andFDS
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Rowa Linea
Location
and
Function
Fire andExplosion
Hazard Ventilationb
Extent ofClassified
Area
NEC -Area NECArea Electrical
Classification (AllClass I, Group D)
Materials ofConstruction
forBuildings or
Structures c
FireProtectionMeasures
connections,flanges,pressurizedunweldedductwork,andodor-controlvessels
c C Areasbeyond 0.9m (3 ft)
Unclassified NC, LC, orLFS
CGD andFDS
d Not enclosed,open to theatmosphere
Areas within0.9 m (3 ft)of leakagesourcessuch asfans,dampers,flexibleconnections,flanges,pressurizedunweldedductwork,andodor-controlvessels
Division 2 NC, LC, LFS FE
e Not enclosed,open to theatmosphere
Areasbeyond 0.9m (3 ft)
Unclassified NC,LC, LFS FE
21 a MAINTENANCEHOLES
Access to sewer forpersonnel entry
Possibleignition offlammablegases andfloatingflammableliquids
NNV Inside Division 1 In accordancewith8.3.1 8.3.5
NR
b B Inside Division 2 In accordancewith8.3.1 8.3.5
NR
22 a JUNCTIONCHAMBERS
Structure wheresewers intersect
Buildup ofvapors fromflammableorcombustibleliquids
NNV Inside Division 1 In accordancewith8.3.1 8.3.5
NR
b B Open andabove gradeor insideandventilated
Division 2 In accordancewith8.3.1 8.3.5
NR
23 INVERTEDSIPHONS Depressedsection of gravitysewer
Possibleignition offlammablegases andfloatingflammableliquids
NNV Interior ofinlet andoutletstructures
Division 1 NC NR
24 CATCH BASINS(Curb inlet) Inletwhere street waterenters a storm orcombined sewer
Buildup ofvapors fromflammableorcombustibleliquids
NNV Enclosedspace
Division 1 In accordancewith8.3.1 8.3.5
NR
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Rowa Linea
Location
and
Function
Fire andExplosion
Hazard Ventilationb
Extent ofClassified
Area
NEC -Area NECArea Electrical
Classification (AllClass I, Group D)
Materials ofConstruction
forBuildings or
Structures c
FireProtectionMeasures
25 a RESIDENTIALDIVERSIONSTRUCTURES
Enclosed structureswhere residentialwastewater can bediverted
Buildup ofvapors fromflammableorcombustibleliquids
NNV Enclosedspace
Division 2 In accordancewith Chapter 8
NR
b B Enclosedspace
Unclassified In accordancewith Chapter 8
NR
26 a RESIDENTIALBELOWGRADEVALVE VAULT
With an exposedresidentialwastewater surface
Possibleignition ofgases andfloatingflammableliquids
NNV Enclosedspace
Division 2 In accordancewith8.3.1 8.3.5
NR
b B Enclosedspace
Unclassified In accordancewith8.3.1 8.3.5
NR
27 a RESIDENTIALCONTROLSTRUCTURESEnclosed structureswhere residentialwastewater flow isregulated
Buildup ofvapors fromflammableorcombustibleliquids
A Enclosedspace
Division 2 In accordancewith Chapter 8
NR
b B Enclosedspace
Unclassified In accordancewith Chapter 8
NR
28 a RESIDENTIALBELOWGRADEMETERING VAULT
With an exposedresidentialwastewater surface
Possibleignition offlammablegases andfloatingflammableliquids
NNV Enclosedspace
Division 2 In accordancewith8.3.1 8.3.5
NR
b B Enclosedspace
Unclassified In accordancewith8.3.1 8.3.5
NR
29 a DIVERSIONSTRUCTURESEnclosed structureswhere wastewatercan be diverted
Buildup ofvapors fromflammableorcombustibleliquids
NNV Enclosedspace
Division 1 In accordancewith Chapter 8
NR
b B Division 2 In accordancewith Chapter 8
NR
30 ABOVEGRADEVALVE VAULT
Physically separatedfrom the wet well;valves in vault inclosed piping system
NA N/A NR NA N/A Unclassified NC, LC, orLFS
NR
31 a BELOWGRADEVALVE VAULTPhysically separatedfrom the wet well andwith closed pipingsystem
Buildup ofvapors fromflammableorcombustibleliquids
NNV Enclosedspace
Division 2 NC, LC, orLFS
NR
b C Enclosedspace
Unclassified NC, LC, orLFS
NR
32 a BELOWGRADEVALVE VAULT Withan exposedwastewater surface
Possibleignition ofgases andfloatingflammableliquids
NNV Enclosedspace
Division 1 NC NR
b B Enclosedspace
Division 2 NC, LC, orLFS
NR
33 a CONTROLSTRUCTURESEnclosed structureswhere wastewater orstorm water flow isregulated
Buildup ofvapors fromflammableorcombustibleliquids
A Enclosedspace
Division 1 In accordancewith Chapter 8
NR
b B Enclosedspace
Division 2 In accordancewith Chapter 8
NR
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Rowa Linea
Location
and
Function
Fire andExplosion
Hazard Ventilationb
Extent ofClassified
Area
NEC -Area NECArea Electrical
Classification (AllClass I, Group D)
Materials ofConstruction
forBuildings or
Structures c
FireProtectionMeasures
34 a WASTEWATERHOLDING BASINSEnclosed structurestemporarily holdinguntreated or partiallytreated wastewater
Possibleignition offlammablegases andfloatingflammableliquids
A Enclosedspace
Division 1 NC NR
b B Enclosedspace
Division 2 NC, LC, orLFS
NR
35 WASTEWATERHOLDING BASINS,LINED OR UNLINEDOpen structuresholding storm water,combinedwastewater,untreated or partiallytreated wastewater
NR NR NR NR NR NR
36 a BELOWGRADEMETERING VAULTPhysically separatedfrom the wet well andwith closed pipingsystem
Buildup ofvapors fromflammableorcombustibleliquids
NNV Enclosedspace
Division 2 NC, LC, orLFS
NR
b C Enclosedspace
Unclassified NC, LC, orLFS
NR
37 a BELOWGRADEMETERING VAULTWith an exposedwastewater surface
Possibleignition offlammablegases andfloatingflammableliquids
NNV Enclosedspace
Division 1 NC NR
b B Enclosedspace
Division 2 NC, LC, orLFS
NR
38 COARSE AND FINESCREENFACILITIES (See“Coarse and FineScreen Facilities” inTable 5.2.)
Note: The following codes are used in this table:
A: No ventilation or ventilated at less than 12 air changes per hour.
B: Continuously ventilated at 12 changes per hour in accordance with Chapter 9.
C: Continuously ventilated at 6 six air changes per hour in accordance with Chapter 9.
CGD: Combustible gas detection system.
D: No ventilation or ventilated at less than 6 six air changes per hour.
FDS: Fire detection system.
FE: Portable fire extinguisher.
LC: Limited-combustible material.
LFS: Low flame spread index material.
NA N/A : Not applicable.
NC: Noncombustible material.
NEC: In accordance with NFPA 70.
NNV: Not normally ventilated.
NR: No requirement.
a The "Row" and "Line" columns are used to refer to specific figures in A.4.2 and specific requirements for eachlocation and function.
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**The NR designation in the "Ventilation" column indicates that no ventilation requirements are established for thespace, and, therefore, Table 9.1.1.4 also has no requirements.
b This column indicates the ventilation requirements for processes. Additional ventilation requirements are provided inChapter 9. Ventilation signaling and alarm requirements are provided in Chapter 7.
c This column indicates the materials of construction for processes. Materials of construction for buildings in whichthese processes are housed are in accordance with the applicable building code and construction requirementsprovided in Chapter 8.
Supplemental Information
File Name Description
ComparisonFDtoSDChapter_4.docx For editorial use only.
FINALSDMtgREVChapter_4.docx For editorial use only.
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Submittal Date: Mon Oct 06 20:24:19 EDT 2014
Committee Statement
CommitteeStatement:
Section 4.2.2 explains that building codes cover general building construction but the components within thebuilding are covered in the table. The Table Column for materials was reworded to better indicate that the generalbuilding construction requirements are provided in chapter 8 but that the materials of construction for particularlocations within the facility are provided in the tables. The table footnotes were modified to better direct the user tothe appropriate chapters in NFPA 820 related to the subject column.
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Chapter 4 Collection Systems
4.1* General.
4.1.1
This chapter shall establish minimum criteria for protection against fire and explosion hazards in the
collection and transportation of municipal wastewater.
4.1.2
This chapter shall not apply to on-site systems, force mains, or those sewers that principally convey
industrial wastes.
4.2* Design and Construction.
4.2.1 The design and construction of collection system facilities shall conform to Table 4.2, which
summarizes the variousthe components associated with wastewater collection and transport
systems shall conform to Table 4.2.
4.2.2 The design and construction of buildings and structures containing wastewater collection and
transport systems shall comply with the applicable building code and the additional requirements in
Chapters 7-9.
Table 4.2 Collection Systems
Row*R
owa
Line*Li
nea
Location .
and .
Function
Fire and
Explosi
on
Hazard
Ventilation**Ven
tilationb
Extent of
Classifie
d Area
NEC-
Area
Electrical
Classific
ation (All
Class I,
Group D)
MaterialMat
erials of
Constructio
n for
Buildings
or
Structuresc
Fire
Protectio
n
Measure
s
1 MATERIALS
USED IN
REHABILITAT
ION,
RECONSTRU
CTION, OR
SLIP-LINING
OF SEWERS
NA NA NA NA In
accordance
with 8.3.1
NA
2 INDUSTRIAL
SEWER
Sewer
transporting
industrial
wastewater
only (no
Not included within the scope of this standard
Row*R
owa
Line*Li
nea
Location .
and .
Function
Fire and
Explosi
on
Hazard
Ventilation**Ven
tilationb
Extent of
Classifie
d Area
NEC-
Area
Electrical
Classific
ation (All
Class I,
Group D)
MaterialMat
erials of
Constructio
n for
Buildings
or
Structuresc
Fire
Protectio
n
Measure
s
sanitary
wastewater)
3 STORM
SEWER
Sewer
transporting
storm water
only (no
sanitary
wastewater)
Possibl
e
ignition
of
flamma
ble
gases
and
floating
flamma
ble
liquids
NNV Inside of
sewer
Division
2
In
accordance
with 8.3.1
NR
4 STORM
WATER
PUMPING
STATION
WET WELLS .
Liquid side of
pumping
station serving
only a storm
sewer system
Possibl
e
ignition
of
flamma
ble
gases
and
floating
flamma
ble
liquids
NNV Entire
room or
space
Division
2
NC, LC, or
LFS
NR
5 a STORM
WATER
PUMPING
STATION
DRY WELLS .
Dry side of a
pumping
station serving
only a storm
Buildup
of
vapors
from
flamma
ble or
combus
tible
liquids
D Entire
dry well
Division
2
NC, LC, or
LFS
FE
b C Entire
dry well
Unclassif
ied
NC, LC, or
LFS
FE
Row*R
owa
Line*Li
nea
Location .
and .
Function
Fire and
Explosi
on
Hazard
Ventilation**Ven
tilationb
Extent of
Classifie
d Area
NEC-
Area
Electrical
Classific
ation (All
Class I,
Group D)
MaterialMat
erials of
Constructio
n for
Buildings
or
Structuresc
Fire
Protectio
n
Measure
s
sewer system
and physically
separated
from wet well
6 PRESSURE
SEWER
(Force main)
Sewer under
pressure
(flooded
discharge pipe
from pump or
tank)
Not included within the scope of this standard
7 BUILDING
SEWER
(Lateral sewer
or drain)
Sewer serving
a house or
single building
(plumbing)
Not included within the scope of this standard
8 INDIVIDUAL
RESIDENTIAL
SEWER .
Sewer serving
one or more
individual
residences
with a total
flow of not
more than
1500 gallons
per day (gpd)
NA NNV Within
enclose
d space
Unclassif
ied
NR NR
Row*R
owa
Line*Li
nea
Location .
and .
Function
Fire and
Explosi
on
Hazard
Ventilation**Ven
tilationb
Extent of
Classifie
d Area
NEC-
Area
Electrical
Classific
ation (All
Class I,
Group D)
MaterialMat
erials of
Constructio
n for
Buildings
or
Structuresc
Fire
Protectio
n
Measure
s
9 INDIVIDUAL
RESIDENTIAL
PUMPING
UNITS .
Pumping units
serving one or
more
individual
residences
with a total
flow of not
more than
1500 gallons
per day (gpd)
(e.g., grinder
pumps, septic
tank effluent
pumps, ejector
pumps)
NA NNV Within
enclose
d space
Unclassif
ied
NR NR
10 a RESIDENTIAL
SEWER .
Sewer
transporting
primarily
residential
wastewater
Possibl
e
ignition
of
flamma
ble
gases
and
floating
flamma
ble
liquids
NNV Within
enclose
d space
Division
2
In
accordance
with 8.3.1
NR
b B Within
enclose
d space
Unclassif
ied
In
accordance
with 8.3.1
NR
11 a RESIDENTIAL
WASTEWATE
R PUMPING
Possibl
e
ignition
A Entire
room or
space
Division
2
NC, LC, or
LFS
CGD
Row*R
owa
Line*Li
nea
Location .
and .
Function
Fire and
Explosi
on
Hazard
Ventilation**Ven
tilationb
Extent of
Classifie
d Area
NEC-
Area
Electrical
Classific
ation (All
Class I,
Group D)
MaterialMat
erials of
Constructio
n for
Buildings
or
Structuresc
Fire
Protectio
n
Measure
s
b STATION
WET WELL .
Pumping
station
transporting
primarily
residential
wastewater
of
flamma
ble
gases
and
floating
flamma
ble
liquids
B Entire
room or
space
Unclassif
ied
NC, LC, or
LFS
CGD
12 a RESIDENTIAL
WASTEWATE
R PUMPING
STATION
DRY WELL .
Dry side of a
pumping
station
transporting
primarily
residential
wastewater
Buildup
of
vapors
from
flamma
ble or
combus
tible
liquids
D Entire
room or
space
Division
2
NC, LC, or
LFS
FE
b C Entire
room or
space
Unclassif
ied
NC, LC, or
LFS
FE
13 OUTFALL
SEWER Final
discharge pipe
from a
treatment
plant,
transporting
treated
wastewater
NA NNV NA Unclassif
ied
NR NR
14 a SANITARY
SEWER
Sewer
Possibl
e
ignition
NNV Inside of
sewer
Division
1
In
accordance
with 8.3.1
NR
Row*R
owa
Line*Li
nea
Location .
and .
Function
Fire and
Explosi
on
Hazard
Ventilation**Ven
tilationb
Extent of
Classifie
d Area
NEC-
Area
Electrical
Classific
ation (All
Class I,
Group D)
MaterialMat
erials of
Constructio
n for
Buildings
or
Structuresc
Fire
Protectio
n
Measure
s
b transporting
domestic,
commercial,
and industrial
wastewater
of
flamma
ble
gases
and
floating
flamma
ble
liquids
B Inside of
sewer
Division
2
In
accordance
with 8.3.1
NR
15 a COMBINED
SEWER
Sewer
transporting
domestic,
commercial,
and industrial
wastewater
and storm
water
Possibl
e
ignition
of
flamma
ble
gases
and
floating
flamma
ble
liquids
NNV Inside of
sewer
Division
1
In
accordance
with 8.3.1
NR
b B Inside of
sewer
Division
2
In
accordance
with 8.3.1
NR
16 a WASTEWATE
R PUMPING
STATION
WET WELLS .
Liquid side of
a pumping
station serving
a sanitary
sewer or
combined
system
Possibl
e
ignition
of
flamma
ble
gases
and
floating
flamma
ble
liquids
A Entire
room or
space
Division
1
NC, LC, or
LFS
CGD
required
if
mechani
cally
ventilate
d or
opens
into a
building
interior
b B Entire
room or
space
Division
2
NC, LC, or
LFS
CGD
Row*R
owa
Line*Li
nea
Location .
and .
Function
Fire and
Explosi
on
Hazard
Ventilation**Ven
tilationb
Extent of
Classifie
d Area
NEC-
Area
Electrical
Classific
ation (All
Class I,
Group D)
MaterialMat
erials of
Constructio
n for
Buildings
or
Structuresc
Fire
Protectio
n
Measure
s
17 a BELOWGRAD
E OR
PARTIALLY
BELOWGRAD
E
WASTEWATE
R PUMPING
STATION
DRY WELL .
Pump room
physically
separated
from wet well;
pumping of
wastewater
from a sanitary
or combined
sewer system
through closed
pumps and
pipes
Buildup
of
vapors
from
flamma
ble or
combus
tible
liquids
C Entire
space or
room
Unclassif
ied
NC, LC, or
LFS
FE
b D Entire
space or
room
Division
2
NC, LC, or
LFS
FE
18 ABOVEGRAD
E
WASTEWATE
R PUMPING
STATION
Pump room
physically
separated with
no personnel
access to wet
well; pumping
of wastewater
from a sanitary
or combined
sewer system
NA NR NA Unclassif
ied
NC, LC, or
LFS
FE
Row*R
owa
Line*Li
nea
Location .
and .
Function
Fire and
Explosi
on
Hazard
Ventilation**Ven
tilationb
Extent of
Classifie
d Area
NEC-
Area
Electrical
Classific
ation (All
Class I,
Group D)
MaterialMat
erials of
Constructio
n for
Buildings
or
Structuresc
Fire
Protectio
n
Measure
s
through closed
pumps and
pipes
19 a ABOVEGRAD
E
WASTEWATE
R PUMPING
STATION
Pump room
not physically
separated
from wet well;
pumping of
wastewater
from a sanitary
or combined
sewer system
through closed
pumps and
pipes
Possibl
e
ignition
of
flamma
ble
gases
and
floating
flamma
ble
liquids
A Entire
space or
room
Division
1
NC FE
b B Entire
space or
room
Division
2
NC, LC, or
LFS
FE
20 a ODOR-
CONTROL
AND
VENTILATION
SYSTEMSSE
RVING
CLASSIFIED
AREAS
Leakag
e and
ignition
of
flamma
ble
gases
and
vapors
D Entire
area if
enclose
d
Division
2
NC, LC, or
LFS
CGD
and FDS
b C Areas
within
0.9 m (3
ft) of
leakage
sources
such as
fans,
damper
s,
flexible
Division
2
NC, LC, or
LFS
CGD
and FDS
Row*R
owa
Line*Li
nea
Location .
and .
Function
Fire and
Explosi
on
Hazard
Ventilation**Ven
tilationb
Extent of
Classifie
d Area
NEC-
Area
Electrical
Classific
ation (All
Class I,
Group D)
MaterialMat
erials of
Constructio
n for
Buildings
or
Structuresc
Fire
Protectio
n
Measure
s
connecti
ons,
flanges,
pressuri
zed
unwelde
d
ductwor
k, and
odor-
control
vessels
c C Areas
beyond
0.9 m (3
ft)
Unclassif
ied
NC, LC, or
LFS
CGD
and FDS
d Not enclosed,
open to the
atmosphere
Areas
within
0.9 m (3
ft) of
leakage
sources
such as
fans,
damper
s,
flexible
connecti
ons,
flanges,
pressuri
zed
unwelde
d
ductwor
k, and
Division
2
NC,LC,
LFS
FE
Row*R
owa
Line*Li
nea
Location .
and .
Function
Fire and
Explosi
on
Hazard
Ventilation**Ven
tilationb
Extent of
Classifie
d Area
NEC-
Area
Electrical
Classific
ation (All
Class I,
Group D)
MaterialMat
erials of
Constructio
n for
Buildings
or
Structuresc
Fire
Protectio
n
Measure
s
odor-
control
vessels
e Not enclosed,
open to the
atmosphere
Areas
beyond
0.9 m (3
ft)
Unclassif
ied
NC,LC,
LFS
FE
21 a MAINTENANC
E HOLES .
Access to
sewer for
personnel
entry
Possibl
e
ignition
of
flamma
ble
gases
and
floating
flamma
ble
liquids
NNV Inside Division
1
In
accordance
with 8.3.1
NR
b B Inside Division
2
In
accordance
with 8.3.1
NR
22 a JUNCTION
CHAMBERS .
Structure
where sewers
intersect
Buildup
of
vapors
from
flamma
ble or
combus
tible
liquids
NNV Inside Division
1
In
accordance
with 8.3.1
NR
b B Open
and
above
grade or
inside
and
ventilate
d
Division
2
In
accordance
with 8.3.1
NR
23 INVERTED
SIPHONS
Depressed
section of
gravity sewer
Possibl
e
ignition
of
flamma
NNV Interior
of inlet
and
outlet
Division
1
NC NR
Row*R
owa
Line*Li
nea
Location .
and .
Function
Fire and
Explosi
on
Hazard
Ventilation**Ven
tilationb
Extent of
Classifie
d Area
NEC-
Area
Electrical
Classific
ation (All
Class I,
Group D)
MaterialMat
erials of
Constructio
n for
Buildings
or
Structuresc
Fire
Protectio
n
Measure
s
ble
gases
and
floating
flamma
ble
liquids
structur
es
24 CATCH
BASINS (Curb
inlet) Inlet
where street
water enters a
storm or
combined
sewer
Buildup
of
vapors
from
flamma
ble or
combus
tible
liquids
NNV Enclose
d space
Division
1
In
accordance
with 8.3.1
NR
25 a RESIDENTIAL
DIVERSION
STRUCTURE
S .
Enclosed
structures
where
residential
wastewater
can be
diverted
Buildup
of
vapors
from
flamma
ble or
combus
tible
liquids
NNV Enclose
d space
Division
2
In
accordance
with
Chapter 8
NR
b B Enclose
d space
Unclassif
ied
In
accordance
with
Chapter 8
NR
26 a RESIDENTIAL
BELOWGRAD
E VALVE
VAULT .
With an
exposed
residential
Possibl
e
ignition
of
gases
and
floating
flamma
NNV Enclose
d space
Division
2
In
accordance
with 8.3.1
NR
b B Enclose
d space
Unclassif
ied
In
accordance
with 8.3.1
NR
Row*R
owa
Line*Li
nea
Location .
and .
Function
Fire and
Explosi
on
Hazard
Ventilation**Ven
tilationb
Extent of
Classifie
d Area
NEC-
Area
Electrical
Classific
ation (All
Class I,
Group D)
MaterialMat
erials of
Constructio
n for
Buildings
or
Structuresc
Fire
Protectio
n
Measure
s
wastewater
surface
ble
liquids
27 a RESIDENTIAL
CONTROL
STRUCTURE
S Enclosed
structures
where
residential
wastewater
flow is
regulated
Buildup
of
vapors
from
flamma
ble or
combus
tible
liquids
A Enclose
d space
Division
2
In
accordance
with
Chapter 8
NR
b B Enclose
d space
Unclassif
ied
In
accordance
with
Chapter 8
NR
28 a RESIDENTIAL
BELOWGRAD
E METERING
VAULT .
With an
exposed
residential
wastewater
surface
Possibl
e
ignition
of
flamma
ble
gases
and
floating
flamma
ble
liquids
NNV Enclose
d space
Division
2
In
accordance
with 8.3.1
NR
b B Enclose
d space
Unclassif
ied
In
accordance
with 8.3.1
NR
29 a DIVERSION
STRUCTURE
S Enclosed
structures
where
wastewater
can be
diverted
Buildup
of
vapors
from
flamma
ble or
combus
tible
liquids
NNV Enclose
d space
Division
1
In
accordance
with
Chapter 8
NR
b B Division
2
In
accordance
with
Chapter 8
NR
Row*R
owa
Line*Li
nea
Location .
and .
Function
Fire and
Explosi
on
Hazard
Ventilation**Ven
tilationb
Extent of
Classifie
d Area
NEC-
Area
Electrical
Classific
ation (All
Class I,
Group D)
MaterialMat
erials of
Constructio
n for
Buildings
or
Structuresc
Fire
Protectio
n
Measure
s
30 ABOVEGRAD
E VALVE
VAULT .
Physically
separated
from the wet
well; valves in
vault in closed
piping system
NA NR NA Unclassif
ied
NC, LC, or
LFS
NR
31 a BELOWGRAD
E VALVE
VAULT
Physically
separated
from the wet
well and with
closed piping
system
Buildup
of
vapors
from
flamma
ble or
combus
tible
liquids
NNV Enclose
d space
Division
2
NC, LC, or
LFS
NR
b C Enclose
d space
Unclassif
ied
NC, LC, or
LFS
NR
32 a BELOWGRAD
E VALVE
VAULT With
an exposed
wastewater
surface
Possibl
e
ignition
of
gases
and
floating
flamma
ble
liquids
NNV Enclose
d space
Division
1
NC NR
b B Enclose
d space
Division
2
NC, LC, or
LFS
NR
33 a CONTROL
STRUCTURE
S Enclosed
structures
where
wastewater or
storm water
Buildup
of
vapors
from
flamma
ble or
combus
A Enclose
d space
Division
1
In
accordance
with
Chapter 8
NR
b B Enclose
d space
Division
2
In
accordance
NR
Row*R
owa
Line*Li
nea
Location .
and .
Function
Fire and
Explosi
on
Hazard
Ventilation**Ven
tilationb
Extent of
Classifie
d Area
NEC-
Area
Electrical
Classific
ation (All
Class I,
Group D)
MaterialMat
erials of
Constructio
n for
Buildings
or
Structuresc
Fire
Protectio
n
Measure
s
flow is
regulated
tible
liquids
with
Chapter 8
34 a WASTEWATE
R HOLDING
BASINS
Enclosed
structures
temporarily
holding
untreated or
partially
treated
wastewater
Possibl
e
ignition
of
flamma
ble
gases
and
floating
flamma
ble
liquids
A Enclose
d space
Division
1
NC NR
b B Enclose
d space
Division
2
NC, LC, or
LFS
NR
35 WASTEWATE
R HOLDING
BASINS,
LINED OR
UNLINED
Open
structures
holding storm
water,
combined
wastewater,
untreated or
partially
treated
wastewater
NR NR NR NR NR NR
36 a BELOWGRAD
E METERING
VAULT
Physically
separated
from the wet
Buildup
of
vapors
from
flamma
ble or
NNV Enclose
d space
Division
2
NC, LC, or
LFS
NR
b C Enclose
d space
Unclassif
ied
NC, LC, or
LFS
NR
Row*R
owa
Line*Li
nea
Location .
and .
Function
Fire and
Explosi
on
Hazard
Ventilation**Ven
tilationb
Extent of
Classifie
d Area
NEC-
Area
Electrical
Classific
ation (All
Class I,
Group D)
MaterialMat
erials of
Constructio
n for
Buildings
or
Structuresc
Fire
Protectio
n
Measure
s
well and with
closed piping
system
combus
tible
liquids
37 a BELOWGRAD
E METERING
VAULT With
an exposed
wastewater
surface
Possibl
e
ignition
of
flamma
ble
gases
and
floating
flamma
ble
liquids
NNV Enclose
d space
Division
1
NC NR
b B Enclose
d space
Division
2
NC, LC, or
LFS
NR
38 COARSE AND
FINE
SCREEN
FACILITIES
(See “Coarse
and Fine
Screen
Facilities” in
Table 5.2.)
Note: The following codes are used in this table:
A: No ventilation or ventilated at less than 12 air changes per hour.
B: Continuously ventilated at 12 changes per hour in accordance with Chapter 9.
C: Continuously ventilated at 6 air changes per hour in accordance with Chapter 9.
CGD: Combustible gas detection system.
D: No ventilation or ventilated at less than 6 air changes per hour.
FDS: Fire detection system.
FE: Portable fire extinguisher.
LC: Limited-combustible material.
LFS: Low flame spread index material.
NA: Not applicable.
NC: Noncombustible material.
NEC: In accordance with NFPA 70.
NNV: Not normally ventilated.
NR: No requirement.
*a The "Row" and "Line" columns are used to refer to specific figures in A.4.2 and specific
requirements for each location and function.
**The NR designation in the "Ventilation"b
This column indicates that nothe ventilation requirements for processes. Additional ventilation
requirements are established for provided in Chapter 9. Ventilation signaling and alarm
requirements are provided in Chapter 7.
c This column indicates the space, and, therefore, Table 9.1.1.4 also has no requirements.materials
of construction for processes. Materials of construction for buildings in which these processes are
housed are in accordance with the applicable building code and construction requirements provided
in Chapter 8.
Chapter 4 Collection Systems
4.1* General.
4.1.1
This chapter shall establish minimum criteria for protection against fire and explosion hazards in the
collection and transportation of municipal wastewater.
4.1.2
This chapter shall not apply to on-site systems, force mains, or those sewers that principally convey
industrial wastes.
4.2* Design and Construction.
4.2.1 The design and construction of the components associated with wastewater collection and
transport systems shall conform to Table 4.2.
4.2.2 The design and construction of buildings and structures containing wastewater collection and
transport systems shall comply with the applicable building code and the additional requirements in
Chapters 7-9.
Table 4.2 Collection Systems
Rowa
Linea
Location .
and .
Function
Fire and
Explosion
Hazard
Ventilatio
nb
Extent of
Classified
Area
NEC-Area
Electrical
Classificati
on (All
Class I,
Group D)
Materials
of
Constructi
on c
Fire
Protection
Measures
1 MATERIALS
USED IN
REHABILITATION
,
RECONSTRUCTI
ON, OR SLIP-
LINING OF
SEWERS
NA NA NA NA In
accordanc
e with
8.3.1
NA
2 INDUSTRIAL
SEWER Sewer
transporting
industrial
wastewater only
(no sanitary
wastewater)
Not included within the scope of this standard
3 STORM SEWER
Sewer transporting
Possible
ignition of
NNV Inside of
sewer
Division 2 In
accordanc
NR
Rowa
Linea
Location .
and .
Function
Fire and
Explosion
Hazard
Ventilatio
nb
Extent of
Classified
Area
NEC-Area
Electrical
Classificati
on (All
Class I,
Group D)
Materials
of
Constructi
on c
Fire
Protection
Measures
storm water only
(no sanitary
wastewater)
flammable
gases and
floating
flammable
liquids
e with
8.3.1
4 STORM WATER
PUMPING
STATION WET
WELLS .
Liquid side of
pumping station
serving only a
storm sewer
system
Possible
ignition of
flammable
gases and
floating
flammable
liquids
NNV Entire
room or
space
Division 2 NC, LC, or
LFS
NR
5 a STORM WATER
PUMPING
STATION DRY
WELLS .
Dry side of a
pumping station
serving only a
storm sewer
system and
physically
separated from
wet well
Buildup of
vapors
from
flammable
or
combustib
le liquids
D Entire dry
well
Division 2 NC, LC, or
LFS
FE
b C Entire dry
well
Unclassifie
d
NC, LC, or
LFS
FE
6 PRESSURE
SEWER (Force
main) Sewer under
pressure (flooded
discharge pipe
from pump or tank)
Not included within the scope of this standard
7 BUILDING
SEWER (Lateral
sewer or drain)
Sewer serving a
Not included within the scope of this standard
Rowa
Linea
Location .
and .
Function
Fire and
Explosion
Hazard
Ventilatio
nb
Extent of
Classified
Area
NEC-Area
Electrical
Classificati
on (All
Class I,
Group D)
Materials
of
Constructi
on c
Fire
Protection
Measures
house or single
building (plumbing)
8 INDIVIDUAL
RESIDENTIAL
SEWER .
