2013 CALIFORNIA PLUMBING CODE 71
CALIFORNIA PLUMBING CODE – MATRIX ADOPTION TABLECHAPTER 5 - WATER HEATERS
(Matrix Adoption Tables are non-regulatory, intended only as an aid to the user. See Chapter 1 for state agency authority and building application.)
Adopting Agency BSC SFMHCD DSA OSHPD
BSCC DPH AGR DWR CA SL SLC1 2 1-AC AC SS SS/CC 1 2 3 4
Adopt Entire Chapter X X X X X X X
Adopt Entire Chapter as amended(amended sections listed below) X X X
Adopt only those sections that arelisted below
Chapter/Section
507.2 X X X
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501.0 General.501.1 Applicability. The regulations of this chapter shall gov-ern the construction, location, and installation of fuel-burningand other water heaters heating potable water, together withchimneys, vents, and their connectors. The minimum capac-ity for storage water heaters shall be in accordance with thefirst hour rating listed in Table 501.1. Design, construction,and workmanship shall be in accordance with accepted engi-neering practices, manufacturer’s instructions, and applica-ble standards and shall be of such character as to secure theresults sought to be obtained by this code. No water heatershall be hereinafter installed that does not comply with thetype and model of each size thereof approved by the Author-ity Having Jurisdiction. A list of accepted gas appliance stan-dards are referenced in Table 1401.1.
502.0 Permits.502.1 General. It shall be unlawful for a person to install,remove, or replace or cause to be installed, removed, orreplaced a water heater without first obtaining a permit fromthe Authority Having Jurisdiction to do so.
503.0 Inspection.503.1 Inspection of Chimneys or Vents. This inspectionshall be made after chimneys, vents, or parts thereof, author-ized by the permit, have been installed and before such ventor part thereof has been covered or concealed.503.2 Final Water Heater Inspection. This inspection shallbe made after work authorized by the permit has beeninstalled. The Authority Having Jurisdiction will make suchinspection as deemed necessary to be assured that the workhas been installed in accordance with the intent of this code.No appliance or part thereof shall be covered or concealeduntil the same has been inspected and approved by theAuthority Having Jurisdiction.
504.0 Water Heater Requirements.504.1 Location. Water heater installations in bedrooms andbathrooms shall be in accordance with one of the following[NFPA 54:10.28.1]:
(1) Fuel-burning water heaters shall be permitted to beinstalled in a closet located in the bedroom or bathroomprovided the closet is equipped with a listed, gasketeddoor assembly and a listed self-closing device. The self-closing door assembly shall meet the requirements ofSection 504.1.1. The door assembly shall be installedwith a threshold and bottom door seal and shall meet therequirements of Section 504.1.2. Combustion air for suchinstallations shall be obtained from the outdoors in accor-dance with Section 506.4. The closet shall be for theexclusive use of the water heater.
(2) Water heater shall be of the direct vent type. [NFPA54:10.28.1(2)]504.1.1 Self-Closing Doors. Self-closing doors shallswing easily and freely and shall be equipped with a self-closing device to cause the door to close and latch eachtime it is opened. The closing mechanism shall not havea hold-open feature. [NFPA 80:6.1.4.2]504.1.2 Gasketing. Gasketing on gasketed doors orframes shall be furnished in accordance with the pub-lished listings of the door, frame, or gasketing materialmanufacturer. [NFPA 80:6.4.8]Exception: Where acceptable to the Authority HavingJurisdiction, gasketing of non-combustible or limited-combustible material shall be permitted to be applied tothe frame, provided closing and latching of the door arenot inhibited.
504.2 Vent. Water heaters of other than the direct-vent typeshall be located as close as practical to the chimney or gasvent.504.3 Clearance.
504.3.1 Listed Water Heaters. The clearances shall notbe such as to interfere with combustion air, draft hoodclearance and relief, and accessibility for servicing.Listed water heaters shall be installed in accordance withtheir listings and the manufacturer’s installation instruc-tions. [NFPA 54:10.28.2.1]504.3.2 Unlisted Water Heaters. Unlisted water heatersshall be installed with a clearance of 12 inches (305 mm)on all sides and rear. Combustible floors under unlistedwater heaters shall be protected in an approved manner.[NFPA 54:10.28.2.2]
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CHAPTER 5WATER HEATERS
Number of Bathrooms 1 to 1.5 2 to 2.5 3 to 3.5Number of Bedrooms 1 2 3 2 3 4 5 3 4 5 6First Hour Rating,2 Gallons 42 54 54 54 67 67 80 67 80 80 80For SI units: 1 gallon = 3.785 LNotes:1 The first hour rating is found on the “Energy Guide” label.2 Solar water heaters shall be sized to meet the appropriate first hour rating as shown in the table.
TABLE 501.1FIRST HOUR RATING1
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504.4 Pressure-Limiting Devices. A water heater installa-tion shall be provided with overpressure protection by meansof an approved, listed device installed in accordance with theterms of its listing and the manufacturer’s installation instruc-tions. [NFPA 54:10.28.3]504.5 Temperature-Limiting Devices. A water heater instal-lation or a hot water storage vessel installation shall be pro-vided with over temperature protection by means of anapproved, listed device installed in accordance with the termsof its listing and the manufacturer’s installation instructions.[NFPA 54:10.28.4]504.6 Temperature, Pressure, and Vacuum Relief Devices.The installation of temperature, pressure, and vacuum reliefdevices or combinations thereof, and automatic gas shutoffdevices, shall be installed in accordance with the terms oftheir listings and the manufacturer’s installation instructions.A shutoff valve shall not be placed between the relief valveand the water heater or on discharge pipes between suchvalves and the atmosphere. The hourly British thermal units(Btu) (kW•h) discharge capacity or the rated steam reliefcapacity of the device shall be not less than the input rating ofthe water heater. [NFPA 54:10.28.5]
505.0 Oil-Burning and Other Water Heaters.505.1 Water Heaters.Water heaters deriving heat from fuelsor types of energy other than gas shall be constructed andinstalled in accordance with approved standards. Vents orchimneys for such appliances shall be approved types. Anadequate supply of air for combustion and for adequate ven-tilation of heater rooms or compartments shall be provided.Each such appliance shall be installed in a location approvedby the Authority Having Jurisdiction and local and state fire-prevention agencies.505.2 Safety Devices. Storage-type water heaters and hotwater boilers deriving heat from fuels or types of energy otherthan gas, shall be provided with, in addition to the primarytemperature controls, an over temperature safety protectiondevice constructed, listed, and installed in accordance withnationally recognized applicable standards for such devicesand a combination temperature and pressure-relief valve.505.3 Oil-Fired Water Heaters. Oil-fired water heaters shallbe installed in accordance with NFPA 31.505.4 Indirect-Fired Water Heaters. Indirect-fired waterheaters shall comply with the applicable sections of theASME Boiler and Pressure Vessel Code, or to one of the otherapplicable standards shown in Table 1401.1. Each waterheater shall bear a label in accordance with ASME require-ments, or an approved testing agency, certifying and attest-ing that such an appliance has been tested, inspected andmeets the requirements of the applicable standards or code.
505.4.1 Single-Wall Heat Exchanger. Indirect-firedwater heater that incorporate a single-wall heatexchanger shall meet the following requirements:(1) Connected to a low-pressure hot water boiler lim-
ited to a maximum of 30 pounds-force per squareinch gauge (psig) (207 kPa) by an approved safety orrelief valve.
(2) Heater transfer medium is either potable water or con-tains fluids having a toxicity rating or Class of 1.
(3) Bear a label with the word “Caution,” followed bythe following statements:(a) The heat-transfer medium shall be water or
other nontoxic fluid having a toxic rating orClass of 1 as listed in Clinical Toxicology ofCommercial Products, 5th edition.
(b) The pressure of the heat-transfer medium shallbe limited to a maximum of 30 psig (207 kPa)by an approved safety or relief valve.
The word “Caution” and the statements inletters shall have an uppercase height of not lessthan 0.120 of an inch (3.048 mm). The verticalspacing between lines of type shall be not lessthan 0.046 of an inch (1.168 mm). Lowercaseletters shall be compatible with the uppercaseletter size specification.
506.0 Air for Combustion and Ventilation.506.1 General. Air for combustion, ventilation, and dilutionof flue gases for appliances installed in buildings shall beobtained by application of one of the methods covered in Sec-tion 506.2.1 through Section 506.7.3. Where infiltration doesnot provide the necessary air, outdoor air shall be introducedin accordance with methods covered in Section 506.4 throughSection 506.7.3.Exception: This provision shall not apply to direct-ventappliances. [NFPA 54:9.3.1.1]
506.1.1 Other Types of Appliances.Appliances of otherthan natural draft design and other than Category I ventedappliances shall be provided with combustion, ventila-tion, and dilution air in accordance with the appliancemanufacturer’s instructions. [NFPA 54:9.3.1.2]506.1.2 Draft Hood and Regulators. Where used, adraft hood or a barometric draft regulator shall beinstalled in the same room or enclosure as the applianceserved so as to prevent a difference in pressure betweenthe hood or regulator and the combustion air supply.[NFPA 54:9.3.1.4]506.1.3 Makeup Air. Where exhaust fans, clothes dry-ers, and kitchen ventilation systems interfere with theoperation of appliances, makeup air shall be provided.[NFPA 54:9.3.1.5]
506.2 Indoor Combustion Air. The required volume ofindoor air shall be determined in accordance with Section506.2.1 or Section 506.2.2 except that where the air infiltra-tion rate is known to be less than 0.40 ACH (air change perhour), Section 506.2.2 shall be used. The total required vol-ume shall be the sum of the required volume calculated forappliances located within the space. Rooms communicatingdirectly with the space in which the appliances are installedthrough openings not furnished with doors, and through com-bustion air openings sized and located in accordance with
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Section 506.3 are considered a part of the required volume.[NFPA 54:9.3.2]
506.2.1 Standard Method. The required volume shallbe not less than 50 cubic feet per 1000 British thermalunits per hour (Btu/h) (4.83 m3/kW). [NFPA 54:9.3.2.1]506.2.2 Known Air Infiltration Rate Method. Wherethe air infiltration rate of a structure is known, the mini-mum required volume shall be determined as follows[NFPA 54:9.3.2.2]:(1) For appliances having other than fan-assisted com-
bustion systems, calculate using Equation506.2.2(1). [NFPA 54:9.3.2.2(1)]
(2) For fan-assisted combustion system appliances, cal-culate using Equation 506.2.2(2). [NFPA54:9.3.2.2(2)]
(3) For purpose of this calculation, an infiltration rategreater than 0.60 ACH shall not be used in the equa-tions. [NFPA 54:9.3.2.2(3)]
[Equation 506.2.2(1)]Required volume other ≥ (21 ft3 /ACH) x (Iother/1000Btu/h)
[Equation 506.2.2(2)]Required volume fan ≥ (15 ft3 /ACH) x (Ifan/1000 Btu/h)
Where:Iother = Appliances other than fan-assisted input in
Btu/hIfan = Fan-assisted appliance input in Btu/hACH = Air change per hour (percent of volume of
space exchanged per hour, expressed as a deci-mal)
For SI units: 1 cubic foot = 0.0283 m3, 1000 British thermal units perhour = 0.293 kW
506.3 Indoor Opening Size and Location. Openings usedto connect indoor spaces shall be sized and located in accor-dance with the following:(1) Each opening shall have a free area of not less than 1
square inch per 1000 Btu/h (0.002 m2/kW) of the totalinput rating of appliances in the space, but not less than100 square inches (0.065 m2). One opening shall com-mence within 12 inches (305 mm) of the top, and oneopening shall commence within 12 inches (305 mm) ofthe bottom of the enclosure (see Figure 506.3). Thedimension of air openings shall be not less than 3 inches(76 mm).
(2) The volumes of spaces in different stories shall be con-sidered as communicating spaces where such spaces areconnected by one or more openings in doors or floorshaving a total free area of not less than 2 square inchesper 1000 Btu/h (0.004 m2/kW) of total input rating ofappliances. [NFPA 54:9.3.2.3]
506.4 Outdoor Combustion Air. Outdoor combustion airshall be provided through opening(s) to the outdoors in accor-dance with methods in Section 506.4.1 or Section 506.4.2.The dimension of air openings shall be not less than 3 inches(76 mm). [NFPA 54:9.3.3]
506.4.1 Two Permanent Openings Method. Two per-manent openings, one commencing within 12 inches (305mm) of the top and one commencing within 12 inches(305 mm) of the bottom of the enclosure shall be pro-vided. The openings shall communicate directly, or byducts, with the outdoors or spaces that freely communi-cate with the outdoors as follows:(1) Where directly communicating with the outdoors or
where communicating to the outdoors through ver-tical ducts, each opening shall have a free area of notless than 1 square inch per 4000 Btu/h (0.0005m2/kW) of total input rating of appliances in theenclosure. [See Figure 506.4(1) and Figure 506.4(2)]
(2) Where communicating with the outdoors throughhorizontal ducts, each opening shall have a free areaof not less than 1 square inch per 2000 Btu/h (0.001m2/kW) of total input rating of appliances in theenclosure. [See Figure 506.4(3)] [NFPA 54:9.3.3.1]
506.4.2 One Permanent Opening Method. One per-manent opening, commencing within 12 inches (305mm) of the top of the enclosure, shall be provided. Theappliance shall have clearances of not less than 1 inch(25.4 mm) from the sides and back and 6 inches (152mm) from the front of the appliance. The opening shall
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FIGURE 506.3COMBUSTION AIR FROM ADJACENT INDOOR SPACESTHROUGH INDOOR COMBUSTION AIR OPENINGS
[NFPA 54: FIGURE A.9.3.2.3(1)]
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FIGURE 506.4(1)COMBUSTION AIR FROM OUTDOORS
INLET AIR FROM VENTILATED CRAWL SPACE ANDOUTLET AIR TO VENTILATED ATTIC[NFPA 54: FIGURE A.9.3.3.1(1)(a)]
For SI units: 1 foot = 304.8 mm
FIGURE 506.4(2)COMBUSTION AIR FROM OUTDOORS
THROUGH VENTILATED ATTIC[NFPA 54: FIGURE A.9.3.3.1(1)(b)]
FIGURE 506.4.2COMBUSTION AIR FROM OUTDOORS THROUGH
SINGLE COMBUSTION AIR OPENING[NFPA 54: FIGURE A.9.3.3.2]
FIGURE 506.4(3)COMBUSTION AIR FROM
OUTDOORS THROUGH HORIZONTAL DUCTS[NFPA 54: FIGURE A.9.3.3.1(2)]
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directly communicate with the outdoors or shall com-municate through a vertical or horizontal duct to the out-doors or spaces that freely communicate with theoutdoors (see Figure 506.4.2) and shall have a minimumfree area of the following:(1) One square inch per 3000 Btu/h (0.0007 m2/kW) of
the total input rating of appliances located in theenclosure, and
(2) Not less than the sum of the areas of vent connectorsin the space. [NFPA 54:9.3.3.2]
506.5 Combination Indoor and Outdoor Combustion Air.The use of a combination of indoor and outdoor combustionair shall be in accordance with Section 506.5.1, Section506.5.2, and Section 506.5.3 (see Appendix J). [NFPA54:9.3.4]
506.5.1 Indoor Openings. Where used, openings con-necting the interior spaces shall be in accordance withSection 506.3. [NFPA 54:9.3.4(1)]506.5.2 Outdoor Openings. Outdoor openings shall belocated in accordance with Section 506.4.1 or Section506.4.2. [NFPA 54:9.3.4(2)]506.5.3 Outdoor Openings Size. The outdoor openingssize shall be calculated in accordance with the following:(1) The ratio of interior spaces shall be the volume of
communicating spaces divided by the volume.(2) The outdoor size reduction factor shall be one minus
the ratio of interior spaces.(3) The minimum size of outdoor openings shall be the
full size of outdoor openings calculated in accor-dance with Section 506.4.1 or Section 506.4.2, mul-tiplied by the reduction factor. The dimension of airopenings shall be not less than 3 inches (76 mm).[NFPA 54:9.3.4(3)]
506.6 Engineered Installations. Engineered combustion airinstallations shall provide a supply of combustion, ventila-tion, and dilution air that is approved by the Authority Hav-ing Jurisdiction. [NFPA 54:9.3.5]506.7 Mechanical Combustion Air Supply. Where com-bustion air is provided by a mechanical air supply system, thecombustion air shall be supplied from outdoors at the mini-mum rate of 0.35 cubic feet per minute per 1000 Btu/h [0.034(m3/min)/kW] for appliances located within the space. [NFPA54:9.3.6]
506.7.1 Exhaust Fans. Where exhaust fans are installed,additional air shall be provided to replace the exhaustedair. [NFPA 54:9.3.6.1]506.7.2 Interlock. Each of the appliances served shallbe interlocked to the mechanical air supply system to pre-vent main burner operation where the mechanical airsupply system is not in operation. [NFPA 54:9.3.6.2]506.7.3 Specified Combustion Air. Where combustionair is provided by the building’s mechanical ventilationsystem, the system shall provide the specified combus-tion air rate in addition to the required ventilation air.[NFPA 54:9.3.6.3]
506.8 Louvers, Grilles, and Screens. The required size ofopenings for combustion, ventilation, and dilution air shallbe based on the net free area of each opening. Where the freearea through a design of louver or grille is known, it shall beused in calculating the size opening required to provide thefree area specified. Where the design and free area are notknown, it shall be assumed that wood louvers have 25 per-cent free area and metal louvers and grilles have 75 percentfree area. Nonmotorized louvers and grilles shall be fixed inthe open position. [NFPA 54:9.3.7.1]
506.8.1 Minimum Screen Mesh Size. Screens shall benot less than 1⁄4 of an inch (6.4 mm) mesh. [NFPA54:9.3.7.2]506.8.2 Motorized Louvers. Motorized louvers shall beinterlocked with the appliance so they are proven in thefull open position prior to main burner ignition and dur-ing main burner operation. Means shall be provided toprevent the main burner from igniting where the louverfail to open during burner start-up and to shut down themain burner where the louvers close during burner oper-ation. [NFPA 54:9.3.7.3]
506.9 Combustion Air Ducts. Combustion air ducts shallcomply with the following [NFPA 54:9.3.8]:(1) Ducts shall be of galvanized steel or a material having
equivalent corrosion resistance, strength, and rigidity.Exception: Within dwelling units, unobstructed stud andjoist spaces shall not be prohibited from conveying com-bustion air, provided that not more than one fireblock isremoved. [NFPA 54:9.3.8.1]
(2) Ducts shall terminate in an unobstructed space, allowingfree movement of combustion air to the appliances.[NFPA 54:9.3.8.2]
(3) Ducts shall serve a single space. [NFPA 54:9.3.8.3](4) Ducts shall not service both upper and lower combustion
air openings where both such openings are used. The sep-aration between ducts serving upper and lower combus-tion air openings shall be maintained to the source ofcombustion air. [NFPA 54:9.3.8.4]
(5) Ducts shall not be screened where terminating in an atticspace. [NFPA 54:9.3.8.5]
(6) Combustion air intake openings located on the exterior ofthe building shall have the lowest side of the combustionair intake openings located not less than 12 inches (305mm) vertically from the adjoining finished ground level.[NFPA 54:9.3.8.8]
(7) Horizontal upper combustion air ducts shall not slopedownward toward the source of combustion air. [NFPA54:9.3.8.6]
(8) The remaining space surrounding a chimney liner, gasvent, special gas vent, or plastic piping installed within amasonry chimney flue, metal or factory-built chimney,shall not be used to supply combustion air unless it islisted and shown in the manufacturer’s installationinstructions. [NFPA 54:9.3.8.7]
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507.0 Other Water Heater Installation Requirements.507.1 Dielectric Insulator. The Authority Having Jurisdic-tion shall have the authority to require the use of an approveddielectric insulator on the water piping connections of waterheaters and related water heating appliances.
507.1.1 Support of Appliances. Appliances shall be fur-nished either with load-distributing bases or with anapproved number of supports to prevent damage to eitherthe building structure or appliance. [NFPA 54:9.1.8.3]
507.2 Seismic Provisions. Water heaters shall be anchoredor strapped to resist horizontal displacement due to earth-quake motion. Strapping shall be at points within the upperone third (1⁄3) and lower one-third (1⁄3) of its vertical dimen-sions. At the lower point, a minimum distance of four (4)inches (102 mm) shall be maintained above the controls withthe strapping.Note: [HCD 1 & HCD 2] Reference Health and Safety CodeSection 19211(a) which addresses new, replacement, andexisting water heaters.Note: The applicable subsection of Health and Safety Code Sec-tion 19211(a) which addresses new, replacement, and existingwater heaters is repeated here for clarity and reads as follows:
Section 19211(a) Notwithstanding Section 19100, all newand replacement water heaters, and all existing residentialwater heaters shall be braced, anchored, or strapped to resistfalling or horizontal displacement due to earthquake motion.At a minimum, any water heater shall be secured in accor-dance with the California Plumbing Code, or modificationsmade thereto by a city, county, or city and county pursuant toSection 17958.5.
507.2.1 Structural Capacity. At the locations selected forinstallation of the appliances and equipment, the dynamicand static load-carrying capacities of the building struc-ture shall be checked to determine whether they are capa-ble to carry the additional loads. The appliance shall besupported and shall be connected to the piping so as not toexert undue stress on the connections. [NFPA 54:9.1.8.4]
507.3 Ground Support. A water heater supported from theground shall rest on level concrete or other approved baseextending not less than 3 inches (76 mm) above the adjoiningground level.507.4 Drainage Pan. Where a water heater is located in anattic, attic-ceiling assembly, floor-ceiling assembly, or floor-subfloor assembly where damage results from a leaking waterheater, a watertight pan of corrosion-resistant materials shallbe installed beneath the water heater with not less than 3⁄4 ofan inch (20 mm) diameter drain to an approved location.507.5 Relief Valve Discharge. Discharge from a relief valveinto a water heater pan shall be prohibited.507.6 Added or Converted Appliances. Where an additionalor replacement appliance is installed or an appliance is con-verted to gas from another fuel, the location in which theappliance is to be operated shall be checked to verify the fol-lowing [NFPA 54:9.1.2]:(1) Air for combustion and ventilation is provided where
required, in accordance with the provisions of Section506.0. Where existing facilities are not adequate, they
shall be upgraded to Section 506.0 specifications. [NFPA54:9.1.2(1)]
(2) The installation components and appliances shall beinstalled with clearances from combustible material sotheir operation will not create a hazard to persons orproperty. Minimum clearances between combustiblewalls and the back and sides of various conventionaltypes of appliances and their vent connectors are speci-fied in Table 509.7.3 and Table 509.7.3(1). [NFPA54:9.2.2]. It shall be determined that the installation andoperation of the additional or replacement appliance doesnot render the remaining appliance unsafe for continuedoperation. [NFPA 54:9.1.2(2)]
(3) The venting system is constructed and sized in accor-dance with the provisions of this chapter. Where the exist-ing venting system is not adequate, it shall be upgraded inaccordance with this chapter. [NFPA 54:9.1.2(3)]
507.7 Types of Gases. The appliance shall be connected tothe fuel gas for which it was designed. No attempt shall bemade to convert the appliance from the gas specified on therating plate for use with a different gas without consulting theinstallation instructions, the serving gas supplier, or the appli-ance manufacturer for complete instructions. [NFPA 54-12:9.1.3]507.8 Safety Shutoff Devices for Unlisted LP-Gas Appli-ance Used Indoors. Unlisted appliances for use with undi-luted liquefied petroleum gases and installed indoors shall beequipped with safety shutoff devices of the complete shutofftype. [NFPA 54:9.1.4]507.9 Use of Air or Oxygen Under Pressure. Where air oroxygen under pressure is used in connection with the gas sup-ply, effective means such as a backpressure regulator andrelief valve shall be provided to prevent air or oxygen frompassing back into the gas piping. Where oxygen is used,installation shall be in accordance with NFPA 51. [NFPA54:9.1.5]507.10 Protection of Gas Appliances from Fumes or Gasesother than Products of Combustion. Non-direct vent-typegas appliances installed in beauty shops, barbershops, or otherfacilities where chemicals that generate corrosive or flam-mable products such as aerosol sprays are routinely used shallbe located in an equipment room separate or partitioned offfrom other areas with provisions for combustion and dilutionair from outdoors. Direct vent appliances shall be installed inaccordance with the appliance manufacturer’s installationinstructions. [NFPA 54:9.1.6.2]507.11 Process Air. In addition to air needed for combustionin commercial or industrial processes, process air shall be pro-vided as required for cooling of equipment or material, con-trolling dew point, heating, drying, oxidation, dilution, safetyexhaust, odor control, air for compressors, and for comfortand proper working conditions for personnel. [NFPA54:9.1.7]507.12 Flammable Vapors. Gas appliances shall not beinstalled in areas where the open use, handling, or dispensingof flammable liquids occurs, unless the design, operation, orinstallation reduces the potential of ignition of the flamma-ble vapors. Appliances installed in accordance with Section
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507.13, Section 507.14, or Section 507.15 shall be consid-ered to be in accordance with the intent of this provision.[NFPA 54:9.1.9]507.13 Installation in Garages. Appliances in garages and inadjacent spaces that open to the garage and are not part of theliving space of a dwelling unit shall be installed so that burn-ers and burner-ignition devices are located not less than 18inches (457 mm) above the floor unless listed as flammablevapor ignition resistant. [NFPA 54:9.1.10.1]
507.13.1 Physical Damage. Appliances installed ingarages, warehouses, or other areas subject to mechani-cal damage shall be guarded against such damage bybeing installed behind protective barriers or by being ele-vated or located out of the normal path of vehicles.507.13.2 Access from the Outside Only. Where suchappliances installed within a garage are enclosed in a sep-arate, approved compartment having access only fromoutside of the garage, such appliances shall be permittedto be installed at floor level, provided the required com-bustion air is taken from and discharged to the exterior ofthe garage. [NFPA 54:9.1.10.3]
507.14 Installation in Commercial Garages.507.14.1 Parking Structures. Appliances installed inenclosed, basement, and underground parking structuresshall be installed in accordance with NFPA 88A. [NFPA54:9.1.11.1]507.14.2 Repair Garages. Appliances installed in repairgarages shall be installed in a detached building or room,separated from repair areas by walls or partitions, floors,or floor-ceiling assemblies that are constructed so as toprohibit the transmission of vapors and having a fire-resistance rating of not less than 1 hour, and that have noopenings in the wall separating the repair area within 8feet (2438 mm) of the floor. Wall penetrations shall befirestopped. Air for combustion purposes shall beobtained from outside the building. The heating roomshall not be used for the storage of combustible materials.Exceptions:(1) Overhead heaters where installed not less than 8 feet
(2438 mm) above the floor shall be permitted.(2) Heating appliances for vehicle repair areas where
there is no dispensing or transferring of Class I orClass II flammable or combustible liquids or lique-fied petroleum gas shall be installed in accordancewith NFPA 30A. [NFPA 54:9.1.11.2]
507.15 Installation in Aircraft Hangars. Heaters in aircrafthangars shall be installed in accordance with NFPA 409.[NFPA 54:9.1.12]507.16 Venting of Flue Gases. Appliances shall be vented inaccordance with the provisions of this chapter. [NFPA54:9.1.14]507.17 Extra Device or Attachment. No device or attach-ment shall be installed on an appliance that is capable ofimpairing the combustion of gas. [NFPA 54:9.1.15]507.18 Adequate Capacity of Piping. Where additionalappliances are being connected to a gas piping system, theexisting piping shall be checked to determine where it has
adequate capacity. Where inadequate, the existing systemshall be enlarged as necessary, or separate gas piping of ade-quate capacity shall be run from the point of delivery to theappliance. [NFPA 54:9.1.16]507.19 Avoiding Strain on Gas Piping. Appliances shall besupported and so connected to the piping as not to exert unduestrain on the connections. [NFPA 54:9.1.17]507.20 Gas Appliance Pressure Regulators. Where the gassupply pressure is higher than that at which the appliance isdesigned to operate or varies beyond the design pressure lim-its of the appliance, a gas appliance pressure regulator shall beinstalled. [NFPA 54:9.1.18]507.21 Venting of Gas Appliance Pressure Regulators.Venting of gas appliance pressure regulators shall be in accor-dance with the following requirements:(1) Gas appliance pressure regulators requiring access to the
atmosphere for successful operation shall be equippedwith vent piping leading outdoors or, where the regula-tor vent is an integral part of the appliance, into the com-bustion chamber adjacent to a continuous pilot, unlessconstructed or equipped with a vent limiting means tolimit the escape of gas from the vent opening in the eventof diaphragm failure.
(2) Vent limiting means shall be employed on listed gasappliance pressure regulators.
(3) In the case of vents leading outdoors, means shall beemployed to prevent water from entering this piping andalso to prevent blockage of vents by insects and foreignmatter.
(4) Under no circumstances shall a regulator be vented to theappliance flue or exhaust system.
(5) In the case of vents entering the combustion chamber,the vent shall be located so the escaping gas will be read-ily ignited by the pilot and the heat liberated thereby willnot adversely affect the normal operation of the safetyshutoff system. The terminus of the vent shall be securelyheld in a fixed position relative to the pilot. For manu-factured gas, the need for a flame arrester in the vent pip-ing shall be determined.
(6) Vent lines from a gas appliance pressure regulator andbleed lines from a diaphragm-type valve shall not be con-nected to a common manifold terminating in a combustionchamber. Vent lines shall not terminate in positive-pres-sure-type combustion chambers. [NFPA 54:9.1.19]
507.22 Bleed Lines for Diaphragm-Type Valves. Bleedlines shall comply with the following requirements:(1) Diaphragm-type valves shall be equipped to convey
bleed gas to the outdoors or into the combustion cham-ber adjacent to a continuous pilot.
(2) In the case of bleed lines leading outdoors, means shallbe employed to prevent water from entering this pipingand also to prevent blockage of vents by insects and for-eign matter.
(3) Bleed lines shall not terminate in the appliance flue orexhaust system.
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(4) In the case of bleed lines entering the combustion cham-ber, the bleed line shall be located so the bleed gas willbe readily ignited by the pilot and the heat liberatedthereby will not adversely affect the normal operation ofthe safety shutoff system. The terminus of the bleed lineshall be securely held in a fixed position relative to thepilot. For manufactured gas, the need for a flame arresterin the bleed line piping shall be determined.
(5) Bleed lines from a diaphragm-type valve and vent linesfrom a gas appliance pressure regulator shall not be con-nected to a common manifold terminating in a combus-tion chamber. Bleed lines shall not terminate inpositive-pressure-type combustion chambers. [NFPA54:9.1.20]
507.23 Combination of Appliances. A combination of appli-ances, attachments, or devices used together in a manner shallbe in accordance with the standards that apply to the individ-ual appliance. [NFPA 54:9.1.21]507.24 Installation Instructions. The installing agency shallcomply with the appliance manufacturer’s installation instruc-tions in completing an installation. The installing agency shallleave the manufacturer’s installation, operating, and mainte-nance instructions in a location on the premises where theywill be readily available for reference and guidance for theAuthority Having Jurisdiction, service personnel, and theowner or operator. [NFPA 54:9.1.22]507.25 Protection of Outdoor Appliances. Appliances notlisted for outdoor installation but installed outdoors shall beprovided with protection to the degree that the environmentrequires. Appliances listed for outdoor installation shall bepermitted to be installed without protection in accordancewith the provisions of its listing. [NFPA 54:9.1.23]507.26 Accessibility for Service.Appliances shall be locatedwith respect to building construction and other equipment soas to permit access to the appliance. Sufficient clearance shallbe maintained to permit cleaning of heating surfaces; thereplacement of filters, blowers, motors, burners, controls, andvent connections; the lubrication of moving parts where nec-essary; the adjustment and cleaning of burners and pilots; andthe proper functioning of explosion vents, where provided.For attic installation, the passageway and servicing area adja-cent to the appliance shall be floored. [NFPA 54:9.2.1]
508.0 Appliances on Roofs.508.1 General. Appliances on roofs shall be designed orenclosed so as to withstand climatic conditions in the area inwhich they are installed. Where enclosures are provided, eachenclosure shall permit easy entry and movement, shall be ofreasonable height, and shall have not less than a 30 inch (762mm) clearance between the entire service access panel(s) ofthe appliance and the wall of the enclosure. [NFPA 54:9.4.1.1]
508.1.1 Load Capacity. Roofs on which an appliance isto be installed shall be capable of supporting the addi-tional load or shall be reinforced to support the additionalload. [NFPA 54:9.4.1.2]508.1.2 Fasteners.Access locks, screws, and bolts shallbe of corrosion-resistant material. [NFPA 54:9.4.1.3]
508.2 Installation of Appliances on Roofs. Appliances shallbe installed in accordance with its listing and the manufac-turer’s installation instructions. [NFPA 54:9.4.2.1]
508.2.1 Clearance. Appliances shall be installed on awell-drained surface of the roof. Not less than 6 feet(1829 mm) of clearance shall be between a part of theappliance and the edge of a roof or similar hazard, orrigidly fixed rails, guards, parapets, or other buildingstructures not less than 42 inches (1067 mm) in heightshall be provided on the exposed side. [NFPA 54:9.4.2.2]508.2.2 Electrical Power.Appliances requiring an exter-nal source of electrical power for its operation shall beprovided with:(1) A readily accessible electrical disconnecting means
within sight of the appliance that will completely de-energize the appliance.
(2) A 120-VAC grounding-type receptacle outlet on theroof adjacent to the appliance. The receptacle outletshall be on the supply side of the disconnect switch.[NFPA 54:9.4.2.3]
508.2.3 Platform or Walkway. Where water stands onthe roof of the appliance or in the passageways to theappliance, or where the roof is of a design having a waterseal, an approved platform, walkway, or both shall beprovided above the waterline. Such platforms or walk-ways shall be located adjacent to the appliance and con-trol panels so that the appliance is capable of being safelyserviced where water stands on the roof. [NFPA54:9.4.2.4]
508.3 Access to Equipment and Appliances on Roofs.Equipment and appliances located on roofs or other elevatedlocations shall be accessible. [NFPA 54:9.4.3.1]
508.3.1 Access. Buildings exceeding 15 feet (4572 mm)in height shall have an inside means of access to the roof,unless other means acceptable to the Authority HavingJurisdiction are used. [NFPA 54:9.4.3.2]508.3.2 Access Type. The inside means of access shall bea permanent, or fold-away inside stairway or ladder, ter-minating in an enclosure, scuttle, or trap door. Such scut-tles or trap doors shall be not less than 22 inches by 24inches (559 mm by 610 mm) in size, shall open easilyand safely under all conditions, especially snow; andshall be constructed so as to permit access from the roofside unless deliberately locked on the inside.
Not less than 6 feet (1829 mm) of clearance shall bebetween the access opening and the edge of the roof orsimilar hazard, or rigidly fixed rails or guards not lessthan 42 inches (1067 mm) in height shall be provided onthe exposed side. Where parapets or other building struc-tures are utilized in lieu of guards or rails, they shall benot less than 42 inches (1067 mm) in height. [NFPA54:9.4.3.3]508.3.3 Permanent Lighting. Permanent lighting shallbe provided at the roof access. The switch for such light-ing shall be located inside the building near the accessmeans leading to the roof. [NFPA 54:9.4.3.4]
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508.4 Appliances in Attics and Under-Floor Spaces. Anattic or under-floor space in which an appliance is installedshall be accessible through an opening and passageway notless than as large as the largest component of the appliance,and not less than 22 inches by 30 inches (559 mm by 762mm).
508.4.1 Length of Passageway.Where the height of thepassageway is less than 6 feet (1829 mm), the distancefrom the passageway access to the appliance shall notexceed 20 feet (6096 mm) measured along the centerlineof the passageway. [NFPA 54:9.5.1.1]508.4.2 Width of Passageway. The passageway shall beunobstructed and shall have solid flooring not less than24 inches (610 mm) wide from the entrance opening tothe appliance. [NFPA 54:9.5.1.2]508.4.3 Work Platform. A level working platform notless than 30 inches (762 mm) by 30 inches (762 mm)shall be provided in front of the service side of the appli-ance. [NFPA 54:9.5.2]508.4.4 Lighting and Convenience Outlet. A perma-nent 120-volt receptacle outlet and a lighting fixture shallbe installed near the appliance. The switch controllingthe lighting fixture shall be located at the entrance to thepassageway. [NFPA 54:9.5.3]
509.0 Venting of Appliances.509.1 Minimum Safe Performance. Venting systems shallbe designed and constructed to convey flue, vent, or bothgases to the outdoors. [NFPA 54-12:12.1]
509.1.1 Installation. Listed vents shall be installed inaccordance with this chapter and the manufacturer’sinstallation instructions. [NFPA 54:12.2.3]509.1.2 Prohibited Discharge. Appliance vents shall notdischarge into a space enclosed by screens having open-ings less than 1⁄4 of an inch (6.4 mm) mesh.