Sewer serving one
or more individual
residences with a
total flow of not
more than 1500
gallons per day
(gpd)
NA NNV Within
enclosed
space
Unclassifie
d
NR NR
9 INDIVIDUAL
RESIDENTIAL
PUMPING UNITS .
Pumping units
serving one or
more individual
residences with a
total flow of not
more than 1500
gallons per day
(gpd) (e.g., grinder
pumps, septic tank
effluent pumps,
ejector pumps)
NA NNV Within
enclosed
space
Unclassifie
d
NR NR
10 a RESIDENTIAL
SEWER .
Sewer transporting
primarily
residential
wastewater
Possible
ignition of
flammable
gases and
floating
flammable
liquids
NNV Within
enclosed
space
Division 2 In
accordanc
e with
8.3.1
NR
b B Within
enclosed
space
Unclassifie
d
In
accordanc
e with
8.3.1
NR
Rowa
Linea
Location .
and .
Function
Fire and
Explosion
Hazard
Ventilatio
nb
Extent of
Classified
Area
NEC-Area
Electrical
Classificati
on (All
Class I,
Group D)
Materials
of
Constructi
on c
Fire
Protection
Measures
11 a RESIDENTIAL
WASTEWATER
PUMPING
STATION WET
WELL .
Pumping station
transporting
primarily
residential
wastewater
Possible
ignition of
flammable
gases and
floating
flammable
liquids
A Entire
room or
space
Division 2 NC, LC, or
LFS
CGD
b B Entire
room or
space
Unclassifie
d
NC, LC, or
LFS
CGD
12 a RESIDENTIAL
WASTEWATER
PUMPING
STATION DRY
WELL .
Dry side of a
pumping station
transporting
primarily
residential
wastewater
Buildup of
vapors
from
flammable
or
combustib
le liquids
D Entire
room or
space
Division 2 NC, LC, or
LFS
FE
b C Entire
room or
space
Unclassifie
d
NC, LC, or
LFS
FE
13 OUTFALL SEWER
Final discharge
pipe from a
treatment plant,
transporting
treated wastewater
NA NNV NA Unclassifie
d
NR NR
14 a SANITARY
SEWER Sewer
transporting
domestic,
commercial, and
industrial
wastewater
Possible
ignition of
flammable
gases and
floating
flammable
liquids
NNV Inside of
sewer
Division 1 In
accordanc
e with
8.3.1
NR
b B Inside of
sewer
Division 2 In
accordanc
e with
8.3.1
NR
Rowa
Linea
Location .
and .
Function
Fire and
Explosion
Hazard
Ventilatio
nb
Extent of
Classified
Area
NEC-Area
Electrical
Classificati
on (All
Class I,
Group D)
Materials
of
Constructi
on c
Fire
Protection
Measures
15 a COMBINED
SEWER Sewer
transporting
domestic,
commercial, and
industrial
wastewater and
storm water
Possible
ignition of
flammable
gases and
floating
flammable
liquids
NNV Inside of
sewer
Division 1 In
accordanc
e with
8.3.1
NR
b B Inside of
sewer
Division 2 In
accordanc
e with
8.3.1
NR
16 a WASTEWATER
PUMPING
STATION WET
WELLS .
Liquid side of a
pumping station
serving a sanitary
sewer or combined
system
Possible
ignition of
flammable
gases and
floating
flammable
liquids
A Entire
room or
space
Division 1 NC, LC, or
LFS
CGD
required if
mechanica
lly
ventilated
or opens
into a
building
interior
b B Entire
room or
space
Division 2 NC, LC, or
LFS
CGD
17 a BELOWGRADE
OR PARTIALLY
BELOWGRADE
WASTEWATER
PUMPING
STATION DRY
WELL .
Pump room
physically
separated from
wet well; pumping
of wastewater from
a sanitary or
combined sewer
system through
Buildup of
vapors
from
flammable
or
combustib
le liquids
C Entire
space or
room
Unclassifie
d
NC, LC, or
LFS
FE
b D Entire
space or
room
Division 2 NC, LC, or
LFS
FE
Rowa
Linea
Location .
and .
Function
Fire and
Explosion
Hazard
Ventilatio
nb
Extent of
Classified
Area
NEC-Area
Electrical
Classificati
on (All
Class I,
Group D)
Materials
of
Constructi
on c
Fire
Protection
Measures
closed pumps and
pipes
18 ABOVEGRADE
WASTEWATER
PUMPING
STATION Pump
room physically
separated with no
personnel access
to wet well;
pumping of
wastewater from a
sanitary or
combined sewer
system through
closed pumps and
pipes
NA NR NA Unclassifie
d
NC, LC, or
LFS
FE
19 a ABOVEGRADE
WASTEWATER
PUMPING
STATION Pump
room not
physically
separated from
wet well; pumping
of wastewater from
a sanitary or
combined sewer
system through
closed pumps and
pipes
Possible
ignition of
flammable
gases and
floating
flammable
liquids
A Entire
space or
room
Division 1 NC FE
b B Entire
space or
room
Division 2 NC, LC, or
LFS
FE
20 a ODOR-CONTROL
AND
VENTILATION
SYSTEMSSERVI
Leakage
and
ignition of
flammable
D Entire
area if
enclosed
Division 2 NC, LC, or
LFS
CGD and
FDS
b C Areas
within 0.9
Division 2 NC, LC, or
LFS
CGD and
FDS
Rowa
Linea
Location .
and .
Function
Fire and
Explosion
Hazard
Ventilatio
nb
Extent of
Classified
Area
NEC-Area
Electrical
Classificati
on (All
Class I,
Group D)
Materials
of
Constructi
on c
Fire
Protection
Measures
NG CLASSIFIED
AREAS
gases and
vapors
m (3 ft) of
leakage
sources
such as
fans,
dampers,
flexible
connection
s, flanges,
pressurize
d
unwelded
ductwork,
and odor-
control
vessels
c C Areas
beyond
0.9 m (3 ft)
Unclassifie
d
NC, LC, or
LFS
CGD and
FDS
d Not
enclosed,
open to
the
atmosphe
re
Areas
within 0.9
m (3 ft) of
leakage
sources
such as
fans,
dampers,
flexible
connection
s, flanges,
pressurize
d
unwelded
ductwork,
and odor-
control
vessels
Division 2 NC,LC,
LFS
FE
Rowa
Linea
Location .
and .
Function
Fire and
Explosion
Hazard
Ventilatio
nb
Extent of
Classified
Area
NEC-Area
Electrical
Classificati
on (All
Class I,
Group D)
Materials
of
Constructi
on c
Fire
Protection
Measures
e Not
enclosed,
open to
the
atmosphe
re
Areas
beyond
0.9 m (3 ft)
Unclassifie
d
NC,LC,
LFS
FE
21 a MAINTENANCE
HOLES .
Access to sewer
for personnel entry
Possible
ignition of
flammable
gases and
floating
flammable
liquids
NNV Inside Division 1 In
accordanc
e with
8.3.1
NR
b B Inside Division 2 In
accordanc
e with
8.3.1
NR
22 a JUNCTION
CHAMBERS .
Structure where
sewers intersect
Buildup of
vapors
from
flammable
or
combustib
le liquids
NNV Inside Division 1 In
accordanc
e with
8.3.1
NR
b B Open and
above
grade or
inside and
ventilated
Division 2 In
accordanc
e with
8.3.1
NR
23 INVERTED
SIPHONS
Depressed section
of gravity sewer
Possible
ignition of
flammable
gases and
floating
flammable
liquids
NNV Interior of
inlet and
outlet
structures
Division 1 NC NR
24 CATCH BASINS
(Curb inlet) Inlet
where street water
enters a storm or
combined sewer
Buildup of
vapors
from
flammable
or
NNV Enclosed
space
Division 1 In
accordanc
e with
8.3.1
NR
Rowa
Linea
Location .
and .
Function
Fire and
Explosion
Hazard
Ventilatio
nb
Extent of
Classified
Area
NEC-Area
Electrical
Classificati
on (All
Class I,
Group D)
Materials
of
Constructi
on c
Fire
Protection
Measures
combustib
le liquids
25 a RESIDENTIAL
DIVERSION
STRUCTURES .
Enclosed
structures where
residential
wastewater can be
diverted
Buildup of
vapors
from
flammable
or
combustib
le liquids
NNV Enclosed
space
Division 2 In
accordanc
e with
Chapter 8
NR
b B Enclosed
space
Unclassifie
d
In
accordanc
e with
Chapter 8
NR
26 a RESIDENTIAL
BELOWGRADE
VALVE VAULT .
With an exposed
residential
wastewater
surface
Possible
ignition of
gases and
floating
flammable
liquids
NNV Enclosed
space
Division 2 In
accordanc
e with
8.3.1
NR
b B Enclosed
space
Unclassifie
d
In
accordanc
e with
8.3.1
NR
27 a RESIDENTIAL
CONTROL
STRUCTURES
Enclosed
structures where
residential
wastewater flow is
regulated
Buildup of
vapors
from
flammable
or
combustib
le liquids
A Enclosed
space
Division 2 In
accordanc
e with
Chapter 8
NR
b B Enclosed
space
Unclassifie
d
In
accordanc
e with
Chapter 8
NR
28 a RESIDENTIAL
BELOWGRADE
METERING
VAULT .
With an exposed
residential
wastewater
surface
Possible
ignition of
flammable
gases and
floating
flammable
liquids
NNV Enclosed
space
Division 2 In
accordanc
e with
8.3.1
NR
b B Enclosed
space
Unclassifie
d
In
accordanc
e with
8.3.1
NR
Rowa
Linea
Location .
and .
Function
Fire and
Explosion
Hazard
Ventilatio
nb
Extent of
Classified
Area
NEC-Area
Electrical
Classificati
on (All
Class I,
Group D)
Materials
of
Constructi
on c
Fire
Protection
Measures
29 a DIVERSION
STRUCTURES
Enclosed
structures where
wastewater can be
diverted
Buildup of
vapors
from
flammable
or
combustib
le liquids
NNV Enclosed
space
Division 1 In
accordanc
e with
Chapter 8
NR
b B Division 2 In
accordanc
e with
Chapter 8
NR
30 ABOVEGRADE
VALVE VAULT .
Physically
separated from the
wet well; valves in
vault in closed
piping system
NA NR NA Unclassifie
d
NC, LC, or
LFS
NR
31 a BELOWGRADE
VALVE VAULT
Physically
separated from the
wet well and with
closed piping
system
Buildup of
vapors
from
flammable
or
combustib
le liquids
NNV Enclosed
space
Division 2 NC, LC, or
LFS
NR
b C Enclosed
space
Unclassifie
d
NC, LC, or
LFS
NR
32 a BELOWGRADE
VALVE VAULT
With an exposed
wastewater
surface
Possible
ignition of
gases and
floating
flammable
liquids
NNV Enclosed
space
Division 1 NC NR
b B Enclosed
space
Division 2 NC, LC, or
LFS
NR
33 a CONTROL
STRUCTURES
Enclosed
structures where
wastewater or
storm water flow is
regulated
Buildup of
vapors
from
flammable
or
combustib
le liquids
A Enclosed
space
Division 1 In
accordanc
e with
Chapter 8
NR
b B Enclosed
space
Division 2 In
accordanc
NR
Rowa
Linea
Location .
and .
Function
Fire and
Explosion
Hazard
Ventilatio
nb
Extent of
Classified
Area
NEC-Area
Electrical
Classificati
on (All
Class I,
Group D)
Materials
of
Constructi
on c
Fire
Protection
Measures
e with
Chapter 8
34 a WASTEWATER
HOLDING
BASINS Enclosed
structures
temporarily holding
untreated or
partially treated
wastewater
Possible
ignition of
flammable
gases and
floating
flammable
liquids
A Enclosed
space
Division 1 NC NR
b B Enclosed
space
Division 2 NC, LC, or
LFS
NR
35 WASTEWATER
HOLDING
BASINS, LINED
OR UNLINED
Open structures
holding storm
water, combined
wastewater,
untreated or
partially treated
wastewater
NR NR NR NR NR NR
36 a BELOWGRADE
METERING
VAULT Physically
separated from the
wet well and with
closed piping
system
Buildup of
vapors
from
flammable
or
combustib
le liquids
NNV Enclosed
space
Division 2 NC, LC, or
LFS
NR
b C Enclosed
space
Unclassifie
d
NC, LC, or
LFS
NR
37 a BELOWGRADE
METERING
VAULT With an
exposed
wastewater
surface
Possible
ignition of
flammable
gases and
floating
flammable
liquids
NNV Enclosed
space
Division 1 NC NR
b B Enclosed
space
Division 2 NC, LC, or
LFS
NR
Rowa
Linea
Location .
and .
Function
Fire and
Explosion
Hazard
Ventilatio
nb
Extent of
Classified
Area
NEC-Area
Electrical
Classificati
on (All
Class I,
Group D)
Materials
of
Constructi
on c
Fire
Protection
Measures
38 COARSE AND
FINE SCREEN
FACILITIES (See
“Coarse and Fine
Screen Facilities”
in Table 5.2.)
Note: The following codes are used in this table:
A: No ventilation or ventilated at less than 12 air changes per hour.
B: Continuously ventilated at 12 changes per hour
C: Continuously ventilated at 6 air changes per hour
CGD: Combustible gas detection system.
D: No ventilation or ventilated at less than 6 air changes per hour.
FDS: Fire detection system.
FE: Portable fire extinguisher.
LC: Limited-combustible material.
LFS: Low flame spread index material.
NA: Not applicable.
NC: Noncombustible material.
NEC: In accordance with NFPA 70.
NNV: Not normally ventilated.
NR: No requirement.
a The "Row" and "Line" columns are used to refer to specific figures in A.4.2 and specific
requirements for each location and function.
b
This column indicates the ventilation requirements for processes. Additional ventilation
requirements are provided in Chapter 9. Ventilation signaling and alarm requirements are provided
in Chapter 7.
c This column indicates the materials of construction for processes. Materials of construction for
buildings in which these processes are housed are in accordance with the applicable building code
and construction requirements provided in Chapter 8.
Second Revision No. 3-NFPA 820-2014 [ Section No. 5.2 ]
5.2* Design and Construction.
The design and construction of liquid stream treatment processes shall conform to Table 5.2 .
5.2.1
The design and construction of liquid stream treatment processes associated with wastewater liquids treatment shallcomply with the applicable building code and the additional requirements in Chapters 7 through 9 .
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5.2.2
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The design and construction of liquid stream treatment processes associated with wastewater liquids treatment shallconform to Table 5.2.2 Table 5.2 Table 5.2.1 .
Table 5.2.2 Liquid Stream Treatment Processes
Rowa LineaLocation
and
Function
Fire andExplosion
HazardVentilationb
Extent ofClassified
Areac
NEC -Area NEC AreaElectrical Classification
(All Class I, Group D)d
Materials ofConstruction
forBuildings or
Structures e
FireProtectionMeasures
1 a DIVERSION ANDCONTROLSTRUCTURESNot preceded byprimary treatment
Possibleignition offlammablegases andfloatingflammableliquids
A Enclosed--entire —entirespace
Division 1 NC FE, H; CGDif enclosedin building
b B Enclosed--entire —entirespace
Division 2 NC, LC, orLFS
FE, H; CGDif enclosedin a building
c Notenclosed,open toatmosphere
Within a 3 m(10 ft)envelopearoundequipmentand openchannel
Division 2 NC, LC, orLFS
FE and H
2 a COARSE ANDFINE SCREENFACILITIES
Removal ofscreenings fromraw wastewater
Possibleignition offlammablegases andfloatingflammableliquids
A Enclosed—entire space
Division 1 NC FE, H, CGD
b B Enclosed—entire space
Division 2 NC, LC, orLFS
FE, H, CGD
c Notenclosed,open toatmosphere
Within a 3 m(10 ft)envelopearoundequipmentand openchannel
Division 2 NC, LC, orLFS
FE, H
3 PUMPINGSTATIONS,DIVERSIONSTRUCTURESAND CONTROLSTRUCTURES
(See “CollectionSystems,” Table4.2.)
4 a FLOWEQUALIZATIONTANKS Storage ofraw or partiallytreated wastewater
Possibleignition offlammablegases andfloatingflammableliquids
A Enclosed—entire space
Division 1 NC FE, H;CGDif enclosedin a building
b B Enclosed—entire space
Division 2 NC, LC, orLFS
FE, H; CGDif enclosedin a building
c Notenclosed,open toatmosphere
Within a 3 m(10 ft)envelopearoundequipmentand open
channele , f f,g
Division 2 NC, LC, orLFS
FE, H
5 a GRIT REMOVALTANKS Separationof grit from rawwastewater
Possibleignition offlammablegases andfloatingflammableliquids
A Enclosed—entire space
Division 1 NC FE, H;CGDif enclosedin a building
b B Enclosed—entire space
Division 2 NC, LC, orLFS
FE, H; CGDif enclosedin a building
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Rowa LineaLocation
and
Function
Fire andExplosion
HazardVentilationb
Extent ofClassified
Areac
NEC -Area NEC AreaElectrical Classification
(All Class I, Group D)d
Materials ofConstruction
forBuildings or
Structures e
FireProtectionMeasures
c Notenclosed,open toatmosphere
Within a 3 m(10 ft)envelopearoundequipmentand open
channele,f f,g
Division 2 NC, LC, orLFS
FE, H
6 a PRE-AERATIONTANKSConditioning ofwastewater prior tofurther treatment
Possibleignition offlammablegases andfloatingflammableliquids
A Enclosed—entire space
Division 1 NC H;CGD ifenclosed ina building
b B Enclosed—entire space
Division 2 NC, LC, orLFS
H; CGD ifenclosed ina building
c Notenclosed,open toatmosphere
Within a 3 m(10 ft)envelopearoundequipmentand open
channele,f f,g
Division 2 NC, LC, orLFS
H
7 a PRIMARYSEDIMENTATIONTANKS Separationof floating orsettleable solidsfrom rawwastewater
Possibleignition offlammablegases andfloatingflammableliquids
A Enclosed—entire space
Division 1 NC H;CGD ifenclosed ina building
b B Enclosed—entire space
Division 2 NC, LC, orLFS
H; CGD ifenclosed ina building
c Notenclosed,open toatmosphere
Interior of thetank from theminimumoperatingwater surfaceto the top ofthe tank wall;envelope 0.46m (18 in.)above the topof the tankand extending0.46 m (18 in.)beyond theexterior wall;envelope 0.46m (18 in.)above gradeextending 3 m(10 ft)horizontallyfrom theexterior tankwalls
Division 2 NC, LC, orLFS
H
8 AERATIONBASIN, POND,LAGOON,OXIDATIONDITCH, AEROBICSUSPENDEDGROWTHSYSTEMS,
NA N/A NR Classified (see PrimarySedimentation)
Unclassified if process ispreceded by primarysedimentation
NR H
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Rowa LineaLocation
and
Function
Fire andExplosion
HazardVentilationb
Extent ofClassified
Areac
NEC -Area NEC AreaElectrical Classification
(All Class I, Group D)d
Materials ofConstruction
forBuildings or
Structures e
FireProtectionMeasures
SEQUENCINGBATCHREACTORSAerobic treatmentof wastewateropen to theatmosphere
9 a1 ENCLOSEDAERATIONBASIN, AEROBICOR SUSPENDEDGROWTHSYSTEMS,MEMBRANEBIOLOGICALREACTORS
Aerobic treatmentnot preceded byprimary treatment
Possibleignition offlammablegases orfloatingflammableliquids
A (Interior oftank)
Entireenclosedspace or tankof system
Division 1 NC NR
a2 A (Interior oftank)
Exterior ofenclosedspace or tank,installed in abuilding
Division 2 NC, LC, orLFS
NR
a3 A (Interior oftank)
Exterior ofenclosedspace or tank,installedoutdoors;envelope 0.46m (18 in.)surroundingtank
Division 2 NC, LC, orLFS
NR
b1 B (Interior oftankmaintained atnegativepressure)
Entireenclosedspace or tankof system
Division 2 NC, LC, orLFS
NR
b2 B (Interior oftankmaintained atnegativepressure)
Exterior ofenclosedspace or tank,installed in abuilding
Unclassified NC, LC, orLFS
NR
b3 B (Interior oftankmaintained atnegativepressure)
Exterior ofenclosedspace or tank,installedoutdoors
Unclassified NC, LC, orLFS
NR
c Notenclosed,open toatmosphere
Interior of tankfrom theminimumoperatingwater surfaceto the top ofthe tank wall;envelope 0.46m (18 in.)above the topof the tankand extending0.46 m (18 in.)beyondexterior wall;envelope 0.46m (18 in.)above gradeand extending
Division 2 NC, LC, orLFS
NR
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Rowa LineaLocation
and
Function
Fire andExplosion
HazardVentilationb
Extent ofClassified
Areac
NEC -Area NEC AreaElectrical Classification
(All Class I, Group D)d
Materials ofConstruction
forBuildings or
Structures e
FireProtectionMeasures
3 m (10 ft)horizontallyfrom theexterior tankwalls
10 a1 RESIDENTIALENCLOSEDAERATIONBASIN, AEROBICOR SUSPENDEDGROWTHSYSTEMS,MEMBRANEBIOLOGICALREACTORSAerobic treatmentnot preceded byprimary treatment,serving one but notmore than fivedwellings
Possibleignition offlammablegases orfloatingflammableliquids
A (Interior oftank)
Entireenclosedspace or tankof system
Division 2 NC NR
a2 A (Interior oftank)
Exterior ofenclosedspace or tank,installed in abuilding
Unclassified NC, LC, orLFS
NR
a3 A (Interior oftank)
Exterior ofenclosedspace or tank,installedoutdoors
Unclassified NC, LC, orLFS
NR
11 ENCLOSEDAERATIONBASIN, AEROBICOR SUSPENDEDGROWTHSYSTEMS,MEMBRANEBIOLOGICALREACTORS
Aerobic treatmentof wastewaterpreceded byprimary treatment
NA N/A NR Entireenclosedspace
Unclassified NC, LC, orLFS
NR
12 TRICKLINGFILTER,BIO-TOWER,AEROBICFIXED-FILMSYSTEMS
Aerobic biologicaltreatment ofwastewater
Notnormally asignificanthazard;however,theseprocessesmightcontainmaterialsthat arecombustibleundercertainconditions
NR NA N/A Classified (see See PrimarySedimentation sedimentation )
Unclassified if unit process ispreceded by primarysedimentation.
NR H
13 a ANAEROBICTOWERS,ANAEROBICFIXED-FILMSYSTEM
Anaerobicbiologicaltreatment if sealedfrom atmosphere
Normallyproducescombustiblegas astreatmentprocessby-product
NA N/A Tank interior Division 1 NC FE and H
b NA N/A 3 m (10 ft)envelopearound tank
Division 2 NC, LC, orLFS
FE and H
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Rowa LineaLocation
and
Function
Fire andExplosion
HazardVentilationb
Extent ofClassified
Areac
NEC -Area NEC AreaElectrical Classification
(All Class I, Group D)d
Materials ofConstruction
forBuildings or
Structures e
FireProtectionMeasures
14 a GAS-HANDLINGSYSTEMS FORLIQUIDTREATMENTPROCESSES
Combustiblegas, oftenunderpressure
A Enclosed—entire space
Division 1 NC FE and H
b B Enclosed—entire space
Division 2 NC, LC, orLFS
FE and H
c Notenclosed,open toatmosphere
Within a 3 m(10 ft)envelopearound
equipmente f
Division 2 NC, LC, orLFS
FE and H
15 OXYGENAERATION TANKSTanks for aerobictreatment ofwastewater usinghigh-purity oxygenrather than air
Ignition offlammablegases andfloatingflammableliquids in anoxygen-
enrichedenvironment
NA N/A Enclosedspace
Division 2 (If unit process isnot preceded by primarysedimentation, see PrimarySedimentation sedimentationTanks in Table 5.2 forclassification.)
Anyequipment ormaterial withinthe reactorspace shall besafe forexposure tovolatile in anoxygen-
enrichedatmosphere
Specialprovisionfor LFLmonitoringandautomaticisolation ofequipmentand oxygensupply
16 INTERMEDIATE,SECONDARY, ORTERTIARYSEDIMENTATIONTANKS
Separate floatingand settleablesolids fromwastewater atvarious treatmentstages
NA N/A NR NA N/A Classified (see See PrimarySedimentation sedimentation )
Unclassified if unit process ispreceded by primarysedimentation.
NR H
17 FLASH MIXER ORFLOCCULATIONTANKS
Tanks for mixingvarious treatmentchemicals withwastewater
NA N/A NR NA N/A Classified (see See PrimarySedimentation sedimentation )
Unclassified if unit process ispreceded by primarysedimentation.
NR H
18 NITRIFICATIONANDDENITRIFICATIONTANKS
Tertiary treatmentof wastewater toreduce or removenitrogen
NA N/A NR NA N/A Classified (see See PrimarySedimentation sedimentation )
Unclassified if unit process ispreceded by primarysedimentation.
NR H
19 BREAKPOINTCHLORINATIONTANKS ANDCHLORINECONTACT TANKS
Application ofchlorine inaqueous solutionto wastewater
NA N/A NR NA N/A Unclassified NR (Theseunit processesuse corrosivechemicals thatrequire theuse of specificmaterials ofconstruction.Specialconsiderationshall be given
H
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Rowa LineaLocation
and
Function
Fire andExplosion
HazardVentilationb
Extent ofClassified
Areac
NEC -Area NEC AreaElectrical Classification
(All Class I, Group D)d
Materials ofConstruction
forBuildings or
Structures e
FireProtectionMeasures
to thesematerials ofconstruction.)
20 AMMONIASTRIPPINGTOWERS
(See“ TricklingFilter” filterin Table5.2.)
NA N/A NA N/A Unclassified NR (Theseunit processesuse corrosivechemicals.Specialconsiderationshall be givento thesematerials ofconstruction.)
H
21 INTERMEDIATEOR FINALPUMPINGSTATIONS ANDOTHER UNITPROCESSESANDSTRUCTURESNOTSPECIFICALLYADDRESSED INTHIS TABLE.Preceded byprimary treatment
NA N/A NR NA N/A Unclassified NR H
22 GRAVITY ANDPRESSUREFILTERS
Filtering of treatedwastewaterthrough sand orother media
NA N/A NR NA N/A Unclassified NR H
23 CARBONCOLUMN ORTANKS
Vessels containingcarbon for tertiarytreatment ofwastewater
Significanthazard fromcombustiblecarbonmaterial
NA N/A NA N//A Unclassified NR H
24 ON-SITE OZONEGENERATIONSYSTEM ANDOZONE CONTACTTANKS
Ozone generationand purification fordisinfection ofwastewater
Similar tooxygengenerationwithaddition ofbeing highlycorrosive(see SeeTable D.1.1)
NA N/A NA N/A Not covered in this standard NR NR
25 BACKWASHWATER ANDWASTEBACKWASHWATER HOLDINGTANKS
Tanks fortemporary storage
NA N/A NA N/A NA N/A Unclassified NR H
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Rowa LineaLocation
and
Function
Fire andExplosion
HazardVentilationb
Extent ofClassified
Areac
NEC -Area NEC AreaElectrical Classification
(All Class I, Group D)d
Materials ofConstruction
forBuildings or
Structures e
FireProtectionMeasures
of backwash water
26 ULTRAVIOLETDISINFECTIONUNIT
Disinfection ofwastewatereffluent byultraviolet radiation
NA N/A NR NA N/A Unclassified NR H
27 EFFLUENTSTRUCTURESVarious structuresconveying treatedwastewater awayfrom treatmentprocesses
NA N/A NR NA N/A Unclassified NR H
28 a ODOR-CONTROLANDVENTILATIONSYSTEMSSERVINGCLASSIFIEDAREAS
(See " CollectionSystems, Table4.2)
b
c
Note: The following codes are used in this table:
A: No ventilation or ventilated at less than 12 air changes per hour.
B: Continuously ventilated at 12 air changes per hour in accordance with Chapter 9.
C: Continuously ventilated at 6 six air changes per hour in accordance with Chapter 9.
CGD: Combustible gas detection system.
D: No ventilation or ventilated at less than 6 six air changes per hour.
FDS: Fire detection system.
FE: Portable fire extinguisher.
H: Hydrant protection in accordance with 7.2.4.
LC: Limited-combustible material.
LFS: Low flame spread index material.
NA N/A : Not applicable.
NC: Noncombustible material.
NEC: In accordance with NFPA 70.
NR: No requirement.
aThe "Row" and "Line" columns are used to refer to specific figures in Figure A.5.2 and specific requirements for eachlocation and function.
b The NR designation in the "Ventilation" column indicates that no ventilation requirements are established for thespace, and, therefore, Table 9.1.1.4 also has no requirements.
b This column indicates the ventilation requirements for processes. Additional ventilation requirements are provided inChapter 9. Ventilation signaling and alarm requirements are provided in Chapter 7.
cOpen channels and open structures upstream from the unit processes are classified the same as the downstreamprocesses they supply.
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dThese unit processes use corrosive chemicals that can have a deteriorating effect on conductors and equipment.Electrical equipment shall be identified for use in the operating environment.
e This column indicates the materials of construction for processes. Materials of construction for buildings in whichthese processes are housed are in accordance with the applicable building code and construction requirementsprovided in Chapter 8.
e f The area beyond the envelope is unclassified.
f g Where liquid turbulence is not induced by aeration or other factors, the following criteria apply: (1) interior of the tankfrom the minimum operating water surface to the top of the tank wall; (2) envelope 0.46 m (18 in.) above the top of thetank and extending 0.46 m (18 in.) beyond the exterior wall; (3) envelope 0.46 m (18 in.) above grade extending 3 m(10 ft) horizontally from the exterior tank walls.
Supplemental Information
File Name Description
ComparisonFDtoSDChapter_5.docx Editorial use only.
FINALSDMtgREVChapter_5.docx Editorial use only.
Submitter Information Verification
Submitter Full Name: [ Not Specified ]
Organization: [ Not Specified ]
Street Address:
City:
State:
Zip:
Submittal Date: Mon Oct 06 20:31:10 EDT 2014
Committee Statement
CommitteeStatement:
Section 5.2.2 explains that building codes cover general building construction but the components within thebuilding are covered in the table. The Table Column for materials was reworded to better indicate that the generalbuilding construction requirements are provided in chapter 8 but that the materials of construction for particularlocations within the facility are provided in the tables. The table footnotes were modified to better direct the user tothe appropriate chapters in NFPA 820 related to the subject column.
ResponseMessage:
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22 of 51 12/1/2014 1:18 PM
Chapter 5 Liquid Stream Treatment Processes
5.1* General.
5.1.1
This chapter shall establish minimum criteria for protection against fire and explosion hazards
associated with liquid stream treatment processes.
5.1.2
This chapter shall not apply to treatment systems serving individual structures or treatment systems
that principally treat industrial wastes.
5.2* Design and Construction.
The5.2.1The design and construction of liquid stream treatment processes associated with
wastewater liquid treatment shall conform to Table 5.2.
5.2.2 The design and construction of buildings and structures containing liquid stream treatment
processes associated with wastewater liquid treatment shall comply with the applicable building
code and the additional requirements of Chapters 7-9.
Table 5.2 Liquid Stream Treatment Processes
Ro
wa
Lin
ea
Location .
and .