509.2 Connection to Venting Systems. Except as permittedin Section 509.2.1 through Section 509.2.5, appliances shallbe connected to venting systems. [NFPA 54:12.3.1]
509.2.1 Appliances Not Required to be Vented. Thefollowing appliances shall not be required to be vented[NFPA 54:12.3.2]:(1) A single listed booster-type (automatic instanta-
neous) water heater, where designed and used solelyfor the sanitizing rinse requirements of a dish-wash-ing machine, provided that the appliance is installedwith the draft hood in place and unaltered where adraft hood is required, in a commercial kitchen hav-ing a mechanical exhaust system; where installed inthis manner, the draft hood outlet shall be not lessthan 36 inches (914 mm) vertically and 6 inches(152 mm) horizontally from a surface other than theappliance. [NFPA 54:12.3.2(5)]
(2) Other appliances listed for unvented use and not pro-vided with flue collars. [NFPA 54:12.3.2(10)]
Where appliances in Section 509.2.1(1) and Sec-tion 509.2.1(2) are installed so the aggregate inputrating exceeds 20 British thermal units per hour per
cubic foot [(Btu/h)/ft3] (0.21 kW/m3) of room orspace in which it is installed, one or more shall beprovided with venting systems or other approvedmeans for conveying the vent gases to the outdoorsso the aggregate input rating of the remainingunvented appliance does not exceed 20 [(Btu/h)/ft3](0.21 kW/m3). Where the calculation includes the vol-ume of an adjacent room or space, the room or spacein which the appliance is installed shall be directlyconnected to the adjacent room or space by a door-way, archway, or other opening of comparable sizethat cannot be closed. [NFPA 54:12.3.2.1, 12.3.2.2]
509.2.2 Ventilating Hoods. Ventilating hoods andexhaust systems shall be permitted to be used to ventappliances installed in commercial applications and tovent industrial appliances, particularly where the processitself requires fume disposal. [NFPA 54:12.3.3]509.2.3Well-Ventilated Spaces. The operation of indus-trial appliances such that its flue gases are dischargeddirectly into a large and well-ventilated space shall bepermitted. [NFPA 54:12.3.4]509.2.4 Direct-Vent Appliances. Listed direct-ventappliances shall be installed in accordance with the man-ufacturer’s installation instructions and Section 509.8.2.[NFPA 54:12.3.5]509.2.5 Appliances with Integral Vents. Appliancesincorporating integral venting means shall be installed inaccordance with the manufacturer’s installation instruc-tions, Section 509.8, and Section 509.8.1. [NFPA 54-12:12.3.6]
509.3 Design and Construction. A venting system shall bedesigned and constructed so as to develop a positive flow toconvey flue or vent gases to the outdoors. [NFPA 54:12.1]
509.3.1 Appliance Draft Requirements. A venting sys-tem shall satisfy the draft requirements of the appliancein accordance with the manufacturer’s instructions.[NFPA 54:12.4.1]509.3.2 Appliance Venting Requirements. Appliancesrequired to be vented shall be connected to a venting sys-tem designed and installed in accordance with the provi-sions of Section 509.4 through Section 509.14 of thiscode. [NFPA 54:12.4.2]509.3.3 Mechanical Draft Systems. Mechanical draftsystems shall be listed and shall be installed in accor-dance with both the appliance and the mechanical draftsystem manufacturer’s installation instructions. [NFPA54:12.4.3.1]
509.3.3.1 Venting. Appliances requiring ventingshall be permitted to be vented by means of mechan-ical draft systems of either forced or induced draftdesign.Exception: Incinerators. [NFPA 54:12.4.3.2]509.3.3.2 Leakage. Forced draft systems and por-tions of induced draft systems under positive pres-sure during operation shall be designed and installedso as to prevent leakage of flue or vent gases into abuilding. [NFPA 54:12.4.3.3]
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509.3.3.3 Vent Connectors. Vent connectors serv-ing appliances vented by natural draft shall not beconnected into mechanical draft systems operatingunder positive pressure. [NFPA 54:12.4.3.4]509.3.3.4 Operation.Where a mechanical draft sys-tem is employed, provision shall be made to preventthe flow of gas to the main burners where the draftsystem is not performing so as to satisfy the operat-ing requirements of the appliance for safe perform-ance. [NFPA 54:12.4.3.5]509.3.3.5 Exit Terminals. The exit terminals ofmechanical draft systems shall be not less than 7 feet(2134 mm) above finished ground level wherelocated adjacent to public walkways and shall belocated as specified in Section 509.8 and Section509.8.1 of this code. [NFPA 54:12.4.3.6]
509.3.4 Ventilating Hoods and Exhaust Systems. Ven-tilating hoods and exhaust systems shall be permitted tobe used to vent appliances installed in commercial appli-cations. [NFPA 54:12.4.4.1]
509.3.4.1 Automatically Operated Appliances.Where automatically operated appliances, other thancommercial cooking appliances, are vented througha ventilating hood or exhaust system equipped witha damper or with a power means of exhaust, provi-sions shall be made to allow the flow of gas to themain burners where the damper is open to a positionto properly vent the appliance and where the powermeans of exhaust is in operation. [NFPA54:12.4.4.2]
509.3.5 Circulating Air Ducts and Furnace Plenums.Venting systems shall not extend into or pass through afabricated air duct or furnace plenum. [NFPA54:12.4.5.1]
509.4 Type of Venting System to be Used. The type of vent-ing system to be used shall be in accordance with Table 509.4.[NFPA 54:12.5.1]
509.4.1 Plastic Piping. Plastic piping used for ventingappliances listed for use with such venting materials shallbe approved. [NFPA 54:12.5.2]509.4.2 Plastic Vent Joints. Plastic pipe and fittings usedto vent appliances shall be installed in accordance withthe appliance manufacturer’s installation instructions.Where primer is required, it shall be of a contrastingcolor. [NFPA 54:12.5.3]509.4.3 Special Gas Vent. Special gas vent shall belisted and installed in accordance with the special gasvent manufacturer’s installation instructions. [NFPA54:12.5.4]
509.5 Masonry, Metal, and Factory-Built Chimneys.509.5.1 Factory-Built Chimneys. Factory-built chim-neys shall be installed in accordance with the manufac-turer’s installation instructions. Factory-built chimneysused to vent appliances that operate at positive vent pres-sure shall be listed for such application. [NFPA54:12.6.1.1]
509.5.2 Metal Chimneys. Metal chimneys shall be builtand installed in accordance with NFPA 211. [NFPA54:12.6.1.2]509.5.3 Masonry Chimneys. Masonry chimneys shallbe built and installed in accordance with NFPA 211 andlined with approved clay flue lining, a listed chimney lin-ing system, or other approved material that resists corro-sion, erosion, softening, or cracking from vent gases attemperatures not exceeding 1800°F (982°C).Exception: Masonry chimney flues lined with a chim-ney lining system specifically listed for use with listedgas appliances with draft hoods, Category I appliances,and other gas appliances listed for use with Type B ventsshall be permitted. The liner shall be installed in accor-
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APPLIANCES TYPE OF VENTING SYSTEMListed Category I appliances Type B gas vent (Section 509.6)Listed appliances equipped
with draft hoodChimney (Section 509.5)
Appliances listed forType B gas vent
Single-wall metal pipe (Section509.7)Listed chimney lining system forgas venting (Section 509.5.3)Special gas vent listed for thisappliance (Section 509.4.3)
Listed vented wall furnaces Type B-W gas vent (Section509.6, Section 509.6.2.2)
Category II appliancesCategory III appliancesCategory IV appliances
As specified or furnished by man-ufacturers of listed appliance (Sec-tion 509.4.1, Section 509.4.3)
Incinerators, outdoors Single-wall metal pipe (Section509.7, Section 509.7.2)
Incinerators, indoors
Appliances that are capable ofbeing converted to use ofsolid fuel
Unlisted combination gas- andoil-burning appliances
Combination gas- and solid-fuel-burning appliances
Appliances listed for use withchimneys only
Unlisted appliances
Chimney (Section 509.5)
Listed combination gas- andoil-burning appliances
Type L vent (Section 509.6) orchimney (Section 509.5)
Decorative appliance invented fireplace
Chimney (UMC Section 907.2)
Direct-vent appliances See Section 509.2.4Appliances with integral vent See Section 509.2.5
TABLE 509.4TYPE OF VENTING SYSTEM TO BE USED
[NFPA 54: TABLE 12.5.1]
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dance with the liner manufacturer’s installation instruc-tions. A permanent identifying label shall be attached atthe point where the connection is to be made to the liner.The label shall read: "This chimney liner is for appli-ances that burn gas only. Do not connect to solid- or liq-uid-fuel-burning appliances or incinerators." [NFPA54:12.6.1.3]509.5.4 Termination. A chimney for a residential-type orlow-heat appliance shall extend not less than 3 feet (914mm) above the highest point where it passes through theroof of a building and not less than 2 feet (610 mm)higher than a portion of a building within a horizontaldistance of 10 feet (3048 mm). (See Figure 509.5.4)[NFPA 54:12.6.2.1]
509.5.4.1 Medium-Heat Gas Appliances.A chim-ney for a medium-heat appliance shall extend notless than 10 feet (3048 mm) above a portion of abuilding within 25 feet (7620 mm). [NFPA54:12.6.2.2]509.5.4.2 Chimney Height. A chimney shall extendnot less than 5 feet (1524 mm) above the highestconnected appliance draft hood outlet or flue collar.[NFPA 54:12.6.2.3]509.5.4.3 Decorative Shrouds. Decorative shroudsshall not be installed at the termination of factory-built chimneys except where such shrouds are listedand labeled for use with the specific factory-builtchimney system and are installed in accordance withthe manufacturer’s installation instructions. [NFPA54:12.6.2.4]
509.5.5 Size of Chimneys. The effective area of a chim-ney venting system serving listed appliances with drafthoods, Category I appliances, and other appliances listedfor use with Type B vents shall be in accordance withone of the following methods [NFPA 54:12.6.3.1]:(1) Section 510.0. [NFPA 54:12.6.3.1(1)](2) For sizing an individual chimney venting system for
a single appliance with a draft hood, the effectiveareas of the vent connector and chimney flue shallbe not less than the area of the appliance flue collaror draft hood outlet or exceeding seven times thedraft hood outlet area. [NFPA 54:12.6.3.1(2)]
(3) For sizing a chimney venting system connected totwo appliances with draft hoods, the effective area ofthe chimney flue shall be not less than the area ofthe larger draft hood outlet plus 50 percent of thearea of the smaller draft hood outlet, or exceedingseven times the smallest draft hood outlet area.[NFPA 54:12.6.3.1(3)]
(4) Other approved engineering methods. [NFPA54:12.6.3.1(5)]
(5) Chimney venting systems using mechanical draftshall be sized in accordance with approved engi-neering methods. [NFPA 54:12.6.3.1(4)]
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FIGURE 509.5.4TYPICAL TERMINATION LOCATIONS FOR CHIMNEYS
AND SINGLE-WALL METAL PIPES SERVINGRESIDENTIAL-TYPE AND LOW-HEAT APPLIANCE
[NFPA 54: FIGURE 12.6.2.1]
For SI units: 1 foot = 304.8 mm
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509.5.6 Inspection of Chimneys. Before replacing anexisting appliance or connecting a vent connector to achimney, the chimney passageway shall be examined toascertain that it is clear and free of obstructions and shallbe cleaned where previously used for venting solid- orliquid-fuel-burning appliances or fireplaces. [NFPA54:12.6.4.1]
509.5.6.1 Standard. Chimneys shall be lined inaccordance with NFPA 211.Exception: Existing chimneys shall be permitted tohave their use continued where an appliance isreplaced by an appliance of similar type, input rat-ing, and efficiency, where the chimney is in accor-dance with Section 509.5.6, and the sizing of thechimney is in accordance with Section 509.5.5.[NFPA 54:12.6.4.2]509.5.6.2 Cleanouts. Cleanouts shall be examinedto determine that they will remain tightly closedwhere not in use. [NFPA 54:12.6.4.3]509.5.6.3 Existing Chimney. Where inspectionreveals that an existing chimney is not safe for theintended application, it shall be repaired, rebuilt,lined, relined, or replaced with a vent or chimney inaccordance with NFPA 211 and shall be approvedfor the appliances to be attached. [NFPA54:12.6.4.4]
509.5.7 Chimney Serving Appliances Burning OtherFuels. An appliance shall not be connected to a chimneyflue serving a separate appliance designed to burn solidfuel. [NFPA 54:12.6.5.1]
509.5.7.1 Multiple Appliances. Where one chim-ney serves gas appliances and liquid fuel-burningappliances, the appliances shall be connectedthrough separate openings or shall be connectedthrough a single opening where joined by a fittinglocated as close as practical to the chimney. Wheretwo or more openings are provided into one chimneyflue, they shall be at different levels. Where the gasappliance is automatically controlled, it shall beequipped with a safety shutoff device. [NFPA54:12.6.5.2]509.5.7.2 Manual Reset Device.A listed combina-tion gas- and solid-fuel-burning appliance connectedto a single chimney flue shall be equipped with amanual reset device to shut off gas to the mainburner in the event of sustained backdraft or flue gasspillage. The chimney flue shall be sized to properlyvent the appliance. [NFPA 54:12.6.5.3]509.5.7.3 Combination Gas- and Oil-BurningAppliances. A single chimney flue serving a listedcombination gas- and oil-burning appliance shall besized to properly vent the appliance. [NFPA54:12.6.5.4]
509.5.8 Support of Chimneys. Portions of chimneysshall be supported for the design and weight of the mate-rials employed. Listed factory-built chimneys shall be
supported and spaced in accordance with their listingsand the manufacturer’s instructions. [NFPA 54:12.6.6]509.5.9 Cleanouts. Where a chimney that formerly car-ried flue products from liquid- or solid-fuel-burningappliances is used with an appliance using fuel gas, anaccessible cleanout shall be provided. The cleanout shallhave a tight-fitting cover and be installed so its upperedge is not less than 6 inches (152 mm) below the loweredge of the lowest chimney inlet opening. [NFPA54:12.6.7]509.5.10 Space Surrounding Lining or Vent. Theremaining space surrounding a chimney liner, gas vent,special gas vent, or plastic piping installed within amasonry chimney flue shall not be used to vent anotherappliance.Exception: The insertion of another liner or vent withinthe chimney as provided in this code and the liner or ventmanufacturer’s instructions. [NFPA 54:12.6.8.1]
509.5.10.1 Combustion Air. The remaining spacesurrounding a chimney liner, gas vent, special gasvent, or plastic piping installed within a masonrychimney flue shall not be used to supply combus-tion air.Exception: Direct-vent appliances designed forinstallation in a solid-fuel-burning fireplace whereinstalled in accordance with the manufacturer’sinstallation instructions. [NFPA 54:12.6.8.2]
509.6 Gas Vents. A gas vent passing through a roof shallextend through the entire roof flashing, roof jack, or roofthimble and be terminated with a listed termination cap.[NFPA 54:12.7.2(6)]
509.6.1 Installation. Type B or Type L vents shall extendin a vertical direction with offsets not exceeding 45degrees (0.79 rad), except that a vent system having notmore than one 60 degree (1.05 rad) offset shall be per-mitted. An angle greater than 45 degrees (0.79 rad) fromthe vertical is considered horizontal. The total horizontaldistance of a vent plus the horizontal vent connector serv-ing draft hood-equipped appliances shall be not greaterthan 75 percent of the vertical height of the vent. [NFPA54:12.7.3.2]
509.6.1.1 Fasteners. Screws, rivets and other fasten-ers shall not penetrate the inner wall of double wallgas vents except at the transition from the appliancedraft hood outlet, flue collar, or single wall metal con-nector to a double wall vent. [NFPA 54:12.7.1(4)]
509.6.2 Additional Termination Requirements. A gasvent shall terminate in accordance with one of the fol-lowing:(1) Gas vents that are 12 inches (305 mm) or less in size
and located not less than 8 feet (2438 mm) from a ver-tical wall or similar obstruction shall terminate abovethe roof in accordance with Figure 509.6.2 and Table509.6.2. Gas vents that are over 12 inches (305 mm)in size or are located less than 8 feet (2438 mm) from
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a vertical wall or similar obstruction, shall terminatenot less than 2 feet (610 mm) above the highest pointwhere they pass through the roof and not less than 2feet (610 mm) above a portion of a building within10 feet (3048 mm) horizontally.
(2) Industrial appliances as provided in Section 509.2.3.(3) Direct-vent systems as provided in Section 509.2.4.(4) Appliances with integral vents as provided in Sec-
tion 509.2.5.(5) Mechanical draft systems as provided in Section
509.3.3.(6) Ventilating hoods and exhaust systems as provided
in Section 509.3.4. [NFPA 54:12.7.2(1)]509.6.2.1 Type B and L Vents. A Type B or a TypeL gas vent shall terminate not less than 5 feet (1524mm) in vertical height above the highest connectedappliance draft hood or flue collar. [NFPA54:12.7.2(2)]509.6.2.2 Type B-W Vents. A Type B-W gas ventshall terminate not less than 12 feet (3658 mm) invertical height above the bottom of the wall furnace.[NFPA 54:12.7.2(3)]509.6.2.3 Exterior Wall Termination. A gas ventextending through an exterior wall shall not termi-nate adjacent to the wall or below eaves or parapets,except as provided in Section 509.2.4 and Section509.3.3. [NFPA 54:12.7.2(4)]509.6.2.4 Decorative Shrouds. Decorative shroudsshall not be installed at the termination of gas ventsexcept where such shrouds are listed for use with thespecific gas venting system and are installed inaccordance with manufacturer’s installation instruc-tions. [NFPA 54:12.7.2(5)]509.6.2.5 Forced Air Inlet. A gas vent shall termi-nate not less than 3 feet (914 mm) above a forcedair inlet located within 10 feet (3048 mm). [NFPA54:12.7.2(7)]
509.6.3 Size of Gas Vents. Venting systems shall besized and constructed in accordance with Section 510.0or other approved engineering methods and the gas ventand gas appliance manufacturer’s instructions. [NFPA54:12.7.3]
509.6.3.1 Category I Appliances. The sizing of nat-ural draft venting systems serving one or more listedappliances equipped with a draft hood or applianceslisted for use with Type B gas vent, installed in a sin-gle story of a building, shall be in accordance withone of the following methods:(1) The provisions of Section 510.0.(2) Vents serving fan-assisted combustion system
appliances, or combinations of fan-assistedcombustion systems and draft hood-equippedappliances, shall be sized in accordance withSection 510.0 or other approved engineeringmethods.
(3) For sizing an individual gas vent for a single,draft hood-equipped appliance, the effectivearea of the vent connector and the gas vent shallbe not less than the area of the appliance drafthood outlet or exceeding seven times the drafthood outlet area.
(4) For sizing a gas vent connected to two appli-ances with draft hoods, the effective area of thevent shall be not less than the area of the largerdraft hood outlet plus 50 percent of the area ofthe smaller draft hood outlet or exceeding seventimes the smaller draft hood outlet area.
(5) Approved engineering practices. [NFPA54:12.7.3.1]
509.6.3.2 Sizing. Chimney venting systems usingmechanical draft shall be sized in accordance withapproved engineering methods. [NFPA 54:12.7.3.4]
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FIGURE 509.6.2GAS VENT TERMINATION LOCATIONS FOR
LISTED CAPS 12 INCHES OR LESS IN SIZE NOTLESS THAN 8 FEET FROM A VERTICAL WALL
[NFPA 54: FIGURE 12.7.2]
ROOF PITCH H (minimum) (feet)Flat to 6⁄12 1.0Over 6⁄12 to 7⁄12 1.25Over 7⁄12 to 8⁄12 1.5Over 8⁄12 to 9⁄12 2.0Over 9⁄12 to 10⁄12 2.5Over 10⁄12 to 11⁄12 3.25Over 11⁄12 to 12⁄12 4.0Over 12⁄12 to 14⁄12 5.0Over 14⁄12 to 16⁄12 6.0Over 16⁄12 to 18⁄12 7.0Over 18⁄12 to 20⁄12 7.5Over 20⁄12 to 21⁄12 8.0For SI Units: 1 inch = 25.4 mm, 1 foot = 304.8 mm
TABLE 509.6.2ROOF PITCH HEIGHT
[NFPA 54: TABLE 12.7.2]
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509.6.4 Gas Vents Serving Appliances on more thanOne Floor. A common vent shall be permitted in multi-story installations to vent Category I appliances locatedon more than one floor level, provided the venting sys-tem is designed and installed in accordance withapproved engineering methods.
For the purpose of this section, crawl spaces, base-ments, and attics shall be considered as floor levels.[NFPA 54-12:12.7.4.1]
509.6.4.1 Habitable Space. Appliances connectedto the common vent shall be located in rooms sepa-rated from a habitable space. Each of these roomsshall have provisions for an adequate supply of com-bustion, ventilation, and dilution air that is not sup-plied from a habitable space. (See Figure 509.6.4.1)[NFPA 54:12.7.4.2]
The size of the connectors and common seg-ments of multistory venting systems for applianceslisted for use with Type B double-wall gas vent shallbe in accordance with Table 510.2(1), provided:(1) The total height (H) for each segment of a mul-
tistory venting system is the vertical distancebetween the level of the highest draft hood out-let or flue collar on that floor and the centerlineof the next highest interconnection tee.
(2) The size of the connector for a segment is deter-mined from the appliance’s gas input rate andconnector rise, and shall not be smaller than thedraft hood outlet or flue collar size.
(3) The size of the common vertical vent segment,and of the interconnection tee at the base of thatsegment, shall be based on the total applianceheat input entering that segment and its totalheight. [NFPA 54:12.7.4.3]
509.6.5 Support of Gas Vents. Gas vents shall be sup-ported and spaced in accordance with their listings andthe manufacturer’s instructions. [NFPA 54:12.7.5]509.6.6 Marking. In those localities where solid and liq-uid fuels are used extensively, gas vents shall be perma-nently identified by a label attached to the wall or ceilingat a point where the vent connector enters the gas vent.The label shall read: "This gas vent is for appliances thatburn gas. Do not connect to solid- or liquid-fuel-burningappliances or incinerators." The Authority Having Juris-diction shall determine whether its area constitutes sucha locality. [NFPA 54:12.7.6]
509.7 Single-Wall Metal Pipe. Single-wall metal pipe shall beconstructed of galvanized sheet steel not less than 0.0304 of aninch (0.7722 mm) thick or of other approved, noncombustible,corrosion-resistant material. [NFPA 54:12.8.1]
509.7.1 Cold Climate. Uninsulated single-wall metalpipe shall not be used outdoors for venting appliances.For venting appliances in regions where the 99 percentwinter design temperature is below 32°F (0°C). [NFPA54:12.8.2]
509.7.2 Termination. The termination of single-wallmetal pipe shall comply with the following requirements:(1) Single-wall metal pipe shall terminate not less than
5 feet (1524 mm) in vertical height above the high-est connected appliance draft hood outlet or flue col-lar.
(2) Single-wall metal pipe shall extend not less than 2feet (610 mm) above the highest point where itpasses through the roof of a building and not lessthan 2 feet (610 mm) exceeding a portion of a build-ing within a horizontal distance of 10 feet (3048mm). (See Figure 509.5.4)
(3) An approved cap or roof assembly shall be attachedto the terminus of a single-wall metal pipe. [NFPA54:12.8.3]
509.7.3 Installation with Appliances Permitted byTable 509.4. Single-wall metal pipe shall not be used asa vent in dwellings and residential occupancies. [NFPA54:12.8.4.1]
509.7.3.1 Limitations. Single-wall metal pipe shallbe used for runs directly from the space in which theappliance is located through the roof or exterior wallto the outer air. A pipe passing through a roof shallextend without interruption through the roof flashing,roof jacket, or roof thimble. [NFPA 54:12.8.4.2]509.7.3.2 Attic or Concealed Space. Single-wallmetal pipe shall not originate in an unoccupied atticor concealed space and shall not pass through anattic, inside wall, concealed space, or floor. For theinstallation of a single-wall metal pipe through anexterior combustible wall see Section 509.7.3.5.[NFPA 54:12.8.4.3]
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FIGURE 509.6.4.1PLAN VIEW OF PRACTICAL SEPARATIONMETHOD FOR MULTISTORY GAS VENTING
[NFPA 54: FIGURE 12.7.4.2]
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509.7.3.3 Incinerator. Single-wall metal pipe usedfor venting an incinerator shall be exposed and read-ily examinable for its full length and shall haverequired clearances maintained. [NFPA 54:12.8.4.4]509.7.3.4 Clearances. Minimum clearances fromsingle-wall metal pipe to combustible material shallbe in accordance with Table 509.7.3. Reduced clear-ances from single-wall metal pipe to combustiblematerial shall be as specified for vent connectors inTable 509.7.3(1). [NFPA 54:12.8.4.5]509.7.3.5 Exterior. Single-wall metal pipe shall notpass through a combustible exterior wall unlessguarded at the point of passage by a ventilated metalthimble not smaller than the following:(1) For listed appliances with draft hoods and appli-
ances listed for use with Type B gas vents, thethimble shall be not less than 4 inches (102 mm)larger in diameter than the metal pipe. Wherethere is a run of not less than 6 feet (1829 mm)of metal pipe in the opening between the drafthood outlet and the thimble, the thimble shallbe a minimum 2 inches (51 mm) larger in diam-eter than the metal pipe.
(2) For unlisted appliances having draft hoods, thethimble shall be a minimum 6 inches (152 mm)larger in diameter than the metal pipe.
(3) For residential and low-heat appliances, thethimble shall be not less than 12 inches (305mm) larger in diameter than the metal pipe.
Exception: In lieu of thimble protection, combustiblematerial in the wall shall be removed a sufficient dis-tance from the metal pipe to provide the specifiedclearance from such metal pipe to combustible mate-rial. Any material used to close up such opening shallbe noncombustible. [NFPA 54:12.8.4.7]509.7.3.6 Roof Thimble.Where a single-wall metalpipe passes through a roof constructed of com-
bustible material, a noncombustible, nonventilatingthimble shall be used at the point of passage. Thethimble shall extend not less than 18 inches (457mm) above and 6 inches (152 mm) below the roofwith the annular space open at the bottom and closedat the top. The thimble shall be sized in accordancewith Section 509.7.3.5. [NFPA 54:12.8.4.6]
509.7.4 Size of Single-Wall Metal Pipe. Single-wallmetal piping shall comply with the following sections.[NFPA 54:12.8.5]
509.7.4.1 Sizing of Venting System. A venting sys-tem of a single-wall metal pipe shall be sized inaccordance with one of the following methods andthe gas appliance manufacturer’s instructions:(1) For a draft hood-equipped appliance, in accor-
dance with Section 510.0.(2) For a venting system for a single appliance with
a draft hood, the areas of the connector and thepipe each shall be not less than the area of theappliance flue collar or draft hood outlet,whichever is smaller. The vent area shall notexceed seven times the draft hood outlet area.
(3) Other approved engineering methods. [NFPA54:12.8.5(1)]
509.7.4.2 Non-Round Metal Pipe.Where a single-wall metal pipe is used and has a shape other thanround, it shall have an effective area equal to theeffective area of the round pipe for which it is sub-stituted, and the internal dimension of the pipe shallbe not less than 2 inches (51 mm). [NFPA54:12.8.5(2)]509.7.4.3 Venting Capacity. The vent cap or a roofassembly shall have a venting capacity not less thanthat of the pipe to which it is attached. [NFPA54:12.8.5(3)]
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TABLE 509.7.3CLEARANCE FOR CONNECTORS
[NFPA 54: TABLE 12.8.4.5]*
For SI units: 1 inch = 25.4 mm* These clearances shall apply unless the installation instructions of a listed appliance or connector specify different clearances, in which case the listed clearances
shall apply.
MINIMUM DISTANCE FROM COMBUSTIBLE MATERIAL (inches)
APPLIANCE LISTED TYPE B GASVENT MATERIAL
LISTED TYPE L VENTMATERIAL
SINGLE-WALLMETAL PIPE
FACTORY-BUILTCHIMNEY SECTIONS
Listed appliances with draft hoods and appliances listedfor use with Type B gas vents
As listed As listed 6 As listed
Residential boilers and furnaces with listed gas conver-sion burner and with draft hood
6 6 9 As listed
Residential appliances listed for use with Type L vents Not permitted As listed 9 As listedUnlisted residential appliances with draft hood Not permitted 6 9 As listedResidential and low-heat appliances other than thoseabove
Not permitted 9 18 As listed
Medium-heat appliances Not permitted Not permitted 36 As listed
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509.7.5 Support of Single-Wall Metal Pipe. Portionsof single-wall metal pipe shall be supported for thedesign and weight of the material employed. [NFPA54:12.8.6]509.7.6 Marking. Single-wall metal pipe shall complywith the marking provisions of Section 509.6.6. [NFPA54:12.8.7]
509.8 Through-the-Wall Vent Termination. (See Figure509.8.) A mechanical draft venting system shall terminate notless than 3 feet (914 mm) above a forced air inlet locatedwithin 10 feet (3048 mm).Exceptions:(1) This provision shall not apply to the combustion air
intake of a direct-vent appliance.(2) This provision shall not apply to the separation of the
integral outdoor air inlet and flue gas discharge of listedoutdoor appliances. [NFPA 54:12.9.1]509.8.1 Mechanical Draft Venting System.A mechan-ical draft venting system of other than direct-vent typeshall terminate not less than 4 feet (1219 mm) below, 4feet (1219 mm) horizontally from, or 1 foot (305 mm)above a door, operable window, or gravity air inlet intoa building. The bottom of the vent terminal shall belocated not less than 12 inches (305 mm) above finishedgrade. [NFPA 54:12.9.2]509.8.2 Direct-Vent Appliance. The vent terminal of adirect-vent appliance with an input of 10 000 Btu/h (3kW) or less shall be located not less than 6 inches (152mm) from an air opening into a building, and such anappliance with an input over 10 000 Btu/h (3 kW) but notexceeding 50 000 Btu/h (14.7 kW) shall be installed with
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Notes:A – Equals the clearance with no protection specified in Table 509.7.3 andTable 509.7.3(1) and in the sections applying to various types of appliances.B – Equals the reduced clearance permitted in accordance with Table509.7.3. The protection applied to the construction using combustible mate-rial shall extend far enough in each direction to make C equal to A.
FIGURE 509.7.3EXTENT OF PROTECTION NECESSARY TO REDUCE CLEAR-ANCES FROM GAS APPLIANCES OR VENT CONNECTORS
[NFPA 54: FIGURE 10.3.2.2(a)]
For SI units: 1 inch = 25.4 mmFIGURE 509.7.3(2)
MASONRY CLEARANCE REDUCTION SYSTEM[NFPA 54: FIGURE 10.3.2.2(c)]
For SI units: 1 inch = 25.4 mmNote: Masonry walls shall be attached to combustible walls using wall ties.Spacers shall not be used directly behind appliance or connector.
FIGURE 509.7.3(1)WALL PROTECTION REDUCTION SYSTEM
[NFPA 54: FIGURE 10.3.2.2(b)]
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a 9 inch (229 mm) vent termination clearance, and anappliance with an input over 50 000 Btu/h (14.7 kW)shall have not less than a 12 inch (305 mm) vent termi-nation clearance. The bottom of the vent terminal and theair intake shall be located not less than 12 inches (305mm) above finished grade. [NFPA 54:12.9.3]509.8.3 Nuisance and Hazard. Through-the-wall ventsfor Category II and Category IV appliances and noncat-egorized condensing appliances shall not terminate overpublic walkways or over an area where condensate orvapor is capable of creating a nuisance or hazard detri-mental to the operation of regulators, relief valves, orother equipment. Where local experience indicates thatcondensate is a problem with Category I and CategoryIII appliances, this provision shall also apply.
Drains for condensate shall be installed in accor-dance with the appliance and the vent manufacturer’sinstallation instructions. [NFPA 54-12:12.9.4]509.8.4 Annular Spaces. Where vents, including thosefor direct-vent appliances or combustion air intake pipes,penetrate outside walls of buildings, the annular spacesaround such penetrations shall be permanently sealedusing approved materials to prevent entry of combustionproducts into the building. [NFPA 54:12.9.5]509.8.5 Vent Terminals. Vent terminals that terminatethrough an outside wall of a building shall be located notless than 10 feet (3048 mm) horizontally from an opera-ble opening in an adjacent building. This shall not applyto operable openings that are not less than 2 feet (610mm) below or 25 feet (7620 mm) above the elevation ofthe vent terminal. [NFPA 54-12:12.9.6]
509.9 Condensation Drain. Provision shall be made to col-lect and dispose of condensate from venting systems servingCategory II and Category IV appliances and noncategorizedcondensing appliances in accordance with Section 509.8.3.[NFPA 54:12.10.1]
509.9.1 Local Experience.Where local experience indi-cates that condensation is a problem, provision shall bemade to drain off and dispose of condensate from vent-ing systems serving Category I and Category III appli-ances in accordance with Section 509.8.3. [NFPA54:12.10.2]
509.10 Vent Connectors for Category I Appliances. A ventconnector shall be used to connect an appliance to a gas vent,chimney, or single-wall metal pipe, except where the gas vent,chimney, or single-wall metal pipe is directly connected tothe appliance. [NFPA 54:12.11.1]
509.10.1 Materials. A vent connector shall be made ofnoncombustible, corrosion resistant material capable ofwithstanding the vent gas temperature produced by theappliance and of a thickness to withstand physical dam-age. [NFPA 54:12.11.2.1]
509.10.1.1 Unconditioned Area. Where the ventconnector used for an appliance having a draft hoodor a Category I appliance is located in or passesthrough an unconditioned area, attic or crawl space,that portion of the vent connector shall be listedType B, Type L, or listed vent material having equiv-alent insulation qualities.Exception: Single-wall metal pipe located within theexterior walls of the building and located in an uncon-
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FIGURE 509.8EXIT TERMINALS OF MECHANICAL DRAFT AND DIRECT-VENT VENTING SYSTEMS
[NFPA 54: FIGURE A.12.9]
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TYPE OF PROTECTION APPLIEDTO AND COVERING SURFACESOF COMBUSTIBLE MATERIALWITHIN THE DISTANCE SPECI-FIED AS THE REQUIRED CLEAR-ANCE WITH NO PROTECTION[SEE FIGURE 509.7.3 THROUGHFIGURE 509.7.3(2)]
WHERE THE REQUIRED CLEARANCE WITH NO PROTECTION FROM APPLIANCE,VENT CONNECTOR, OR SINGLE-WALL METAL PIPE IS:
36 (inches) 18 (inches) 12 (inches) 9 (inches) 6 (inches)ALLOWABLE CLEARANCES WITH SPECIFIED PROTECTION (inches)
USE COLUMN 1 FOR CLEARANCES ABOVE APPLIANCE OR HORIZONTAL CONNECTOR. USECOLUMN 2 FOR CLEARANCES FROM APPLIANCES, VERTICAL CONNECTOR, AND SINGLE-WALL METAL PIPE.
ABOVECOLUMN 1
SIDES ANDREAR
COLUMN 2ABOVE
COLUMN 1SIDES AND
REARCOLUMN 2
ABOVECOLUMN 1
SIDES ANDREAR
COLUMN 2ABOVE
COLUMN 1SIDES AND
REARCOLUMN 2
ABOVECOLUMN 1
SIDES ANDREAR
COLUMN 2(1) 31⁄2 inch thick masonry
wall without ventilated airspace
–– 24 –– 12 –– 9 –– 6 –– 5
(2) 1⁄2 of an inch insulationboard over 1 inch glassfiber or mineral wool batts
24 18 12 9 9 6 6 5 4 3
(3) 0.024 inch sheet metal over1 inch glass fiber or mineralwool batts reinforced withwire on rear face with ven-tilated air space
18 12 9 6 6 4 5 3 3 3
(4) 31⁄2 inch thick masonry wallwith ventilated air space –– 12 –– 6 –– 6 –– 6 –– 6
(5) 0.024 inch sheet metal withventilated air space 18 12 9 6 6 4 5 3 3 2
(6) 1⁄2 of an inch thick insula-tion board with ventilatedair space
18 12 9 6 6 4 5 3 3 3
(7) 0.024 inch sheet metal withventilated air space over0.024 inch sheet metal withventilated air space
18 12 9 6 6 4 5 3 3 3
(8) 1 inch glass fiber or mineralwool batts sandwichedbetween two sheets 0.024inch sheet metal with venti-lated air space
18 12 9 6 6 4 5 3 3 3
TABLE 509.7.3(1)REDUCTION OF CLEARANCES WITH SPECIFIED FORMS OF PROTECTION1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11
[NFPA 54: TABLE 10.2.3(b)]
For SI units: 1 inch = 25.4 mm, °C = (°F-32)/1.8Notes:1 Reduction of clearances from combustible materials shall not interfere with combustion air, draft hood clearance and relief, and accessibility of servicing.2 Clearances shall be measured from the outer surface of the combustible material to the nearest point on the surface of the appliance, disregarding an inter-
vening protection applied to the combustible material.3 Spacers and ties shall be of noncombustible material. No spacer or tie shall be used directly opposite the appliance or connector.4 Where clearance reduction systems use a ventilated air space, adequate provision for air circulation shall be provided as described. [See Figure 509.7.3(1)
and Figure 509.7.3(2)]5 There shall be not less than 1 inch (25.4 mm) between clearance reduction systems and combustible walls and ceilings for reduction systems using a ven-
tilated air space.6 Where a wall protector is mounted on a single flat wall away from corners, it shall have a minimum 1 inch (25.4 mm) air gap. To provide air circulation,
the bottom and top edges, or only the side and top edges, or edges shall be left open.7 Mineral wool batts (blanket or board) shall have a minimum density of 8 pounds per cubic foot (lb/ft3) (128 kg/m3) and a minimum melting point of 1500°F
(816°C).8 Insulation material used as part of a clearance reduction system shall have a thermal conductivity of 1 British thermal unit inch per hour square foot degree
Fahrenheit [Btu•in/(h•ft2•°F)] [0.1 W/(m•K)] or less.9 There shall be not less than 1 inch (25.4 mm) between the appliance and the protector. In no case shall the clearance between the appliance and the com-
bustible surface be reduced below that allowed in this table.10 Clearances and thicknesses are minimum; larger clearances and thicknesses are acceptable.11 Listed single-wall connectors shall be installed in accordance with the terms of their listing and the manufacturer’s installation instructions.
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ditioned area other than an attic or a crawl space hav-ing a local 99 percent winter design temperature of5°F (-15°C) or higher. [NFPA 54-12:12.11.2.2]509.10.1.2 Residential-Type Appliances.Vent con-nectors for residential-type appliances shall complywith the following:(1) Vent connectors for listed appliances having
draft hoods, appliances having draft hoods andequipped with listed conversion burners that arenot installed in attics, crawl spaces, or otherunconditioned areas shall be one of the follow-ing:(a) Type B or Type L vent material.(b) Galvanized sheet steel not less than 0.018
of an inch (0.457 mm) thick.(c) Aluminum (1100 or 3003 alloy or equiva-
lent) sheet not less than 0.027 of an inch(0.686 mm) thick.
(d) Stainless steel sheet not less than 0.012 ofan inch (0.305 mm) thick.
(e) Smooth interior wall metal pipe having resist-ance to heat and corrosion equal to or exceed-ing that of Section 509.10.1.2(1)(b), Section509.10.1.2(1)(c), or Section 509.10.1.2(1)(d)above.
(f) A listed vent connector.(2) Vent connectors shall not be covered with insu-
lation.Exception: Listed insulated vent connectors shallbe installed in accordance with the manufacturer’sinstallation instructions. [NFPA 54:12.11.2.4]509.10.1.3 Non-Residential Low-Heat Appli-ances. A vent connector for a non-residential low-heat appliance shall be a factory-built chimneysection or steel pipe having resistance to heat andcorrosion equivalent to the galvanized pipe speci-fied in Table 509.10.1. Factory-built chimney sec-tions shall be installed in accordance with thechimney manufacturer’s installation instructions.[NFPA 54:12.11.2.5]509.10.1.4 Medium-Heat Appliances. Vent con-nectors for medium-heat appliances, and commer-cial and industrial incinerators, shall be constructedof factory-built, medium-heat chimney sections orsteel of a thickness not less than that specified inTable 509.10.1(1) and shall comply with the fol-lowing:(1) A steel vent connector for appliances with a
vent gas temperature in excess of 1000°F(538°C) measured at the entrance to the con-nector shall be lined with medium-duty firebrick or the equivalent.
(2) The lining shall be not less than 21⁄2 inches (64mm) thick for a vent connector having a diam-
eter or greatest cross-sectional dimension of 18inches (457 mm) or less.
(3) The lining shall be not less than 41⁄2 inches (114mm) thick laid on the 41⁄2 inch (114 mm) bedfor a vent connector having a diameter or cross-sectional dimension exceeding 18 inches (457mm).