Function
Fire and
Explosio
n Hazard
Ventilati
onb
Extent of
Classified Areac
NEC-Area
Electrical
Classificati
on .
(All Class I,
Group D)d
MaterialMate
rials of
Constructio
n for
Buildings or
Structurese
Fire
Protecti
on
Measur
es
1 a DIVERSION AND
CONTROL
STRUCTURES
Not preceded by
primary treatment
Possible
ignition
of
flammabl
e gases
and
floating
flammabl
e liquids
A Enclosed--entire
space
Division 1 NC FE, H;
CGD if
enclose
d in
building
b B Enclosed--entire
space
Division 2 NC, LC, or
LFS
FE, H;
CGD if
enclose
d in a
building
c Not
enclose
d, open
to
atmosph
ere
Within a 3 m (10
ft) envelope
around
equipment and
open channel
Division 2 NC, LC, or
LFS
FE and
H
Ro
wa
Lin
ea
Location .
and .
Function
Fire and
Explosio
n Hazard
Ventilati
onb
Extent of
Classified Areac
NEC-Area
Electrical
Classificati
on .
(All Class I,
Group D)d
MaterialMate
rials of
Constructio
n for
Buildings or
Structurese
Fire
Protecti
on
Measur
es
2 a COARSE AND
FINE SCREEN
FACILITIES .
Removal of
screenings from
raw wastewater
Possible
ignition
of
flammabl
e gases
and
floating
flammabl
e liquids
A Enclosed—
entire space
Division 1 NC FE, H,
CGD
b B Enclosed—
entire space
Division 2 NC, LC, or
LFS
FE, H,
CGD
c Not
enclose
d, open
to
atmosph
ere
Within a 3 m (10
ft) envelope
around
equipment and
open channel
Division 2 NC, LC, or
LFS
FE, H
3 PUMPING
STATIONS,
DIVERSION
STRUCTURES
AND CONTROL
STRUCTURES .
(See “Collection
Systems,” Table
4.2.)
4 a FLOW
EQUALIZATION
TANKS Storage of
raw or partially
treated wastewater
Possible
ignition
of
flammabl
e gases
and
floating
flammabl
e liquids
A Enclosed—
entire space
Division 1 NC FE,
H;CGD
if
enclose
d in a
building
b B Enclosed—
entire space
Division 2 NC, LC, or
LFS
FE, H;
CGD if
enclose
d in a
building
c Not
enclose
d, open
to
Within a 3 m (10
ft) envelope
around
equipment and
open
Division 2 NC, LC, or
LFS
FE, H
Ro
wa
Lin
ea
Location .
and .
Function
Fire and
Explosio
n Hazard
Ventilati
onb
Extent of
Classified Areac
NEC-Area
Electrical
Classificati
on .
(All Class I,
Group D)d
MaterialMate
rials of
Constructio
n for
Buildings or
Structurese
Fire
Protecti
on
Measur
es
atmosph
ere
channele,fchann
elf,g
5 a GRIT REMOVAL
TANKS Separation
of grit from raw
wastewater
Possible
ignition
of
flammabl
e gases
and
floating
flammabl
e liquids
A Enclosed—
entire space
Division 1 NC FE,
H;CGD
if
enclose
d in a
building
b B Enclosed—
entire space
Division 2 NC, LC, or
LFS
FE, H;
CGD if
enclose
d in a
building
c Not
enclose
d, open
to
atmosph
ere
Within a 3 m (10
ft) envelope
around
equipment and
open
channele,fchann
elf,g
Division 2 NC, LC, or
LFS
FE, H
6 a PRE-AERATION
TANKS
Conditioning of
wastewater prior to
further treatment
Possible
ignition
of
flammabl
e gases
and
floating
flammabl
e liquids
A Enclosed—
entire space
Division 1 NC H;CGD
if
enclose
d in a
building
b B Enclosed—
entire space
Division 2 NC, LC, or
LFS
H; CGD
if
enclose
d in a
building
c Not
enclose
d, open
to
Within a 3 m (10
ft) envelope
around
equipment and
open
Division 2 NC, LC, or
LFS
H
Ro
wa
Lin
ea
Location .
and .
Function
Fire and
Explosio
n Hazard
Ventilati
onb
Extent of
Classified Areac
NEC-Area
Electrical
Classificati
on .
(All Class I,
Group D)d
MaterialMate
rials of
Constructio
n for
Buildings or
Structurese
Fire
Protecti
on
Measur
es
atmosph
ere
channele,fchann
elf,g
7 a PRIMARY
SEDIMENTATION
TANKS Separation
of floating or
settleable solids
from raw
wastewater
Possible
ignition
of
flammabl
e gases
and
floating
flammabl
e liquids
A Enclosed—
entire space
Division 1 NC H;CGD
if
enclose
d in a
building
b B Enclosed—
entire space
Division 2 NC, LC, or
LFS
H; CGD
if
enclose
d in a
building
c Not
enclose
d, open
to
atmosph
ere
Interior of the
tank from the
minimum
operating water
surface to the
top of the tank
wall; envelope
0.46 m (18 in.)
above the top of
the tank and
extending 0.46
m (18 in.)
beyond the
exterior wall;
envelope 0.46 m
(18 in.) above
grade extending
3 m (10 ft)
horizontally from
the exterior tank
walls
Division 2 NC, LC, or
LFS
H
8 AERATION
BASIN, POND,
LAGOON,
NA NR Classified
(see
Primary
NR H
Ro
wa
Lin
ea
Location .
and .
Function
Fire and
Explosio
n Hazard
Ventilati
onb
Extent of
Classified Areac
NEC-Area
Electrical
Classificati
on .
(All Class I,
Group D)d
MaterialMate
rials of
Constructio
n for
Buildings or
Structurese
Fire
Protecti
on
Measur
es
OXIDATION
DITCH, AEROBIC
SUSPENDED
GROWTH
SYSTEMS,
SEQUENCING
BATCH
REACTORS
Aerobic treatment
of wastewater
open to the
atmosphere
Sedimenta
tion) .
Unclassifie
d if
process is
preceded
by primary
sedimentat
ion
9 a1 ENCLOSED
AERATION
BASIN, AEROBIC
OR SUSPENDED
GROWTH
SYSTEMS,
MEMBRANE
BIOLOGICAL
REACTORS .
Aerobic treatment
not preceded by
primary treatment
Possible
ignition
of
flammabl
e gases
or
floating
flammabl
e liquids
A
(Interior
of tank)
Entire enclosed
space or tank of
system
Division 1 NC NR
a2 A
(Interior
of tank)
Exterior of
enclosed space
or tank, installed
in a building
Division 2 NC, LC, or
LFS
NR
a3 A
(Interior
of tank)
Exterior of
enclosed space
or tank, installed
outdoors;
envelope 0.46 m
(18 in.)
surrounding
tank
Division 2 NC, LC, or
LFS
NR
b1 B
(Interior
of tank
maintain
ed at
negative
pressure
)
Entire enclosed
space or tank of
system
Division 2 NC, LC, or
LFS
NR
Ro
wa
Lin
ea
Location .
and .
Function
Fire and
Explosio
n Hazard
Ventilati
onb
Extent of
Classified Areac
NEC-Area
Electrical
Classificati
on .
(All Class I,
Group D)d
MaterialMate
rials of
Constructio
n for
Buildings or
Structurese
Fire
Protecti
on
Measur
es
b2 B
(Interior
of tank
maintain
ed at
negative
pressure
)
Exterior of
enclosed space
or tank, installed
in a building
Unclassifie
d
NC, LC, or
LFS
NR
b3 B
(Interior
of tank
maintain
ed at
negative
pressure
)
Exterior of
enclosed space
or tank, installed
outdoors
Unclassifie
d
NC, LC, or
LFS
NR
c Not
enclose
d, open
to
atmosph
ere
Interior of tank
from the
minimum
operating water
surface to the
top of the tank
wall; envelope
0.46 m (18 in.)
above the top of
the tank and
extending 0.46
m (18 in.)
beyond exterior
wall; envelope
0.46 m (18 in.)
above grade
and extending 3
m (10 ft)
horizontally from
the exterior tank
walls
Division 2 NC, LC, or
LFS
NR
Ro
wa
Lin
ea
Location .
and .
Function
Fire and
Explosio
n Hazard
Ventilati
onb
Extent of
Classified Areac
NEC-Area
Electrical
Classificati
on .
(All Class I,
Group D)d
MaterialMate
rials of
Constructio
n for
Buildings or
Structurese
Fire
Protecti
on
Measur
es
10 a1 RESIDENTIAL
ENCLOSED
AERATION
BASIN, AEROBIC
OR SUSPENDED
GROWTH
SYSTEMS,
MEMBRANE
BIOLOGICAL
REACTORS
Aerobic treatment
not preceded by
primary treatment,
serving one but not
more than five
dwellings
Possible
ignition
of
flammabl
e gases
or
floating
flammabl
e liquids
A
(Interior
of tank)
Entire enclosed
space or tank of
system
Division 2 NC NR
a2 A
(Interior
of tank)
Exterior of
enclosed space
or tank, installed
in a building
Unclassifie
d
NC, LC, or
LFS
NR
a3 A
(Interior
of tank)
Exterior of
enclosed space
or tank, installed
outdoors
Unclassifie
d
NC, LC, or
LFS
NR
11 ENCLOSED
AERATION
BASIN, AEROBIC
OR SUSPENDED
GROWTH
SYSTEMS,
MEMBRANE
BIOLOGICAL
REACTORS .
Aerobic treatment
of wastewater
preceded by
primary treatment
NA NR Entire enclosed
space
Unclassifie
d
NC, LC, or
LFS
NR
12 TRICKLING
FILTER, BIO-
TOWER,
AEROBIC FIXED-
FILM SYSTEMS .
Aerobic biological
treatment of
wastewater
Not
normally
a
significan
t hazard;
however,
these
processe
NR NA Classified
(see
Primary
Sedimenta
tion) .
Unclassifie
d if unit
process is
NR H
Ro
wa
Lin
ea
Location .
and .
Function
Fire and
Explosio
n Hazard
Ventilati
onb
Extent of
Classified Areac
NEC-Area
Electrical
Classificati
on .
(All Class I,
Group D)d
MaterialMate
rials of
Constructio
n for
Buildings or
Structurese
Fire
Protecti
on
Measur
es
s might
contain
materials
that are
combusti
ble under
certain
condition
s
preceded
by primary
sedimentat
ion.
13 a ANAEROBIC
TOWERS,
ANAEROBIC
FIXED-FILM
SYSTEM .
Anaerobic
biological
treatment if sealed
from atmosphere
Normally
produces
combusti
ble gas
as
treatmen
t process
by-
product
NA Tank interior Division 1 NC FE and
H
b NA 3 m (10 ft)
envelope
around tank
Division 2 NC, LC, or
LFS
FE and
H
14 a GAS-HANDLING
SYSTEMS FOR
LIQUID
TREATMENT
PROCESSES
Combust
ible gas,
often
under
pressure
A Enclosed—
entire space
Division 1 NC FE and
H
b B Enclosed—
entire space
Division 2 NC, LC, or
LFS
FE and
H
c Not
enclose
d, open
to
atmosph
ere
Within a 3 m (10
ft) envelope
around
equipmenteequi
pmentf
Division 2 NC, LC, or
LFS
FE and
H
15 OXYGEN
AERATION
TANKS Tanks for
aerobic treatment
of wastewater
using high-purity
Ignition
of
flammabl
e gases
and
floating
flammabl
NA Enclosed space Division 2
(If unit
process is
not
preceded
by primary
sedimentat
Any
equipment
or material
within the
reactor
space shall
be safe for
Special
provisio
n for
LFL
monitor
ing and
automa
Ro
wa
Lin
ea
Location .
and .
Function
Fire and
Explosio
n Hazard
Ventilati
onb
Extent of
Classified Areac
NEC-Area
Electrical
Classificati
on .
(All Class I,
Group D)d
MaterialMate
rials of
Constructio
n for
Buildings or
Structurese
Fire
Protecti
on
Measur
es
oxygen rather than
air
e liquids
in an
oxygen- .
enriched
environm
ent
ion, see
Primary
Sedimenta
tion Tanks
in Table
5.2 for
classificati
on.)
exposure to
volatile in an
oxygen- .
enriched
atmosphere
tic
isolatio
n of
equipm
ent and
oxygen
supply
16 INTERMEDIATE,
SECONDARY, OR
TERTIARY
SEDIMENTATION
TANKS .
Separate floating
and settleable
solids from
wastewater at
various treatment
stages
NA NR NA Classified
(see
Primary
Sedimenta
tion) .
Unclassifie
d if unit
process is
preceded
by primary
sedimentat
ion.
NR H
17 FLASH MIXER OR
FLOCCULATION
TANKS .
Tanks for mixing
various treatment
chemicals with
wastewater
NA NR NA Classified
(see
Primary
Sedimenta
tion) .
Unclassifie
d if unit
process is
preceded
by primary
sedimentat
ion.
NR H
18 NITRIFICATION
AND
DENITRIFICATIO
N TANKS .
NA NR NA Classified
(see
Primary
NR H
Ro
wa
Lin
ea
Location .
and .
Function
Fire and
Explosio
n Hazard
Ventilati
onb
Extent of
Classified Areac
NEC-Area
Electrical
Classificati
on .
(All Class I,
Group D)d
MaterialMate
rials of
Constructio
n for
Buildings or
Structurese
Fire
Protecti
on
Measur
es
Tertiary treatment
of wastewater to
reduce or remove
nitrogen
Sedimenta
tion) .
Unclassifie
d if unit
process is
preceded
by primary
sedimentat
ion.
19 BREAKPOINT
CHLORINATION
TANKS AND
CHLORINE
CONTACT TANKS .
Application of
chlorine in
aqueous solution
to wastewater
NA NR NA Unclassifie
d
NR (These
unit
processes
use
corrosive
chemicals
that require
the use of
specific
materials of
construction.
Special
consideratio
n shall be
given to
these
materials of
construction.
)
H
20 AMMONIA
STRIPPING
TOWERS
(See
“Trickling
Filter” in
Table
5.2.)
NA NA Unclassifie
d
NR (These
unit
processes
use
corrosive
chemicals.
Special
consideratio
n shall be
H
Ro
wa
Lin
ea
Location .
and .
Function
Fire and
Explosio
n Hazard
Ventilati
onb
Extent of
Classified Areac
NEC-Area
Electrical
Classificati
on .
(All Class I,
Group D)d
MaterialMate
rials of
Constructio
n for
Buildings or
Structurese
Fire
Protecti
on
Measur
es
given to
these
materials of
construction.
)
21 INTERMEDIATE
OR FINAL
PUMPING
STATIONS AND
OTHER UNIT
PROCESSES
AND
STRUCTURES
NOT
SPECIFICALLY
ADDRESSED IN
THIS TABLE.
Preceded by
primary treatment
NA NR NA Unclassifie
d
NR H
22 GRAVITY AND
PRESSURE
FILTERS .
Filtering of treated
wastewater
through sand or
other media
NA NR NA Unclassifie
d
NR H
23 CARBON
COLUMN OR
TANKS .
Vessels containing
carbon for tertiary
treatment of
wastewater
Significa
nt hazard
from
combusti
ble
carbon
material
NA NA Unclassifie
d
NR H
24 ON-SITE OZONE
GENERATION
SYSTEM AND
Similar to
oxygen
generatio
NA NA Not
covered in
NR NR
Ro
wa
Lin
ea
Location .
and .
Function
Fire and
Explosio
n Hazard
Ventilati
onb
Extent of
Classified Areac
NEC-Area
Electrical
Classificati
on .
(All Class I,
Group D)d
MaterialMate
rials of
Constructio
n for
Buildings or
Structurese
Fire
Protecti
on
Measur
es
OZONE
CONTACT TANKS .
Ozone generation
and purification for
disinfection of
wastewater
n with
addition
of being
highly
corrosive
(see
Table
D.1.1)
this
standard
25 BACKWASH
WATER AND
WASTE
BACKWASH
WATER HOLDING
TANKS .
Tanks for
temporary storage
of backwash water
NA NA NA Unclassifie
d
NR H
26 ULTRAVIOLET
DISINFECTION
UNIT .
Disinfection of
wastewater
effluent by
ultraviolet radiation
NA NR NA Unclassifie
d
NR H
27 EFFLUENT
STRUCTURES
Various structures
conveying treated
wastewater away
from treatment
processes
NA NR NA Unclassifie
d
NR H
28 a ODOR-CONTROL
AND
VENTILATIONSY
STEMS SERVING
b
c
Ro
wa
Lin
ea
Location .
and .
Function
Fire and
Explosio
n Hazard
Ventilati
onb
Extent of
Classified Areac
NEC-Area
Electrical
Classificati
on .
(All Class I,
Group D)d
MaterialMate
rials of
Constructio
n for
Buildings or
Structurese
Fire
Protecti
on
Measur
es
CLASSIFIED
AREAS .
(See "Collection
Systems, Table
4.2)
Note: The following codes are used in this table:
A: No ventilation or ventilated at less than 12 air changes per hour.
B: Continuously ventilated at 12 air changes per hour in accordance with Chapter 9.
C: Continuously ventilated at 6 air changes per hour in accordance with Chapter 9.
CGD: Combustible gas detection system.
D: No ventilation or ventilated at less than 6 air changes per hour.
FDS: Fire detection system.
FE: Portable fire extinguisher.
H: Hydrant protection in accordance with 7.2.4.
LC: Limited-combustible material.
LFS: Low flame spread index material.
NA: Not applicable.
NC: Noncombustible material.
NEC: In accordance with NFPA 70.
NR: No requirement.
aThe "Row" and "Line" columns are used to refer to Figure A.5.specific figures in A..2 and specific
requirements for each location and function. bThe NR designation in the "Ventilation" bThis column indicates that nothe ventilation requirements for processes. Additional ventilation
requirements are established for the space,provided in Chapter 9. Ventilation signaling and,
therefore, Table 9.1.1.4 also has no alarm requirements. are provided in Chapter 7.
cOpen channels and open structures upstream from the unit processes are classified the same as
the downstream processes they supply.
dThese unit processes use corrosive chemicals that can have a deteriorating effect on conductors
and equipment. Electrical equipment shall be identified for use in the operating environment. eThe
eThis column indicates the materials of construction for processes. Materials of construction for
buildings in which these processes are housed are in accordance with the applicable building code
and construction requirements provided in Chapter 8.
fThe area beyond the envelope is unclassified. fWhere gWhere liquid turbulence is not induced by aeration or other factors, the following criteria apply: (1)
interior of the tank from the minimum operating water surface to the top of the tank wall; (2)
envelope 0.46 m (18 in.) above the top of the tank and extending 0.46 m (18 in.) beyond the exterior
wall; (3) envelope 0.46 m (18 in.) above grade extending 3 m (10 ft) horizontally from the exterior
tank walls.
Chapter 5 Liquid Stream Treatment Processes
5.1* General.
5.1.1
This chapter shall establish minimum criteria for protection against fire and explosion hazards
associated with liquid stream treatment processes.
5.1.2
This chapter shall not apply to treatment systems serving individual structures or treatment systems
that principally treat industrial wastes.
5.2* Design and Construction.
5.2.1The design and construction of liquid stream treatment processes associated with wastewater
liquid treatment shall conform to Table 5.2.
5.2.2 The design and construction of buildings and structures containing liquid stream treatment
processes associated with wastewater liquid treatment shall comply with the applicable building
code and the additional requirements of Chapters 7-9.
Table 5.2 Liquid Stream Treatment Processes
Rowa
Linea
Location .
and .
Function
Fire and
Explosion
Hazard
Ventilatio
nb
Extent of
Classified
Areac
NEC-Area
Electrical
Classificatio
n .
(All Class I,
Group D)d
Materials
of
Constructi
on e
Fire
Protectio
n
Measure
s
1 a DIVERSION AND
CONTROL
STRUCTURES Not
preceded by primary
treatment
Possible
ignition of
flammable
gases and
floating
flammable
liquids
A Enclosed-
-entire
space
Division 1 NC FE, H;
CGD if
enclose
d in
building
b B Enclosed-
-entire
space
Division 2 NC, LC, or
LFS
FE, H;
CGD if
enclose
d in a
building
c Not
enclosed,
open to
atmosphe
re
Within a 3
m (10 ft)
envelope
around
equipmen
t and
Division 2 NC, LC, or
LFS
FE and
H
Rowa
Linea
Location .
and .
Function
Fire and
Explosion
Hazard
Ventilatio
nb
Extent of
Classified
Areac
NEC-Area
Electrical
Classificatio
n .
(All Class I,
Group D)d
Materials
of
Constructi
on e
Fire
Protectio
n
Measure
s
open
channel
2 a COARSE AND FINE
SCREEN
FACILITIES .
Removal of
screenings from raw
wastewater
Possible
ignition of
flammable
gases and
floating
flammable
liquids
A Enclosed
— entire
space
Division 1 NC FE, H,
CGD
b B Enclosed
— entire
space
Division 2 NC, LC, or
LFS
FE, H,
CGD
c Not
enclosed,
open to
atmosphe
re
Within a 3
m (10 ft)
envelope
around
equipmen
t and
open
channel
Division 2 NC, LC, or
LFS
FE, H
3 PUMPING
STATIONS,
DIVERSION
STRUCTURES AND
CONTROL
STRUCTURES .
(See “Collection
Systems,” Table 4.2.)
4 a FLOW
EQUALIZATION
TANKS Storage of
raw or partially
treated wastewater
Possible
ignition of
flammable
gases and
floating
flammable
liquids
A Enclosed
— entire
space
Division 1 NC FE,
H;CGD
if
enclose
d in a
building
b B Enclosed
— entire
space
Division 2 NC, LC, or
LFS
FE, H;
CGD if
enclose
d in a
building
Rowa
Linea
Location .
and .
Function
Fire and
Explosion
Hazard
Ventilatio
nb
Extent of
Classified
Areac
NEC-Area
Electrical
Classificatio
n .
(All Class I,
Group D)d
Materials
of
Constructi
on e
Fire
Protectio
n
Measure
s
c Not
enclosed,
open to
atmosphe
re
Within a 3
m (10 ft)
envelope
around
equipmen
t and
open
channelf,g
Division 2 NC, LC, or
LFS
FE, H
5 a GRIT REMOVAL
TANKS Separation of
grit from raw
wastewater
Possible
ignition of
flammable
gases and
floating
flammable
liquids
A Enclosed
— entire
space
Division 1 NC FE,
H;CGD
if
enclose
d in a
building
b B Enclosed
— entire
space
Division 2 NC, LC, or
LFS
FE, H;
CGD if
enclose
d in a
building
c Not
enclosed,
open to
atmosphe
re
Within a 3
m (10 ft)
envelope
around
equipmen
t and
open
channelf,g
Division 2 NC, LC, or
LFS
FE, H
6 a PRE-AERATION
TANKS Conditioning
of wastewater prior to
further treatment
Possible
ignition of
flammable
gases and
floating
flammable
liquids
A Enclosed
— entire
space
Division 1 NC H;CGD
if
enclose
d in a
building
b B Enclosed
— entire
space
Division 2 NC, LC, or
LFS
H; CGD
if
enclose
Rowa
Linea
Location .
and .
Function
Fire and
Explosion
Hazard
Ventilatio
nb
Extent of
Classified
Areac
NEC-Area
Electrical
Classificatio
n .
(All Class I,
Group D)d
Materials
of
Constructi
on e
Fire
Protectio
n
Measure
s
d in a
building
c Not
enclosed,
open to
atmosphe
re
Within a 3
m (10 ft)
envelope
around
equipmen
t and
open
channelf,g
Division 2 NC, LC, or
LFS
H
7 a PRIMARY
SEDIMENTATION
TANKS Separation of
floating or settleable
solids from raw
wastewater
Possible
ignition of
flammable
gases and
floating
flammable
liquids
A Enclosed
— entire
space
Division 1 NC H;CGD
if
enclose
d in a
building
b B Enclosed
— entire
space
Division 2 NC, LC, or
LFS
H; CGD
if
enclose
d in a
building
c Not
enclosed,
open to
atmosphe
re
Interior of
the tank
from the
minimum
operating
water
surface to
the top of
the tank
wall;
envelope
0.46 m
(18 in.)
above the
top of the
tank and
Division 2 NC, LC, or
LFS
H
Rowa
Linea
Location .
and .
Function
Fire and
Explosion
Hazard
Ventilatio
nb
Extent of
Classified
Areac
NEC-Area
Electrical
Classificatio
n .
(All Class I,
Group D)d
Materials
of
Constructi
on e
Fire
Protectio
n
Measure
s
extending
0.46 m
(18 in.)
beyond
the
exterior
wall;
envelope
0.46 m
(18 in.)
above
grade
extending
3 m (10
ft)
horizontal
ly from
the
exterior
tank walls
8 AERATION BASIN,
POND, LAGOON,
OXIDATION DITCH,
AEROBIC
SUSPENDED
GROWTH
SYSTEMS,
SEQUENCING
BATCH REACTORS
Aerobic treatment of
wastewater open to
the atmosphere
NA NR Classified
(see Primary
Sedimentati
on) .
Unclassified
if process is
preceded by
primary
sedimentatio
n
NR H
9 a1 ENCLOSED
AERATION BASIN,
AEROBIC OR
SUSPENDED
GROWTH
Possible
ignition of
flammable
gases or
floating
A (Interior
of tank)
Entire
enclosed
space or
tank of
system
Division 1 NC NR
Rowa
Linea
Location .
and .
Function
Fire and
Explosion
Hazard
Ventilatio
nb
Extent of
Classified
Areac
NEC-Area
Electrical
Classificatio
n .
(All Class I,
Group D)d
Materials
of
Constructi
on e
Fire
Protectio
n
Measure
s
a2 SYSTEMS,
MEMBRANE
BIOLOGICAL
REACTORS .
Aerobic treatment not
preceded by primary
treatment
flammable
liquids
A (Interior
of tank)
Exterior
of
enclosed
space or
tank,
installed
in a
building
Division 2 NC, LC, or
LFS
NR
a3 A (Interior
of tank)
Exterior
of
enclosed
space or
tank,
installed
outdoors;
envelope
0.46 m
(18 in.)
surroundi
ng tank
Division 2 NC, LC, or
LFS
NR
b1 B (Interior
of tank
maintaine
d at
negative
pressure)
Entire
enclosed
space or
tank of
system
Division 2 NC, LC, or
LFS
NR
b2 B (Interior
of tank
maintaine
d at
negative
pressure)
Exterior
of
enclosed
space or
tank,
installed
in a
building
Unclassified NC, LC, or
LFS
NR
b3 B (Interior
of tank
Exterior
of
Unclassified NC, LC, or
LFS
NR
Rowa
Linea
Location .
and .
Function
Fire and
Explosion
Hazard
Ventilatio
nb
Extent of
Classified
Areac
NEC-Area
Electrical
Classificatio
n .
(All Class I,
Group D)d
Materials
of
Constructi
on e
Fire
Protectio
n
Measure
s
maintaine
d at
negative
pressure)
enclosed
space or
tank,
installed
outdoors
c Not
enclosed,
open to
atmosphe
re
Interior of
tank from
the
minimum
operating
water
surface to
the top of
the tank
wall;
envelope
0.46 m
(18 in.)
above the
top of the
tank and
extending
0.46 m
(18 in.)
beyond
exterior
wall;
envelope
0.46 m
(18 in.)
above
grade
and
extending
3 m (10
ft)
horizontal
Division 2 NC, LC, or
LFS
NR
Rowa
Linea
Location .
and .
Function
Fire and
Explosion
Hazard
Ventilatio
nb
Extent of
Classified
Areac
NEC-Area
Electrical
Classificatio
n .
(All Class I,
Group D)d
Materials
of
Constructi
on e
Fire
Protectio
n
Measure
s
ly from
the
exterior
tank walls
10 a1 RESIDENTIAL
ENCLOSED
AERATION BASIN,
AEROBIC OR
SUSPENDED
GROWTH
SYSTEMS,
MEMBRANE
BIOLOGICAL
REACTORS Aerobic
treatment not
preceded by primary
treatment, serving
one but not more
than five dwellings
Possible
ignition of
flammable
gases or
floating
flammable
liquids
A (Interior
of tank)
Entire
enclosed
space or
tank of
system
Division 2 NC NR
a2 A (Interior
of tank)
Exterior
of
enclosed
space or
tank,
installed
in a
building
Unclassified NC, LC, or
LFS
NR
a3 A (Interior
of tank)
Exterior
of
enclosed
space or
tank,
installed
outdoors
Unclassified NC, LC, or
LFS
NR
11 ENCLOSED
AERATION BASIN,
AEROBIC OR
SUSPENDED
GROWTH
SYSTEMS,
MEMBRANE
BIOLOGICAL
REACTORS .
Aerobic treatment of
wastewater preceded
by primary treatment
NA NR Entire
enclosed
space
Unclassified NC, LC, or
LFS
NR
Rowa
Linea
Location .
and .
Function
Fire and
Explosion
Hazard
Ventilatio
nb
Extent of
Classified
Areac
NEC-Area
Electrical
Classificatio
n .
(All Class I,
Group D)d
Materials
of
Constructi
on e
Fire
Protectio
n
Measure
s
12 TRICKLING FILTER,
BIO-TOWER,
AEROBIC FIXED-
FILM SYSTEMS .
Aerobic biological
treatment of
wastewater
Not
normally a
significant
hazard;
however,
these
processes
might
contain
materials
that are
combustib
le under
certain
conditions
NR NA Classified
(see Primary
Sedimentati
on) .
Unclassified
if unit
process is
preceded by
primary
sedimentatio
n.
NR H
13 a ANAEROBIC
TOWERS,
ANAEROBIC FIXED-
FILM SYSTEM .
Anaerobic biological
treatment if sealed
from atmosphere
Normally
produces
combustib
le gas as
treatment
process
by-
product
NA Tank
interior
Division 1 NC FE and
H
b NA 3 m (10
ft)
envelope
around
tank
Division 2 NC, LC, or
LFS
FE and
H
14 a GAS-HANDLING
SYSTEMS FOR
LIQUID
TREATMENT
PROCESSES
Combusti
ble gas,
often
under
pressure
A Enclosed
— entire
space
Division 1 NC FE and
H
b B Enclosed
— entire
space
Division 2 NC, LC, or
LFS
FE and
H
c Not
enclosed,
open to
atmosphe
re
Within a 3
m (10 ft)
envelope
around
equipmen
tf
Division 2 NC, LC, or
LFS
FE and
H
Rowa
Linea
Location .
and .
Function
Fire and
Explosion
Hazard
Ventilatio
nb
Extent of
Classified
Areac
NEC-Area
Electrical
Classificatio
n .
(All Class I,
Group D)d
Materials
of
Constructi
on e
Fire
Protectio
n
Measure
s
15 OXYGEN
AERATION TANKS
Tanks for aerobic
treatment of
wastewater using
high-purity oxygen
rather than air
Ignition of
flammable
gases and
floating
flammable
liquids in
an
oxygen- .
enriched
environme
nt
NA Enclosed
space
Division 2 (If
unit process
is not
preceded by
primary
sedimentatio
n, see
Primary
Sedimentati
on Tanks in
Table 5.2 for
classification
.)