(4) Factory-built chimney sections, whereemployed, shall be installed in accordance withthe chimney manufacturer’s installation instruc-tions. [NFPA 54:12.11.2.6]
509.10.2 Size of Vent Connector. A vent connector for anappliance with a single draft hood or for a Category I fan-assisted combustion system appliance shall be sized andinstalled in accordance with Section 510.0 or otherapproved engineering methods. [NFPA 54:12.11.3.1]
509.10.2.1 Manifold. For a single appliance havingmore than one draft hood outlet or flue collar, themanifold shall be constructed according to theinstructions of the appliance manufacturer. Wherethere are no instructions, the manifold shall bedesigned and constructed in accordance withapproved engineering practices. As an alternatemethod, the effective area of the manifold shallequal the combined area of the flue collars or drafthood outlets, and the vent connectors shall have notless than 1 foot (305 mm) rise. [NFPA 54:12.11.3.2]
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DIAMETER OF CONNECTOR(inches)
MINIMUM THICKNESS (inches)
Less than 6 0.0196 to less than 10 0.023
10 to 12 inclusive 0.02914 to 16 inclusive 0.034
Over 16 0.056
TABLE 509.10.1MINIMUM THICKNESS FOR GALVANIZED STEEL VENT
CONNECTORS FOR LOW-HEAT APPLIANCES[NFPA 54: TABLE 12.11.2.5]
For SI units: 1 inch = 25.4 mm, 1 square inch = 0.000645 m2
TABLE 509.10.1(1)MINIMUM THICKNESS FOR STEEL VENT CONNECTORS FOR
MEDIUM-HEAT APPLIANCES AND COMMERCIAL ANDINDUSTRIAL INCINERATORS [NFPA 54: TABLE 12.11.2.6]
For SI units: 1 inch = 25.4 mm, 1 square inch = 0.000645 m2
VENT CONNECTOR SIZE
DIAMETER (inches) AREA(square inches)
MINIMUMTHICKNESS (inches)
Up to 14 Up to 154 0.053Over 14 to 16 154 to 201 0.067Over 16 to 18 201 to 254 0.093
Over 18 Exceeding 254 0.123
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509.10.2.2 Size. Where two or more appliances areconnected to a common vent or chimney, each ventconnector shall be sized in accordance with Section510.0 or other approved engineering methods.[NFPA 54:12.11.3.3]
As an alternative method applicable where theappliances are draft hood-equipped, each vent con-nector shall have an effective area not less than thearea of the draft hood outlet of the appliance towhich it is connected. [NFPA 54:12.11.3.4]509.10.2.3 Height. Where two or more appliancesare vented through a common vent connector or ventmanifold, the common vent connector or vent man-ifold shall be located at the highest level consistentwith available headroom and clearance to com-bustible material and shall be sized in accordancewith Section 510.0 or other approved engineeringmethods. [NFPA 54:12.11.3.5]
As an alternate method applicable where thereare two draft hood-equipped appliances, the effec-tive area of the common vent connector or vent man-ifold and junction fittings shall be not less than thearea of the larger vent connector plus 50 percent ofthe areas of smaller flue collar outlets. [NFPA54:12.11.3.6]509.10.2.4 Size Increase. Where the size of a ventconnector is increased to overcome installation lim-itations and obtain connector capacity equal to theappliance input, the size increase shall be made atthe appliance draft hood outlet. [NFPA 54:12.11.3.7]
509.10.3 Two or More Appliances Connected to a Sin-gle Vent. Where two or more openings are provided intoone chimney flue or vent, the openings shall be at dif-ferent levels, or the connectors shall be attached to thevertical portion of the chimney or vent at an angle of 45degrees (0.79 rad) or less relative to the vertical. [NFPA54:12.11.4.1]
509.10.3.1 Height of Connector. Where two ormore vent connectors enter a common vent, chim-ney flue, or single-wall metal pipe, the smaller con-nector shall enter at the highest level consistent withthe available headroom or clearance to combustiblematerial. [NFPA 54-12:12.11.4.2]509.10.3.2 Pressure.Vent connectors serving Cate-gory I appliances shall not be connected to a portionof a mechanical draft system operating under posi-tive static pressure, such as those serving CategoryIII or Category IV appliances. [NFPA 54:12.11.4.3]
509.10.4 Clearance. Minimum clearances from ventconnectors to combustible material shall comply withTable 509.7.3.Exception: The clearance between a vent connector andcombustible material shall be permitted to be reducedwhere the combustible material is protected as specifiedfor vent connectors in Table 509.7.3(1). [NFPA54:12.11.5]
509.10.5 Joints. Joints between sections of connectorpiping and connections to flue collars or draft hood out-lets shall be fastened in accordance with one of the fol-lowing methods:(1) By sheet metal screws.(2) Vent connectors of listed vent material shall be
assembled and connected to flue collars or drafthood outlets in accordance with the manufacturer’sinstallation instructions.
(3) Other approved means. [NFPA 54:12.11.7]509.10.6 Slope. A vent connector shall be installed with-out dips or sags and shall slope upward toward the ventor chimney not less than 1⁄4 inch per foot (20.8 mm/m).Exception: Vent connectors attached to a mechanicaldraft system installed in accordance with the applianceand draft system manufacturer’s installation instructions.[NFPA 54:12.11.8]509.10.7 Length of Vent Connector.
509.10.7.1 Single Wall Connector. The maximumhorizontal length of a single-wall connector shall be75 percent of the height of the chimney or ventexcept for engineered systems. [NFPA 54:12.11.9.2]509.10.7.2 Type B Double Wall Connector. Themaximum horizontal length of a Type B double-wallconnector shall be 100 percent of the height of thechimney or vent, except for engineered systems. Themaximum length of an individual connector for achimney or vent system serving multiple appliances,from the appliance outlet to the junction with thecommon vent or another connector, shall be 100 per-cent of the height of the chimney or vent. [NFPA54:12.11.9.3]
509.10.8 Support. A vent connector shall be supportedfor the design and weight of the material employed tomaintain clearances and prevent physical damage andseparation of joints. [NFPA 54:12.11.10]509.10.9 Chimney Connection. Where entering a flue ina masonry or metal chimney, the vent connector shall beinstalled above the extreme bottom to avoid stoppage.Where a thimble or slip joint is used to facilitate removalof the connector, the connector shall be attached to orinserted into the thimble or slip joint to prevent the con-nector from falling out. Means shall be employed to pre-vent the connector from entering so far as to restrict thespace between its end and the opposite wall of the chim-ney flue. [NFPA 54:12.11.11]509.10.10 Inspection. The entire length of a vent con-nector shall be readily accessible for inspection, clean-ing, and replacement. [NFPA 54:12.11.12]509.10.11 Fireplaces. A vent connector shall not be con-nected to a chimney flue serving a fireplace unless thefireplace flue opening is permanently sealed. [NFPA54:12.11.13]
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509.10.12 Passage through Ceilings, Floors, or Walls.A vent connector shall not pass through a ceiling, floor,or fire-resistance-rated wall. A single-wall metal pipeconnector shall not pass through an interior wall.Exception: Vent connectors made of listed Type B orType L vent material and serving listed appliances withdraft hoods and other appliances listed for use with TypeB gas vents that pass through walls or partitions con-structed of combustible material shall be installed withnot less than the listed clearance to combustible material.
509.10.12.1 Medium-Heat Appliances. Vent con-nectors for medium-heat appliances shall not passthrough walls or partitions constructed of com-bustible material. [NFPA 54:12.11.14.2]
509.11 Draft Hoods and Draft Controls. Vented appliancesshall be installed with draft hoods.Exception:Dual oven-type combination ranges; incinerators;direct-vent appliances; fan-assisted combustion system appli-ances; appliances requiring chimney draft for operation; sin-gle firebox boilers equipped with conversion burners withinputs exceeding 400 000 Btu/h (117 kW); appliancesequipped with blast, power, or pressure burners that are notlisted for use with draft hoods; and appliances designed forforced venting. [NFPA 54:12.13.1]
509.11.1 Installation. A draft hood supplied with orforming a part of listed vented appliances shall beinstalled without alteration, exactly as furnished andspecified by the appliance manufacturer.
Where a draft hood is not supplied by the appliancemanufacturer where one is required, a draft hood shallbe installed, be of a listed or approved type, and, in theabsence of other instructions, be of the same size as theappliance flue collar. Where a draft hood is required witha conversion burner, it shall be of a listed or approvedtype.
Where a draft hood of special design is needed orpreferable, the installation shall be in accordance withthe recommendations of the appliance manufacturer andshall be with the approval of the Authority Having Juris-diction. [NFPA 54:12.13.2]509.11.2 Draft Control Devices. Where a draft controldevice is part of the appliance or is supplied by the appli-ance manufacturer, it shall be installed in accordancewith the manufacturer’s installation instructions. In theabsence of manufacturer’s installation instructions, thedevice shall be attached to the flue collar of the appli-ance or as near to the appliance as practical. [NFPA54:12.13.3]509.11.3 Additional Devices. Appliances (except incin-erators) requiring controlled chimney draft shall be per-mitted to be equipped with a listed double-actingbarometric draft regulator installed and adjusted in accor-dance with the manufacturer’s installation instructions.[NFPA 54:12.13.4]
509.11.4 Location. Draft hoods and barometric draft reg-ulators shall be installed in the same room or enclosureas the appliance in such a manner as to prevent a differ-ence in pressure between the hood or regulator and thecombustion air supply. [NFPA 54:12.13.5]509.11.5 Positioning. Draft hoods and draft regulatorsshall be installed in the position for which they weredesigned with reference to the horizontal and verticalplanes and shall be located so that the relief opening isnot obstructed by a part of the appliance or adjacent con-struction. The appliance and its draft hood shall belocated so that the relief opening is accessible for check-ing vent operation. [NFPA 54:12.13.6]509.11.6 Clearance. A draft hood shall be located so thatits relief opening is not less than 6 inches (152 mm) froma surface except that of the appliance it serves and theventing system to which the draft hood is connected.Where a greater or lesser clearance is indicated on theappliance label, the clearance shall not be less than thatspecified on the label. Such clearances shall not bereduced. [NFPA 54:12.13.7]
509.12 Manually Operated Dampers. A manually operateddamper shall not be placed in an appliance vent connector.Fixed baffles shall not be classified as manually operateddampers. [NFPA 54:12.14]509.13 Automatically Operated Vent Dampers. An auto-matically operated vent damper shall be of a listed type.[NFPA 54:12.15]509.14 Obstructions. Devices that retard the flow of ventgases shall not be installed in a vent connector, chimney, orvent. The following shall not be considered as obstructions:(1) Draft regulators and safety controls specifically listed for
installation in venting systems and installed in accor-dance with the manufacturer’s installation instructions.
(2) Approved draft regulators and safety controls designedand installed in accordance with approved engineeringmethods.
(3) Listed heat reclaimers and automatically operated ventdampers installed in accordance with the manufacturer’sinstallation instructions.
(4) Vent dampers serving listed appliances installed in accor-dance with Section 510.0 or other approved engineeringmethods.
(5) Approved economizers, heat reclaimers, and recupera-tors installed in venting systems of appliances notrequired to be equipped with draft hoods, provided theappliance manufacturer’s installation instructions coverthe installation of such a device in the venting systemand performance in accordance with Section 509.3 andSection 509.3.1 is obtained. [NFPA 54:12.16]
510.0 Sizing of Category I Venting Systems.510.1 Installation. These venting tables shall not be usedwhere obstructions are installed in the venting system. The
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installation of vents serving listed appliances with ventdampers shall be installed in accordance with the appliancemanufacturer’s installation instructions or in accordance withthe following:(1) The maximum capacity of the vent system shall be deter-
mined using the NAT Max column.(2) The minimum capacity shall be determined as though the
appliance were a fan-assisted appliance, using the FANMin column to determine the minimum capacity of thevent system. Where the corresponding “FAN Min” is“NA”, the vent configuration shall not be permitted andan alternative venting configuration shall be utilized.[NFPA 54:13.1.1]510.1.1 Vent Downsizing. Where the vent size deter-mined from the tables is smaller than the appliance drafthood outlet or flue collar, the use of the smaller size shallbe permitted provided that the installation is in accor-dance with the following requirements:(1) The total vent height (H) is not less than 10 feet
(3048 mm).(2) Vents for appliance draft hood outlets or flue collars
12 inches (305 mm) in diameter or smaller are notreduced more than one table size.
(3) Vents for appliance draft hood outlets or flue collarsexceeding 12 inches (305 mm) in diameter are notreduced more than two table sizes.
(4) The maximum capacity listed in the tables for a fan-assisted appliance is reduced by 10 percent (0.90 xmaximum table capacity).
(5) The draft hood outlet exceeds 4 inches (102 mm) indiameter. A 3 inch (76 mm) diameter vent shall notbe connected to a 4 inch (102 mm) diameter drafthood outlet. This provision shall not apply to fan-assisted appliances. [NFPA 54:13.1.2]
510.1.2 Elbows. Single-appliance venting configurationswith zero lateral lengths in Table 510.1.2(1), Table510.1.2(2), and Table 510.1.2(5) shall not have elbows inthe venting system. Single-appliance venting with laterallengths, include two 90 degree (1.57 rad) elbows. Foreach additional elbow up to and including 45 degrees(0.79 rad), the maximum capacity listed in the ventingtables shall be reduced by 5 percent. For each additionalelbow greater than 45 degrees (0.79 rad) up to andincluding 90 degrees (1.57 rad), the maximum capacitylisted in the venting tables shall be reduced by 10 per-cent. Where multiple offsets occur in a vent, the total lat-eral length of offsets combined shall not exceed thatspecified in Table 510.1.2(1) through Table 510.1.2(5).[NFPA 54:13.1.3]510.1.3 Zero Lateral. Zero lateral (L) shall apply to astraight vertical vent attached to a top outlet draft hood orflue collar. [NFPA 54:13.1.4]510.1.4 High-Altitude Installations. Sea level input rat-ings shall be used where determining maximum capacity
for high-altitude installation. Actual input (derated foraltitude) shall be used for determining minimum capac-ity for high-altitude installation. [NFPA 54:13.1.5]510.1.5 Multiple Input Ratings. For appliances withmore than one input rate, the minimum vent capacity(FAN Min) determined from the tables shall be less thanthe lowest appliance input rating, and the maximum ventcapacity (FAN Max/NAT Max) determined from thetables shall exceed the highest appliance rating input.[NFPA 54:13.1.6]510.1.6 Corrugated Chimney Liner Reduction. Listedcorrugated metallic chimney liner systems in masonrychimneys shall be sized by using Table 510.1.2(1) orTable 510.1.2(2) for Type B vents with the maximumcapacity reduced by 20 percent (0.80 x maximum capac-ity) and the minimum capacity as shown in Table510.1.2(1) or Table 510.1.2(2).
Corrugated metallic liner systems installed withbends or offsets shall have their maximum capacity fur-ther reduced in accordance with Section 510.1.2. The 20percent reduction for corrugated metallic chimney linersystems includes an allowance for one long radius 90degree (1.57 rad) turn at the bottom of the liner. [NFPA54:13.1.7]510.1.7 Connection to Chimney Liners. Connectionsbetween chimney liners and listed double-wall connec-tors shall be made with listed adapters designed for suchpurposes. [NFPA 54:13.1.8]510.1.8 Vertical Vent Upsizing Using 7 x Rule. Wherethe vertical vent has a larger diameter than the vent con-nector, the vertical vent diameter shall be used to deter-mine the minimum vent capacity, and the connectordiameter shall be used to determine the maximum ventcapacity. The flow area of the vertical vent shall notexceed seven times the flow area of the listed appliancecategorized vent area, flue collar area, or draft hood out-let area unless designed in accordance with approvedengineering methods. [NFPA 54:13.1.9]510.1.9 Draft Hood Conversion Accessories. Drafthood conversion accessories for use with masonry chim-neys venting listed Category I fan-assisted appliancesshall be listed and installed in accordance with the listedaccessory manufacturer’s installation instructions.[NFPA 54:13.1.10]510.1.10 Chimney and Vent Locations. Table510.1.2(1) through Table 510.1.2(5) shall be used forchimneys and vents not exposed to the outdoors belowthe roof line. A Type B vent or listed chimney lining sys-tem passing through an unused masonry chimney flueshall not be considered to be exposed to the outdoors.Where vents extend outdoors above the roof more than 5feet (1524 mm) higher than required by Table 509.6.2,and where vents terminate in accordance with Section509.6.2(1), the outdoor portion of the vent shall be
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enclosed as required by this section for vents not con-sidered to be exposed to the outdoors or such venting sys-tem shall be engineered. A Type B vent passing throughan unventilated enclosure or chase insulated to a valueof not less than R-8 shall not be considered to be exposedto the outdoors. Table 510.1.2(3) in combination withTable 510.1.2(6) shall be used for clay-tile-lined exteriormasonry chimneys, provided the following requirementsare met:(1) The vent connector is Type B double wall.(2) The vent connector length is limited to 18 inches per
inch (18 mm/mm) of vent connector diameter.(3) The appliance is draft hood-equipped.(4) The input rating is less than the maximum capacity
given in Table 510.1.2(3).(5) For a water heater, the outdoor design temperature
shall be not less than 5°F (-15°C).(6) For a space-heating appliance, the input rating
exceeds the minimum capacity given by Table510.1.2(6). [NFPA 54-12:13.1.11]
510.1.11 Corrugated Vent Connector Size. Corrugatedvent connectors shall not be smaller than the listed appli-ance categorized vent diameter, flue collar diameter, ordraft hood outlet diameter. [NFPA 54:13.1.12]510.1.12 Upsizing. Vent connectors shall not be upsizedmore than two sizes exceeding the listed appliance cate-gorized vent diameter, flue collar diameter, or draft hoodoutlet diameter. [NFPA 54:13.1.13]510.1.13 Single Run of Vent. In a single run of vent orvent connector, more than one diameter and type shallbe permitted to be used, provided that the sizes and typesare permitted by the tables. [NFPA 54:13.1.14]510.1.14 Interpolation. Interpolation shall be permittedin calculating capacities for vent dimensions that fallbetween table entries. [NFPA 54:13.1.15]510.1.15 Extrapolation. Extrapolation beyond the tableentries shall not be permitted. [NFPA 54:13.1.16]510.1.16 Engineering Methods. For vent heights lowerthan 6 feet (1829 mm) and higher than vent heightsshown in the tables, engineering methods shall be used tocalculate vent capacities. [NFPA 54:13.1.17]510.1.17 Height Entries. Where the actual height of avent falls between entries in the height column of theapplicable table in Table 510.1.2(1) through Table510.1.2(6), either:(1) Interpolation shall be used.(2) The lower vent capacity shown in the table entries
shall be used for FAN Max and NAT Max columnvalues and the higher vent capacity shall be used forthe FAN Min column values. [NFPA 54-12:13.1.18]
510.2 Additional Requirements to Multiple ApplianceVent Table 510.2(1) through Table 510.2(9). These ventingtables shall not be used where obstructions are installed in the
venting system. The installation of vents serving listed appli-ances with vent dampers shall be installed in accordance withthe appliance manufacturer’s installation instructions or inaccordance with the following:(1) The maximum capacity of the vent connector shall be
determined using the NAT Max column.(2) The maximum capacity of the vertical vent or chimney
shall be determined using the FAN + NAT column wherethe second appliance is a fan-assisted appliance, or theNAT + NAT column where the second appliance isequipped with a draft hood.
(3) The minimum capacity shall be determined as if theappliance were a fan-assisted appliance.(a) The minimum capacity of the vent connector shall
be determined using the FAN Min column.(b) The FAN + FAN column shall be used where the
second appliance is a fan-assisted appliance, and theFAN + NAT column shall be used where the secondappliance is equipped with a draft hood, to deter-mine whether the vertical vent or chimney configu-ration is not permitted (NA). Where the ventconfiguration is NA, the vent configuration shall notbe permitted and an alternative venting configura-tion shall be utilized. [NFPA 54:13.2.1]
510.2.1 Vent Connector Maximum Length. The max-imum vent connector horizontal length shall be 18 inchesper inch (18 mm/mm) of connector diameter as shownin Table 510.2.1, or as permitted by Section 510.2.2.[NFPA 54-12:13.2.2]510.2.2 Vent Connector Exceeding Maximum Length.The vent connector shall be routed to the vent utilizingthe shortest possible route. Connectors with longer hor-izontal lengths than those listed in Table 510.2.1 are per-mitted under the following conditions:(1) The maximum capacity (FAN Max or NAT Max) of
the vent connector shall be reduced 10 percent foreach additional multiple of the length listed in Table510.2.1. For example, the length listed for a 4 inch(102 mm) connector shall not exceed 6 feet (1829mm). With a connector length exceeding 6 feet (1829mm) but not exceeding 12 feet (3658 mm), the max-imum capacity shall be reduced by 10 percent (0.90 xmaximum vent connector capacity). With a connectorlength exceeding 12 feet (3658 mm) but not exceed-ing 18 feet (5486 mm), the maximum capacity shallbe reduced by 20 percent (0.80 x maximum ventcapacity).