Any
equipment
or material
within the
reactor
space shall
be safe for
exposure
to volatile
in an
oxygen- .
enriched
atmospher
e
Special
provisio
n for
LFL
monitori
ng and
automati
c
isolation
of
equipme
nt and
oxygen
supply
16 INTERMEDIATE,
SECONDARY, OR
TERTIARY
SEDIMENTATION
TANKS .
Separate floating and
settleable solids from
wastewater at
various treatment
stages
NA NR NA Classified
(see Primary
Sedimentati
on) .
Unclassified
if unit
process is
preceded by
primary
sedimentatio
n.
NR H
17 FLASH MIXER OR
FLOCCULATION
TANKS .
Tanks for mixing
various treatment
chemicals with
wastewater
NA NR NA Classified
(see Primary
Sedimentati
on) .
Unclassified
if unit
process is
preceded by
primary
sedimentatio
n.
NR H
Rowa
Linea
Location .
and .
Function
Fire and
Explosion
Hazard
Ventilatio
nb
Extent of
Classified
Areac
NEC-Area
Electrical
Classificatio
n .
(All Class I,
Group D)d
Materials
of
Constructi
on e
Fire
Protectio
n
Measure
s
18 NITRIFICATION
AND
DENITRIFICATION
TANKS .
Tertiary treatment of
wastewater to reduce
or remove nitrogen
NA NR NA Classified
(see Primary
Sedimentati
on) .
Unclassified
if unit
process is
preceded by
primary
sedimentatio
n.
NR H
19 BREAKPOINT
CHLORINATION
TANKS AND
CHLORINE
CONTACT TANKS .
Application of
chlorine in aqueous
solution to
wastewater
NA NR NA Unclassified NR (These
unit
processes
use
corrosive
chemicals
that require
the use of
specific
materials
of
constructio
n. Special
considerati
on shall be
given to
these
materials
of
constructio
n.)
H
20 AMMONIA
STRIPPING
TOWERS
(See
“Trickling
Filter” in
Table
5.2.)
NA NA Unclassified NR (These
unit
processes
use
corrosive
H
Rowa
Linea
Location .
and .
Function
Fire and
Explosion
Hazard
Ventilatio
nb
Extent of
Classified
Areac
NEC-Area
Electrical
Classificatio
n .
(All Class I,
Group D)d
Materials
of
Constructi
on e
Fire
Protectio
n
Measure
s
chemicals.
Special
considerati
on shall be
given to
these
materials
of
constructio
n.)
21 INTERMEDIATE OR
FINAL PUMPING
STATIONS AND
OTHER UNIT
PROCESSES AND
STRUCTURES NOT
SPECIFICALLY
ADDRESSED IN
THIS TABLE.
Preceded by primary
treatment
NA NR NA Unclassified NR H
22 GRAVITY AND
PRESSURE
FILTERS .
Filtering of treated
wastewater through
sand or other media
NA NR NA Unclassified NR H
23 CARBON COLUMN
OR TANKS .
Vessels containing
carbon for tertiary
treatment of
wastewater
Significant
hazard
from
combustib
le carbon
material
NA NA Unclassified NR H
24 ON-SITE OZONE
GENERATION
SYSTEM AND
Similar to
oxygen
generatio
NA NA Not covered
in this
standard
NR NR
Rowa
Linea
Location .
and .
Function
Fire and
Explosion
Hazard
Ventilatio
nb
Extent of
Classified
Areac
NEC-Area
Electrical
Classificatio
n .
(All Class I,
Group D)d
Materials
of
Constructi
on e
Fire
Protectio
n
Measure
s
OZONE CONTACT
TANKS .
Ozone generation
and purification for
disinfection of
wastewater
n with
addition of
being
highly
corrosive
(see
Table
D.1.1)
25 BACKWASH
WATER AND
WASTE BACKWASH
WATER HOLDING
TANKS .
Tanks for temporary
storage of backwash
water
NA NA NA Unclassified NR H
26 ULTRAVIOLET
DISINFECTION
UNIT .
Disinfection of
wastewater effluent
by ultraviolet
radiation
NA NR NA Unclassified NR H
27 EFFLUENT
STRUCTURES
Various structures
conveying treated
wastewater away
from treatment
processes
NA NR NA Unclassified NR H
28 a ODOR-CONTROL
AND
VENTILATIONSYST
EMS SERVING
CLASSIFIED AREAS .
b
c
Rowa
Linea
Location .
and .
Function
Fire and
Explosion
Hazard
Ventilatio
nb
Extent of
Classified
Areac
NEC-Area
Electrical
Classificatio
n .
(All Class I,
Group D)d
Materials
of
Constructi
on e
Fire
Protectio
n
Measure
s
(See "Collection
Systems, Table 4.2)
Note: The following codes are used in this table:
A: No ventilation or ventilated at less than 12 air changes per hour.
B: Continuously ventilated at 12 air changes per hour in accordance with Chapter 9.
C: Continuously ventilated at 6 air changes per hour in accordance with Chapter 9.
CGD: Combustible gas detection system.
D: No ventilation or ventilated at less than 6 air changes per hour.
FDS: Fire detection system.
FE: Portable fire extinguisher.
H: Hydrant protection in accordance with 7.2.4.
LC: Limited-combustible material.
LFS: Low flame spread index material.
NA: Not applicable.
NC: Noncombustible material.
NEC: In accordance with NFPA 70.
NR: No requirement.
aThe "Row" and "Line" columns are used to refer to specific figures in A.5.2 and specific
requirements for each location and function.
bThis column indicates the ventilation requirements for processes. Additional ventilation
requirements are provided in Chapter 9. Ventilation signaling and alarm requirements are provided
in Chapter 7.
cOpen channels and open structures upstream from the unit processes are classified the same as
the downstream processes they supply.
dThese unit processes use corrosive chemicals that can have a deteriorating effect on conductors
and equipment. Electrical equipment shall be identified for use in the operating environment.
eThis column indicates the materials of construction for processes. Materials of construction for
buildings in which these processes are housed are in accordance with the applicable building code
and construction requirements provided in Chapter 8.
fThe area beyond the envelope is unclassified.
gWhere liquid turbulence is not induced by aeration or other factors, the following criteria apply: (1)
interior of the tank from the minimum operating water surface to the top of the tank wall; (2)
envelope 0.46 m (18 in.) above the top of the tank and extending 0.46 m (18 in.) beyond the exterior
wall; (3) envelope 0.46 m (18 in.) above grade extending 3 m (10 ft) horizontally from the exterior
tank walls.
Second Revision No. 4-NFPA 820-2014 [ Section No. 6.2 ]
6.2* Design and Construction.
The design and construction of solids treatment processes shall conform to Table 6.2(a) and Table 6.2(b) .
6.2.1
The design and construction of buildings and structures containing solids treatment processes associated withwastewater solids treatment shall comply with the applicable building code and the additional requirements ofChapters 7 through 9 .
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6.2.2
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The design and construction of solids treatment processes associated with wastewater solids treatment shall conformto Table 6.2.2(a) Table 6.2(a) Table 6.2.1(a) and Table 6.2.2(b) Table 6.2(b) Table 6.2.1(b) .
Table 6.2.2(a) Solids Treatment Processes
Rowa Linea Location andFunction
Fire andExplosion
HazardVentilationb,c,d
Extent ofClassified
Area
NEC -Area NECArea ElectricalClassification(All Class I,
Group D)d
Materials ofConstruction
forBuildings or
Structures e
FireProtectionMeasures
1 COARSE AND FINESCREENINGS-
HANDLINGBUILDINGS
Storage, conveying,or dewatering ofscreenings (noexposed flow ofwastewater throughbuilding or area)
NA N/A NR NA N/A Unclassified NC, LC, orLFS
H, FE, andFAS
2 GRIT-HANDLINGBUILDING
Storage, conveying,and dewatering ofheavy smallscreenings and grit(no exposed flow ofwastewater throughbuilding or area)
NA N/A NR NA N/A Unclassified NC, LC, orLFS
H, FE, andFAS
3 a SCUM-HANDLINGBUILDING ORAREA Holding,dewatering, orstorage
Possiblegrease orflammableliquidscarryover
A Enclosedspace
Division 2 NC, LC, orLFS
H andFE;CGD ifenclosed inbuilding
b B Enclosedspace
Unclassified NC, LC, orLFS
H and FE;CGD ifenclosed inbuilding
c Not enclosed,open toatmosphere
NA N/A Unclassified NC, LC, orLFS
H and FE
4 a SCUM PITS Buildup ofvapors fromflammable orcombustibleliquids
A Enclosed—entire space
Division 1 NC HandFE;CGD ifenclosed inbuilding
b B Enclosed—entire space
Division 2 NC, LC, orLFS
H and FE;CGD ifenclosed inbuilding
c Not enclosed,open toatmosphere
Within a 3 m(10 ft)envelopearoundequipment and
open channelc
Division 2 NC, LC, orLFS
H and FE
5 a SCUM-PUMPINGAREAS Pumping ofscum, wet side ofpumping station
Buildup ofvapors fromflammable orcombustibleliquids.
A Enclosed —entire space
Division 1 NC Hand FE;CGD ifenclosed inbuilding
b B Enclosed —entire space
Division 2 NC, LC, orLFS
Hand FE;CGD ifenclosed inbuilding
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Rowa Linea Location andFunction
Fire andExplosion
HazardVentilationb,c,d
Extent ofClassified
Area
NEC -Area NECArea Electrical
Classification (AllClass I, Group
D)d
Materials ofConstruction
forBuildings or
Structures e
FireProtectionMeasures
c Not enclosed,open toatmosphere
Within a 3 m(10 ft)envelopearoundequipment and
open channelc
Division 2 NC, LC, orLFS
H and FE
6 a SCUM-PUMPINGAREAS Pumping ofscum, dry side ofpumping station
Buildup ofvapors fromflammable andcombustibleliquids.
D Enclosedspace
Division 2 NC, LC, orLFS
H and FE
b C Enclosedspace
Unclassified NC, LC, orLFS
H and FE
c Not enclosed,open toatmosphere
NA N/A Unclassified NC, LC, orLFS
H and FE
7 SCUM
INCINERATORSef
Elimination of scumthrough burning
Fireboxexplosion frompossiblecarryover offlammablescum
NR Incineratorarea ifseparated fromscum storage
Unclassified NC, LC, orLFS
FSS (ifindoors), H,and FE
8 a SLUDGETHICKENER(CLARIFIER) Sludgeconcentration andremoval, gravity, ordissolved airflotation
Possiblegeneration ofmethane fromsludge;carryover offloatingflammableliquids
A Enclosed —entire space
Division 1 NC HandFE;CGD ifenclosed inbuilding
b B Enclosed —entire space
Division 2 NC, LC, orLFS
Hand FE;CGD ifenclosed inbuilding
c Not enclosed,open toatmosphere
Envelope 0.46m (18 in.)above watersurface and
3 m (10 ft)horizontallyfrom wetted
wallsc
H and FE
9 a SLUDGE PUMPINGSTATION DRYWELLS
Dry side of a sludgepumping station
Buildup ofmethane gasor flammablevapors
D Entire dry wellwhenphysicallyseparated froma wet well orseparatestructures
Division 2 NC, LC, orLFS
H and FE
b C Entire dry wellwhenphysicallyseparated froma wet well orseparatestructures
Unclassified NC, LC, orLFS
H and FE
10 a SLUDGE STORAGEWET WELLS, PITS,AND HOLDINGTANKS
Possiblegeneration ofmethane gasin explosiveconcentrations;
A Enclosed —entire space
Division 1 NC CGD, H,and FE iftankenclosed inbuilding
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Rowa Linea Location andFunction
Fire andExplosion
HazardVentilationb,c,d
Extent ofClassified
Area
NEC -Area NECArea Electrical
Classification (AllClass I, Group
D)d
Materials ofConstruction
forBuildings or
Structures e
FireProtectionMeasures
Retaining of sludge carryover offloatingflammableliquids
b B Enclosed —entire space
Division 2 NC, LC, orLFS
CGD, H,and FE iftankenclosed inbuilding
c Not enclosed,open toatmosphere
Envelope 0.46m (18 in.)above watersurface and
3 m (10 ft)horizontallyfrom wetted
wallsc
Division 2 NC, LC, orLFS
NR
11 a SLUDGE-BLENDING TANKSAND HOLDINGWELLS
Retaining of sludgewith some agitation
Possiblegeneration ofmethane gasin explosiveconcentrations;carryover offloatingflammableliquids
A Enclosed —entire space
Division 1 NC H, FE, andCGD if tankenclosed inbuilding
b B Enclosed —entire space
Division 2 NC, LC, orLFS
H, FE, andCGD if tankenclosed inbuilding
c Not enclosed,open toatmosphere
Envelope 0.46m (18 in.)above watersurface and
3 m (10 ft)horizontallyfrom wetted
wallsc
Division 2 NC, LC, orLFS
NR
12 a DEWATERINGBUILDINGSCONTAININGCENTRIFUGES,GRAVITY BELTTHICKENERS,BELT ANDVACUUM FILTERS,AND FILTERPRESSES
Removal of waterfrom sludge and theconveyance ofsludge cake
Accumulationof methanegas
C Entire room Unclassified NC, LC, orLFS
H, FE, andFAS
b D Entire room Division 2 NC, LC, orLFS
H, FE, andFAS
13 a ENCLOSEDSLUDGE CAKESTORAGE Storageof dewatered sludgecake andconveyance ofsludge cake
Accumulationof methanegas
C Entire room Unclassified NC, LC, orLFS
H, FE, andFAS
b D Entire room Division 2 NC, LC, orLFS
H, FE, andFAS
14 INCINERATORSe f
AND INCINERATORBUILDINGS
Conveying andburning of sludgecake
Fireboxexplosion
NR NA N/A Unclassified NC, LC, orLFS
FSS (ifindoors), H,and FE
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Rowa Linea Location andFunction
Fire andExplosion
HazardVentilationb,c,d
Extent ofClassified
Area
NEC -Area NECArea Electrical
Classification (AllClass I, Group
D)d
Materials ofConstruction
forBuildings or
Structures e
FireProtectionMeasures
15 HEAT TREATMENTUNITS, LOW- ORHIGH-PRESSUREOXIDATION UNITS
Closed oxidation ofsludge
None, otherthan inhigh-pressuresystems
NR NA N/A Unclassified NC, LC, orLFS
H and FE
16 a ANAEROBICDIGESTERS, BOTHFIXED ROOF ANDFLOATING COVERGeneration of sludgegas from digestingsludge
Leakage ofgas fromcover, piping,emergencyrelief valves,andappurtenances
Not enclosed,open toatmosphere
Tank interior;areas aboveand arounddigester cover;envelope 3 m(10 ft) abovethe highestpoint of cover,when cover isat its maximumelevation, and1.5 m (5 ft)from any wall
Division 1 NC H and FE
b Not enclosed,open toatmosphere
Envelope
4.6 m (15 ft)above Division1 area overcover and 1.5m (5 ft) beyondDivision 1 areaaround tankwalls
Division 2 NC H and FE
c A For digestertanks enclosedin a building:tank interior;entire areainside building
Division 1 NC CGD ifenclosed inbuilding
d B For digestertanks enclosedin a building:tank interior;areas aboveand arounddigester cover;envelope 3 m(10 ft) abovehighest point ofcover, whencover is at itsmaximumelevation, and1.5 m (5 ft)from any wallof digester tank
Division 1 NC CGD ifenclosed inbuilding
e B Remainingspace inenclosed area
Division 2 NC, LC, orLFS
CGD ifenclosed inbuilding
17 a ANAEROBICDIGESTER
Leaking andignition of
A Entire building Division 1 NC CGD, H,and FE
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Rowa Linea Location andFunction
Fire andExplosion
HazardVentilationb,c,d
Extent ofClassified
Area
NEC -Area NECArea Electrical
Classification (AllClass I, Group
D)d
Materials ofConstruction
forBuildings or
Structures e
FireProtectionMeasures
CONTROLBUILDING
Storage, handling, orburning of sludgegas
sludge gasb B Enclosed areasthat containgas-handlingequipment
Division 2 NC, LC, orLFS
CGD, H,and FE
c C Physicallyseparated fromgas-handlingequipment
Unclassified NC, LC, orLFS
CGD, H,and FE
18 a DIGESTERGAS-PROCESSINGROOMS Gascompression,handling, andprocessing
Sludge gasignition
A Entire room Division 1 NC CGD, H,and FE
b B Within 1.5 m (5ft) ofequipment
Division 1 NC, LC, orLFS
CGD, H,and FE
c B Entire room Division 2 NC, LC, orLFS
CGD, H,and FE
19 ANAEROBICDIGESTER GASSTORAGE
Storage of sludgegas
Gas storagepiping andhandling
NNV Within a 3 m(10 ft)envelope oftanks, valves,andappurtenances
Division 1 NC, LC, orLFS
Hand FE;CGD ifenclosed inbuilding
20 a WASTE
GAS
BURNERS
Combusting excessgas
Gas piping andappurtenances
NA N/A Within 3 m (10ft) envelope ofall fixtures,appurtenances,and housing
Division 1 NC NR
b Envelope
4.6 m (15 ft)above Division1 envelope and1.5 m (5 ft) onall sides
Division 2 NC NR
21 CHLORINEOXIDATION UNITS
Chlorine reactionwith sludge
Chlorine is avery strongoxidizing agent
NR NA N/A Unclassified NR (Theseunit processesuse corrosivechemicals thatrequire theuse of specificmaterials ofconstruction.Specialconsiderationshall be givento suchmaterials ofconstruction.)
H and FE
22 a UNDERGROUND(PIPING) TUNNELSCONTAININGNATURAL GASPIPING ORSLUDGE GASPIPING
Transmission of gas,sludge, water, air,and steam viapiping; also might
Ignition ofnatural gas orsludge gases
D Within 3 m (10ft) of valvesandappurtenances
Division 1 NC, LC, orLFS
CGD, FDS,and FE
b D Entire tunnel Division 2 NC, LC, orLFS
CGD, FDS,and FE
c C Areas within 3m (10 ft) ofvalves, meters,gas checkvalves,
Division 2 NC, LC, orLFS
CGD, FDS,and FE
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Rowa Linea Location andFunction
Fire andExplosion
HazardVentilationb,c,d
Extent ofClassified
Area
NEC -Area NECArea Electrical
Classification (AllClass I, Group
D)d
Materials ofConstruction
forBuildings or
Structures e
FireProtectionMeasures
contain power cableand conduit
condensatetraps, andother pipingappurtenances
d C Areas beyond3 m (10 ft)
Unclassified NC, LC, orLFS
CGD, FDS,and FE
23 UNDERGROUND(PIPING) TUNNELSNOT CONTAININGNATURAL GASPIPING ORSLUDGE GASPIPINGTransmissionof sludge, water, air,and steam piping;also might containpower cable andconduit
NA N/A NR NA N/A Unclassified NC, LC, orLFS
FDS andFE
24 a COMPOSTINGPILES
Aerobic sludgereduction
Liberation ofammonia andtoxic gas(compostingmaterials canself-ignite)
D Enclosed area Division 2 NC, LC, orLFS
H and FDS
b C Enclosed area Unclassified NC, LC, orLFS
H and FDS
25 a IN-VESSELCOMPOSTINGAerobic sludgereduction
Liberation ofammonia andtoxic gas(compostingmaterials canself-ignite)
As required byprocess
If enclosed,interior ofreactor vesselplus a 3 m (10ft) envelopearound reactorvessel
Division 2 NC H and FDS
b As required byprocess
Areas beyond3 m (10 ft)
Unclassified NC H and FDS
26 ODOR-CONTROLAND VENTILATIONSYSTEMSSERVINGCLASSIFIEDAREAS ((See"CollectionSystems," Table 4.2)
27 PUMPING OFDRAINAGE FROMDIGESTEDSLUDGE-
DEWATERINGPROCESSESPumping of centrate,filtrate, leachate,drying beds, and soforth
NA N/A NR NA N/A Unclassified NC, LC, orLFS
H
Note: The following codes are used in this table:
A: No ventilation or ventilated at less than 12 air changes per hour.
B: Continuously ventilated at 12 air changes per hour in accordance with Chapter 9.
C: Continuously ventilated at 6 six air changes per hour in accordance with Chapter 9.
CGD: Combustible gas detection system.
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D: No ventilation or ventilated at less than 6 six air changes per hour.
FAS: Fire alarm system.
FDS: Fire detection system.
FE: Portable fire extinguisher.
FSS: Fire suppression system (e.g., automatic sprinkler, water spray, foam, gaseous, or dry chemical).
H: Hydrant protection in accordance with 7.2.4.
LC: Limited-combustible material.
LFS: Low flame spread index material.
NA N/A : Not applicable.
NC: Noncombustible material.
NEC: In accordance with NFPA 70.
NNV: Not normally ventilated.
NR: No requirement.
aThe “Row” and “Line” columns are used to refer to specific figures in A.6.2 and specific requirements for each locationand function.
b The NR designation in the "Ventilation" column indicates that no ventilation requirements are established for thespace, and, therefore, Table 9.1.1.4 also has no requirements.
b This column indicates the ventilation requirements for processes. Additional ventilation requirements are provided inChapter 9. Ventilation signaling and alarm requirements are provided in Chapter 7.
cThe area beyond the envelope is unclassified.
dThese unit processes use corrosive chemicals that can have a deteriorating effect on conductors and equipment.Electrical equipment shall be identified for use in the operating environment.
e This column indicates the materials of construction for processes. Materials of construction for buildings in whichthese processes are housed are in accordance with the applicable building code and construction requirementsprovided in Chapter 8.
e f See NFPA 54, NFPA 82, and NFPA 85.
Table 6.2.2(b) Solids Treatment Processes — Sludge Drying
Row LineLocation and
Function
Fire andExplosion
HazardVentilationa,b
Extent ofClassified
Area
NEC -Area NECArea ElectricalClassification(All Class II,
Group G)c
Materials ofConstruction
forBuildings or
Structures d
FireProtectionMeasures
1 a SLUDGE-DRYING
PROCESSESd e
Potentialfor ignitionof dust
NR If exposedtocombustibleparticulatesolids,entire
roome f
Division 1 NC(Constructionin accordancewith NFPA 30,NFPA 68,NFPA 69,NFPA 499,and NFPA654)
H, FAS,and FSS(See NFPA30, NFPA61, NFPA69, NFPA85, NFPA499, andNFPA 654)
b NR Areaswithinequipmentprocessingcombustibleparticulatesolids
Division 1 NC(Constructionin accordancewith NFPA 30,NFPA 68,NFPA 69,NFPA 499,and NFPA654)
H, FAS,and FSS(See NFPA30, NFPA61, NFPA69, NFPA85, NFPA499, andNFPA 654)
c NR Areaswithin 3 m(10 ft) of
Division 2 NC(Constructionin accordance
H, FAS,and FSS(See NFPA
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Row LineLocation and
Function
Fire andExplosion
HazardVentilationa,b
Extent ofClassified
Area
NEC -Area NECArea Electrical
Classification (AllClass II, Group
G)c
Materials ofConstruction
forBuildings or
Structures d
FireProtectionMeasures
equipmentprocessingcombustibleparticulatesolids
with NFPA 30,NFPA 68,NFPA 69,NFPA 499,and NFPA654)
30, NFPA61, NFPA69, NFPA85, NFPA499, andNFPA 654)
d NR Areasbeyond 3 m(10 ft) ofequipmentprocessingcombustibleparticulatesolids
Unclassified NC(Constructionin accordancewith NFPA 30,NFPA 68,NFPA 69,NFPA 499,and NFPA654)
H, FAS,and FSS(See NFPA30, NFPA61, NFPA69, NFPA85, NFPA499, andNFPA 654)
2 a DRIED SLUDGESTORAGEAREAS, IFENCLOSED
Potentialfor ignitionof dust
NR If exposedto driedsludge,entire
roome
Division 1 NC(Constructionin accordancewith NFPA 68and NFPA 69,NFPA 499,and NFPA654)
H, FAS(See NFPA61, NFPA69, NFPA497, andNPFA 654)
b NR Areaswithin tanksstoringdriedsludge
Division 1 NC(Constructionin accordancewith NFPA 68,NFPA 69,NFPA 499,and NFPA654)
H and FAS(See NFPA61, NFPA69, NFPA497, andNFPA 654)
c NR Areaswithin 3 m(10 ft) oftanksstoringdriedsludge
Division 2 NC(Constructionin accordancewith NFPA 68,NFPA 69,NFPA 499,and NFPA654)
H and FAS(See NFPA61, NFPA69, NFPA497, andNFPA 654)
d NR Areasbeyond 3 m(10 ft) oftanksstoringdriedsludge
Unclassified NC(Constructionin accordancewith NFPA 68,NFPA 69,NFPA 499,and NFPA654)
H and FAS(See NFPA61, NFPA69, NFPA497, andNFPA 654)
Note: The following codes are used in this table:
FAS: Fire alarm system.
FSS: Fire suppression system (e.g., automatic sprinkler, water spray, foam, gaseous, or dry chemical).
H: Hydrant protection in accordance with 7.2.4.
NC: Noncombustible material.
NEC: In accordance with NFPA 70.
NR: No requirement.
aThe NR designation in the “Ventilation” This column indicates that no the ventilation requirements are established for
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the space, and, therefore, Table 9.1.1.4 also has no requirements. for processes. Additional ventilation requirementsare provided in Chapter 9. Ventilation signaling and alarm requirements are provided in Chapter 7.
bFor sludge-drying processes that use flammable or combustible liquids, ventilate in accordance with NFPA 30.
cOr if acceptable to the authority having jurisdiction with classification in NFPA 499.
d This column indicates the materials of construction for processes. Materials of construction for buildings in whichthese processes are housed are in accordance with the applicable building code and construction requirementsprovided in Chapter 8.
d e See NFPA 54, NFPA 85, NFPA 499, and NFPA 654. For sludge-drying processes that use flammable orcombustible liquids, see NFPA 30.
e f The area beyond the envelope is unclassified.
Supplemental Information
File Name Description
ComparisonFDtoSDChapter_6.docx Editorial use only.
_FINALSDMtgREVChapter_6.docx Editorial use only.
Submitter Information Verification
Submitter Full Name: [ Not Specified ]
Organization: [ Not Specified ]
Street Address:
City:
State:
Zip:
Submittal Date: Mon Oct 06 20:40:04 EDT 2014
Committee Statement
CommitteeStatement:
Section 6.2.2 explains that building codes cover general building construction but the components within thebuilding are covered in the table. The Table Column for materials was reworded to better indicate that the generalbuilding construction requirements are provided in chapter 8 but that the materials of construction for particularlocations within the facility are provided in the tables. The table footnotes were modified to better direct the user tothe appropriate chapters in NFPA 820 related to the subject column.
ResponseMessage:
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Chapter 6 Solids Treatment Processes
6.1* General.
6.1.1
This chapter shall establish minimum criteria for protection against fire and explosion hazards
associated with solids treatment processes.
6.1.2
This chapter shall not apply to the treatment of solids from industrial waste treatment processes.
6.2* Design and Construction.
The6.2.1The design and construction of solids treatment processes associated with wastewater
solids treatment shall conform to Table 6.2(a) and Table 6.2(b).
6.2.2 The design and construction of buildings and structures containing solids treatment processes
associated with wastewater solids treatment shall comply with the applicable building code and the
additional requirements of Chapters 7-9.
Table 6.2(a) Solids Treatment Processes
Ro
wa
Lin
ea Location and Function
Fire and
Explosion
Hazard
Ventilatio
nb,c,d
Extent of
Classified
Area
NEC-Area
Electrical
Classifica
tion (All
Class I,
Group D)d
MaterialMat
erials of
Constructio
n for
Buildings or
Structurese
Fire
Protect
ion
Measur
es
1 COARSE AND FINE
SCREENINGS- .
HANDLING BUILDINGS .
Storage, conveying, or
dewatering of screenings
(no exposed flow of
wastewater through
building or area)
NA NR NA Unclassifi
ed
NC, LC, or
LFS
H, FE,
and
FAS
2 GRIT-HANDLING
BUILDING .
Storage, conveying, and
dewatering of heavy
small screenings and grit
(no exposed flow of
wastewater through
building or area)
NA NR NA Unclassifi
ed
NC, LC, or
LFS
H, FE,
and
FAS
Ro
wa
Lin
ea Location and Function
Fire and
Explosion
Hazard
Ventilatio
nb,c,d
Extent of
Classified
Area
NEC-Area
Electrical
Classifica
tion (All
Class I,
Group D)d
MaterialMat
erials of
Constructio
n for
Buildings or
Structurese
Fire
Protect
ion
Measur
es
3 a SCUM-HANDLING
BUILDING OR AREA
Holding, dewatering, or
storage
Possible
grease or
flammable
liquids
carryover
A Enclosed
space
Division 2 NC, LC, or
LFS
H and
FE;CG
D if
enclos
ed in
buildin
g
b B Enclosed
space
Unclassifi
ed
NC, LC, or
LFS
H and
FE;
CGD if
enclos
ed in
buildin
g
c Not
enclosed,
open to
atmosphe
re
NA Unclassifi
ed
NC, LC, or
LFS
H and
FE
4 a SCUM PITS Buildup of
vapors
from
flammable
or
combustibl
e liquids
A Enclosed
— entire
space
Division 1 NC Hand
FE;CG
D if
enclos
ed in
buildin
g
b B Enclosed
— entire
space
Division 2 NC, LC, or
LFS
H and
FE;
CGD if
enclos
ed in
buildin
g
c Not
enclosed,
open to
Within a 3
m (10 ft)
envelope
Division 2 NC, LC, or
LFS
H and
FE
Ro
wa
Lin
ea Location and Function
Fire and
Explosion
Hazard
Ventilatio
nb,c,d
Extent of
Classified
Area
NEC-Area
Electrical
Classifica
tion (All
Class I,
Group D)d
MaterialMat
erials of
Constructio
n for
Buildings or
Structurese
Fire
Protect
ion
Measur
es
atmosphe
re
around
equipment
and open
channelc
5 a SCUM-PUMPING
AREAS Pumping of
scum, wet side of
pumping station
Buildup of
vapors
from
flammable
or
combustibl
e liquids.
A Enclosed
— entire
space
Division 1 NC Hand
FE;
CGD if
enclos
ed in
buildin
g
b B Enclosed
— entire
space
Division 2 NC, LC, or
LFS
Hand
FE;
CGD if
enclos
ed in
buildin
g
c Not
enclosed,
open to
atmosphe
re
Within a 3
m (10 ft)
envelope
around
equipment
and open
channelc
Division 2 NC, LC, or
LFS
H and
FE
6 a SCUM-PUMPING
AREAS Pumping of
scum, dry side of
pumping station
Buildup of
vapors
from
flammable
and
combustibl
e liquids.
D Enclosed
space
Division 2 NC, LC, or
LFS
H and
FE
b C Enclosed
space
Unclassifi
ed
NC, LC, or
LFS
H and
FE
c Not
enclosed,
open to
atmosphe
re
NA Unclassifi
ed
NC, LC, or
LFS
H and
FE
Ro
wa
Lin
ea Location and Function
Fire and
Explosion
Hazard
Ventilatio
nb,c,d
Extent of
Classified
Area
NEC-Area
Electrical
Classifica
tion (All
Class I,
Group D)d
MaterialMat
erials of
Constructio
n for
Buildings or
Structurese
Fire
Protect
ion
Measur
es
7 SCUM
INCINERATORSeINCIN
ERATORSf Elimination of
scum through burning
Firebox
explosion
from
possible
carryover
of
flammable
scum
NR Incinerator
area if
separated
from scum
storage
Unclassifi
ed
NC, LC, or
LFS
FSS (if
indoor
s), H,
and FE
8 a SLUDGE THICKENER
(CLARIFIER) Sludge
concentration and
removal, gravity, or
dissolved air flotation
Possible
generation
of
methane
from
sludge;
carryover
of floating
flammable
liquids
A Enclosed
— entire
space
Division 1 NC Hand
FE;CG
D if
enclos
ed in
buildin
g
b B Enclosed
— entire
space
Division 2 NC, LC, or
LFS
Hand
FE;
CGD if
enclos
ed in
buildin
g
c Not
enclosed,
open to
atmosphe
re
Envelope
0.46 m (18
in.) above
water
surface
and .
3 m (10 ft)
horizontall
y from
wetted
wallsc
H and
FE
9 a SLUDGE PUMPING
STATION DRY WELLS .
Buildup of
methane
gas or
D Entire dry
well when
physically
Division 2 NC, LC, or
LFS
H and
FE
Ro
wa
Lin
ea Location and Function
Fire and
Explosion
Hazard
Ventilatio
nb,c,d
Extent of
Classified
Area
NEC-Area
Electrical
Classifica
tion (All
Class I,
Group D)d
MaterialMat
erials of
Constructio
n for
Buildings or
Structurese
Fire
Protect
ion
Measur
es
Dry side of a sludge
pumping station
flammable
vapors
separated
from a wet
well or
separate
structures
b C Entire dry
well when
physically
separated
from a wet
well or
separate
structures
Unclassifi
ed
NC, LC, or
LFS
H and
FE
10 a SLUDGE STORAGE
WET WELLS, PITS,
AND HOLDING TANKS .
Retaining of sludge
Possible
generation
of
methane
gas in
explosive
concentrat
ions;
carryover
of floating
flammable
liquids
A Enclosed
— entire
space
Division 1 NC CGD,
H, and
FE if
tank
enclos
ed in
buildin
g
b B Enclosed
— entire
space
Division 2 NC, LC, or
LFS
CGD,
H, and
FE if
tank
enclos
ed in
buildin
g
c Not
enclosed,
open to
atmosphe
re
Envelope
0.46 m (18
in.) above
water
surface
and .
Division 2 NC, LC, or
LFS
NR
Ro
wa
Lin
ea Location and Function
Fire and
Explosion
Hazard
Ventilatio
nb,c,d
Extent of
Classified
Area
NEC-Area
Electrical
Classifica
tion (All
Class I,
Group D)d
MaterialMat
erials of
Constructio
n for
Buildings or
Structurese
Fire
Protect
ion
Measur
es
3 m (10 ft)
horizontall
y from
wetted
wallsc
11 a SLUDGE-BLENDING
TANKS AND HOLDING
WELLS .
Retaining of sludge with
some agitation
Possible
generation
of
methane
gas in
explosive
concentrat
ions;
carryover
of floating
flammable
liquids
A Enclosed
— entire
space
Division 1 NC H, FE,
and
CGD if
tank
enclos
ed in
buildin
g
b B Enclosed
— entire
space
Division 2 NC, LC, or
LFS
H, FE,
and
CGD if
tank
enclos
ed in
buildin
g
c Not
enclosed,
open to
atmosphe
re
Envelope
0.46 m (18
in.) above
water
surface
and .
3 m (10 ft)
horizontall
y from
wetted
wallsc
Division 2 NC, LC, or
LFS
NR
12 a DEWATERING
BUILDINGS
CONTAINING
Accumulat
ion of
C Entire
room
Unclassifi
ed
NC, LC, or
LFS
H, FE,
and
FAS
Ro
wa
Lin
ea Location and Function
Fire and
Explosion
Hazard
Ventilatio
nb,c,d
Extent of
Classified
Area
NEC-Area
Electrical
Classifica
tion (All
Class I,
Group D)d
MaterialMat
erials of
Constructio
n for
Buildings or
Structurese
Fire
Protect
ion
Measur
es
b CENTRIFUGES,
GRAVITY BELT
THICKENERS, BELT
AND VACUUM
FILTERS, AND FILTER
PRESSES .
Removal of water from
sludge and the
conveyance of sludge
cake
methane
gas
D Entire
room
Division 2 NC, LC, or
LFS
H, FE,
and
FAS
13 a ENCLOSED SLUDGE
CAKE STORAGE
Storage of dewatered
sludge cake and
conveyance of sludge
cake
Accumulat
ion of
methane
gas
C Entire
room
Unclassifi
ed
NC, LC, or
LFS
H, FE,
and
FAS
b D Entire
room
Division 2 NC, LC, or
LFS
H, FE,
and
FAS
14 INCINERATORSeINCIN
ERATORS f AND INCINERATOR
BUILDINGS .
Conveying and burning
of sludge cake
Firebox
explosion
NR NA Unclassifi
ed
NC, LC, or
LFS
FSS (if
indoor
s), H,
and FE
15 HEAT TREATMENT
UNITS, LOW- OR HIGH-
PRESSURE
OXIDATION UNITS .
Closed oxidation of
sludge
None,
other than
in high-
pressure
systems
NR NA Unclassifi
ed
NC, LC, or
LFS
H and
FE
16 a ANAEROBIC
DIGESTERS, BOTH
FIXED ROOF AND
FLOATING COVER
Generation of sludge gas
from digesting sludge
Leakage
of gas
from
cover,
piping,
emergenc
y relief
Not
enclosed,
open to
atmosphe
re
Tank
interior;
areas
above and
around
digester
cover;
Division 1 NC H and
FE
Ro
wa
Lin
ea Location and Function
Fire and
Explosion
Hazard
Ventilatio
nb,c,d
Extent of
Classified
Area
NEC-Area
Electrical
Classifica
tion (All
Class I,
Group D)d
MaterialMat
erials of
Constructio
n for
Buildings or
Structurese
Fire
Protect
ion
Measur
es
valves,
and
appurtena
nces
envelope 3
m (10 ft)
above the
highest
point of
cover,
when
cover is at
its
maximum
elevation,
and 1.5 m
(5 ft) from
any wall
b Not
enclosed,
open to
atmosphe
re
Envelope .
4.6 m (15
ft) above
Division 1
area over
cover and
1.5 m (5 ft)
beyond
Division 1
area
around
tank walls
Division 2 NC H and
FE
c A For
digester
tanks
enclosed
in a
building:
tank
interior;
entire area
inside
building
Division 1 NC CGD if
enclos
ed in
buildin
g
Ro
wa
Lin
ea Location and Function
Fire and
Explosion
Hazard
Ventilatio
nb,c,d
Extent of
Classified
Area
NEC-Area
Electrical
Classifica
tion (All
Class I,
Group D)d
MaterialMat
erials of
Constructio
n for
Buildings or
Structurese
Fire
Protect
ion
Measur
es
d B For
digester
tanks
enclosed
in a
building:
tank
interior;
areas
above and
around
digester
cover;
envelope 3
m (10 ft)
above
highest
point of
cover,
when
cover is at
its
maximum
elevation,
and 1.5 m
(5 ft) from
any wall of
digester
tank
Division 1 NC CGD if
enclos
ed in
buildin
g
e B Remaining
space in
enclosed
area
Division 2 NC, LC, or
LFS
CGD if
enclos
ed in
buildin
g
17 a ANAEROBIC
DIGESTER CONTROL
BUILDING
Leaking
and
A Entire
building
Division 1 NC CGD,
H, and
FE
Ro
wa
Lin
ea Location and Function
Fire and
Explosion
Hazard
Ventilatio
nb,c,d
Extent of
Classified
Area
NEC-Area
Electrical
Classifica
tion (All
Class I,
Group D)d
MaterialMat
erials of
Constructio
n for
Buildings or
Structurese
Fire
Protect
ion
Measur
es
b .
Storage, handling, or
burning of sludge gas
ignition of
sludge gas
B Enclosed
areas that
contain
gas-
handling
equipment
Division 2 NC, LC, or
LFS
CGD,
H, and
FE
c C Physically
separated
from gas-
handling
equipment
Unclassifi
ed
NC, LC, or
LFS
CGD,
H, and
FE
18 a DIGESTER GAS-
PROCESSING ROOMS
Gas compression,
handling, and processing
Sludge
gas
ignition
A Entire
room
Division 1 NC CGD,
H, and
FE
b B Within 1.5
m (5 ft) of
equipment
Division 1 NC, LC, or
LFS
CGD,
H, and
FE
c B Entire
room
Division 2 NC, LC, or
LFS
CGD,
H, and
FE
19 ANAEROBIC
DIGESTER GAS
STORAGE .
Storage of sludge gas
Gas
storage
piping and
handling
NNV Within a 3
m (10 ft)
envelope
of tanks,
valves,
and
appurtena
nces
Division 1 NC, LC, or
LFS
Hand
FE;
CGD if
enclos
ed in
buildin
g
20 a WASTE .
GAS .
BURNERS .
Combusting excess gas
Gas piping
and
appurtena
nces
NA Within 3 m
(10 ft)
envelope
of all
fixtures,
appurtena
Division 1 NC NR
Ro
wa
Lin
ea Location and Function
Fire and
Explosion
Hazard
Ventilatio
nb,c,d
Extent of
Classified
Area
NEC-Area
Electrical
Classifica
tion (All
Class I,
Group D)d
MaterialMat
erials of
Constructio
n for
Buildings or
Structurese
Fire
Protect
ion
Measur
es
nces, and
housing
b Envelope .
4.6 m (15
ft) above
Division 1
envelope
and 1.5 m
(5 ft) on all
sides
Division 2 NC NR
21 CHLORINE OXIDATION
UNITS .
Chlorine reaction with
sludge
Chlorine is
a very
strong
oxidizing
agent
NR NA Unclassifi
ed
NR (These
unit
processes
use
corrosive
chemicals
that require
the use of
specific
materials of
construction
. Special
consideratio
n shall be
given to
such
materials of
construction
.)
H and
FE
22 a UNDERGROUND
(PIPING) TUNNELS
CONTAINING NATURAL
GAS PIPING OR
SLUDGE GAS PIPING
Ignition of
natural
gas or
sludge
gases
D Within 3 m
(10 ft) of
valves and
appurtena
nces
Division 1 NC, LC, or
LFS
CGD,
FDS,
and FE
Ro
wa
Lin
ea Location and Function
Fire and
Explosion
Hazard
Ventilatio
nb,c,d
Extent of
Classified
Area
NEC-Area
Electrical
Classifica
tion (All
Class I,
Group D)d
MaterialMat
erials of
Constructio
n for
Buildings or
Structurese
Fire
Protect
ion
Measur
es
b .
Transmission of gas,
sludge, water, air, and
steam via piping; also
might contain power
cable and conduit
D Entire
tunnel
Division 2 NC, LC, or
LFS
CGD,
FDS,
and FE
c C Areas
within 3 m
(10 ft) of
valves,
meters,
gas check
valves,
condensat
e traps,
and other
piping
appurtena
nces
Division 2 NC, LC, or
LFS
CGD,
FDS,
and FE
d C Areas
beyond 3
m (10 ft)
Unclassifi
ed
NC, LC, or
LFS
CGD,
FDS,
and FE
23 UNDERGROUND
(PIPING) TUNNELS
NOT CONTAINING
NATURAL GAS PIPING
OR SLUDGE GAS
PIPING Transmission of
sludge, water, air, and
steam piping; also might
contain power cable and
conduit
NA NR NA Unclassifi
ed
NC, LC, or
LFS
FDS
and FE
24 a COMPOSTING PILES .
Aerobic sludge reduction
Liberation
of
ammonia
and toxic
gas
(composti
ng
D Enclosed
area
Division 2 NC, LC, or
LFS
H and
FDS
b C Enclosed
area
Unclassifi
ed
NC, LC, or
LFS
H and
FDS
Ro
wa
Lin
ea Location and Function
Fire and
Explosion
Hazard
Ventilatio
nb,c,d
Extent of
Classified
Area
NEC-Area
Electrical
Classifica
tion (All
Class I,
Group D)d
MaterialMat
erials of
Constructio
n for
Buildings or
Structurese
Fire
Protect
ion
Measur
es
materials
can self-
ignite)
25 a IN-VESSEL
COMPOSTING Aerobic
sludge reduction
Liberation
of
ammonia
and toxic
gas
(composti
ng
materials
can self-
ignite)
As
required
by
process
If
enclosed,
interior of
reactor
vessel
plus a 3 m
(10 ft)
envelope
around
reactor
vessel
Division 2 NC H and
FDS
b As
required
by
process
Areas
beyond 3
m (10 ft)
Unclassifi
ed
NC H and
FDS
26 ODOR-CONTROL AND
VENTILATION
SYSTEMSSERVING
CLASSIFIED AREAS (
(See "Collection
Systems," Table 4.2)
27 PUMPING OF
DRAINAGE FROM
DIGESTED SLUDGE- .
DEWATERING
PROCESSES Pumping
of centrate, filtrate,
leachate, drying beds,
and so forth
NA NR NA Unclassifi
ed
NC, LC, or
LFS
H
Note: The following codes are used in this table:
A: No ventilation or ventilated at less than 12 air changes per hour.
B: Continuously ventilated at 12 air changes per hour in accordance with Chapter 9.
C: Continuously ventilated at 6 air changes per hour in accordance with Chapter 9.
CGD: Combustible gas detection system.
D: No ventilation or ventilated at less than 6 air changes per hour.
FAS: Fire alarm system.
FDS: Fire detection system.
FE: Portable fire extinguisher.
FSS: Fire suppression system (e.g., automatic sprinkler, water spray, foam, gaseous, or dry
chemical).
H: Hydrant protection in accordance with 7.2.4.
LC: Limited-combustible material.
LFS: Low flame spread index material.
NA: Not applicable.
NC: Noncombustible material.
NEC: In accordance with NFPA 70.
NNV: Not normally ventilated.
NR: No requirement.
aThe “Row” and “Line” columns are used to refer to specific figures in A.6.2 and specific
requirements for each location and function.
bThe NR designation in the "Ventilation"b This column indicates that nothe ventilation requirements
for processes. Additional ventilation requirements are established for the space,provided in
Chapter 9. Ventilation signaling and, therefore, Table 9.1.1.4 also has no alarm requirements. are
provided in Chapter 7.
cThe area beyond the envelope is unclassified.
dThese unit processes use corrosive chemicals that can have a deteriorating effect on conductors
and equipment. Electrical equipment shall be identified for use in the operating environment. eSee e This column indicates the materials of construction for processes. Materials of construction for
buildings in which these processes are housed are in accordance with the applicable building code
and construction requirements provided in Chapter 8.
f See NFPA 54, NFPA 82, and NFPA 85.
Table 6.2(b) Solids Treatment Processes — Sludge Drying
Ro
w
Lin
e Location and Function
Fire and
Explosi
on
Hazard
Ventilationa,b
Extent of
Classified
Area
NEC-Area
Electrical
Classificati
on (All
Class II,
Group G)c
Material of
Constructi
on for
Buildings
or
Structuresd
Fire
Protecti
on
Measure
s
1 a SLUDGE- DRYING
PROCESSESdPROCES
SESe
Potentia
l for
ignition
of dust
NR If
exposed
to
combustib
le
particulat
e solids,
entire
roomeroo
mf
Division 1 NC
(Constructi
on in
accordanc
e with
NFPA 30,
NFPA 68,
NFPA 69,
NFPA 499,
and NFPA
654)
H, FAS,
and
FSS
(See
NFPA
30,
NFPA
61,
NFPA
69,
NFPA
85,
NFPA
499,
and
NFPA
654)
b NR Areas
within
equipmen
t
processin
g
combustib
le
particulat
e solids
Division 1 NC
(Constructi
on in
accordanc
e with
NFPA 30,
NFPA 68,
NFPA 69,
NFPA 499,
and NFPA
654)
H, FAS,
and
FSS
(See
NFPA
30,
NFPA
61,
NFPA
69,
NFPA
85,
NFPA
499,
and
NFPA
654)
c NR Areas
within 3 m
(10 ft) of
Division 2 NC
(Constructi
on in
H, FAS,
and
FSS
Ro
w
Lin
e Location and Function
Fire and
Explosi
on
Hazard
Ventilationa,b
Extent of
Classified
Area
NEC-Area
Electrical
Classificati
on (All
Class II,
Group G)c
Material of
Constructi
on for
Buildings
or
Structuresd
Fire
Protecti
on
Measure
s
equipmen
t
processin
g
combustib
le
particulat
e solids
accordanc
e with
NFPA 30,
NFPA 68,
NFPA 69,
NFPA 499,
and NFPA
654)
(See
NFPA
30,
NFPA
61,
NFPA
69,
NFPA
85,
NFPA
499,
and
NFPA
654)
d NR Areas
beyond 3
m (10 ft)
of
equipmen
t
processin
g
combustib
le
particulat
e solids
Unclassifie
d
NC
(Constructi
on in
accordanc
e with
NFPA 30,
NFPA 68,
NFPA 69,
NFPA 499,
and NFPA
654)
H, FAS,
and
FSS
(See
NFPA
30,
NFPA
61,
NFPA
69,
NFPA
85,
NFPA
499,
and
NFPA
654)
2 a DRIED SLUDGE
STORAGE AREAS, IF
ENCLOSED
Potentia
l for
ignition
of dust
NR If
exposed
to dried
sludge,
entire
roome
Division 1 NC
(Constructi
on in
accordanc
e with
NFPA 68
H, FAS
(See
NFPA
61,
NFPA
69,
Ro
w
Lin
e Location and Function
Fire and
Explosi
on
Hazard
Ventilationa,b
Extent of
Classified
Area
NEC-Area
Electrical
Classificati
on (All
Class II,
Group G)c
Material of
Constructi
on for
Buildings
or
Structuresd
Fire
Protecti
on
Measure
s
and NFPA
69, NFPA
499, and
NFPA 654)
NFPA
497,
and
NPFA
654)
b NR Areas
within
tanks
storing
dried
sludge
Division 1 NC
(Constructi
on in
accordanc
e with
NFPA 68,
NFPA 69,
NFPA 499,
and NFPA
654)
H and
FAS
(See
NFPA
61,
NFPA
69,
NFPA
497,
and
NFPA
654)
c NR Areas
within 3 m
(10 ft) of
tanks
storing
dried
sludge
Division 2 NC
(Constructi
on in
accordanc
e with
NFPA 68,
NFPA 69,
NFPA 499,
and NFPA
654)
H and
FAS
(See
NFPA
61,
NFPA
69,
NFPA
497,
and
NFPA
654)
d NR Areas
beyond 3
m (10 ft)
of tanks
storing
dried
sludge
Unclassifie
d
NC
(Constructi
on in
accordanc
e with
NFPA 68,
NFPA 69,
NFPA 499,
H and
FAS
(See
NFPA
61,
NFPA
69,
NFPA
Ro
w
Lin
e Location and Function
Fire and
Explosi
on
Hazard
Ventilationa,b
Extent of
Classified
Area
NEC-Area
Electrical
Classificati
on (All
Class II,
Group G)c
Material of
Constructi
on for
Buildings
or
Structuresd
Fire
Protecti
on
Measure
s
and NFPA
654)
497,
and
NFPA
654)
Note: The following codes are used in this table:
FAS: Fire alarm system.
FSS: Fire suppression system (e.g., automatic sprinkler, water spray, foam, gaseous, or dry
chemical).
H: Hydrant protection in accordance with 7.2.4.
NC: Noncombustible material.
NEC: In accordance with NFPA 70.
NR: No requirement.
aThe NR designation in the “Ventilation”a This column indicates that nothe ventilation requirements
for processes. Additional ventilation requirements are established for the space,provided in
Chapter 9. Ventilation signaling and, therefore, Table 9.1.1.4 also has no alarm requirements. are
provided in Chapter 7.
bFor sludge-drying processes that use flammable or combustible liquids, ventilate in accordance
with NFPA 30.
cOr if acceptable to the authority having jurisdiction with classification in NFPA 499. dSeed This column indicates the materials of construction for processes. Materials of construction
for buildings in which these processes are housed are in accordance with the applicable building
code and construction requirements provided in Chapter 8.
eSee NFPA 54, NFPA 85, NFPA 499, and NFPA 654. For sludge-drying processes that use
flammable or combustible liquids, see NFPA 30.
eThefThe area beyond the envelope is unclassified.
Chapter 6 Solids Treatment Processes
6.1* General.
6.1.1
This chapter shall establish minimum criteria for protection against fire and explosion hazards
associated with solids treatment processes.
6.1.2
This chapter shall not apply to the treatment of solids from industrial waste treatment processes.
6.2* Design and Construction.
6.2.1The design and construction of solids treatment processes associated with wastewater solids
treatment shall conform to Table 6.2(a) and Table 6.2(b).
6.2.2 The design and construction of buildings and structures containing solids treatment processes
associated with wastewater solids treatment shall comply with the applicable building code and the
additional requirements of Chapters 7-9.
Table 6.2(a) Solids Treatment Processes
Rowa
Linea
Location and
Function
Fire and
Explosion
Hazard
Ventilationb
,c,d
Extent of
Classified
Area
NEC-Area
Electrical
Classificati
on (All
Class I,
Group D)d
Materials
of
Constructi
on e
Fire
Protecti
on
Measure
s
1 COARSE AND
FINE
SCREENINGS- .
HANDLING
BUILDINGS .
Storage,
conveying, or
dewatering of
screenings (no
exposed flow of
wastewater
through building
or area)
NA NR NA Unclassifie
d
NC, LC, or
LFS
H, FE,
and
FAS
2 GRIT-
HANDLING
BUILDING .
NA NR NA Unclassifie
d
NC, LC, or
LFS
H, FE,
and
FAS
Rowa
Linea
Location and
Function
Fire and
Explosion
Hazard
Ventilationb
,c,d
Extent of
Classified
Area
NEC-Area
Electrical
Classificati
on (All
Class I,
Group D)d
Materials
of
Constructi
on e
Fire
Protecti
on
Measure
s
Storage,
conveying, and
dewatering of
heavy small
screenings and
grit (no exposed
flow of
wastewater
through building
or area)
3 a SCUM-
HANDLING
BUILDING OR
AREA Holding,
dewatering, or
storage
Possible
grease or
flammable
liquids
carryover
A Enclosed
space
Division 2 NC, LC, or
LFS
H and
FE;CG
D if
enclose
d in
building
b B Enclosed
space
Unclassifie
d
NC, LC, or
LFS
H and
FE;
CGD if
enclose
d in
building
c Not
enclosed,
open to
atmospher
e
NA Unclassifie
d
NC, LC, or
LFS
H and
FE
4 a SCUM PITS Buildup of
vapors from
flammable
or
combustible
liquids
A Enclosed—
entire space
Division 1 NC Hand
FE;CG
D if
enclose
d in
building
b B Enclosed—
entire space
Division 2 NC, LC, or
LFS
H and
FE;
CGD if
Rowa
Linea
Location and
Function
Fire and
Explosion
Hazard
Ventilationb
,c,d
Extent of
Classified
Area
NEC-Area
Electrical
Classificati
on (All
Class I,
Group D)d
Materials
of
Constructi
on e
Fire
Protecti
on
Measure
s
enclose
d in
building
c Not
enclosed,
open to
atmospher
e
Within a 3 m
(10 ft)
envelope
around
equipment
and open
channelc
Division 2 NC, LC, or
LFS
H and
FE
5 a SCUM-
PUMPING
AREAS Pumping
of scum, wet side
of pumping
station
Buildup of
vapors from
flammable
or
combustible
liquids.
A Enclosed—
entire space
Division 1 NC Hand
FE;
CGD if
enclose
d in
building
b B Enclosed—
entire space
Division 2 NC, LC, or
LFS
Hand
FE;
CGD if
enclose
d in
building
c Not
enclosed,
open to
atmospher
e
Within a 3 m
(10 ft)
envelope
around
equipment
and open
channelc
Division 2 NC, LC, or
LFS
H and
FE
6 a SCUM-
PUMPING
AREAS Pumping
of scum, dry side
of pumping
station
Buildup of
vapors from
flammable
and
combustible
liquids.
D Enclosed
space
Division 2 NC, LC, or
LFS
H and
FE
b C Enclosed
space
Unclassifie
d
NC, LC, or
LFS
H and
FE
c Not
enclosed,
NA Unclassifie
d
NC, LC, or
LFS
H and
FE
Rowa
Linea
Location and
Function
Fire and
Explosion
Hazard
Ventilationb
,c,d
Extent of
Classified
Area
NEC-Area
Electrical
Classificati
on (All
Class I,
Group D)d
Materials
of
Constructi
on e
Fire
Protecti
on
Measure
s
open to
atmospher
e
7 SCUM
INCINERATORSf Elimination of
scum through
burning
Firebox
explosion
from
possible
carryover of
flammable
scum
NR Incinerator
area if
separated
from scum
storage
Unclassifie
d
NC, LC, or
LFS
FSS (if
indoors)
, H, and
FE
8 a SLUDGE
THICKENER
(CLARIFIER)
Sludge
concentration
and removal,
gravity, or
dissolved air
flotation
Possible
generation
of methane
from sludge;
carryover of
floating
flammable
liquids
A Enclosed—
entire space
Division 1 NC Hand
FE;CG
D if
enclose
d in
building
b B Enclosed—
entire space
Division 2 NC, LC, or
LFS
Hand
FE;
CGD if
enclose
d in
building
c Not
enclosed,
open to
atmospher
e
Envelope
0.46 m (18
in.) above
water
surface and .
3 m (10 ft)
horizontally
from wetted
wallsc
H and
FE
9 a SLUDGE
PUMPING
STATION DRY
WELLS
Buildup of
methane
gas or
D Entire dry
well when
physically
separated
Division 2 NC, LC, or
LFS
H and
FE
Rowa
Linea
Location and
Function
Fire and
Explosion
Hazard
Ventilationb
,c,d
Extent of
Classified
Area
NEC-Area
Electrical
Classificati
on (All
Class I,
Group D)d
Materials
of
Constructi
on e
Fire
Protecti
on
Measure
s
.
Dry side of a
sludge pumping
station
flammable
vapors
from a wet
well or
separate
structures
b C Entire dry
well when
physically
separated
from a wet
well or
separate
structures
Unclassifie
d
NC, LC, or
LFS
H and
FE
10 a SLUDGE
STORAGE WET
WELLS, PITS,
AND HOLDING
TANKS .
Retaining of
sludge
Possible
generation
of methane
gas in
explosive
concentratio
ns;
carryover of
floating
flammable
liquids
A Enclosed—
entire space
Division 1 NC CGD,
H, and
FE if
tank
enclose
d in
building
b B Enclosed—
entire space
Division 2 NC, LC, or
LFS
CGD,
H, and
FE if
tank
enclose
d in
building
c Not
enclosed,
open to
atmospher
e
Envelope
0.46 m (18
in.) above
water
surface and .
3 m (10 ft)
horizontally
from wetted
wallsc
Division 2 NC, LC, or
LFS
NR
Rowa
Linea
Location and
Function
Fire and
Explosion
Hazard
Ventilationb
,c,d
Extent of
Classified
Area
NEC-Area
Electrical
Classificati
on (All
Class I,
Group D)d
Materials
of
Constructi
on e
Fire
Protecti
on
Measure
s
11 a SLUDGE-
BLENDING
TANKS AND
HOLDING
WELLS .
Retaining of
sludge with some
agitation
Possible
generation
of methane
gas in
explosive
concentratio
ns;
carryover of
floating
flammable
liquids
A Enclosed—
entire space
Division 1 NC H, FE,
and
CGD if
tank
enclose
d in
building
b B Enclosed—
entire space
Division 2 NC, LC, or
LFS
H, FE,
and
CGD if
tank
enclose
d in
building
c Not
enclosed,
open to
atmospher
e
Envelope
0.46 m (18
in.) above
water
surface and .
3 m (10 ft)
horizontally
from wetted
wallsc
Division 2 NC, LC, or
LFS
NR
12 a DEWATERING
BUILDINGS
CONTAINING
CENTRIFUGES,
GRAVITY BELT
THICKENERS,
BELT AND
VACUUM
FILTERS, AND
FILTER
PRESSES .
Removal of
water from
Accumulatio
n of
methane
gas
C Entire room Unclassifie
d
NC, LC, or
LFS
H, FE,
and
FAS
b D Entire room Division 2 NC, LC, or
LFS
H, FE,
and
FAS
Rowa
Linea
Location and
Function
Fire and
Explosion
Hazard
Ventilationb
,c,d
Extent of
Classified
Area
NEC-Area
Electrical
Classificati
on (All
Class I,
Group D)d
Materials
of
Constructi
on e
Fire
Protecti
on
Measure
s
sludge and the
conveyance of
sludge cake
13 a ENCLOSED
SLUDGE CAKE
STORAGE
Storage of
dewatered
sludge cake and
conveyance of
sludge cake
Accumulatio
n of
methane
gas
C Entire room Unclassifie
d
NC, LC, or
LFS
H, FE,
and
FAS
b D Entire room Division 2 NC, LC, or
LFS
H, FE,
and
FAS
14 INCINERATORS f AND
INCINERATOR
BUILDINGS .
Conveying and
burning of sludge
cake
Firebox
explosion
NR NA Unclassifie
d
NC, LC, or
LFS
FSS (if
indoors)
, H, and
FE
15 HEAT
TREATMENT
UNITS, LOW-
OR HIGH-
PRESSURE
OXIDATION
UNITS .
Closed oxidation
of sludge
None, other
than in high-
pressure
systems
NR NA Unclassifie
d
NC, LC, or
LFS
H and
FE
16 a ANAEROBIC
DIGESTERS,
BOTH FIXED
ROOF AND
FLOATING
COVER
Generation of
sludge gas from
digesting sludge
Leakage of
gas from
cover,
piping,
emergency
relief valves,
and
appurtenanc
es
Not
enclosed,
open to
atmospher
e
Tank
interior;
areas above
and around
digester
cover;
envelope 3
m (10 ft)
above the
Division 1 NC H and
FE
Rowa
Linea
Location and
Function
Fire and
Explosion
Hazard
Ventilationb
,c,d
Extent of
Classified
Area
NEC-Area
Electrical
Classificati
on (All
Class I,
Group D)d
Materials
of
Constructi
on e
Fire
Protecti
on
Measure
s
highest point
of cover,
when cover
is at its
maximum
elevation,
and 1.5 m (5
ft) from any
wall
b Not
enclosed,
open to
atmospher
e
Envelope .
4.6 m (15 ft)
above
Division 1
area over
cover and
1.5 m (5 ft)
beyond
Division 1
area around
tank walls
Division 2 NC H and
FE
c A For digester
tanks
enclosed in
a building:
tank interior;
entire area
inside
building
Division 1 NC CGD if
enclose
d in
building
d B For digester
tanks
enclosed in
a building:
tank interior;
areas above
and around
digester
Division 1 NC CGD if
enclose
d in
building
Rowa
Linea
Location and
Function
Fire and
Explosion
Hazard
Ventilationb
,c,d
Extent of
Classified
Area
NEC-Area
Electrical
Classificati
on (All
Class I,
Group D)d
Materials
of
Constructi
on e
Fire
Protecti
on
Measure
s
cover;
envelope 3
m (10 ft)
above
highest point
of cover,
when cover
is at its
maximum
elevation,
and 1.5 m (5
ft) from any
wall of
digester tank
e B Remaining
space in
enclosed
area
Division 2 NC, LC, or
LFS
CGD if
enclose
d in
building
17 a ANAEROBIC
DIGESTER
CONTROL
BUILDING .