(2) For a connector serving a fan-assisted appliance, theminimum capacity (FAN Min) of the connector shallbe determined by referring to the corresponding sin-gle appliance table. For Type B double-wall con-nectors, Table 510.1.2(1) shall be used. Forsingle-wall connectors, Table 510.1.2(2) shall beused. The height (H) and lateral (L) shall be meas-
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ured according to the procedures for a single appli-ance vent, as if the other appliances were not pres-ent. [NFPA 54:13.2.3]
510.2.3 Ten Percent Reduction.Where the vent connec-tors are combined prior to entering the vertical portion ofthe common vent to form a common vent manifold, thesize of the common vent manifold and the common ventshall be determined by applying a 10 percent reduction(0.90 x maximum common vent capacity) to the Com-mon Vent Capacity part of the common vent tables. Thelength of the common vent connector manifold (LM) shallnot exceed 18 inches per inch (18 mm/mm) of commonvent diameter (D). [NFPA 54:13.2.4]510.2.4 Vent Offset. Where the common vertical vent isoffset, the maximum capacity of the common vent shallbe reduced in accordance with Section 510.2.5, and thehorizontal length of the common vent offset shall notexceed 18 inches per inch (18 mm/mm) of common ventdiameter. Where multiple offsets occur in a commonvent, the total horizontal length of offsets combined shallnot exceed 18 inches per inch (18 mm/mm) of commonvent diameter. [NFPA 54:13.2.5]510.2.5 Elbow Reduction. For each elbow up to andincluding 45 degrees (0.79 rad) in the common vent, themaximum common vent capacity listed in the ventingtables shall be reduced by 5 percent. For each elbowexceeding 45 degrees (0.79 rad) up to and including 90degrees (1.57 rad), the maximum common vent capacitylisted in the venting tables shall be reduced by 10 per-cent. [NFPA 54:13.2.6]510.2.6 Common Vent Minimum Size. The cross-sec-tional area of the common vent shall be equal to orexceeding the cross-sectional area of the largest connec-tor. [NFPA 54:13.2.8]510.2.7 Tee and Wye Fittings. Tee and wye fittings con-nected to a common gas vent shall be considered as partof the common gas vent and constructed of materialsconsistent with that of the common gas vent. [NFPA54:13.2.9]510.2.8 Size of Fittings. At the point where tee or wyefittings connect to a common gas vent, the opening sizeof the fitting shall be equal to the size of the commonvent. Such fittings shall not be prohibited from havingreduced size openings at the point of connection of appli-ance gas vent connectors. [NFPA 54:13.2.10]510.2.9 High-Altitude Installations. Sea level input rat-ings shall be used where determining maximum capacityfor high-altitude installation. Actual input (derated foraltitude) shall be used for determining minimum capac-ity for high-altitude installation. [NFPA 54:13.2.11]510.2.10 Connector Rise. The connector rise (R) foreach appliance connector shall be measured from thedraft hood outlet or flue collar to the centerline where thevent gas streams come together. [NFPA 54:13.2.12]
510.2.11 Vent Height. For multiple units of applianceslocated on one floor, total height (H) shall be measuredfrom the highest draft hood outlet or flue collar up to thelevel of the outlet of the common vent. [NFPA54:13.2.13]510.2.12 Multistory Installations. For multistory instal-lations, total height (H) for each segment of the systemshall be the vertical distance between the highest drafthood outlet or flue collar entering that segment and thecenterline of the next higher interconnection tee. [NFPA54:13.2.14]510.2.13 Size of Vents for Multistory Installations. Thesize of the lowest connector and of the vertical vent lead-ing to the lowest interconnection of a multistory systemshall be in accordance with Table 510.1.2(1) or Table510.1.2(2) for available total height (H) up to the lowestinterconnection. [NFPA 54:13.2.15]510.2.14 Vent Type Multistory Installations. Whereused in multistory systems, vertical common vents shallbe Type B double-wall and shall be installed with a listedvent cap. [NFPA 54:13.2.16]510.2.15 Offsets in Multistory Installations.Offsets inmultistory common vent systems shall be limited to asingle offset in each system, and systems with an offsetshall comply with the following:(1) The offset angle shall not exceed 45 degrees (0.79
rad) from vertical.(2) The horizontal length of the offset shall not exceed
18 inches per inch (18 mm/mm) of common ventdiameter of the segment in which the offset islocated.
(3) For the segment of the common vertical vent con-taining the offset, the common vent capacity listed in
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CONNECTOR DIAMETER (inches)
MAXIMUM CONNECTOR HORIZONTAL LENGTH (feet)
3 41⁄24 65 71⁄26 97 101⁄28 129 131⁄210 1512 1814 2116 2418 2720 3022 3324 36
TABLE 510.2.1VENT CONNECTOR MAXIMUM LENGTH
[NFPA 54: TABLE 13.2.2]
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm
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the common venting tables shall be reduced by 20percent (0.80 x maximum common vent capacity).
(4) A multistory common vent shall not be reduced insize above the offset. [NFPA 54:13.2.17]
510.2.16 Flow Area of Vent. Where two or more appli-ances are connected to a vertical vent or chimney, theflow area of the largest section of vertical vent or chim-ney shall not exceed seven times the smallest listed appli-ance categorized vent areas, flue collar area, or drafthood outlet area unless designed in accordance withapproved engineering methods. [NFPA 54:13.2.18]510.2.17 Multiple Input Ratings. For appliances withmore than one input rate, the minimum vent connectorcapacity (FAN Min) determined from the tables shall beless than the lowest appliance input rating, and the max-imum vent connector capacity (FAN Max or NAT Max)determined from the table shall exceed the highest appli-ance input rating. [NFPA 54:13.2.19]510.2.18 Corrugated Metallic Chimney Liner Reduc-tion. Listed corrugated metallic chimney liner systemsin masonry chimneys shall be sized by using Table510.2(1) or Table 510.2(2) for Type B vents, with themaximum capacity reduced by 20 percent (0.80 x maxi-mum capacity) and the minimum capacity as shown inTable 510.2(1) or Table 510.2(2). Corrugated metallicliner systems installed with bends or offsets shall havetheir maximum capacity further reduced in accordancewith Section 510.2.4 and Section 510.2.5. The 20 per-cent reduction for corrugated metallic chimney liner sys-tems includes an allowance for one long radius 90 degree(1.57 rad) turn at the bottom of the liner. [NFPA54:13.2.20]510.2.19 Chimneys and Vents. Table 510.2(1) throughTable 510.2(5) shall be used for chimneys and vents notexposed to the outdoors below the roof line. A Type Bvent passing through an unventilated enclosure or chaseinsulated to a value of not less than R-8 shall not be con-sidered to be exposed to the outdoors. Where ventsextend outdoors above the roof more than 5 feet (1524mm) higher than required by Table 509.6.2, and wherevents terminate in accordance with Section 509.6.2(1),the outdoor portion of the vent shall be enclosed asrequired by this section for vents not considered to beexposed to the outdoors or such venting system shall beengineered. Table 510.2(6) through Table 510.2(9) shallbe used for clay-tile-lined exterior masonry chimneys,provided the following conditions are met:(1) Vent connector is Type B double-wall.(2) One appliance is draft hood-equipped.(3) The combined appliance input rating is less than the
maximum capacity given by Table 510.2(6) (forNAT + NAT) or Table 510.2(8) (for FAN + NAT).
(4) The input rating of each space-heating applianceexceeds the minimum input rating given by Table
510.2(7) (for NAT + NAT) or Table 510.2(9) (forFAN + NAT).
(5) The vent connector sizing is in accordance withTable 510.2(3). [NFPA 54-12:13.2.22]
510.2.20 Vent Connector Size Limitations. Vent con-nectors shall not be increased more than two sizesexceeding the listed appliance categorized vent diame-ter, flue collar diameter, or draft hood outlet diameter.Vent connectors for draft hood-equipped appliances shallnot be smaller than the draft hood outlet diameter. Wherevent connector sizes determined from the tables for fan-assisted appliances are smaller than the flue collar diam-eter, the use of the smaller sizes shall be permittedprovided that the installation is in accordance with thefollowing conditions:(1) Vent connectors for fan-assisted appliance flue col-
lars 12 inches (305 mm) in diameter or smaller arenot reduced by more than one table size [e.g., 12inches to 10 inches (305 mm to 254 mm) is a onesize reduction] and those exceeding 12 inches (305mm) in diameter are not reduced exceeding twotable sizes [e.g., 24 inches to 20 inches (610 mm to508 mm) is a two size reduction].
(2) Fan-assisted appliances are common vented with adraft hood-equipped appliance.
(3) The vent connector has a smooth interior wall.[NFPA 54:13.2.24]
510.2.21 Combination of Pipe Types and Sizes. Com-binations of pipe sizes, single-wall, and double-wallmetal pipe shall be allowed within a connector run orwithin the common vent, provided the appropriate tablespermit the desired sizes and types of pipe, where theywere used for the entire length of the subject connectoror vent. Where single-wall and Type B double-wall metalpipes are used for vent connectors within the same vent-ing system, the common vent shall be sized in accor-dance with Table 510.2(2) or Table 510.2(4). [NFPA54:13.2.25]510.2.22 Multiple Connector and Vent Sizes. Where atable permits more than one diameter of pipe to be usedfor a connector or vent, the permitted sizes shall be per-mitted to be used. [NFPA 54:13.2.26]510.2.23 Interpolation. Interpolation shall be permittedin calculating capacities for vent dimensions that fallbetween table entries. [NFPA 54:13.2.27]510.2.24 Extrapolation. Extrapolation beyond the tableentries shall not be permitted. [NFPA 54:13.2.28]510.2.25 Engineering Methods. For vent heights lowerthan 6 feet (1829 mm) and exceeding vent heights shownin the tables, engineering methods shall be used to cal-culate vent capacities. [NFPA 54:13.2.29]510.2.26 Height Entries. Where the actual height of avent falls between entries in the height column of theapplicable table in Table 510.2(1) through Table510.2(9), either:
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(1) Interpolation shall be used.(2) The lower vent capacity shown in the table entries
shall be used for FAN Max and NAT Max columnvalues and the higher vent capacity shall be used forthe FAN Min column values. [NFPA 54-12:13.2.30]
511.0 Direct-Vent Appliances.511.1 General. Listed direct-vent appliances shall be con-sidered properly vented where installed in accordance withthe terms of its listing, the manufacturer’s instructions, andSection 509.8.2. [NFPA 54:12.3.5]
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For SI units: °C = (°F-32)/1.8
FIGURE 510.1.2(6)RANGE OF WINTER DESIGN TEMPERATURES USED IN ANALYZING EXTERIOR MASONRY CHIMNEYS IN THE UNITED STATES
[NFPA 54: FIGURE G.2.4]
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TABLE 510.1.2(1)TYPE B DOUBLE-WALL GAS VENT [NFPA 54: TABLE 13.1(a)]*
NUMBER OF APPLIANCES: SINGLEAPPLIANCE TYPE: CATEGORY I
APPLIANCE VENT CONNECTION: CONNECTED DIRECTLY TO VENTVENT DIAMETER – D (inch)
3 4 5 6 7APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR
HEIGHTH
(feet)
LATERALL
(feet)
FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT
Min Max Max Min Max Max Min Max Max Min Max Max Min Max Max
6 0246
0132125
78514946
46363432
0183036
152979491
86676461
0273947
251157153149
141105103100
0325059
375232227223
205157153149
0446678
524321316310
285217211205
8 0258
0122328
84575349
50403835
0163239
16510910398
94757166
0254251
276178171164
155120115109
0285364
415263255247
235180173165
0427084
583365356347
320247237227
10 02510
0122330
88615751
53424036
0173241
175118113104
100817770
0234154
295194187176
166129124115
0265267
447289280267
255195188175
0406888
631402392376
345273263245
15 0251015
011222935
9469655953
5848454137
015304048
191136130121112
11293878276
020395161
327226219206195
187150142135128
022496476
502339330315301
285225217208198
038648498
716475463445429
390316300288275
20 025101520
01021283448
977571645852
615148444035
01429384655
202149143133124116
11910096898478
01838505969
349250242229217206
202166160150142134
02047627384
540377367351337322
307249241228217206
033628194107
776531519499481464
430346337321308295
30 02510152030
0921273356NA
1008177706458NA
64565450NANANA
0132837445373
213166160150141132113
1281121081029690NA
0143648576688
374283275262249237214
220185176171163154NA
01845597080104
587432421405389374346
336280273261249237219
027587790102131
853613600580560542507
475394385371357343321
50 02510152030
08202659NANA
10186827670NANA
6761NANANANANA
0112735425069
216183177168158149131
134122119114NANANA
0143545546384
397320312299287275250
232206200190180169NA
0154356667699
633497487471455440410
363314308298288278259
02255738597123
932715702681662642605
518445438426413401376
100 0251015203050
NANANANANANANANA
NANANANANANANANA
NANANANANANANANA
01026334047NANA
218194189182174166NANA
NANANANANANANANA
0123343505978NA
407354347335321311290NA
NANANANANANANANA
0134053627192147
665566557542528513483428
400375369361353344NANA
01852688090115180
997831820801782763726651
560510504493482471449405
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
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TABLE 510.1.2(1)TYPE B DOUBLE-WALL GAS VENT [NFPA 54: TABLE 13.1(a)] (continued)
NUMBER OF APPLIANCES: SINGLEAPPLIANCE TYPE: CATEGORY I
APPLIANCE VENT CONNECTION: CONNECTED DIRECTLY TO VENTVENT DIAMETER – D (inch)
8 9 10 12 14APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR
HEIGHTH
(feet)
LATERALL
(feet)
FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT
Min Max Max Min Max Max Min Max Max Min Max Max Min Max Max
6 0246
0537993
698425419413
370285279273
06393110
897543536530
470370362354
075110128
1121675668661
570455445435
0103147171
1645982975967
850650640630
0138191219
2267134613381330
1170890880870
8 0258
0508399
780483473463
415322313303
06099117
1006619607596
537418407396
071115137
1261770758746
660515503490
098154180
1858112411101097
970745733720
0130199231
2571154315281514
1320102010101000
10 02510
04881104
847533522504
450355346330
05795122
1096684671651
585457446427
068112142
1377852839817
720560547525
093149187
2036124412291204
1060850829795
0124192238
2825171316961669
1450113011051080
15 0251015
0457699115
970633620600580
525414403386373
05390116134
1263815800777755
682544529507491
063105135155
159610191003977953
840675660635610
086140177202
23801495147614461418
1240985967936905
0114182227257
33232062204120091976
17201350132712891250
20 025101520
0417395111125
1057711697675654634
575470460443427410
05086112129145
1384917902877853830
752612599576557537
059101130150167
175611501133110510781052
930755738710688665
081135172195217
263716941674164116091578
13501100107910451018990
0107174220248273
370123432320228222452210
190015201498146014251390
30 02510152030
0336991105119149
1173826811788765743702
650535524507490473444
04282107124139171
15481072105510281002977929
855700688668648628594
05496125143160195
1977135113321301127212431189
1060865851829807784745
074127164187207246
3004200419811944190818731807
1550131012891254122011851130
098164209237260305
4252278627592716267426332555
2170180017751733169216501585
50 02510152030
0266586100113141
1297975960935911888844
708615605589572556522
03377101117131161
1730127612591230120311761125
952813798773747722670
04190118136151183
2231162016001567153615051446
11951010996972948924876
066118154177195232
3441243124062366232722882214
1825151314951466143714081349
086151196222244287
4934340933803332328532393150
2550212521022064202619871910
100 0251015203050
021608093105131197
1411115511411118109510731029944
770700692679666653627575
0257194109122149217
19081536151914921465143813871288
1040935926910895880849787
03082108126141170241
24911975195519231892186118021688
13101170115911421124110710711000
044107142163181215292
39253027300229612920288028032657
20501820180317751747171916631550
072136180206226265350
57294313428242314182413340373856
29502550253125002469243823752250
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
READ ONLY
102 2013 CALIFORNIA PLUMBING CODE
WATER HEATERS
TABLE 510.1.2(1)TYPE B DOUBLE-WALL GAS VENT [NFPA 54: TABLE 13.1(a)] (continued)
NUMBER OF APPLIANCES: SINGLEAPPLIANCE TYPE: CATEGORY I
APPLIANCE VENT CONNECTION: CONNECTED DIRECTLY TO VENTVENT DIAMETER – D (inch)
16 18 20 22 24APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR
HEIGHTH
(feet)
LATERALL
(feet)
FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT
Min Max Max Min Max Max Min Max Max Min Max Max Min Max Max
6 0246
0178242276
2983176917611753
1530117011601150
0225300341
3802225022422235
1960148014751470
0296390437
4721278227742767
2430185018351820
0360469523
5737337733703363
2950222022152210
0426555618
6853403040234017
3520267026602650
8 0258
0168251289
3399203020132000
1740134013301320
0212311354
4333258425632552
2220170016851670
0278398450
5387319631803163
2750211020902070
0336476537
6555388238633850
3360256025452530
0401562630
7838463446124602
4010305030403030
10 02510
0161243298
3742225622382209
1925148014611430
0202300364
4782286828492818
2450189018711840
0264382459
5955355635363504
3050234023182280
0319458546
7254432243014268
3710284028182780
0378540641
8682515351325099
4450339033713340
15 0251015
0147229283318
44232719269626592623
22701770174817121675
0186283346385
56783467344234023363
29002260223521932150
0239355432479
70994304427842344192
36202800277727392700
0290426510564
86655232520451595115
44103410338533433300
0346501599665
10 3936251622261756129