Storage,
handling, or
burning of sludge
gas
Leaking and
ignition of
sludge gas
A Entire
building
Division 1 NC CGD,
H, and
FE
b B Enclosed
areas that
contain gas-
handling
equipment
Division 2 NC, LC, or
LFS
CGD,
H, and
FE
c C Physically
separated
from gas-
handling
equipment
Unclassifie
d
NC, LC, or
LFS
CGD,
H, and
FE
18 a DIGESTER
GAS-
PROCESSING
Sludge gas
ignition
A Entire room Division 1 NC CGD,
H, and
FE
Rowa
Linea
Location and
Function
Fire and
Explosion
Hazard
Ventilationb
,c,d
Extent of
Classified
Area
NEC-Area
Electrical
Classificati
on (All
Class I,
Group D)d
Materials
of
Constructi
on e
Fire
Protecti
on
Measure
s
b ROOMS Gas
compression,
handling, and
processing
B Within 1.5 m
(5 ft) of
equipment
Division 1 NC, LC, or
LFS
CGD,
H, and
FE
c B Entire room Division 2 NC, LC, or
LFS
CGD,
H, and
FE
19 ANAEROBIC
DIGESTER GAS
STORAGE .
Storage of
sludge gas
Gas storage
piping and
handling
NNV Within a 3 m
(10 ft)
envelope of
tanks,
valves, and
appurtenanc
es
Division 1 NC, LC, or
LFS
Hand
FE;
CGD if
enclose
d in
building
20 a WASTE .
GAS .
BURNERS .
Combusting
excess gas
Gas piping
and
appurtenanc
es
NA Within 3 m
(10 ft)
envelope of
all fixtures,
appurtenanc
es, and
housing
Division 1 NC NR
b Envelope .
4.6 m (15 ft)
above
Division 1
envelope
and 1.5 m (5
ft) on all
sides
Division 2 NC NR
21 CHLORINE
OXIDATION
UNITS .
Chlorine reaction
with sludge
Chlorine is a
very strong
oxidizing
agent
NR NA Unclassifie
d
NR (These
unit
processes
use
corrosive
chemicals
that
require the
H and
FE
Rowa
Linea
Location and
Function
Fire and
Explosion
Hazard
Ventilationb
,c,d
Extent of
Classified
Area
NEC-Area
Electrical
Classificati
on (All
Class I,
Group D)d
Materials
of
Constructi
on e
Fire
Protecti
on
Measure
s
use of
specific
materials
of
constructio
n. Special
considerati
on shall be
given to
such
materials
of
constructio
n.)
22 a UNDERGROUN
D (PIPING)
TUNNELS
CONTAINING
NATURAL GAS
PIPING OR
SLUDGE GAS
PIPING .
Transmission of
gas, sludge,
water, air, and
steam via piping;
also might
contain power
cable and
conduit
Ignition of
natural gas
or sludge
gases
D Within 3 m
(10 ft) of
valves and
appurtenanc
es
Division 1 NC, LC, or
LFS
CGD,
FDS,
and FE
b D Entire tunnel Division 2 NC, LC, or
LFS
CGD,
FDS,
and FE
c C Areas within
3 m (10 ft) of
valves,
meters, gas
check
valves,
condensate
traps, and
other piping
appurtenanc
es
Division 2 NC, LC, or
LFS
CGD,
FDS,
and FE
d C Areas
beyond 3 m
(10 ft)
Unclassifie
d
NC, LC, or
LFS
CGD,
FDS,
and FE
Rowa
Linea
Location and
Function
Fire and
Explosion
Hazard
Ventilationb
,c,d
Extent of
Classified
Area
NEC-Area
Electrical
Classificati
on (All
Class I,
Group D)d
Materials
of
Constructi
on e
Fire
Protecti
on
Measure
s
23 UNDERGROUN
D (PIPING)
TUNNELS NOT
CONTAINING
NATURAL GAS
PIPING OR
SLUDGE GAS
PIPING
Transmission of
sludge, water,
air, and steam
piping; also
might contain
power cable and
conduit
NA NR NA Unclassifie
d
NC, LC, or
LFS
FDS
and FE
24 a COMPOSTING
PILES .
Aerobic sludge
reduction
Liberation of
ammonia
and toxic
gas
(composting
materials
can self-
ignite)
D Enclosed
area
Division 2 NC, LC, or
LFS
H and
FDS
b C Enclosed
area
Unclassifie
d
NC, LC, or
LFS
H and
FDS
25 a IN-VESSEL
COMPOSTING
Aerobic sludge
reduction
Liberation of
ammonia
and toxic
gas
(composting
materials
can self-
ignite)
As required
by process
If enclosed,
interior of
reactor
vessel plus
a 3 m (10 ft)
envelope
around
reactor
vessel
Division 2 NC H and
FDS
b As required
by process
Areas
beyond 3 m
(10 ft)
Unclassifie
d
NC H and
FDS
26
Rowa
Linea
Location and
Function
Fire and
Explosion
Hazard
Ventilationb
,c,d
Extent of
Classified
Area
NEC-Area
Electrical
Classificati
on (All
Class I,
Group D)d
Materials
of
Constructi
on e
Fire
Protecti
on
Measure
s
ODOR-
CONTROL AND
VENTILATION
SYSTEMSSERV
ING
CLASSIFIED
AREAS ( (See
"Collection
Systems," Table
4.2)
27 PUMPING OF
DRAINAGE
FROM
DIGESTED
SLUDGE- .
DEWATERING
PROCESSES
Pumping of
centrate, filtrate,
leachate, drying
beds, and so
forth
NA NR NA Unclassifie
d
NC, LC, or
LFS
H
Note: The following codes are used in this table:
A: No ventilation or ventilated at less than 12 air changes per hour.
B: Continuously ventilated at 12 air changes per hour in accordance with Chapter 9.
C: Continuously ventilated at 6 air changes per hour in accordance with Chapter 9.
CGD: Combustible gas detection system.
D: No ventilation or ventilated at less than 6 air changes per hour.
FAS: Fire alarm system.
FDS: Fire detection system.
FE: Portable fire extinguisher.
FSS: Fire suppression system (e.g., automatic sprinkler, water spray, foam, gaseous, or dry
chemical).
H: Hydrant protection in accordance with 7.2.4.
LC: Limited-combustible material.
LFS: Low flame spread index material.
NA: Not applicable.
NC: Noncombustible material.
NEC: In accordance with NFPA 70.
NNV: Not normally ventilated.
NR: No requirement.
aThe “Row” and “Line” columns are used to refer to specific figures in A.6.2 and specific
requirements for each location and function.
b This column indicates the ventilation requirements for processes. Additional ventilation
requirements are provided in Chapter 9. Ventilation signaling and alarm requirements are provided
in Chapter 7.
cThe area beyond the envelope is unclassified.
dThese unit processes use corrosive chemicals that can have a deteriorating effect on conductors
and equipment. Electrical equipment shall be identified for use in the operating environment.
e This column indicates the materials of construction for processes. Materials of construction for
buildings in which these processes are housed are in accordance with the applicable building code
and construction requirements provided in Chapter 8.
f See NFPA 54, NFPA 82, and NFPA 85.
Table 6.2(b) Solids Treatment Processes — Sludge Drying
Ro
w
Lin
e
Location and
Function
Fire and
Explosio
n Hazard
Ventilationa,
b
Extent of
Classified
Area
NEC-Area
Electrical
Classificatio
n (All Class
II, Group G)c
Material of
Construction d
Fire
Protectio
n
Measures
1 a SLUDGE-
DRYING
PROCESSESe
Potential
for
ignition of
dust
NR If exposed
to
combustibl
e
particulate
solids,
entire roomf
Division 1 NC
(Constructio
n in
accordance
with NFPA
30, NFPA
68, NFPA
69, NFPA
H, FAS,
and FSS
(See
NFPA 30,
NFPA 61,
NFPA 69,
NFPA 85,
NFPA
Ro
w
Lin
e
Location and
Function
Fire and
Explosio
n Hazard
Ventilationa,
b
Extent of
Classified
Area
NEC-Area
Electrical
Classificatio
n (All Class
II, Group G)c
Material of
Construction d
Fire
Protectio
n
Measures
499, and
NFPA 654)
499, and
NFPA
654)
b NR Areas
within
equipment
processing
combustibl
e
particulate
solids
Division 1 NC
(Constructio
n in
accordance
with NFPA
30, NFPA
68, NFPA
69, NFPA
499, and
NFPA 654)
H, FAS,
and FSS
(See
NFPA 30,
NFPA 61,
NFPA 69,
NFPA 85,
NFPA
499, and
NFPA
654)
c NR Areas
within 3 m
(10 ft) of
equipment
processing
combustibl
e
particulate
solids
Division 2 NC
(Constructio
n in
accordance
with NFPA
30, NFPA
68, NFPA
69, NFPA
499, and
NFPA 654)
H, FAS,
and FSS
(See
NFPA 30,
NFPA 61,
NFPA 69,
NFPA 85,
NFPA
499, and
NFPA
654)
d NR Areas
beyond 3 m
(10 ft) of
equipment
processing
combustibl
e
particulate
solids
Unclassified NC
(Constructio
n in
accordance
with NFPA
30, NFPA
68, NFPA
69, NFPA
499, and
NFPA 654)
H, FAS,
and FSS
(See
NFPA 30,
NFPA 61,
NFPA 69,
NFPA 85,
NFPA
499, and
NFPA
654)
Ro
w
Lin
e
Location and
Function
Fire and
Explosio
n Hazard
Ventilationa,
b
Extent of
Classified
Area
NEC-Area
Electrical
Classificatio
n (All Class
II, Group G)c
Material of
Construction d
Fire
Protectio
n
Measures
2 a DRIED
SLUDGE
STORAGE
AREAS, IF
ENCLOSED
Potential
for
ignition of
dust
NR If exposed
to dried
sludge,
entire
roome
Division 1 NC
(Constructio
n in
accordance
with NFPA
68 and
NFPA 69,
NFPA 499,
and NFPA
654)
H, FAS
(See
NFPA 61,
NFPA 69,
NFPA
497, and
NPFA
654)
b NR Areas
within tanks
storing
dried
sludge
Division 1 NC
(Constructio
n in
accordance
with NFPA
68, NFPA
69, NFPA
499, and
NFPA 654)
H and
FAS (See
NFPA 61,
NFPA 69,
NFPA
497, and
NFPA
654)
c NR Areas
within 3 m
(10 ft) of
tanks
storing
dried
sludge
Division 2 NC
(Constructio
n in
accordance
with NFPA
68, NFPA
69, NFPA
499, and
NFPA 654)
H and
FAS (See
NFPA 61,
NFPA 69,
NFPA
497, and
NFPA
654)
d NR Areas
beyond 3 m
(10 ft) of
tanks
storing
dried
sludge
Unclassified NC
(Constructio
n in
accordance
with NFPA
68, NFPA
69, NFPA
499, and
NFPA 654)
H and
FAS (See
NFPA 61,
NFPA 69,
NFPA
497, and
NFPA
654)
Note: The following codes are used in this table:
FAS: Fire alarm system.
FSS: Fire suppression system (e.g., automatic sprinkler, water spray, foam, gaseous, or dry
chemical).
H: Hydrant protection in accordance with 7.2.4.
NC: Noncombustible material.
NEC: In accordance with NFPA 70.
NR: No requirement.
a This column indicates the ventilation requirements for processes. Additional ventilation
requirements are provided in Chapter 9. Ventilation signaling and alarm requirements are provided
in Chapter 7.
bFor sludge-drying processes that use flammable or combustible liquids, ventilate in accordance
with NFPA 30.
cOr if acceptable to the authority having jurisdiction with classification in NFPA 499. d This column indicates the materials of construction for processes. Materials of construction for
buildings in which these processes are housed are in accordance with the applicable building code
and construction requirements provided in Chapter 8.
eSee NFPA 54, NFPA 85, NFPA 499, and NFPA 654. For sludge-drying processes that use
flammable or combustible liquids, see NFPA 30.
fThe area beyond the envelope is unclassified.
Second Revision No. 15-NFPA 820-2014 [ Chapter 7 ]
Chapter 7 Fire and Explosion Prevention and Protection
7.1* Scope.
This chapter shall establish minimum requirements for overall protection against fire and explosion hazards inwastewater facilities and associated collection systems.
7.1.1
Gases, liquids, and solids shall be assigned to one of the following two categories:
Flammable/combustible hazards
Safety and health hazards
This standard shall apply to the flammability properties of a particular substance, process, or area within wastewaterand collection facilities.
7.1.2
This standard shall apply to the flammability aspects of a particular substance, process, or area within wastewater andcollection facilities Chapter 10 shall be referenced for additional requirements to protect against fire and safetyhazards .
7.1.3
Chapter 10 shall be referenced for additional requirements to protect against fire and safety hazards.
7.2 Fire Protection Measures.
7.2.1 General.
7.2.1.1
Collection systems, liquid stream treatment processes, and solids-handling processes shall be provided with fireprotection for the fire hazards, as described in Table 4.2.2 Table 4.2 , Table 5.2.2 Table 5.2 , Table 6.2.2(a) Table6.2(a) , and Table 6.2.2(b) Table 6.2(b) .
7.2.1.2
Enclosed spaces classified as explosion hazard areas under this document shall be physically separated from allunclassified enclosures.
7.2.1.3
In addition to the fire protection specified in Chapter 8, buildings, structures, and process elements, under someconditions, shall be provided with automatic-extinguishing systems in accordance with this chapter.
7.2.2 Automatic Sprinkler Systems.
7.2.2.1
An automatic Automatic sprinkler systems , where required by this standard or by referenced publications, shallconform to NFPA 13 and shall be approved by the authority having jurisdiction.
7.2.2.2
Other automatic-extinguishing systems shall be permitted in certain areas of the wastewater treatment plant, such asthe following:
(1) Chemical storage
(2) Underground tunnels or structures
(3) Areas where electrical hazard is a principal concern
(4) Areas where water damage would seriously impair the integrity of the treatment plant
7.2.3 Other Automatic-Extinguishing Systems.
Where required or used in place of automatic sprinkler systems, special hazard–extinguishing systems andnonwater non-water automatic-extinguishing systems shall be designed, installed, and maintained in accordance withthe following standards, as applicable:
(1) NFPA 11, Standard for Low-, Medium-, and High-Expansion Foam
(2) NFPA 12, Standard on Caron Dioxide Extinguishing Systems
(3) NFPA 12A, Standard on Halon 1301 Fire Extinguishing Systems
(4) NFPA 15, Standard for Water Spray Fixed Systems for Fire Protection
(5) NFPA 16, Standard for Installation of Foam-Water Sprinkler and Foam-Water Spray Systems
(6) NFPA 17, Standard for Dry Chemical Extinguishing Systems
(7) NFPA 2001, Standard for Fixed Aerosol Fire-Extinguishing Systems
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7.2.4 Water Supplies, Standpipes, Hose Systems, and Hydrants.
7.2.4.1
Water supplies shall be capable of delivering the total demand of sprinklers, hose streams, and foam systems.
7.2.4.1.1
In areas where there is no public water supply or where the supply is not capable of meeting the total demandrequired, treatment plant effluent shall be permitted for fire protection use.
7.2.4.1.2
The requirements of the public health authority having jurisdiction shall be determined and followed.
7.2.4.2
Water supplies and hydrants shall be installed in accordance with the following standards, as applicable:
(1) NFPA 22, Standard for Water Tanks for Private Fire Protection
(2) NFPA 24, Standard for the Installation of Private Fire Service Mains and Their Appurtenances
(3) NFPA 1142, Standard for Suburban and Rural Fire Fighting
7.2.4.3
Standpipes and hose systems shall be installed and inspected in accordance with NFPA 14.
7.2.4.4
Where fire pumps are used as a separate and sole source of supply, the system shall provide capacity to meetsimultaneous fire water flow requirements for both manual and automatic fire suppression systems and the followingshall apply:
(1) A standby power supply shall be provided.
(2) Pumps shall be automatic starting and manual shutdown.
(3) Pumps shall be installed in accordance with NFPA 20.
7.2.5 Portable Fire Extinguishers.
7.2.5.1
Portable fire extinguishers shall be installed, located, and maintained in accordance with NFPA 10.
7.2.5.2
The requirement for portable fire extinguishers shall be permitted to be waived where areas are not commonlyoccupied and the approval of the authority having jurisdiction has been obtained.
7.3 Fire Detection and Alarm Systems.
7.3.1
Fire detection and alarm systems for each treatment and collection facility area shall be provided as identified in Table4.2.2 Table 4.2 , Table 5.2.2 Table 5.2 , Table 6.2.2(a) Table 6.2(a) , and Table 6.2.2(b) Table 6.2(b) or in accordancewith referenced publications.
7.3.2
Fire detection and alarm systems shall be installed and maintained in accordance with NFPA 72.
7.4 Combustible Gas Detection.
7.4.1
Combustible gas detectors shall be located in accordance with Table 4.2.2 Table 4.2 , Table 5.2.2 Table 5.2 , andTable 6.2.2(a) Table 6.2(a) .
7.4.2*
The selection of combustible gas detector types and their placement shall be determined by a qualified person asdefined by NFPA 70 .
7.4.3*
Combustible gas detectors shall be listed and labeled for the intended application and shall be listed for theatmosphere in which it is installed.
7.4.4
Detectors and signaling systems shall be provided with an auxilliary auxiliary power supply to ensure continuousoperation during any failure of normal power supply.
7.4.5
The installation, calibration, and maintenance, and testing of combustible gas detectors shall be in accordance withtheir listing requirements and the manufacturers' instructions.
7.4.6
Combustible gas detection equipment located in hazardous (classified) locations, as defined in accordance withNFPA 70 , shall be listed for use in such atmospheres. Detectors required as fire protection measures in Table4.2.2 Table 4.2 , Table 5.2.2 Table 5.2 , Table 6.2.2(a) Table 6.2(a) and Table 6.2.2(b) Table 6.2(b) shall be set toalarm at 10 percent of the lower explosive limit (LEL) in accordance with the manufacturers’ calibration instructionsand shall be connected to alarm signaling systems that shall comply with the requirements of Section 7.6 .
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7.4.6.1
Where permitted by the authority having jurisdiction, the alarm limits shall be permitted to be set at higher than 10percent of the lower explosive limit (LEL), also known as the lower flammable limit (LFL), where experience indicatesambient levels would produce spurious alarms.
7.4.7
Detectors required as fire protection measures in Chapters 4 , 5 , and 6 of this standard shall be set to alarm at10 percent of the lower flammable limit (LFL) in accordance with the manufacturers’ calibration instructions and shallbe connected to alarm signaling systems that shall comply with the requirements of 7.6 .
7.4.7.1
Where permitted by the authority having jurisdiction, the alarm limits shall be permitted to be set at higher than 10percent of the lower flammable limit where experience indicates ambient levels would produce spurious alarms.
7.5 Ventilation Monitoring.
7.5.1
All continuous ventilation systems that are used to reduce the classification of a space shall be fitted with flow detectiondevices connected to alarm signaling systems to indicate inadequate ventilation and ventilation system failure toprovide the required air changes .
7.5.1.1
The flow detection devices shall monitor both the supply and exhaust fans, where a two-fan system is used.
7.5.2
The alarm signaling systems shall comply with the requirements of Section 7.6.
7.6 Alarm Signaling Systems.
7.6.1*
Distinct local and remote alarms shall be displayed in accordance with Table 7.6.1.
Table 7.6.1 Location and Type of Alarm Signaling Notification Appliances Required in 7.7.1 7.6.1
Location Alarm Notification Appliances
Entrance(s) to spaces*
in occupied facilitiesVisual and audible alarms
Entrances to remote spaces that are not constantly attendedVisual and audible alarms or a dual light warningsystem
Within spaces Visual and audible alarms
Constantly attended location (local or remote) Visual and audible alarms
*Where locations are not constantly attended, the use of a nonaudible signal is permitted if a dual-light system isused. A dual-light system is to include a “go”/”no go” or green light/red light type of warning system instead of theaudible alarm.
7.6.2*
Local and remote alarms required in Table 7.6.1 shall be located so as to be readily heard and seen by responsiblepersonnel.
7.6.3
Alarm signaling system equipment shall be provided with an auxiliary power supply to ensure continuous operationduring the failure of the normal power supply and shall be of sufficient duration to alert responsible personnel.
7.6.4
A telephone dialer shall be allowed to meet the intent of the constantly attended location listing in Table 7.6.1.
7.6.5
Visual and audible alarms required in Table 7.6.1 shall be tested quarterly to verify their functionality or in accordancewith 7.6.6.
7.6.6
The quarterly testing requirement shall be permitted to be reduced to semiannually where the conductors of the visualand audible notification appliances are continuously monitored for open circuits, short circuits, and ground faults.
7.7 Laboratories.
Fire protection for laboratories shall be in accordance with NFPA 45 .
7.8 Pressurization Monitoring.
All pressurization systems used to downgrade the electrical classification of a space shall be in accordance withNFPA 496 . Failure of the pressurization system shall activate alarm signaling systems that comply with therequirements of 7.6 .
7.8 Laboratories.
Fire protection for laboratories shall be in accordance with NFPA 45 .
7.8 Special Fire Protection Measures.
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7.8.1 Fire Protection During Construction.
Fire protection measures during construction at both new and existing wastewater facilities shall be provided inaccordance with NFPA 241.
7.8.2 Lightning Protection.
Lightning protection shall be provided in accordance with NFPA 780.
7.8.3 Drainage.
7.8.3.1
Provisions shall be made in all fire areas of the plant for removal of all liquids for containment in the fire area withoutflooding of equipment and without endangering other areas.
7.8.3.2
The provisions for drainage and any associated drainage facilities shall be sized to simultaneously accommodatesimultaneously all of the following:
(1) The spill of the largest single container of any flammable or combustible liquids in the area
(2) The maximum expected number of fire hose lines [31.5 L/sec (500 gal/min) minimum] operating for a minimum of10 minutes
(3) The maximum design discharge of fixed fire suppression systems operating for a minimum of 10 minutes
Supplemental Information
File Name Description
ComparisonFDtoSDChapter_7.docx For editorial use only.
FINALSDMtgREVChapter_7.docx For editorial use only.
A.7.4.2NEW.docx
Submitter Information Verification
Submitter Full Name: [ Not Specified ]
Organization: [ Not Specified ]
Street Address:
City:
State:
Zip:
Submittal Date: Tue Oct 14 18:26:43 EDT 2014
Committee Statement
CommitteeStatement:
The chapter was revised to further clarify changes made in first draft. Key chapter revisions were made at firstdraft so as not to conflict with NFPA 72. Note that the term LFL was changed back to LEL since manufacturersof CGD still use the term LEL.
ResponseMessage:
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Chapter 7 Fire and Explosion Prevention and Protection
7.1* Scope.
This chapter shall establish minimum requirements for overall protection against fire and explosion
hazards in wastewater facilities and associated collection systems.
7.1.1
Gases, liquids, and solids shall be assigned to one of the following two categories:
(1) Flammable/combustible hazards
(2) Safety and health hazards
This standard shall apply to the flammability properties of a particular substance, process, or area
within wastewater and collection facilities.
7.1.2
This standard shall apply to the flammability aspects of a particular substance, process, or area
within wastewater and collection facilities.
7.1.3
Chapter 10shall10 shall be referenced for additional requirements to protect against fire and safety
hazards.
7.2 Fire Protection Measures.
7.2.1 General.
7.2.1.1
Collection1Collection systems, liquid stream treatment processes, and solids-handling processes shall be
provided with fire protection for the fire hazards, as described in Table 4.2, Table 5.2, Table 6.2(a), and
Table 6.2(b).
7.2.1.2
Enclosed spaces classified as explosion hazard areas under this document shall be physically separated
from all unclassified enclosures.
7.2.1.3
In addition to the fire protection specified in Chapter 8, buildings, structures, and process elements, under
some conditions, shall be provided with automatic-extinguishing systems in accordance with this chapter.
7.2.2 Automatic Sprinkler Systems.
7.2.2.1
An automaticAutomatic sprinkler system, wheresystems required by this standard or by referenced
publications, shall conform to NFPA 13 and shall be approved by the authority having jurisdiction.
7.2.2.2 Other automatic-extinguishing systems shall be permitted in certain areas of the wastewater
treatment plant, such as the following:
(1) Chemical storage
(2) Underground tunnels or structures
(3) Areas where electrical hazard is a principal concern
(4) Areas where water damage would seriously impair the integrity of the treatment plant
7.2.3 Other Automatic-Extinguishing Systems.
Where required or used in place of automatic sprinkler systems, special hazard–extinguishing systems
and nonwaternon-water automatic-extinguishing systems shall be designed, installed, and maintained in
accordance with the following standards, as applicable:
(1) NFPA 11
(2) NFPA 12
(3) NFPA 12A
(4) NFPA 15
(5) NFPA 16
(6) NFPA 17
(7) NFPA 2001
7.2.4 Water Supplies, Standpipes, Hose Systems, and Hydrants.
7.2.4.1
Water supplies shall be capable of delivering the total demand of sprinklers, hose streams, and foam
systems.
7.2.4.1.1
In areas where there is no public water supply or where the supply is not capable of meeting the total
demand required, treatment plant effluent shall be permitted for fire protection use.
7.2.4.1.2
The requirements of the public health authority having jurisdiction shall be determined and followed.
7.2.4.2
Water supplies and hydrants shall be installed in accordance with the following standards, as applicable:
(1) NFPA 22
(2) NFPA 24
(3) NFPA 1142
7.2.4.3
Standpipes and hose systems shall be installed and inspected in accordance with NFPA 14.
7.2.4.4
Where fire pumps are used as a separate and sole source of supply, the system shall provide capacity to
meet simultaneous fire water flow requirements for both manual and automatic fire suppression systems
and the following shall apply:
(1) A standby power supply shall be provided.
(2) Pumps shall be automatic starting and manual shutdown.
(3) Pumps shall be installed in accordance with NFPA 20.
7.2.5 Portable Fire Extinguishers.
7.2.5.1
Portable fire extinguishers shall be installed, located, and maintained in accordance with NFPA 10.
7.2.5.2
The requirement for portable fire extinguishers shall be permitted to be waived where areas are not
commonly occupied and the approval of the authority having jurisdiction has been obtained.
7.3 Fire Detection and Alarm Systems.
7.3.1
Fire detection and alarm systems for each treatment and collection facility area shall be provided as
identified in Table 4.2, Table 5.2, Table 6.2(a), and Table 6.2(b) or in accordance with referenced
publications.
7.3.2
Fire detection and alarm systems shall be installed and maintained in accordance with NFPA 72.
7.4 Combustible Gas Detection.
7.4.1*
Combustible gas detectors shall be located in accordance with Table 4.2, Table 5.2, and Table 6.2(a).
7.4.2*
The selection of combustible gas detector types and their placement shall be determined by a qualified
person as defined by NFPA 70..
7.4.3*
Combustible gas detectors shall be listed and labeled for the intended application and shall be listed for
the atmosphere in which it is installed.
7.4.4
Detectors and signaling systems shall be provided with an auxilliaryauxiliary power supply to ensure
continuous operation during any failure of normal power supply.
7.4.5
The installation, calibration, and maintenance, and testing of combustible gas detectors shall be in
accordance with their listing requirements and the manufacturers' instructions.
7.4.6
Combustible gas detection equipment located in hazardous (classified) locations, as defined in
accordance with NFPA 70, shall be listed for use in such atmospheres.
7.4.7
Detectors required as fire protection measures in ChaptersTable 4,.2, Table 5,.2, Table 6.2(a), and 6 of
this standardTable 6.2(b) shall be set to alarm at 10 percent of the lower flammableexplosive limit
(LFLLEL) in accordance with the manufacturers’ calibration instructions and shall be connected to alarm
signaling systems that shall comply with the requirements of 7.6.
7.4.76.1
Where permitted by the authority having jurisdiction, the alarm limits shall be permitted to be set at higher
than 10 percent of the lower explosive limit (lower flammable limit) where experience indicates ambient
levels would produce spurious alarms.
7.5 Ventilation Monitoring.
7.5.1
All continuous ventilation systems that are used to reduce the classification of a space shall be fitted with
flow detection devices connected to alarm signaling systems to indicate inadequate ventilation and
ventilation system failure to provide the required air changes..
7.5.1.1 The flow detection devices shall monitor both the supply and exhaust fans, where a two fan
system is used.
7.5.2
The alarm signaling systems shall comply with the requirements of 7.6.
7.6 Alarm Signaling Systems.
7.6.1*
Distinct local and remote alarms shall be displayed in accordance with Table 7.6.1.
Table 7.6.1 Location and Type of Alarm Signaling Notification Appliances Required in 7.76.1
Location Alarm Notification Appliances
Entrance(s) to spaces* in occupied facilities VisualVisibleual and audible alarms
Entrances to remote spaces that are not constantly
attended.
Visibleual and audible alarms or a dual light
warning system.
Within spaces Visual and audible alarms
Constantly attended location (local or remote) Visual and audible alarms
*Where locations are not constantly attended, the use of a nonaudible signal is permitted if a dual-light
system is used. A dual-light system is to include a “go”/”no go” or green light/red light type of warning
system instead of the audible alarm.
7.6.2*
Local and remote alarms required in Table 7.6.1 shall be located so as to be readily heard and seen by
responsible personnel.
7.6.3
Alarm signaling system equipment shall be provided with an auxiliary power supply to ensure continuous
operation during the failure of the normal power supply and shall be of sufficient duration to alert
responsible personnel.
7.6.4
A telephone dialer shall be allowed to meet the intent of the constantly attended location listing in Table
7.6.1.
7.6.5
Visual and audible alarms required in Table 7.6.1 shall be tested quarterly to verify their functionality or in
accordance with 7.6.6.
7.6.6
The quarterly testing requirement shall be permitted to be reduced to semiannually where the conductors
of the visual and audible notification appliances are continuously monitored for open circuits, short
circuits, and ground faults.
7.7 Pressurization Monitoring.
All pressurization systems used to downgrade the electrical classification of a space shall be in
accordance with NFPA 496. Failure of the pressurization system shall activate alarm signaling systems
that comply with the requirements of 7.6.
7.8 Laboratories.
Fire protection for laboratories shall be in accordance with NFPA 45.
7.98 Special Fire Protection Measures.
7.98.1 Fire Protection During Construction.
Fire protection measures during construction at both new and existing wastewater facilities shall be
provided in accordance with NFPA 241.
7.98.2 Lightning Protection.
Lightning protection shall be provided in accordance with NFPA 780.
7.9.3 Drainage.
7.9.3.1
Provisions shall be made in all fire areas of the plant for removal of all liquids for containment in the fire
area without flooding of equipment and without endangering other areas.
7.9.3.2
The provisions for drainage and any associated drainage facilities shall be sized to simultaneously
accommodate all of the following:
(1) The spill of the largest single container of any flammable or combustible liquids in the area
(2) The maximum expected number of fire hose lines [31.5 L/sec (500 gal/min) minimum] operating for a
minimum of 10 minutes
(3) The maximum design discharge of fixed fire suppression systems operating for a minimum of 10
minutes
Chapter 7 Fire and Explosion Prevention and Protection
7.1* Scope.
This chapter shall establish minimum requirements for overall protection against fire and explosion
hazards in wastewater facilities and associated collection systems.
7.1.1
This standard shall apply to the flammability properties of a particular substance, process, or area
within wastewater and collection facilities.
7.1.2
Chapter 10 shall be referenced for additional requirements to protect against fire and safety
hazards.
7.2 Fire Protection Measures.
7.2.1 General.
7.2.1.1Collection systems, liquid stream treatment processes, and solids-handling processes shall
be provided with fire protection for the fire hazards, as described in Table 4.2, Table 5.2, Table
6.2(a), and Table 6.2(b).
7.2.1.2
Enclosed spaces classified as explosion hazard areas under this document shall be physically
separated from all unclassified enclosures.
7.2.1.3
In addition to the fire protection specified in Chapter 8, buildings, structures, and process elements,
under some conditions, shall be provided with automatic-extinguishing systems in accordance with
this chapter.
7.2.2 Automatic Sprinkler Systems.
7.2.2.1 Automatic sprinkler systems required by this standard shall conform to NFPA 13 and shall
be approved by the authority having jurisdiction.
7.2.2.2 Other automatic-extinguishing systems shall be permitted in certain areas of the wastewater
treatment plant, such as the following:
(1) Chemical storage
(2) Underground tunnels or structures
(3) Areas where electrical hazard is a principal concern
(4) Areas where water damage would seriously impair the integrity of the treatment plant
7.2.3 Other Automatic-Extinguishing Systems.
Where required or used in place of automatic sprinkler systems, special hazard–extinguishing
systems and non-water automatic-extinguishing systems shall be designed, installed, and
maintained in accordance with the following standards, as applicable:
(1) NFPA 11
(2) NFPA 12
(3) NFPA 12A
(4) NFPA 15
(5) NFPA 16
(6) NFPA 17
(7) NFPA 2001
7.2.4 Water Supplies, Standpipes, Hose Systems, and Hydrants.
7.2.4.1
Water supplies shall be capable of delivering the total demand of sprinklers, hose streams, and
foam systems.
7.2.4.1.1
In areas where there is no public water supply or where the supply is not capable of meeting the
total demand required, treatment plant effluent shall be permitted for fire protection use.
7.2.4.1.2
The requirements of the public health authority having jurisdiction shall be determined and followed.
7.2.4.2
Water supplies and hydrants shall be installed in accordance with the following standards, as
applicable:
(1) NFPA 22
(2) NFPA 24
(3) NFPA 1142
7.2.4.3
Standpipes and hose systems shall be installed and inspected in accordance with NFPA 14.
7.2.4.4
Where fire pumps are used as a separate and sole source of supply, the system shall provide
capacity to meet simultaneous fire water flow requirements for both manual and automatic fire
suppression systems and the following shall apply:
(1) A standby power supply shall be provided.
(2) Pumps shall be automatic starting and manual shutdown.
(3) Pumps shall be installed in accordance with NFPA 20.
7.2.5 Portable Fire Extinguishers.
7.2.5.1
Portable fire extinguishers shall be installed, located, and maintained in accordance with NFPA 10.
7.2.5.2
The requirement for portable fire extinguishers shall be permitted to be waived where areas are not
commonly occupied and the approval of the authority having jurisdiction has been obtained.
7.3 Fire Detection and Alarm Systems.
7.3.1
Fire detection and alarm systems for each treatment and collection facility area shall be provided as
identified in Table 4.2, Table 5.2, Table 6.2(a), and Table 6.2(b) or in accordance with referenced
publications.
7.3.2
Fire detection and alarm systems shall be installed and maintained in accordance with NFPA 72.
7.4 Combustible Gas Detection.
7.4.1
Combustible gas detectors shall be located in accordance with Table 4.2, Table 5.2, and Table
6.2(a).
7.4.2*
The selection of combustible gas detector types and their placement shall be determined by a
qualified person.
7.4.3*
Combustible gas detectors shall be listed and labeled for the intended application and shall be listed
for the atmosphere in which it is installed.
7.4.4
Detectors and signaling systems shall be provided with an auxiliary power supply to ensure
continuous operation during any failure of normal power supply.
7.4.5
The installation, calibration, and maintenance, and testing of combustible gas detectors shall be in
accordance with their listing requirements and the manufacturers' instructions.
7.4.6 Detectors required as fire protection measures in Table 4.2, Table 5.2, Table 6.2(a), and Table
6.2(b) shall be set to alarm at 10 percent of the lower explosive limit (LEL) in accordance with the
manufacturers’ calibration instructions and shall be connected to alarm signaling systems that shall
comply with the requirements of 7.6.
7.4.6.1
Where permitted by the authority having jurisdiction, the alarm limits shall be permitted to be set at
higher than 10 percent of the lower explosive limit (lower flammable limit) where experience
indicates ambient levels would produce spurious alarms.
7.5 Ventilation Monitoring.
7.5.1
All continuous ventilation systems that are used to reduce the classification of a space shall be fitted
with flow detection devices connected to alarm signaling systems to indicate inadequate ventilation
and ventilation system failure.
7.5.1.1 The flow detection devices shall monitor both the supply and exhaust fans, where a two fan
system is used.
7.5.2
The alarm signaling systems shall comply with the requirements of 7.6.
7.6 Alarm Signaling Systems.
7.6.1*
Distinct local and remote alarms shall be displayed in accordance with Table 7.6.1.
Table 7.6.1 Location and Type of Alarm Signaling Notification Appliances Required in 7.6.1
Location Alarm Notification Appliances
Entrance(s) to spaces in occupied facilities Visible and audible alarms
Entrances to remote spaces that are not constantly
attended.
Visible and audible alarms or a dual light warning
system.
Within spaces Visual and audible alarms
Constantly attended location (local or remote) Visual and audible alarms
7.6.2*
Local and remote alarms required in Table 7.6.1 shall be located so as to be readily heard and seen
by responsible personnel.
7.6.3
Alarm signaling system equipment shall be provided with an auxiliary power supply to ensure
continuous operation during the failure of the normal power supply and shall be of sufficient duration
to alert responsible personnel.
7.6.4
A telephone dialer shall be allowed to meet the intent of the constantly attended location listing in
Table 7.6.1.
7.6.5
Visual and audible alarms required in Table 7.6.1 shall be tested quarterly to verify their functionality
or in accordance with 7.6.6.
7.6.6
The quarterly testing requirement shall be permitted to be reduced to semiannually where the
conductors of the visual and audible notification appliances are continuously monitored for open
circuits, short circuits, and ground faults.
7.7 Laboratories.
Fire protection for laboratories shall be in accordance with NFPA 45.
7.8 Special Fire Protection Measures.
7.8.1 Fire Protection During Construction.
Fire protection measures during construction at both new and existing wastewater facilities shall be
provided in accordance with NFPA 241.
7.8.2 Lightning Protection.
Lightning protection shall be provided in accordance with NFPA 780.
7.9.3 Drainage.
7.9.3.1
Provisions shall be made in all fire areas of the plant for removal of all liquids for containment in the
fire area without flooding of equipment and without endangering other areas.
7.9.3.2
The provisions for drainage and any associated drainage facilities shall be sized to simultaneously
accommodate all of the following:
(1) The spill of the largest single container of any flammable or combustible liquids in the area
(2) The maximum expected number of fire hose lines [31.5 L/sec (500 gal/min) minimum] operating
for a minimum of 10 minutes
(3) The maximum design discharge of fixed fire suppression systems operating for a
minimum of 10 minutes
A.7.4.2 Other types of detectors, such as heat and smoke detectors, have standards recommending
spacing usually based on a certain area per detector. There are no known recognized standards or
guidelines for the locating or spacing of combustible gas detectors.
Whether natural or mechanical, air movement is a very important consideration in installing combustible
gas detectors. This aspect should be carefully investigated, including the effect of doors, windows, vents,
and other openings. It could be necessary to conduct a ventilation study that could involve a nontoxic
smoke movement analysis.
Dispersion characteristics can also affect detector placement. Vapors and gases will disperse inversely
proportional to their specific density in a quiescent environment. Vapors and gases with densities less
than that of air will diffuse quickly at first until the vapor or gas becomes diluted. Heavier-than-air vapors
and gases will tend to settle at a low area and not diffuse into the atmosphere unless dispersed by
ventilation or temperature currents. Vapors with densities close to that of air will exhibit little mixing effect
and will be transported largely by air currents.
There are various types of sensing devices. It is important to select the proper sensing device for each
application and for the environment in which it will be placed. Most organic and inorganic compounds can
be monitored safely with a catalytic combustion–type sensor. However, organic and metallic solvents
containing lead, silicones, plasticizers, or halogens can poison the catalytic element.
Qualified means one who, by possession of a recognized degree, certificate, or professional standing, or
who by extensive knowledge, training and experience, has successfully demonstrated his ability to solve
or resolve problems relating to the subject matter, the work, or the project.
Second Revision No. 8-NFPA 820-2014 [ Section No. 7.7 ]
7.7 Laboratories.
Fire protection for laboratories shall be in accordance with NFPA 45 .
7.8 Pressurization Monitoring.
All pressurization systems used to downgrade the electrical classification of a space shall be in accordance withNFPA 496 . Failure of the pressurization system shall activate alarm signaling systems that comply with therequirements of 7.6 .
Submitter Information Verification
Submitter Full Name: [ Not Specified ]
Organization: [ Not Specified ]
Street Address:
City:
State:
Zip:
Submittal Date: Tue Oct 07 13:55:21 EDT 2014
Committee Statement
Committee Statement: The term reduce is used to be consistent with terminology used elsewhere in the document.
Response Message:
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Second Revision No. 7-NFPA 820-2014 [ Chapter 8 ]
Chapter 8 Materials of Construction
8.1 General.
This chapter shall apply to the selection of materials of construction for buildings, structures, and process elementsfor protection against fire and explosion in wastewater treatment plants and associated collection systems.
8.1.1*
This chapter shall apply to the selection of materials of construction for buildings, structures, and process elements forprotection against fire and explosion in wastewater treatment plants and associated collection systems. Facilities shallbe constructed in accordance with the applicable building code and the additional requirements in this standard.
8.1.2
Materials of construction and interior coatings and finishes shall provide a maximum degree of fire resistance with theminimum amount of flame spread and smoke generation associated with a particular application. In areas wherecorrosive environments are present, including classified areas, the mitigation of corrosion problems in the selectionand use of materials for nonstructural assemblies shall include the use of the following:
(1) Corrosion-resistant metallic or nonmetallic grating
(2) Corrosion-resistant railings, steps and stairs, conduit
(3) Corrosion-resistant electric equipment enclosures
8.1.3
Materials shall be selected that reduce or eliminate the effects of fire and explosion by maintaining structural integrity,controlling flame spread and smoke generation, minimizing the release of toxic products of combustion, andmaintaining the serviceability and operation of critical processes.
8.1.3.1
The purpose of the criteria for selecting materials of construction shall not be to provide protection of personnel fromthe risk of exposure to an asphyxiating or toxic atmosphere generated during a fire.
8.1.3.2
Criteria for selecting materials of construction shall not apply to nonprocess contents of the building, structure, orassembly where such contents are not a part of the building, structure, or assembly, including the following:
Equipment or equipment enclosures
Grating, walkways, ladders, railings, weirs, process piping, and appurtenances
Process media
Aeration devices
Slide and sluice gates
Pump packing and seal material
Electrical conduit
Hardware
Liners for basins that are open to the atmosphere
Materials used in rehabilitation or for lining existing sewer pipes
Other components as allowed by the AHJ
8.1.4
In areas where corrosive environments are present, including classified areas, the mitigation of corrosion problems inthe selection and use of materials for nonstructural assemblies shall include the use of the following:
Corrosion-resistant metallic or nonmetallic grating
Railings, steps and stairs, conduit
Electric equipment enclosures
8.2 Materials Selection.
8.2.1
Materials shall be selected based on the criteria for a particular the intended application.
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8.2.2 Limited-Combustible Material.
A material shall be considered a limited-combustible material where both of the following conditions of 8.2.2(1) , and8.2.2(2) , and the conditions of either 8.2.2.1 or 8.2.2.2 are met:
The material does not comply with the requirements for a noncombustible material in accordance with 8.2.3.
The material, in the form in which it is used, exhibits a potential heat value not exceeding 3500 Btu/lb (8141kJ/kg), when tested in accordance with NFPA 259, Standard Test Method for Potential Heat of BuildingMaterials . [ 5000: 7.1.4.2]
Selection criteria shall include specification of the following:
(1) Structural requirements
(2) Location and operating environment
(3) Fire resistance rating
(4) Flame spread index value
(5)
(6) Products of combustion
(7) Corrosion resistance
8.2.2.1
The material shall have a structural base of noncombustible material with a surfacing not exceeding a thickness of1 ⁄8 in. (3.2 mm) where the surfacing exhibits a flame spread index not greater than 50 when tested in accordancewith ASTM E 84, Standard Test Method for Surface Burning Characteristics of Building Materials , or ANSI/UL 723,Standard for Test for Surface Burning Characteristics of Building Materials . [ 5000: 7.1.4.2.1]
8.2.2.2
The material shall be composed of materials that in the form and thickness used, neither exhibit a flame spread indexgreater than 25 nor evidence of continued progressive combustion when tested in accordance with ASTM E 84 orANSI/UL 723 and are of such composition that all surfaces that would be exposed by cutting through the material onany plane would neither exhibit a flame spread index greater than 25 nor exhibit evidence of continued progressivecombustion when tested in accordance with ASTM E 84 or ANSI/UL 723. [ 5000: 7.1.4.2.2]
8.2.2.3
Where the term limited-combustible is used in this standard, it shall also include the term noncombustible .[ 5000: 7.1.4.2.3]
8.2.3 Noncombustible Material.
A material that complies with any one of the following shall be considered a noncombustible material:
The material is reported as passing ASTM E 136, Standard Test Method for Behavior of Materials in a VerticalTube Furnace at 750 Degrees C
The material is reported as complying with the pass/fail criteria of ASTM E 136 when tested in accordance withthe test method and procedure in ASTM E 2652, Standard Test Method for Behavior of Materials in a TubeFurnace with a Cone-shaped Airflow Stabilizer, at 750 Degrees C
[5000: 7.1.4.1.1]
For the purpose of this document, materials of construction shall be divided into the following four basic categories asdefined in 8.2.3.1 through 8.2.3.4 :
(1) Combustible
(2) Noncombustible
(3) Limited-combustible
(4) Low flame spread index
8.2.3.1 Combustible Material.
Where the term limited-combustible is used in this standard, it shall also include the term noncombustible .[ 5000: 7.1.4.1.2] A material that, in the form in which it is used and under the conditions anticipated, will ignite andburn; a material that does not meet the definition of noncombustible or limited-combustible shall be considered acombustible material.
8.2.3.2* Noncombustible Material.
* Smoke developed index or other smoke generation values
* The material, in the form in which it is used, and under the conditions anticipated, will not ignite, burn, supportcombustion, or release flammable vapors when subjected to fire or heat
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A material that complies with any one of the following shall be considered a noncombustible material:
(1)
(2) The material is reported as passing ASTM E136, Standard Test Method for Behavior of Materials in a VerticalTube Furnace at 750 Degrees C .
(3) The material is reported as complying with the pass/fail criteria of ASTM E136 when tested in accordance withthe test method and procedure in ASTM E2652, Standard Test Method for Behavior of Materials in a TubeFurnace with a Cone-shaped Airflow Stabilizer , at 750 Degrees C.
[ 5000: 7.1.4.1.1]
8.2.3.2.1
Where the term limited-combustible is used in this standard, it shall also include the term noncombustible .
[ 5000: 7.1.4.1.2]
8.2.3.3* Limited-Combustible Material.
A material shall be considered a limited-combustible material where both of the following conditions of 8.2.2(1) ,8.2.2(2) , and the conditions of either 8.2.3.3.1 or 8.2.3.3.2 are met:
(1) The material does not comply with the requirements for a noncombustible material in accordance with 8.2.3 .
(2) The material, in the form in which it is used, exhibits a potential heat value not exceeding 3500 Btu/lb (8141kJ/kg), when tested in accordance with NFPA 259 . [ 5000: 7.1.4.2]
8.2.3.3.1
The material shall have a structural base of noncombustible material with a surfacing not exceeding a thickness of1 ⁄8 in. (3.2 mm) where the surfacing exhibits a flame spread index not greater than 50 when tested in accordancewith ASTM E84, Standard Test Method for Surface Burning Characteristics of Building Materials , or ANSI/UL 723,Standard for Test for Surface Burning Characteristics of Building Materials . [ 5000: 7.1.4.2.1]
8.2.3.3.2
The material shall be composed of materials that in the form and thickness used, neither exhibit a flame spread indexgreater than 25 nor evidence of continued progressive combustion when tested in accordance with ASTM E84 orANSI/UL 723 and are of such composition that all surfaces that would be exposed by cutting through the material onany plane would neither exhibit a flame spread index greater than 25 nor exhibit evidence of continued progressivecombustion when tested in accordance with ASTM E84 or ANSI/UL 723. [ 5000: 7.1.4.2.2]
8.2.3.3.3
Where the term limited-combustible is used in this standard, it shall also include the term noncombustible .[ 5000: 7.1.4.2.3]
8.2.3.4*
Flame spread index shall be considered a comparative measure, expressed as a dimensionless number, derivedfrom visual measurements of the spread of flame versus time for a material tested in accordance with ASTM E84,Standard Test Method for Surface Burning Characteristics of Building Materials , or UL 723, Standard for Test forSurface Burning Characteristics of Building Materials .
8.2.4
Selection criteria shall include the following:
Structural requirements
Location and operating environment
Fire resistance rating
Flame spread index value
Smoke developed index or other smoke generation values
Products of combustion
Corrosion resistance
Materials of construction used for unit processes located in classified areas shall be selected based upon adocumented fire risk evaluation.
* The material, in the form in which it is used, and under the conditions anticipated, will not ignite, burn,support combustion, or release flammable vapors when subjected to fire or heat.
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8.2.4.1
Where conditions or applications warrant the selection of combustible materials, limited-combustible, or low flamespread index materials, the following shall be included as part of the fire risk evaluation:
(1) Flame spread
(2) Smoke generation
(3) Corrosion resistance
(4) Products of combustion
(5) Impact of a fire or explosion on the structural integrity and operability
(6) Economic and environmental consequences of having the facility out of service
8.2.5
For the purpose of this document, materials of construction shall be divided into the following four basic categories:
Combustible
Noncombustible
Limited-combustible
Low flame spread index
8.2.6
Materials of construction used for unit processes located in areas with an NFPA 70 classification of Class I, Division1 or Division 2, and Class II shall be selected based on an overall evaluation, including the following:
Fire risk of the material attributes
Economic impact of replacing the unit process
Potential environmental dangers caused by having the unit process out of service for an extended period oftime due to fire or explosion
8.3 Applications.
8.3.1 Sewers and Appurtenances General .
Buildings and structures, including domes and covers, shall be constructed of materials in accordance with Table4.2 , Table 5.2 , Table 6.2(a) , and Table 6.2(b) except as indicated in 8.3.1.1 or 8.3.1.2 .
8.3.1.1
Small aboveground buildings and structures, including domes and covers, with a floor or surface area of 9.3 m 2
(100 ft 2 ) or less that are physically separated from other buildings or structures and that do not present a firehazard to other buildings or structures shall be permitted to be constructed of any appropriate materials.
8.3.1.2
Materials other than those required by Table 4.2 , Table 5.2 , Table 6.2(a) and Table 6.2(b) shall be permitted inbuildings or structures that are fully sprinklered in accordance with NFPA 13 and approved by the AHJ.
8.3.2* Pumping Facilities Critical Unit Processes .
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Materials selected for wastewater pumping facilities shall be in accordance with Table 4.2 unless otherwise specifiedby either of the following:
Where conditions or applications warrant the selection of combustible materials for pumping facilities, thefollowing shall be included as part of the fire risk evaluation:
Flame spread
Smoke generation
Corrosion resistance
Products of combustion
Impact of a fire or explosion on the structural integrity and operability of the pumping facility
Economic and environmental consequences of having the pumping facility out of service
Small aboveground pumping facilities with a floor area of 9.3 m 2 (100 ft 2 ) or less and physically separatedfrom the wet well and that do not present a fire hazard to other buildings or structures shall be permitted to beconstructed of any appropriate materials.
Buildings and structures containing critical unit processes shall be of noncombustible materials in accordance withTable 4.2 , Table 5.2 , Table 6.2(a) and Table 6.2(b) .
8.3.2.1
Where structural assemblies and partitions are required in critical unit process areas for fire separation in accordancewith the fire risk evaluation, they shall have a minimum 3-hour fire rating.
8.3.2.2
Nonstructural assemblies such as ventilation ducts and piping shall be constructed of noncombustible, limited-combustible, or low flame spread index materials.
8.3.3* Buildings and Structures Essential Unit Processes .
Buildings and structures containing essential unit processes shall be constructed of materials meeting the definitionsof noncombustible, limited-combustible, or low flame spread index in accordance with Table 4.2 , Table 5.2 , Table6.2(a) and Table 6.2(b) .
8.3.3.1 General.
Buildings and structures, including domes and covers, shall be constructed of materials in accordance with Table 4.2 ,Table 5.2 , Table 6.2(a) , and Table 6.2(b) , unless otherwise specified by any of the following:
Where conditions or applications warrant the selection of combustible materials for buildings and structures, thefollowing shall be included as part of the fire risk evaluation:
Flame spread
Smoke generation
Corrosion resistance
Products of combustion
Impact of a fire or explosion on structural integrity and operability of the facility
Economic and environmental consequences of having the facility out of service
Small aboveground buildings and structures, including domes and covers, with a floor or surface area of 9.3
m 2 (100 ft 2 ) or less that are physically separated from other buildings or structures and that do not present afire hazard to other buildings or structures shall be permitted to be constructed of any appropriate materials.
Materials other than those required by Table 4.2 , Table 5.2 , Table 6.2(a) , and Table 6.2(b) shall bepermitted in buildings or structures that are fully sprinklered in accordance with NFPA 13 .
Where structural assemblies and partitions are used in essential unit process areas for fire separation, they shall havea minimum 2-hour fire rating.
8.3.3.2* Critical Unit Processes.
Nonstructural assemblies such as ventilation ducts and piping shall be constructed of noncombustible, limited-combustible, or low flame spread index materials.
8.3.3.2.1
Buildings and structures, including domes and covers, containing unit processes that are critical to maintaining theintegrity of the treatment plant (e.g., headworks, main pumping facility, primary clarifiers), and that if out of service foreven a few hours could permanently damage the environment or endanger public health by allowing the release ofraw wastewater or sludge, shall be constructed of materials meeting the definition of noncombustible.
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8.3.3.2.2
The requirements of 8.3.3.2.1 shall not apply where otherwise permitted by 8.3.3.1 .
8.3.3.2.3
Where structural assemblies and partitions are required in critical unit process areas for fire separation in accordancewith the fire risk evaluation, they shall have a minimum 3-hour fire rating.
8.3.3.2.4
Nonstructural assemblies such as ventilation ducts and piping shall be constructed of noncombustible, limited-combustible, or low flame spread index materials.
8.3.3.3 Essential Unit Processes.
8.3.3.3.1
Buildings or structures, including domes and covers, containing unit processes that are essential to maintaining theintegrity of the treatment plant (e.g., secondary biological treatment, secondary clarifiers, or disinfection facilities),and that if out of service for short periods of time would not permanently damage the environment or endanger publichealth but would become critical if out of service for several days, shall be constructed of materials meeting thedefinitions of noncombustible, limited-combustible, or low flame spread index.
8.3.3.3.2
The requirements of 8.3.3.3.1 shall not apply where otherwise permitted by 8.3.3.1 .
8.3.3.3.3
Where structural assemblies and partitions are used in essential unit process areas for fire separation, they shallhave a minimum 2-hour fire rating.
8.3.3.3.4*
Nonstructural assemblies such as ventilation ducts and piping shall be constructed of noncombustible, limited-combustible, or low flame spread index materials.
8.3.3.4 Other Unit Processes.
8.3.3.4.1
Buildings and structures containing unit processes, including sludge-processing operations, that are not critical oressential to maintaining the integrity of the treatment plant, and that if out of service for long periods of time (i.e., aweek or more) would not permanently damage the environment or endanger public health, shall be constructed ofmaterials considered applicable by the authority having jurisdiction.
8.3.3.4.2
The requirements of 8.3.3.4.1 shall not apply where otherwise permitted by 8.3.3.1 .
8.3.3.4.3
Where structural assemblies and partitions are used in other unit process areas for fire separation, they shall have aminimum 1-hour fire rating.
8.3.3.4.4
Nonstructural assemblies such as ventilation ducts and piping shall be constructed of materials meeting thedefinitions of noncombustible, limited-combustible, or low flame spread index.
8.3.3.5 Combustible Gas Generation and Combustion Processes.
8.3.3.5.1
Buildings and structures containing unit processes that generate, process, or utilize combustible gases (e.g.,anaerobic wastewater treatment processes, anaerobic digesters, compressors, storage spheres, piping, waste gasburners, gas-fired equipment including sludge incinerators) shall be constructed of materials meeting the definition ofnoncombustible.
8.3.3.5.2
The requirements of 8.3.3.5.1 shall not apply where otherwise permitted by 8.3.3.1 .
8.3.3.6 Air Supply and Exhaust.
8.3.3.6.1
Noncombustible, limited-combustible, or low flame spread index materials shall be used for air supply and exhaustsystems.
8.3.3.6.2
Systems supplying or exhausting air at a rate greater than 56.6 m 3 /min (2000 ft 3 /min) shall include listed smokedampers, listed fire dampers, and smoke detection and shall cause the ventilation system to shut down upondetection of smoke.
8.3.3.6.3
Separate smoke ventilation systems shall be used where applicable, unless otherwise permitted by the following:
Smoke venting shall be permitted to be integrated into installed ventilation systems using automatic ormanually positioned dampers and motor speed control in accordance with NFPA 90A , and NFPA 204 shallbe reviewed for further information.
Smoke venting also shall be permitted to be accomplished through the use of portable smoke ejectors.
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8.3.3.7 Miscellaneous Materials.
8.3.3.7.1
Cellular or foamed plastic materials shall only be used in accordance with NFPA 101 ® .
8.3.3.7.2
Roof coverings shall be Class A in accordance with ASTM E 108, Standard Test Methods for Fire Tests of RoofCoverings , or UL 790, Standard Test Methods for Fire Tests of Roof Coverings .
8.3.3.7.3
Metal roof deck construction shall be Class I or shall be fire classified.
8.3.3.7.4
Class II metal roof deck construction shall be permitted in buildings or structures that are fully sprinklered inaccordance with 7.2.2 .
8.3.4* Combustible Gas Generation and Combustion Processes.
Buildings and structures containing other unit processes shall be constructed of materials as determined by the firerisk evaluation.
8.3.5* Sewers and Appurtenances.
Materials of construction for sewers and appurtenances such as maintenance holes, junction chambers, and catchbasins shall be based on the results of a written materials risk assessment.
8.3.6 Pumping Facilities.
Materials selected for wastewater pumping facilities shall be in accordance with Table 4.2 , except as indicated in8.3.6.1 .
8.3.6.1
Small aboveground pumping facilities with a floor area of 9.3 m 2 (100 ft 2 ) or less and physically separated fromthe wet well and that do not present a fire hazard to other buildings or structures shall be permitted to be constructedof any appropriate materials.
8.3.7* Other Unit Processes.
Buildings and structures containing other unit processes shall be constructed of materials as determined by the firerisk evaluation.
8.3.7.1
Where structural assemblies and partitions are used in other unit process areas for fire separation, they shall have aminimum 1-hour fire rating.
8.3.7.2
Nonstructural assemblies such as ventilation ducts and piping shall be constructed of materials meeting thedefinitions of noncombustible, limited-combustible, or low flame spread index.
8.3.8 Air Supply and Exhaust.
8.3.8.1
Noncombustible, limited-combustible, or low flame spread index materials shall be used for air supply and exhaustsystems.
8.3.8.2
Systems supplying or exhausting air at a rate greater than 56.6 m 3 /min (2000 ft 3 /min) shall include listed smokedampers, listed fire dampers, and smoke detection and shall cause the ventilation system to shut down upondetection of smoke.
8.3.8.3
Separate smoke ventilation systems designed and installed in accordance with NFPA 92 or NFPA 204 shall beused where applicable, unless otherwise permitted by the following:
(1) Smoke venting shall be permitted to be integrated into installed ventilation systems using automatic ormanually positioned dampers and motor speed control in accordance with NFPA 90A , NFPA 92 , and NFPA204 .
(2) Smoke venting also shall be permitted to be accomplished using listed portable smoke ejectors.
Supplemental Information
File Name Description
ComparisonFDtoSDChapter_8.docx For Committee use to compare first draft to second draft.
FINALSDMtgREVChapter_8.docx New Chapter 8 to be inserted. For editorial use.
AnnexA_Chapter8_820.docx New Annex A material for chapter 8 to be inserted. For editorial use.
Submitter Information Verification
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Submitter Full Name: [ Not Specified ]
Organization: [ Not Specified ]
Street Address:
City:
State:
Zip:
Submittal Date: Tue Oct 07 11:59:00 EDT 2014
Committee Statement
CommitteeStatement:
A task group was formed to review the building construction requirements and a second revision was created toreference the building code where appropriate and retain provisions specific for wastewater treatment facilitieswhere building codes do not cover these requirements. Definitions were added to the chapter and the order of theprocesses was modified to provide requirements for critical processes before non critical processes.
ResponseMessage:
Public Comment No. 7-NFPA 820-2014 [Chapter 8]
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Chapter 8 Materials of Construction
8.1 General.
8.1.1
This chapter shall apply to the selection of materials of construction for buildings, structures, and
process elements for protection against fire and explosion in wastewater treatment plants and
associated collection systems.
8.1.2
Materials of construction and interior coatings and finishes shall provide a maximum degree of fire
resistance with the minimum amount of flame spread and smoke generation associated with a
particular application.
8.1.1.3 *
Materials shall be selected that reduce or eliminate the effects of fire and explosion by maintaining
structural integrity, controlling flame spread and smoke generation, minimizing the release of toxic
products of combustion, and maintaining the serviceability and operation of critical processes.
8.1.3.1
The purpose of the criteria for selecting materials of construction shall not be to provide protection of
personnel from the risk of exposure to an asphyxiating or toxic atmosphere generated during a fire.
8.1.3.2
Criteria for selecting materials of construction shall not apply to nonprocess contents of the building,
structure, or assembly where such contents are not a part of the building, structure, or assembly,
including the following:
(1) Equipment or equipment enclosures
(2) Grating, walkways, ladders, railings, weirs, process piping, and appurtenances
(3) Process media
(4) Aeration devices
(5) Slide and sluice gates
(6) Pump packing and seal material
(7) Electrical conduit
(8) Hardware
(9) Liners for basins that are open to the atmosphere
(10) Materials used in rehabilitation or for lining existing sewer pipes
(11) Other components as allowed by the AHJ
8.1.4Facilities shall be constructed in accordance with the applicable building code and the
additional requirements in this standard.