53004080405740193980
20 025101520
0139219273306335
494830973071302929882948
252020001978194019101880
0175270334372404
637639553926388038353791
325025702544250024652430
0220337413459495
798849164885483547864737
406032003174313030903050
0269403489541585
978559835950589658445792
498039103880383037953760
0321475573631689
11 75371547119706370076953
600047004662460045754550
30 02510152030
0127206259292319369
5725369636663617357035233433
2920238023502300225022002130
0159252316354384440
7420473447014647459445424442
3770305030202970292028702785
0199312386431467540
9341590058635803574456865574
4750381037833739369536503565
0241373456507548635
11 483719471557090702669646842
5850465046224574452744804375
0285439535590639739
13 848861785748505843783708239
7060560055525471539153105225
50 02510152030
0113191243274300347
6711455445204464440943564253
3440284028132767272126752631
0141234295330361412
8774586458265763570156415523
4460367036393585353434813431
0171283355396433494
11 129733972957224715570866953
5635463045974542451144794421
0209336419465506577
13 767898089338855877987048557
6940569556545585554655065444
0251394491542586672
16 69410 78810 73710 65210 57010 48810 328
8430686068186749671066706603
100 0251015203050
095172223252277319415
79145834579757375678561955055289
40503500347534343392335132673100
0120208268304330378486
10 4857591754874787409734172096956
53004600456645094451439442794050
0138245318358387446572
13 4549577952894479367928991368841
67005800576957175665561355095300
0169293374418452514659
16 81711 80311 74811 65811 56911 48211 31010 979
86007200716271007037697568506600
0204341436487523592752
20 57814 26414 20414 10514 00713 91013 72013 354
10 3008800875686838610853783918100
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
READ ONLY
1032013 CALIFORNIA PLUMBING CODE
WATER HEATERS
TABLE 510.1.2(2)TYPE B DOUBLE-WALL GAS VENT [NFPA 54: TABLE 13.1(b)]*
NUMBER OF APPLIANCES: SINGLEAPPLIANCE TYPE: CATEGORY I
APPLIANCE VENT CONNECTION: SINGLE-WALL METAL CONNECTORVENT DIAMETER – D (inch)
3 4 5 6 7APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR
HEIGHTH
(feet)
LATERALL
(feet)
FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT
Min Max Max Min Max Max Min Max Max Min Max Max Min Max Max
6 0246
3839NANA
7751NANA
45363331
59607483
151969289
85666360
8585102114
249156152147
14010410299
126123146163
373231225220
204156152148
165159187207
522320313307
284213208203
8 0258
3739NANA
8356NANA
50393733
58597790
16410810295
93756964
8383107122
273176168161
154119114107
123121151175
412261252243
234179171163
161155193223
580363352342
319246235225
10 02510
373952NA
876156NA
53413934
57597697
174117111100
99807668
8282105132
293193185171
165128122112
120119148188
444287277261
254194186171
158153190237
628400388369
344272261241
15 0251015
363851NANA
936963NANA
57474439NA
56577595NA
190136128116NA
11193867972
8080102128158
325225216201186
186149140131124
116115144182220
499337326308290
283224217203192
153148182228272
713473459438418
388314298284269
20 025101520
353750NANANA
967468NANANA
60504741NANA
54567393NANA
200148140129NANA
11899948680NA
7878100125155186
346248239223208192
201165158146136126
114113141177216254
537375363344325306
306248239224210196
149144178222264309
772528514491469448
428344334316301285
30 02510152030
343749NANANANA
998074NANANANA
635652NANANANA
53557291115NA NA
211164157144131NANA
12711110698NANANA
767698122151181NA
372281271255239223NA
219183173168157NANA
110109136171208246NA
584429417397377357NA
334279271257242228NA
144139171213255298389
849610595570547524477
472392382367349333305
50 02510152030
333648NANANANA
998480NANANANA
6661NANANANANA
51537089112NANA
213181174160148NANA
133121117NANANANA
737394118145176NA
394318308292275257NA
230205198186174NANA
105104131162199236315
629495482461441420376
361312305292280267NA
138133164203244285373
928712696671646622573
515443435420405389NA
100 0251015203050
NANANANANANANANA
NANANANANANANANA
NANANANANANANANA
49516785132NANANA
214192186175162NANANA
NANANANANANANANA
697090113138168231NA
403351342324310295264NA
NANANANANANANANA
10098125153188224301NA
659563551532511487448NA
395373366354343NANANA
131125156191230270355540
991828813789764739685584
555508501486473458NANA
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
READ ONLY
104 2013 CALIFORNIA PLUMBING CODE
WATER HEATERS
TABLE 510.1.2(2)TYPE B DOUBLE-WALL GAS VENT [NFPA 54: TABLE 13.1(b)] (continued)*
NUMBER OF APPLIANCES: SINGLEAPPLIANCE TYPE: CATEGORY I
APPLIANCE VENT CONNECTION: SINGLE-WALL METAL CONNECTORVENT DIAMETER – D (inch)
8 9 10 12APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR
HEIGHTH
(feet)
LATERALL
(feet)
FAN NAT FAN NAT FAN NAT FAN NAT
Min Max Max Min Max Max Min Max Max Min Max Max
6 0246
211201237263
695423416409
369284277271
267251295327
894541533526
469368360352
371347409449
1118673664656
569453443433
537498584638
1639979971962
849648638627
8 0258
206197245280
777482470458
414321311300
258246305344
1002617604591
536417404392
360339418470
1257768754740
658513500486
521486598665
1852112011041089
967743730715
10 02510
202193241296
844531518497
449354344325
253242299363
1093681667643
584456443423
351332409492
1373849834808
718559544520
507475584688
2031124212241194
1057848825788
15 0251015
195187231284334
966631616592568
523413400381367
244232287349404
1259812795768742
681543526501484
336319392470540
15911015997966937
838673657628601
488457562664750
23741491146914331399
1237983963928894
20 025101520
190182224277325374
1053708692666640616
573468457437419400
238227279339393448
1379914896866838810
750611596570549526
326309381457526592
175111461126109210601028
927754734702677651
473443547646730808
263116891665162615871550
13461098107410371005973
30 02510152030
184175215265312360461
1168823806777750723670
647533521501481461426
229219269327379433541
1542106910491017985955895
852698684662638615574
312296366440507570704
1971134613241287125112161147
1056863846821794768720
454424524620702780937
2996199919711927188418411759
1545130812831243120511661101
50 02510152030
176168204253299345442
1292971953923894866809
704613602583562543502
220209257313363415521
1724127312521217118311501086
948811795765736708649
295280347418481544674
2223161515911551151214731399
11891007991963934906848
428401496589668741892
3432242623962347229922512159
1818150914901455142113871318
100 0251015203050
166158194238281325418617
140411521134110410751046988866
765698688672656639NANA
207196240293342391491711
19001532151114771443141013431205
1033933921902884864824NA
273259322389447507631895
24791970194519051865182517471591
1300116811531133111010871041NA
3953714605476186908341138
39123021299029382888283827392547
20421817179617631730169616271489
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
READ ONLY
1052013 CALIFORNIA PLUMBING CODE
WATER HEATERS
TABLE 510.1.2(3)MASONRY CHIMNEY [NFPA 54: TABLE 13.1(c)]*
NUMBER OF APPLIANCES: SINGLEAPPLIANCE TYPE: CATEGORY I
APPLIANCE VENT CONNECTION: TYPE B DOUBLE-WALL CONNECTOR
TYPE B DOUBLE-WALL CONNECTOR DIAMETER – D (inch)TO BE USED WITH CHIMNEY AREAS WITHIN THE SIZE LIMITS AT BOTTOM
3 4 5 6 7APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR
HEIGHTH
(feet)
LATERALL
(feet)
FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT
Min Max Max Min Max Max Min Max Max Min Max Max Min Max Max
6 25
NANA
NANA
2825
NANA
NANA
5249
NANA
NANA
8682
NANA
NANA
130117
NANA
NANA
180165
8 258
NANANA
NANANA
292624
NANANA
NANANA
555248
NANANA
NANANA
938883
NANANA
NANANA
145134127
NANANA
NANANA
198183175
10 2510
NANANA
NANANA
312825
NANANA
NANANA
615750
NANANA
NANANA
1039687
NANANA
NANANA
162148139
NANANA
NANANA
221204191
15 251015
NANANANA
NANANANA
353528NA
NANANANA
NANANANA
67625548
NANANANA
NANANANA
1141079789
NANANANA
NANANANA
179164153141
53NANANA
475NANANA
250231216201
20 25101520
NANANANANA
NANANANANA
3836NANANA
NANANANANA
NANANANANA
746860NANA
NANANANANA
NANANANANA
1241161079783
NANANANANA
NANANANANA
201184172159148
5180NANANA
522503NANANA
274254237220206
30 2510152030
NANANANANANA
NANANANANANA
41NANANANANA
NANANANANANA
NANANANANANA
827667NANANA
NANANANANANA
NANANANANANA
13712811510791NA
NANANANANANA
NANANANANANA
216198184171159NA
4775NANANANA
581561NANANANA
303281263243227188
50 2510152030
NANANANANANA
NANANANANANA
NANANANANANA
NANANANANANA
NANANANANANA
92NANANANANA
NANANANANANA
NANANANANANA
161151138127NANA
NANANANANANA
NANANANANANA
251230215199185NA
NANANANANANA
NANANANANANA
351323304282264NA
Minimuminternal area of
chimney(square inches)
12 19 28 38 50
Maximuminternal area of
chimney(square inches)
Seven times the listed appliance categorized vent area, flue collar area, or draft hood outlet areas.
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
READ ONLY
106 2013 CALIFORNIA PLUMBING CODE
WATER HEATERS
TABLE 510.1.2(3)MASONRY CHIMNEY [NFPA 54: TABLE 13.1(c)] (continued)*
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
NUMBER OF APPLIANCES: SINGLEAPPLIANCE TYPE: CATEGORY I
APPLIANCE VENT CONNECTION: TYPE B DOUBLE-WALL CONNECTORTYPE B DOUBLE-WALL CONNECTOR DIAMETER – D (inch)
TO BE USED WITH CHIMNEY AREAS WITHIN THE SIZE LIMITS AT BOTTOM8 9 10 12
APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR
HEIGHTH
(feet)
LATERALL
(feet)
FAN NAT FAN NAT FAN NAT FAN NAT
Min Max Max Min Max Max Min Max Max Min Max Max
6 25
NANA
NANA
247231
NANA
NANA
320298
NANA
NANA
401376
NANA
NANA
581561
8 258
NANANA
NANANA
266247239
84NANA
590NANA
350328318
100149173
728711695
446423410
139201231
10241007990
651640623
10 2510
68NANA
519NANA
298277263
82124155
655638610
388365347
98146182
810791762
491466444
136196240
114411241093
724712668
15 251015
64 99126NA
613594565NA
336313296281
77118148171
779759727698
441416394375
92139173198
968946912880
562533567485
127186229259
1376135213151280
841828777742
20 25101520
6195122NANA
678658627NANA
375350332314296
73113143165186
867845811780750
491463440418397
87133167191214
108310591022987955
627597566541513
121179221251277
15481523148214431406
953933879840807
30 2510152030
5790115NANANA
762741709NANANA
421393373353332288
68106135156176NA
985962927893860NA
558526500476450416
81125158181203249
124012161176113911031035
717683648621592555
111169210239264318
179317661721167916381560
111210941025981940877
50 2510152030
5183NANANANA
840819NANANANA
477445424400376327
6198126146165NA
1106108310471010977NA
633596567539511468
72116147170190233
141313871347130712691196
812774733702669623
99155195222246295
208020522006196119161832
12431225114710991050984
Minimuminternal area of
chimney(square inches)
63 78 95 132
Maximuminternal area of
chimney(square inches)
Seven times the listed appliance categorized vent area, flue collar area, or draft hood outlet areas.
READ ONLY
1072013 CALIFORNIA PLUMBING CODE
WATER HEATERS
TABLE 510.1.2(4)MASONRY CHIMNEY [NFPA 54: TABLE 13.1(d)]*
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
NUMBER OF APPLIANCES: SINGLEAPPLIANCE TYPE: CATEGORY I
APPLIANCE VENT CONNECTION: SINGLE-WALL METAL CONNECTOR
SINGLE-WALL METAL CONNECTOR DIAMETER – D (inch)TO BE USED WITH CHIMNEY AREAS WITHIN THE SIZE LIMITS AT BOTTOM
3 4 5 6 7APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR
HEIGHTH
(feet)
LATERALL
(feet)
FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT
Min Max Max Min Max Max Min Max Max Min Max Max Min Max Max
6 25
NANA
NANA
2825
NANA
NANA
5248
NANA
NANA
8681
NANA
NANA
130116
NANA
NANA
180164
8 258
NANANA
NANANA
292623
NANANA
NANANA
555147
NANANA
NANANA
938782
NANANA
NANANA
145133126
NANANA
NANANA
197182174
10 2510
NANANA
NANANA
312824
NANANA
NANANA
615649
NANANA
NANANA
1029586
NANANA
NANANA
161147137
NANANA
NANANA
220203189
15 251015
NANANANA
NANANANA
353227NA
NANANANA
NANANANA
67615446
NANANANA
NANANANA
1131069687
NANANANA
NANANANA
178163151138
166NANANA
473NANANA
249230214198
20 25101520
NANANANANA
NANANANANA
3835NANANA
NANANANANA
NANANANANA
736759NANA
NANANANANA
NANANANANA
1231151059580
NANANANANA
NANANANANA
200183170156144
163NANANANA
520NANANANA
273252235217202
30 2510152030
NANANANANANA
NANANANANANA
41NANANANANA
NANANANANANA
NANANANANANA
817566NANANA
NANANANANANA
NANANANANANA
13612711310588NA
NANANANANANA
NANANANANANA
215196182168155NA
158NANANANANA
578NANANANANA
302279260240223182
50 2510152030
NANANANANANA
NANANANANANA
NANANANANANA
NANANANANANA
NANANANANANA
91NANANANANA
NANANANANANA
NANANANANANA
160149136124NANA
NANANANANANA
NANANANANANA
250228212195180NA
NANANANANANA
NANANANANANA
350321301278258NA
Minimuminternal area of
chimney(square inches)
12 19 28 38 50
Maximuminternal area of
chimney(square inches)
Seven times the listed appliance categorized vent area, flue collar area, or draft hood outlet areas.
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108 2013 CALIFORNIA PLUMBING CODE
WATER HEATERS
TABLE 510.1.2(4)MASONRY CHIMNEY [NFPA 54: TABLE 13.1(d)] (continued)*
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
NUMBER OF APPLIANCES: SINGLEAPPLIANCE TYPE: CATEGORY I
APPLIANCE VENT CONNECTION: SINGLE-WALL METAL CONNECTORSINGLE-WALL METAL CONNECTOR DIAMETER – D (inch)
TO BE USED WITH CHIMNEY AREAS WITHIN THE SIZE LIMITS AT BOTTOM8 9 10 12
APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR
HEIGHTH
(feet)
LATERALL
(feet)
FAN NAT FAN NAT FAN NAT FAN NAT
Min Max Max Min Max Max Min Max Max Min Max Max
6 25
NANA
NANA
247230
NANA
NANA
319297
NANA
NANA
400375
NANA
NANA
580560
8 258
NANANA
NANANA
265246237
NANANA
NANANA
349327317
382NANA
725NANA
445422408
549673747
10211003985
650638621
10 2510
216NANA
518NANA
297276261
271334NA
654635NA
387364345
373459547
808789758
490465441
536657771
114211211088
722710665
15 251015
211261NANA
611591NANA
335312294278
264325392452
776755722692
440414392372
362444531606
965942907873
560531504481
520637749841
1373134813091272
840825774738
20 25101520
206255312NANA
675655622NANA
374348330311292
258317382442NA
864842806773NA
490461437414392
252433517591663
107910551016979944
625594562539510
508623733823911
15441518147514341394
950930875835800
30 2510152030
200245300NANANA
759737703NANANA
420391370349327281
249306370428NANA
982958920884NANA
556524496471445408
340417500572643NA
12371210116811281089NA
715680644615585544
4896007087988831055
178917601713166816241539
111010901020975932865
50 2510152030
191NANANANANA
837NANANANANA
475442420395370318
238293355NANANA
110310781038NANANA
631593562533504458
323398447546616NA
14081381133712941251NA
810770728695660610
4635716747618441009
207620441994194518981805
12401220114010901040970
Minimuminternal area of
chimney(square inches)
63 78 95 132
Maximuminternal area of
chimney(square inches)
Seven times the listed appliance categorized vent area, flue collar area, or draft hood outlet areas.
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1092013 CALIFORNIA PLUMBING CODE
WATER HEATERS
TABLE 510.1.2(5)SINGLE-WALL METAL PIPE OR TYPE B ASBESTOS-CEMENT VENT [NFPA 54: TABLE 13.1(e)]*
NUMBER OF APPLIANCES: SINGLEAPPLIANCE TYPE: DRAFT HOOD-EQUIPPED
APPLIANCE VENT CONNECTION: CONNECTED DIRECTLY TO PIPE OR VENT
DIAMETER – D (inch)TO BE USED WITH CHIMNEY AREAS WITHIN THE SIZE LIMITS AT BOTTOM
3 4 5 6 7 8 10 12HEIGHT
H(feet)
LATERALL
(feet)
APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOURMAXIMUM APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR
6 025
393128
705551
1169488
170141128
232194177
312260242
500415390
750620600
8 02510
42322924
76615649
1261029586
185154141131
252210194180
340284264250
542451430406
815680648625
10 0251015
45353227NA
8467615446
1381111049484
202168153143130
279233215200186
372311289274258
606505480455432
912760724700666
15 025101520
49393530NANA
9172675850NA
1511221101039382
223186170158144132
312260240223207195
420350325308291273
684570540514488466
1040865825795760726
20 025101520
53423832NANA
10180746555NA
16313612311510491
252210192178163149
342286264246228214
470392364345326306
770641610571550525
1190990945910870832
30 02510152030
5644NANANANANA
108847868NANANA
18314813712511399NA
276230210196177163NA
384320296274258240192
529441410388366344295
878730694656625596540
13701140108010501000960890
50 02510152030
NANANANANANANA
12095NANANANANA
210171159146NANANA
310260234221200185NA
443370342318292276222
590492474456407384330
980820780730705670605
1550129012301190113010801010
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
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110 2013 CALIFORNIA PLUMBING CODE
WATER HEATERS
TABLE 510.1.2(6)EXTERIOR MASONRY CHIMNEY [NFPA 54-12: TABLE 13.1(f)]1, 2
NUMBER OF APPLIANCES: SINGLEAPPLIANCE TYPE: NAT
APPLIANCE VENT CONNECTION: TYPE B DOUBLE-WALL CONNECTORMINIMUM ALLOWABLE INPUT RATING OF SPACE-HEATING APPLIANCE IN THOUSANDS OF BTU PER HOUR
VENT HEIGHTH
(feet)
INTERNAL AREA OF CHIMNEY (square inches)
12 19 28 38 50 63 78 113
681015203050
Local 99% winter design temperature: 37°F or greater000
NANANANA
0000
NANANA
0000
123NANA
0000
190NANA
0000
249NANA
0000
184393NA
00000
334NA
000000
579
681015203050
Local 99% winter design temperature: 27°F to 36°F000
NANANANA
0051NANANANA
688297NANANANA
116127141NANANANA
156167183233NANANA
180187201253307419NA
212214225274330445NA
266263265305362485763
681015203050
Local 99% winter design temperature: 17°F to 26°FNANANANANANANA
NANANANANANANA
NANANANANANANA
NANANANANANANA
NA197214NANANANA
215226245296352NANA
259264278331387507NA
349352358398457581NA
681015203050
Local 99% winter design temperature: 5°F to 16°FNANANANANANANA
NANANANANANANA
NANANANANANANA
NANANANANANANA
NANANANANANANA
NANA289NANANANA
NA312331393450NANA
416423430485547682972
681015203050
Local 99% winter design temperature: -10°F to 4°FNANANANANANANA
NANANANANANANA
NANANANANANANA
NANANANANANANA
NANANANANANANA
NANANANANANANA
NANANANANANANA
4844945135866508051003
Local 99% winter design temperature: -11°F or lowerNot recommended for any vent configurations
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2, °C = (°F-32)/1.8Notes:1 See Figure 510.1.2(6) for a map showing local 99 percent winter design temperatures in the United States.2 NA: Not applicable.