8.1.2
In areas where corrosive environments are present, including classified areas, the mitigation of
corrosion problems in the selection and use of materials for nonstructural assemblies shall include
the use of the following:
(1) Corrosion-resistant metallic or nonmetallic grating
(2) RailingsCorrosion-resistant railings, steps and stairs, conduit
(3) ElectricCorrosion-resistant electric equipment enclosures
8.2 Materials Selection .
8.2.1 Materials shall be selected based on the criteria for a particularthe intended application.
8.2.2*
Selection criteria shall include specification of the following:
(1) Structural requirements
(2) Location and operating environment
(3) Fire resistance rating
(4) Flame spread index value
(5) *Smoke developed index or other smoke generation values
(6) Products of combustion
(7) Corrosion resistance
8.2.3
For the purpose of this document, materials of construction shall be divided into the following four
basic categories as defined in 8.2.3.1-8.2.3.4:
(1) Combustible
(2) Noncombustible
(3) Limited-combustible
(4) Low flame spread index Limited- 8.2.3.1 Combustible Material. A material that, in the form in which it is used and under the conditions anticipated, will ignite and burn; a material that does not meet the definition of noncombustible or limited-combustible shall be considered a combustible material.
A material shall be considered a limited-combustible material where both of the following conditions
of 8.2.2(1), and 8.2.2(2), and the conditions of either 8.2.2.1 or 8.2.2.2 are met:
(1) The material does not comply with the requirements for a noncombustible material in
accordance with 8.2.3.
(2) The material, in the form in which it is used, exhibits a potential heat value not exceeding 3500
Btu/lb (8141 kJ/kg), when tested in accordance with NFPA 259, Standard Test Method for Potential
Heat of Building Materials. [5000:7.1.4.2]
8.2.3.2.1
The material shall have a structural base of noncombustible material with a surfacing not exceeding
a thickness of 1⁄8 in. (3.2 mm) where the surfacing exhibits a flame spread index not greater than
50 when tested in accordance with ASTM E 84, Standard Test Method for Surface Burning
Characteristics of Building Materials, or ANSI/UL 723, Standard for Test for Surface Burning
Characteristics of Building Materials. [5000:7.1.4.2.1]
8.2.2.2
The material shall be composed of materials that in the form and thickness used, neither exhibit a
flame spread index greater than 25 nor evidence of continued progressive combustion when tested
in accordance with ASTM E 84 or ANSI/UL 723 and are of such composition that all surfaces that
would be exposed by cutting through the material on any plane would neither exhibit a flame
spread index greater than 25 nor exhibit evidence of continued progressive combustion when
tested in accordance with ASTM E 84 or ANSI/UL 723. [5000:7.1.4.2.2]
8.2.2.3
Where the term limited-combustible is used in this standard, it shall also include the term
noncombustible. [5000:7.1.4.2.3]
8.2.3* Noncombustible Material. ( A.8.2.3 here and A.8.2.3(1) here)
A material that complies with any one of the following shall be considered a noncombustible
material:
(1) *The material, in the form in which it is used, and under the conditions anticipated, will not
ignite, burn, support combustion, or release flammable vapors when subjected to fire or heat
(2) The material is reported as passing ASTM E 136, Standard Test Method for Behavior of
Materials in a Vertical Tube Furnace at 750 Degrees C
(3) The material is reported as complying with the pass/fail criteria of ASTM E 136 when tested in
accordance with the test method and procedure in ASTM E 2652, Standard Test Method for
Behavior of Materials in a Tube Furnace with a Cone-shaped Airflow Stabilizer, at 750 Degrees C
[5000:7.1.4.1.1]
8.2.3.2.1
Where the term limited-combustible is used in this standard, it shall also include the term
noncombustible. [5000:7.1.4.1.2]
8.2.4*
Selection criteria shall include the following:
(1) Structural requirements
(2) Location and operating environment
(3) Fire resistance rating
(4) Flame spread index value
(5) Smoke developed index or other smoke generation values
(6) Products of combustion
(7) Corrosion resistance
8.2.5
For the purpose of this document, materials of construction shall be divided into the following four
basic categories:
(1) 3.3* Limited-Combustible Material.
A material shall be considered a limited-combustible material where both of the following conditions
of 8.2.2(1), and 8.2.2(2), and the conditions of either 8.2.3.3.1 or 8.2.3.3.2 are met:
(1) The material does not comply with the requirements for a noncombustible material in
accordance with 8.2.3.
(2) The material, in the form in which it is used, exhibits a potential heat value not exceeding 3500
Btu/lb (8141 kJ/kg), when tested in accordance with NFPA 259, Standard Test Method for Potential
Heat of Building Materials. [5000:7.1.4.2]
(2) Noncombustible
(3) Limited-combustible
(4) Low flame spread index 8.2.3.3.1
The material shall have a structural base of noncombustible material with a surfacing not exceeding
a thickness of 1⁄8 in. (3.2 mm) where the surfacing exhibits a flame spread index not greater than
50 when tested in accordance with ASTM E 84, Standard Test Method for Surface Burning
Characteristics of Building Materials, or ANSI/UL 723, Standard for Test for Surface Burning
Characteristics of Building Materials. [5000:7.1.4.2.1]
8.2.3.3.2
The material shall be composed of materials that in the form and thickness used, neither exhibit a
flame spread index greater than 25 nor evidence of continued progressive combustion when tested
in accordance with ASTM E 84 or ANSI/UL 723 and are of such composition that all surfaces that
would be exposed by cutting through the material on any plane would neither exhibit a flame
spread index greater than 25 nor exhibit evidence of continued progressive combustion when
tested in accordance with ASTM E 84 or ANSI/UL 723. [5000:7.1.4.2.2]
8.2.3.3.3
Where the term limited-combustible is used in this standard, it shall also include the term
noncombustible. [5000:7.1.4.2.3]
6
8.2.3.4 *Flame Spread Index. A comparative measure, expressed as a dimensionless number, derived from visual measurements of the spread of flame versus time for a material tested in accordance with ASTM E 84, Standard Test Method for Surface Burning Characteristics of Building Materials; or UL 723, Standard for Test for Surface Burning Characteristics of Building Materials.
8.2.4 Materials of construction used for unit processes located in classified areas with an NFPA 70 classification of Class I, Division 1 or Division 2, and Class II shall be selected based on an overall upon a documented fire risk evaluation, including the following:.
(1) Fire risk of the material attributes
(2) Economic impact of replacing the unit process
(3) Potential environmental dangers caused by having the unit process out of service for an
extended period of time due to fire or explosion
8.3 Applications.
8.3.1* Sewers and Appurtenances.
Materials of construction for sewers and appurtenances such as maintenance holes, junction
chambers, and catch basins shall be based on the results of a written materials risk assessment.
8.3.2 Pumping Facilities.
Materials selected for wastewater pumping facilities shall be in accordance with Table 2.4.2 unless
otherwise specified by either of the following:
(1 ) Where conditions or applications warrant the selection of combustible materials for pumping
facilitieslimited-combustible, or low flame spread index materials, the following shall be included as
part of the fire risk evaluation:
(a) Flame spread
(b) Smoke generation
(c) Corrosion resistance
(d) Products of combustion
(e) Impact of a fire or explosion on the structural integrity and operability of the pumping facility
(f) Economic and environmental consequences of having the pumping facility out of service
(2) Small aboveground pumping facilities with a floor area of 9.3 m2 (100 ft2) or less and physically
separated from the wet well and that do not present a fire hazard to other buildings or structures
shall be permitted to be constructed of any appropriate materials.
8.3 Applications
8.3.3 Buildings and Structures.
8.3.3.1 General.
Buildings and structures, including domes and covers, shall be constructed of materials in
accordance with Table 4.2, Table 5.2, Table 6.2(a), and Table 6.2(b), unless otherwise specified by
any of the following:) except as indicated in 8.3.1.1 or 8.3.1.2.
8.3.(1) Where conditions or applications warrant the selection of combustible materials for
buildings and structures, the following shall be included as part of the fire risk evaluation:
(a) Flame spread
(b) Smoke generation
(c) Corrosion resistance
(d) Products of combustion
(e) Impact of a fire or explosion on structural integrity and operability of the facility
(f) Economic and environmental consequences of having the facility out of service
(2)1.1 Small aboveground buildings and structures, including domes and covers, with a floor or
surface area of 9.3 m2 (100 ft2) or less that are physically separated from other buildings or
structures and that do not present a fire hazard to other buildings or structures shall be permitted to
be constructed of any appropriate materials.
(
8.3).1.2 Materials other than those required by Table 4.2, Table 5.2, Table 6.2(a), and Table
6.2(b) shall be permitted in buildings or structures that are fully sprinklered in accordance with
NFPA 13 and approved by the AHJ.
8.3.3.2* Critical Unit Processes.
8.3.3.2.1
Buildings and structures, including domes and covers, containing critical unit processes that are
critical to maintaining the integrity of the treatment plant (e.g., headworks, main pumping facility,
primary clarifiers), and that if out of service for even a few hours could permanently damage the
environment or endanger public health by allowing the release of raw wastewater or sludge, shall
be constructed of non-combustible materials meeting the definition of noncombustible.in
accordance with Table 4.2, Table 5
8.3.3.2, Table 6.2
The requirements of 8.3.3(a), and Table 6.2.1 shall not apply where otherwise permitted by
8.3.3.1.(b).
8.3.3.2.31
Where structural assemblies and partitions are required in critical unit process areas for fire
separation in accordance with the fire risk evaluation, they shall have a minimum 3-hour fire rating.
8.3.3.2.4
Nonstructural assemblies such as ventilation ducts and piping shall be constructed of
noncombustible, limited-combustible, or low flame spread index materials.
8.3.3.3 Essential Unit Processes.
8.3.3.3.1
Buildings or structures, including domes and covers, containing unit processes that are essential to
maintaining the integrity of the treatment plant (e.g., secondary biological treatment, secondary
clarifiers, or disinfection facilities), and that if out of service for short periods of time would not
permanently damage the environment or endanger public health but would become critical if out of
service for several days, shall be constructed of materials meeting the definitions of noncombustible,
limited-combustible, or low flame spread index.
8.3.3.3.2
The requirements of 8.3.3.3.1 shall not apply where otherwise permitted by 8.3.3.1.
8.3.3.3.3
Where structural assemblies and partitions are used in essential unit process areas for fire
separation, they shall have a minimum 2-hour fire rating.
8.3.3.3.4*
Nonstructural assemblies such as ventilation ducts and piping shall be constructed of
noncombustible, limited-combustible, or low flame spread index materials.
8.3.3.4 Other* Essential Unit Processes.
8.3.3.4.1
(2) Buildings and structures containing essential unit processes, including sludge-processing
operations, that are not critical or essential to maintaining the integrity of the treatment plant, and
that if out of service for long periods of time (i.e., a week or more) would not permanently damage
the environment or endanger public health, shall be constructed of materials considered applicable
by the authority having jurisdiction.meeting the definitions of noncombustible, limited-combustible,
or low flame spread index in accordance with Table 4.2, Table 5.2, Table 6.2(a), and Table 6.2(b).
8.3.3.1
Where structural assemblies and partitions are used in essential unit process areas for fire
separation, they shall have a minimum 2-hour fire rating.
4.2
The requirements of
8.3.3.2* Nonstructural assemblies such as ventilation ducts and piping shall be constructed of
noncombustible, limited-combustible, or low flame spread index materials.
8.3.3.4.1* Combustible Gas Generation and Combustion Processes.
Buildings and structures containing other unit processes shall be constructed of materials as
determined by the fire risk evaluation.
8.3.5* Sewers and Appurtenances.
Materials of construction for sewers and appurtenances such as maintenance holes, junction
chambers, and catch basins shall be based on the results of a written materials risk assessment.
8.3.6 Pumping Facilities.
Materials selected for wastewater pumping facilities shall be in accordance with Table 4.2 except as
indicated in 8.3.6.1.
8.3.6.1 Small aboveground pumping facilities with a floor area of 9.3 m2 (100 ft2) or less and
physically separated from the wet well and that do not apply where otherwisepresent a fire hazard
to other buildings or structures shall be permitted to be constructed of any appropriate materials.
8.3.7* Other Unit Processes.
Buildings and structures containing other unit processes shall be constructed of materials as
determined by 8.3.3.1.the fire risk evaluation.
8.3.3.4.37.1
Where structural assemblies and partitions are used in other unit process areas for fire separation,
they shall have a minimum 1-hour fire rating.
8.3.3.4.47.2
Nonstructural assemblies such as ventilation ducts and piping shall be constructed of materials
meeting the definitions of noncombustible, limited-combustible, or low flame spread index.
8.3.3.5 Combustible Gas Generation and Combustion Processes.
8.3.3.5.1
Buildings and structures containing unit processes that generate, process, or utilize combustible
gases (e.g., anaerobic wastewater treatment processes, anaerobic digesters, compressors, storage
spheres, piping, waste gas burners, gas-fired equipment including sludge incinerators) shall be
constructed of materials meeting the definition of noncombustible.
8.3.3.5.2
The requirements of 8.3.3.5.1 shall not apply where otherwise permitted by 8.3.3.1.
8.3.3.6 Air Supply and Exhaust.
8.3.3.68.1
Noncombustible, limited-combustible, or low flame spread index materials shall be used for air
supply and exhaust systems.
8.3.3.68.2
Systems supplying or exhausting air at a rate greater than 56.6 m3/min (2000 ft3/min) shall include
listed smoke dampers, listed fire dampers, and smoke detection and shall cause the ventilation
system to shut down upon detection of smoke.
8.3.8.3.6.3
Separate smoke ventilation systems designed and installed in accordance with NFPA 92 or NFPA
204 shall be used where applicable, unless otherwise permitted by the following:
(1) Smoke venting shall be permitted to be integrated into installed ventilation systems using
automatic or manually positioned dampers and motor speed control in accordance with NFPA 90A,
NFPA 92 and NFPA 204 shall be reviewed for further information..
(2) Smoke venting also shall be permitted to be accomplished through the use of listed portable
smoke ejectors.
8.3.3.7 Miscellaneous Materials.
8.3.3.7.1
Cellular or foamed plastic materials shall only be used in accordance with NFPA 101® .
8.3.3.7.2
Roof coverings shall be Class A in accordance with ASTM E 108, Standard Test Methods for Fire
Tests of Roof Coverings, or UL 790, Standard Test Methods for Fire Tests of Roof Coverings.
8.3.3.7.3
Metal roof deck construction shall be Class I or shall be fire classified.
8.3.3.7.4
Class II metal roof deck construction shall be permitted in buildings or structures that are fully
sprinklered in accordance with 7.2.2.
Chapter 8 Materials of Construction
8.1 General
This chapter shall apply to the selection of materials of construction for buildings, structures, and
process elements for protection against fire and explosion in wastewater treatment plants and
associated collection systems.
8.1.1 *
Facilities shall be constructed in accordance with the applicable building code and the additional
requirements in this standard.
8.1.2
In areas where corrosive environments are present, including classified areas, the mitigation of
corrosion problems in the selection and use of materials for nonstructural assemblies shall include
the use of the following:
(1) Corrosion-resistant metallic or nonmetallic grating
(2) Corrosion-resistant railings, steps and stairs, conduit
(3) Corrosion-resistant electric equipment enclosures
8.2 Materials Selection
8.2.1 Materials shall be selected based on the criteria for the intended application.
8.2.2*
Selection criteria shall include specification of the following:
(1) Structural requirements
(2) Location and operating environment
(3) Fire resistance rating
(4) Flame spread index value
(5) *Smoke developed index or other smoke generation values
(6) Products of combustion
(7) Corrosion resistance
8.2.3
For the purpose of this document, materials of construction shall be divided into the following four
basic categories as defined in 8.2.3.1-8.2.3.4:
(1) Combustible
(2) Noncombustible
(3) Limited-combustible
(4) Low flame spread index
8.2.3.1 Combustible Material. A material that, in the form in which it is used and under the conditions anticipated, will ignite and burn; a material that does not meet the definition of noncombustible or limited-combustible shall be considered a combustible material.
8.2.3.2* Noncombustible Material.
A material that complies with any one of the following shall be considered a noncombustible
material:
(1) *The material, in the form in which it is used, and under the conditions anticipated, will not
ignite, burn, support combustion, or release flammable vapors when subjected to fire or heat
(2) The material is reported as passing ASTM E 136, Standard Test Method for Behavior of
Materials in a Vertical Tube Furnace at 750 Degrees C
(3) The material is reported as complying with the pass/fail criteria of ASTM E 136 when tested in
accordance with the test method and procedure in ASTM E 2652, Standard Test Method for
Behavior of Materials in a Tube Furnace with a Cone-shaped Airflow Stabilizer, at 750 Degrees C
[5000:7.1.4.1.1]
8.2.3.2.1
Where the term limited-combustible is used in this standard, it shall also include the term
noncombustible. [5000:7.1.4.1.2]
8.2.3.3* Limited-Combustible Material.
A material shall be considered a limited-combustible material where both of the following conditions
of 8.2.2(1), and 8.2.2(2), and the conditions of either 8.2.3.3.1 or 8.2.3.3.2 are met:
(1) The material does not comply with the requirements for a noncombustible material in
accordance with 8.2.3.
(2) The material, in the form in which it is used, exhibits a potential heat value not exceeding 3500
Btu/lb (8141 kJ/kg), when tested in accordance with NFPA 259, Standard Test Method for Potential
Heat of Building Materials. [5000:7.1.4.2]
8.2.3.3.1
The material shall have a structural base of noncombustible material with a surfacing not exceeding
a thickness of 1⁄8 in. (3.2 mm) where the surfacing exhibits a flame spread index not greater than
50 when tested in accordance with ASTM E 84, Standard Test Method for Surface Burning
Characteristics of Building Materials, or ANSI/UL 723, Standard for Test for Surface Burning
Characteristics of Building Materials. [5000:7.1.4.2.1]
8.2.3.3.2
The material shall be composed of materials that in the form and thickness used, neither exhibit a
flame spread index greater than 25 nor evidence of continued progressive combustion when tested
in accordance with ASTM E 84 or ANSI/UL 723 and are of such composition that all surfaces that
would be exposed by cutting through the material on any plane would neither exhibit a flame
spread index greater than 25 nor exhibit evidence of continued progressive combustion when
tested in accordance with ASTM E 84 or ANSI/UL 723. [5000:7.1.4.2.2]
8.2.3.3.3
Where the term limited-combustible is used in this standard, it shall also include the term
noncombustible. [5000:7.1.4.2.3]
8.2.3.4 *Flame Spread Index shall be considered a comparative measure, expressed as a dimensionless number, derived from visual measurements of the spread of flame versus time for a material tested in accordance with ASTM E 84, Standard Test Method for Surface Burning Characteristics of Building Materials; or UL 723, Standard for Test for Surface Burning Characteristics of Building Materials.
8.2.4 Materials of construction used for unit processes located in classified areas shall be selected based upon a documented fire risk evaluation.
8.2.4.1 Where conditions or applications warrant the selection of combustible materials limited-
combustible, or low flame spread index materials, the following shall be included as part of the fire
risk evaluation:
(a) Flame spread
(b) Smoke generation
(c) Corrosion resistance
(d) Products of combustion
(e) Impact of a fire or explosion on the structural integrity and operability
(f) Economic and environmental consequences of having the facility out of service
8.3 Applications
8.3.1 General.
Buildings and structures, including domes and covers, shall be constructed of materials in
accordance with Table 4.2, Table 5.2, Table 6.2(a), and Table 6.2(b) except as indicated in 8.3.1.1
or 8.3.1.2.
8.3.1.1 Small aboveground buildings and structures, including domes and covers, with a floor or
surface area of 9.3 m2 (100 ft2) or less that are physically separated from other buildings or
structures and that do not present a fire hazard to other buildings or structures shall be permitted to
be constructed of any appropriate materials.
8.3.1.2 Materials other than those required by Table 4.2, Table 5.2, Table 6.2(a), and Table 6.2(b)
shall be permitted in buildings or structures that are fully sprinklered in accordance with NFPA 13
and approved by the AHJ.
8.3.2* Critical Unit Processes.
Buildings and structures containing critical unit processes shall be of non-combustible materials in
accordance with Table 4.2, Table 5.2, Table 6.2(a), and Table 6.2(b).
8.3.2.1
Where structural assemblies and partitions are required in critical unit process areas for fire
separation in accordance with the fire risk evaluation, they shall have a minimum 3-hour fire rating.
8.3.2.2
Nonstructural assemblies such as ventilation ducts and piping shall be constructed of
noncombustible, limited-combustible, or low flame spread index materials.
Formatted: Font: Not Bold
8.3.3* Essential Unit Processes. (2) Buildings and structures containing essential unit processes
shall be constructed of materials meeting the definitions of noncombustible, limited-combustible, or
low flame spread index in accordance with Table 4.2, Table 5.2, Table 6.2(a), and Table 6.2(b).
8.3.3.1
Where structural assemblies and partitions are used in essential unit process areas for fire
separation, they shall have a minimum 2-hour fire rating.
8.3.3.2* Nonstructural assemblies such as ventilation ducts and piping shall be constructed of
noncombustible, limited-combustible, or low flame spread index materials.
8.3.4* Combustible Gas Generation and Combustion Processes.
Buildings and structures containing other unit processes shall be constructed of materials as
determined by the fire risk evaluation.
8.3.5* Sewers and Appurtenances.
Materials of construction for sewers and appurtenances such as maintenance holes, junction
chambers, and catch basins shall be based on the results of a written materials risk assessment.
8.3.6 Pumping Facilities.
Materials selected for wastewater pumping facilities shall be in accordance with Table 4.2 except as
indicated in 8.3.6.1.
8.3.6.1 Small aboveground pumping facilities with a floor area of 9.3 m2 (100 ft2) or less and
physically separated from the wet well and that do not present a fire hazard to other buildings or
structures shall be permitted to be constructed of any appropriate materials.
8.3.7* Other Unit Processes.
Buildings and structures containing other unit processes shall be constructed of materials as
determined by the fire risk evaluation.
8.3.7.1
Where structural assemblies and partitions are used in other unit process areas for fire separation,
they shall have a minimum 1-hour fire rating.
8.3.7.2
Nonstructural assemblies such as ventilation ducts and piping shall be constructed of materials
meeting the definitions of noncombustible, limited-combustible, or low flame spread index.
8.3.8 Air Supply and Exhaust.
8.3.8.1
Noncombustible, limited-combustible, or low flame spread index materials shall be used for air
supply and exhaust systems.
Formatted: Font: Bold
8.3.8.2
Systems supplying or exhausting air at a rate greater than 56.6 m3/min (2000 ft3/min) shall include
listed smoke dampers, listed fire dampers, and smoke detection and shall cause the ventilation
system to shut down upon detection of smoke.
8.3.8.3
Separate smoke ventilation systems designed and installed in accordance with NFPA 92 or NFPA
204 shall be used where applicable, unless otherwise permitted by the following:
(1) Smoke venting shall be permitted to be integrated into installed ventilation systems using
automatic or manually positioned dampers and motor speed control in accordance with NFPA 90A,
NFPA 92 and NFPA 204.
(2) Smoke venting also shall be permitted to be accomplished through the use of listed portable
smoke ejectors.
A.8.1.1 For more information on building construction types refer to the applicable building code or NFPA 5000®, Building Construction and Safety Code® and NFPA 220, Standard on Types of Building Construction. These NFPA documents provide additional details and cross-references for the building construction types described in four other model building codes. For AHJs where one of these model building codes are used, the cross references provide helpful information to assist in the proper application of the materials of construction requirements in NFPA 820.
A.8.2.2 (5)
The smoke developed index is assessed by means of testing via ASTM E 84 or ANSI/UL 723.The smoke
developed index is assessed by means of testing via ASTM E 84 or ANSI/UL 723.
A.8.2.3.2
The provisions of 7.1.4.1 of NFPA 5000 do not require inherently noncombustible materials to be tested in
order to be classified as noncombustible materials.
A.8.2.3.2 (1)
Examples of such materials include steel, concrete, masonry, and glass.
A.8.2.3.3
Materials subject to increase in combustibility or flame spread index beyond the limits herein established
through the effects of age, moisture, or other atmospheric conditions are considered combustible. (See
NFPA 259, Standard Test Method for Potential Heat of Building Materials, and NFPA 220, Standard on
Types of Building Construction.)
A.8.2.3.4 A flame spread index of 25 or less (LFS) is a flame spread index for a Class A material in
accordance with ASTM E 84 and is generally considered a low flame spread index.
A.8.3.2 Buildings and structures, including domes and covers, containing unit processes that are critical
to maintaining the integrity of the treatment plant (e.g., headworks, main pumping facility, primary
clarifiers), and that if out of service for even a few hours could permanently damage the environment or
endanger public health by allowing the release of raw wastewater or sludge.
A.8.3.3 Buildings or structures, including domes and covers, containing unit processes that are essential
to maintaining the integrity of the treatment plant (e.g., secondary biological treatment, secondary
clarifiers, or disinfection facilities), and that if out of service for short periods of time would not
permanently damage the environment or endanger public health but would become critical if out of
service for several days.
A.8.3.3.2
Plastic or fiberglass-reinforced plastic products are often used as materials of construction in unit
processes such as rotating biological contactors (RBC), bio-towers, trickling filters, inclined plate (tube)
settlers, ventilation ducts, and other equipment that might be subject to corrosion. Under normal operating
conditions, these plastic or fiberglass-reinforced plastic materials might be submerged. However, during
maintenance or repair, they can become exposed. During maintenance and repair operations, extreme
care should be taken with open flame such as cutting torches, because these exposed plastic or
fiberglass-reinforced plastic materials might present a considerable fuel load if ignited.
A. 8.3.4
Buildings and structures containing unit processes that generate, process, or utilize combustible gases
(e.g., anaerobic wastewater treatment processes, anaerobic digesters, compressors, storage spheres,
piping, waste gas burners, gas-fired equipment including sludge incinerators) should be constructed of
materials meeting the definition of noncombustible.
A.8.3.5
See Annex C of this document.
A.8.3.7 Buildings and structures containing unit processes, including sludge-processing operations, that
are not critical or essential to maintaining the integrity of the treatment plant, and that if out of service for
long periods of time (i.e., a week or more) would not permanently damage the environment or endanger
public health, should be constructed of materials considered applicable by the authority having
jurisdiction.
Second Revision No. 13-NFPA 820-2014 [ New Section after 9.1.1.1 ]
Submitter Information Verification
Submitter Full Name: [ Not Specified ]
Organization: [ Not Specified ]
Street Address:
City:
State:
Zip:
Submittal Date: Tue Oct 14 16:39:22 EDT 2014
Committee Statement
Committee Statement: This has been added to point to the alarm and signaling requirements in Chapter 7.
Response Message:
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Second Revision No. 10-NFPA 820-2014 [ Section No. 9.2.7 ]
9.2.7
Ventilation systems for hazardous areas that are designed to operate intermittently or only when the space is occupiedshall not be permitted to be used for the purpose of downgrading reducing the electrical classification of areas. (SeeChapters 4, 5, and 6 for further information.)
Submitter Information Verification
Submitter Full Name: [ Not Specified ]
Organization: [ Not Specified ]
Street Address:
City:
State:
Zip:
Submittal Date: Tue Oct 07 15:52:41 EDT 2014
Committee Statement
Committee Statement: Changed terminology to match that in 9.3.2. Reducing is a better term than downgrading.
Response Message:
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Second Revision No. 18-NFPA 820-2014 [ Section No. 10.4 ]
10.4 Fire Prevention Program.
Each plant shall establish a fire prevention program that includes all of the following items:
(1) Fire safety information for all employees and contractors that includes, as a minimum, the following:
(a) Familiarization with fire protection equipment and procedures
(b) Plant emergency alarms and procedures
(c) Procedures for reporting a fire
(2) Documented plant inspections, including provisions for handling remedial actions to correct conditions thatincrease fire hazards
(3) Description of the general housekeeping procedures and the control of transient combustibles, including control ofsuch materials stored in areas containing toxic or reactive chemicals
(4) Control of flammable and combustible liquids and gases in accordance with NFPA 30 and NFPA 54
(5) Control of ignition sources that include smoking, grinding, welding, and cutting in accordance with NFPA 51B
(6) Fire prevention surveillance in accordance with NFPA 601
(7)
(8) Planning documents and training conducted in accordance with NFPA 56 for flammable gas piping repairs,cleaning, purging and planned releases of gases
Submitter Information Verification
Submitter Full Name: Sonia Barbosa
Organization: [ Not Specified ]
Street Address:
City:
State:
Zip:
Submittal Date: Mon Oct 27 15:56:56 EDT 2014
Committee Statement
CommitteeStatement:
NFPA 56 contains numerous safe work practices related to cleaning, repairing, and purging flammable gaspiping systems. This comment provides a reference for the inclusion of NFPA 56 by reference as per PI #33and PC #2.
ResponseMessage:
Public Comment No. 2-NFPA 820-2014 [New Section after 10.4]
* Fire report, including an investigation and a statement on the corrective action to be taken
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Second Revision No. 9-NFPA 820-2014 [ Section No. A.3.3.16.1 ]
A.3.3.16.1 Gas-Handling Equipment.
Gas-handling equipment does not include equipment or devices for the utilization of the gas, such as boilers, andengines, and waste gas burners .
Submitter Information Verification
Submitter Full Name: [ Not Specified ]
Organization: [ Not Specified ]
Street Address:
City:
State:
Zip:
Submittal Date: Tue Oct 07 15:05:52 EDT 2014
Committee Statement
CommitteeStatement:
Waste gas burners was added to the requirements in table 6.2(a) Row 20 therefore this needed to beremoved from the annex material for gas handling equipment since it conflicts with the new requirements.
ResponseMessage:
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Second Revision No. 1-NFPA 820-2014 [ Sections A.3.3.34.1, A.3.3.34.2 ]
A.3.3.35.1 Combustible Liquid.
Definition applies as determined by the test procedures and apparatus set forth in Chapter 4 of NFPA 30, Flammableand Combustible Liquids Code . Combustible liquids are classified as Class II or Class III as follows:
(1) Class II — Any any liquid that has a flash point at or above 37.8°C (100°F) and below 60°C (140°F)
(2) Class IIIA — Any any liquid that has a flash point at or above 60°C (140°F), but below 93°C (200°F)
(3) Class IIIB — Any any liquid that has a flash point at or above 93°C (200°F)
A.3.3.35.2 Flammable Liquid.
See NFPA 30 . Definition applies as determined by the test procedures and apparatus set forth in Chapter 4 of NFPA30. Flammable liquids are further subclassified in accordance with the following:
(1) Class IA Liquid — any liquid that has a flash point below 73°F (22.8°C) and a boiling point below 100°F(37.8°C)
(2) Class IB Liquid — any liquid that has a flash point below 73°F (22.8°C) and a boiling point at or above 100°F(37.8°C)
(3) Class IC Liquid — any liquid that has a flash point at or above 73°F (22.8°C), but below 100°F (37.8°C)
Submitter Information Verification
Submitter Full Name: [ Not Specified ]
Organization: [ Not Specified ]
Street Address:
City:
State:
Zip:
Submittal Date: Mon Oct 06 20:00:29 EDT 2014
Committee Statement
CommitteeStatement:
Added annex to be consistent with the annex for combustible liquids. Definitions and annex have beentaken from NFPA 30.
Response Message:
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