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1112013 CALIFORNIA PLUMBING CODE
WATER HEATERS
TABLE 510.2(1)TYPE B DOUBLE-WALL VENT [NFPA 54: TABLE 13.2(a)]*
NUMBER OF APPLIANCES: TWO OR MOREAPPLIANCE TYPE: CATEGORY I
APPLIANCE VENT CONNECTION: TYPE B DOUBLE-WALL CONNECTORVENT CONNECTOR CAPACITY
TYPE B DOUBLE-WALL VENT AND CONNECTOR DIAMETER – D (inch)3 4 5 6 7
APPLIANCE INPUT RATING LIMITS IN THOUSANDS OF BTU PER HOURVENTHEIGHT
H(feet)
CONNECTORRISER
(feet)
FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT
Min Max Max Min Max Max Min Max Max Min Max Max Min Max Max
6 123
222324
374144
263135
353738
667581
465562
464849
106121132
728696
586062
164183199
104124139
777982
225253275
142168189
8 123
222324
404447
273236
353637
728087
485764
495153
114128139
7690101
646667
176195210
109129145
848688
243269290
148175198
10 123
222324
434750
283337
343637
788692
505967
495152
123136146
7893104
656769
189206220
113134150
899194
257282303
154182205
15 123
212224
505355
303540
333536
8996102
536371
474951
142153163
8399111
646668
220235248
120142160
889193
298320339
163193218
20 123
212223
545760
313742
333435
99105110
566674
464850
157167176
87104116
626466
246259271
125149168
868991
334354371
171202228
30 123
202122
626466
333944
313334
113118123
597079
454748
181190198
93110124
606264
288299309
134158178
838588
391408423
182215242
50 123
192122
717375
364348
303233
133137141
647686
434546
216223229
101119134
575961
349358366
145172194
788183
477490502
197234263
100 123
181920
828384
374450
283031
158161163
667989
404244
262267272
104123138
535557
442447452
150178200
737578
611619627
204242272
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
COMMON VENT CAPACITYTYPE B DOUBLE-WALL COMMON VENT DIAMETER – D (inch)
4 5 6 7COMBINED APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR
VENTHEIGHT
H(feet)
FAN+FAN
FAN+NAT
NAT+NAT
FAN+FAN
FAN+NAT
NAT+NAT
FAN+FAN
FAN+NAT
NAT+NAT
FAN+FAN
FAN+NAT
NAT+NAT
681015203050100
92101110125136152167175
819097112123138153163
65737991102118134NA
140155169195215244279311
116129141164183210244277
103114124144160185214NA
204224243283314361421489
161178194228255297353421
147163178206229266310NA
309339367427475547641751
248275299352394459547658
200223242280310360423479
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112 2013 CALIFORNIA PLUMBING CODE
WATER HEATERS
TABLE 510.2(1)TYPE B DOUBLE-WALL VENT [NFPA 54: TABLE 13.2(a)] (continued)
NUMBER OF APPLIANCES: TWO OR MOREAPPLIANCE TYPE: CATEGORY I
APPLIANCE VENT CONNECTION: TYPE B DOUBLE-WALL CONNECTORVENT CONNECTOR CAPACITY
TYPE B DOUBLE-WALL VENT AND CONNECTOR DIAMETER – D (inch)8 9 10
APPLIANCE INPUT RATING LIMITS IN THOUSANDS OF BTU PER HOURVENTHEIGHT
H(feet)
CONNECTORRISER
(feet)
FAN NAT FAN NAT FAN NAT
Min Max Max Min Max Max Min Max Max
6 123
929597
296333363
185220248
109112114
376424463
237282317
128131134
466526575
289345386
8 123
100103105
320356384
194230258
118121123
408454492
248294330
138141143
507564612
303358402
10 123
106109111
341374402
200238268
125128131
436479515
257305342
146149152
542596642
314372417
15 123
110112115
389419445
214253286
134137140
493532565
273323365
162165167
609658700
333394444
20 123
107110113
436463486
224265300
131134137
552587618
285339383
158161164
681725764
347414466
30 123
103105108
512535555
238282317
125129132
649679706
305360405
151155158
802840874
372439494
50 123
97100103
627645661
257306343
120123126
797820842
330392441
144148151
98410141043
403478538
100 123
919497
810822834
266316355
112115118
103810541069
341405455
135139142
128513061327
417494555
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
COMMON VENT CAPACITYTYPE B DOUBLE-WALL COMMON VENT DIAMETER – D (inch)
8 9 10COMBINED APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR
VENT HEIGHT
H(feet)
FAN+FAN
FAN+NAT
NAT+NAT
FAN+FAN
FAN+NAT
NAT+NAT
FAN+FAN
FAN+NAT
NAT+NAT
681015203050100
4044444775566217208541025
314348377444499585706873
260290315365405470550625
54760264975384297911641408
4344805226126888089771215
335378405465523605705800
6727408009241035120914511784
52057762773382697511881502
410465495565640740860975
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1132013 CALIFORNIA PLUMBING CODE
WATER HEATERS
TABLE 510.2(1)TYPE B DOUBLE-WALL VENT [NFPA 54: TABLE 13.2(a)] (continued)*
NUMBER OF APPLIANCES: TWO OR MOREAPPLIANCE TYPE: CATEGORY I
APPLIANCE VENT CONNECTION: TYPE B DOUBLE-WALL CONNECTORVENT CONNECTOR CAPACITY
TYPE B DOUBLE-WALL VENT AND CONNECTOR DIAMETER – D (inch)12 14 16 18
APPLIANCE INPUT RATING LIMITS IN THOUSANDS OF BTU PER HOURVENTHEIGHT
H(feet)
CONNECTORRISER
(feet)
FAN NAT FAN NAT FAN NAT FAN NAT
Min Max Max Min Max Max Min Max Max Min Max Max
6 246
174180NA
764897NA
496616NA
223230NA
10461231NA
653827NA
281287NA
13711617NA
8531081NA
346352NA
17722069NA
10801370NA
8 246
186192198
8229521050
516644772
238244252
112613071445
6968841072
298305313
147817191902
91011501390
365372380
192022112434
115014601770
10 246
196201207
8709971095
536664792
249256263
119513711509
7309241118
311318325
157018041989
95512051455
379387395
204923322556
120515351865
15 246
214221228
96710851181
568712856
272279286
133414991632
79010061222
336344351
176019782157
103013201610
408416424
231725792796
130516652025
20 246
223230237
105111621253
596748900
291298307
144315971726
84010641288
357365373
191121162287
109513951695
430438450
253327782984
138517652145
30 246
216223231
121713161400
632792952
286294303
166418021920
91011601410
367376384
218323662524
119015101830
461474485
289131103299
154019202340
50 246
206213221
147915611631
6898601031
273281290
202321392242
100712911575
350359369
265928142951
131516852055
435447461
354837303893
166521352605
100 246
192200208
192319842035
7128881064
254263272
264427312811
105013461642
326336346
349036063714
137017602150
402414426
470748424968
174022202700
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
COMMON VENT CAPACITYTYPE B DOUBLE-WALL COMMON VENT DIAMETER – D (inch)
12 14 16 18COMBINED APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR
VENTHEIGHT
H(feet)
FAN+FAN
FAN+NAT
NAT+NAT
FAN+FAN
FAN+NAT
NAT+NAT
FAN+FAN
FAN+NAT
NAT+NAT
FAN+FAN
FAN+NAT
NAT+NAT
681015203050100
900994107612471405165820242569
6967738419861116132716402131
588652712825916102512801670
12841423154217942006237329113732
9901103120014101588189223473076
81591299511581290152518632450
17351927209324402722322039645125
13361491162519102147255831834202
10651190130015101690199024303200
22532507272731843561419751846749
17321936211324842798332641495509
13451510164519102140252030754050
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114 2013 CALIFORNIA PLUMBING CODE
WATER HEATERS
TABLE 510.2(1)TYPE B DOUBLE-WALL VENT [NFPA 54: TABLE 13.2(a)] (continued)*
NUMBER OF APPLIANCES: TWO OR MOREAPPLIANCE TYPE: CATEGORY I
APPLIANCE VENT CONNECTION: TYPE B DOUBLE-WALL CONNECTORVENT CONNECTOR CAPACITY
TYPE B DOUBLE-WALL VENT AND CONNECTOR DIAMETER – D (inch)20 22 24
APPLIANCE INPUT RATING LIMITS IN THOUSANDS OF BTU PER HOURVENTHEIGHT
H(feet)
CONNECTORRISER
(feet)
FAN NAT FAN NAT FAN NAT
Min Max Max Min Max Max Min Max Max
6 246
NANANA
NANANA
NANANA
NANANA
NANANA
NANANA
NANANA
NANANA
NANANA
8 246
NA471478
NA27373018
NA18002180
NA560568
NA33193665
NA21802640
NA662669
NA39574373
NA25903130
10 246
NA486494
NA28873169
NA18902290
NA581589
NA35023849
NA22802760
NA686694
NA41754593
NA27103270
15 246
NA523533
NA31973470
NA20602510
NA624634
NA38814216
NA24903030
NA734743
NA46315035
NA29603600
20 246
NA554567
NA34473708
NA21802650
NA661671
NA41904511
NA26303190
NA772785
NA50055392
NA31303790
30 246
NA619632
NA38404080
NA23652875
NA728741
NA48614976
NA28603480
NA847860
NA56065961
NA34104150
50 246
NA580594
NA46014808
NA26333208
NA709724
NA55695826
NA31853885
NA851867
NA66336943
NA37904620
100 246
NA523539
NA59826143
NA27503350
NA639654
NA72547453
NA33304070
NA769786
NA86508892
NA39504810
COMMON VENT CAPACITYTYPE B DOUBLE-WALL COMMON VENT DIAMETER – D (inch)
20 22 24COMBINED APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR
VENTHEIGHT
H(feet)
FAN+FAN
FAN+NAT
NAT+NAT
FAN+FAN
FAN+NAT
NAT+NAT
FAN+FAN
FAN+NAT
NAT+NAT
681015203050100
28383162344440264548530365678597
21802439266531333552419352406986
16601860203023602640311038005000
3488389042414971557365398116
10 681
26772998327838624352515764588648
19702200240027903120368045005920
4206469551236016674979409837
13 004
3226361639574670526162477813
10 499
23902680292034003800448054757200
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
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1152013 CALIFORNIA PLUMBING CODE
WATER HEATERS
TABLE 510.2(2)TYPE B DOUBLE-WALL VENT [NFPA 54: TABLE 13.2(b)]*
NUMBER OF APPLIANCES: TWO OR MOREAPPLIANCE TYPE: CATEGORY I
APPLIANCE VENT CONNECTION: SINGLE-WALL METAL CONNECTORVENT CONNECTOR CAPACITY
SINGLE-WALL METAL VENT CONNECTOR DIAMETER – D (inch)3 4 5 6 7
APPLIANCE INPUT RATING LIMITS IN THOUSANDS OF BTU PER HOURVENTHEIGHT
H(feet)
CONNECTORRISER
(feet)
FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT
Min Max Max Min Max Max Min Max Max Min Max Max Min Max Max
6 123
NANANA
NANANA
263134
NANANA
NANANA
465562
NANA121
NANA131
718595
NA168175
NA182198
102123138
207215222
223251273
140167188
8 123
NANANA
NANANA
273235
NANANA
NANANA
485764
NA125130
NA126138
7589
100
NA184191
NA193208
106127144
226234241
240266287
145173197
10 123
NANANA
NANANA
283336
NA8489
NA8591
505967
119124129
121134144
7791
102
182189197
186203217
110132148
240248257
253278299
150183203
15 123
NANANA
NANANA
293439
798387
8794
100
526270
116121127
138150160
8197
109
177185193
214230243
116138157
238246255
291314333
158189215
20 123
495255
565962
303640
788287
97103107
546472
115120125
152163172
84101113
175182190
238252264
120144164
233243252
325346363
165197223
30 123
475154
606264
313742
778185
110115119
576776
112117122
175185193
89106120
169177185
278290300
129152172
226236244
380397412
175208235
50 123
464952
697172
344045
757983
128132136
607282
109114119
207215221
96113123
162170178
336345353
137164186
217226235
460473486
188223252
100 123
454851
798081
344146
717579
150153157
617385
104110114
249255260
98115129
153160168
424428433
140167190
205212222
585593603
192228256
COMMON VENT CAPACITYTYPE B DOUBLE-WALL COMMON VENT DIAMETER – D (inch)
4 5 6 7COMBINED APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR
VENTHEIGHT
H(feet)
FAN+FAN
FAN+NAT
NAT+NAT
FAN+FAN
FAN+NAT
NAT+NAT
FAN+FAN
FAN+NAT
NAT+NAT
FAN+FAN
FAN+NAT
NAT+NAT
681015203050100
NANANA121131145159166
788794108118132145153
6471768898113128NA
NANA163189208236268297
113126137159177202233263
99111120140156180208NA
200218237275305350406469
158173189221247286337398
144159174200223257296NA
304331357416463533622726
244269292343383446529633
196218236274302349410464
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
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116 2013 CALIFORNIA PLUMBING CODE
WATER HEATERS
TABLE 510.2(2)TYPE B DOUBLE-WALL VENT [NFPA 54: TABLE 13.2(b)] (continued)
NUMBER OF APPLIANCES: TWO OR MOREAPPLIANCE TYPE: CATEGORY I
APPLIANCE VENT CONNECTION: SINGLE-WALL METAL CONNECTORVENT CONNECTOR CAPACITY
SINGLE-WALL METAL VENT CONNECTOR DIAMETER – D (inch)8 9 10
APPLIANCE INPUT RATING LIMITS IN THOUSANDS OF BTU PER HOURVENTHEIGHT
H(feet)
CONNECTORRISER
(feet)
FAN NAT FAN NAT FAN NAT
Min Max Max Min Max Max Min Max Max
6 123
262271279
293331361
183219247
325334344
373422462
234281316
447458468
463524574
286344385
8 123
285293302
316353381
191228256
352360370
403450489
244292328
481492501
502560609
299355400
10 123
302311320
335369398
196235265
372381391
429473511
252302339
506517528
534589637
308368413
15 123
312321331
380411438
208248281
397407418
482522557
266317360
556568579
596646690
324387437
20 123
306317326
425453476
217259294
390400412
538574607
276331375
546558570
664709750
336403457
30 123
296307316
497521542
230274309
378389400
630662690
294349394
528541555
779819855
358425482
50 123
284294304
604623640
245293331
364376387
768793816
314375423
507520535
9519831013
384458518
100 123
269279289
774788801
249299339
345358368
99310111027
321383431
476490506
123612591280
393469527
COMMON VENT CAPACITYTYPE B DOUBLE-WALL COMMON VENT DIAMETER – D (inch)
8 9 10COMBINED APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR
VENTHEIGHT
H(feet)
FAN+FAN
FAN+NAT
NAT+NAT
FAN+FAN
FAN+NAT
NAT+NAT
FAN+FAN
FAN+NAT
NAT+NAT
681015203050100
398436467544606703833999
310342369434487570686846
257285309357395459535606
54159263873882495811391378
4294735125996737909541185
332373398456512593689780
6657307879051013118314181741
51556961771880895211571459
407460487553626723838948
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
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1172013 CALIFORNIA PLUMBING CODE
WATER HEATERS
TABLE 510.2(3)MASONRY CHIMNEY [NFPA 54: TABLE 13.2(c)]*
NUMBER OF APPLIANCES: TWO OR MOREAPPLIANCE TYPE: CATEGORY I
APPLIANCE VENT CONNECTION: TYPE B DOUBLE-WALL CONNECTORVENT CONNECTOR CAPACITY
TYPE B DOUBLE-WALL VENT CONNECTOR DIAMETER – D (inch)3 4 5 6 7
APPLIANCE INPUT RATING LIMITS IN THOUSANDS OF BTU PER HOURVENTHEIGHT
H(feet)
CONNECTORRISER
(feet)
FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT
Min Max Max Min Max Max Min Max Max Min Max Max Min Max Max
6 123
242627
334349
212834
394142
627992
405261
525355
106133155
678597
656769
194230262
101124143
878991
274324369
141173203
8 123
242627
394752
222934
394042
728797
415362
555759
117140159
698698
717375
213246269
105127145
949799
304350383
148179206
10 123
242627
425055
222935
384041
8093105
425463
555758
130153170
7187100
747678
232261284
108129148
101103106
324366397
153184209
15 123
242526
485559
233135
383941
93105115
445564
545657
154174189
7489102
727476
277299319
114134153
100103105
384419448
164192215
20 123
242526
525863
243135
373940
102114123
465665
535557
172190204
7791104
717375
313335353
119138157
98101104
437467493
173199222
30 123
242526
546064
253236
373840
111122131
485866
525456
192208221
8295107
697274
357376392
127145163
9699101
504531554
187209233
50 123
232426
515964
253236
363739
116127135
516169
515355
209225237
89102115
677072
405421435
143161180
929598
582604624
213235260
100 123
232425
465359
243135
353738
108120130
506068
495153
208224237
92105118
656769
428444458
155174193
889294
640660679
237260285
COMMON VENT CAPACITYMINIMUM INTERNAL AREA OF MASONRY CHIMNEY FLUE (square inches)
12 19 28 38 50COMBINED APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR
VENTHEIGHT
H(feet)
FAN+FAN
FAN+NAT
NAT+NAT
FAN+FAN
FAN+NAT
NAT+NAT
FAN+FAN
FAN+NAT
NAT+NAT
FAN+FAN
FAN+NAT
NAT+NAT
FAN+FAN
FAN+NAT
NAT+NAT
681015203050100
NANANANANANANANA
748084NANANANANA
2528313641NANANA
NANANANANANANANA
119130138152NANANANA
4653566775NANANA
NANANANANANANANA
178193207233250270NANA
718290106122137NANA
NANANANANANANANA
257279299334368404NANA
103119131152172198NANA
NANANA523565615NANA
351384409467508564620NA
143163177212243278328348
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
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118 2013 CALIFORNIA PLUMBING CODE
WATER HEATERS
TABLE 510.2(3)MASONRY CHIMNEY [NFPA 54: TABLE 13.2(c)] (continued)*
NUMBER OF APPLIANCES: TWO OR MOREAPPLIANCE TYPE: CATEGORY I
APPLIANCE VENT CONNECTION: TYPE B DOUBLE-WALL CONNECTORVENT CONNECTOR CAPACITY
TYPE B DOUBLE-WALL VENT CONNECTOR DIAMETER – D (inch)8 9 10
APPLIANCE INPUT RATING LIMITS IN THOUSANDS OF BTU PER HOURVENTHEIGHT
H(feet)
CONNECTORRISER
(feet)
FAN NAT FAN NAT FAN NAT
Min Max Max Min Max Max Min Max Max
6 123
104107109
370436491
201232270
124127129
479562633
253300349
145148151
599694795
319378439
8 123
113116119
414473517
210240276
134137139
539615672
267311358
156160163
682776848
335394452
10 123
120123126
444498540
216247281
142145147
582652705
277321366
165168171
739825893
348407463
15 123
125128131
511558597
229260292
153156159
658718760
297339382
184187190
824900960
375432486
20 123
123126129
584625661
239270301
150153156
752805851
312354396
180184187
94310111067
397452505
30 123
119122125
680715746
255287317
145149152
883928968
337378418
175179182
111511711220
432484535
50 123
115118121
798827854
294326357
140143147
104910851118
392433474
168172176
133413791421
506558611
100 123
109113116
907933956
334368399
134138141
122212531282
454497540
161165169
158916261661
596651705
COMMON VENT CAPACITYMINIMUM INTERNAL AREA OF MASONRY CHIMNEY FLUE (square inches)
63 78 113COMBINED APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR
VENTHEIGHT
H(feet)
FAN+FAN
FAN+NAT
NAT+NAT
FAN+FAN
FAN+NAT
NAT+NAT
FAN+FAN
FAN+NAT
NAT+NAT
681015203050100
NANA606682742816879NA
458501538611668747831NA
188218236283325381461499
NA72477687495510621165NA
5826366867818589691089NA
246278302365419496606669
10411144122613741513170219052053
853937101011561286147316921921
NA4084545466487499221058
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
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1192013 CALIFORNIA PLUMBING CODE
WATER HEATERS
TABLE 510.2(4)MASONRY CHIMNEY [NFPA 54: TABLE 13.2(d)]*
NUMBER OF APPLIANCES: TWO OR MOREAPPLIANCE TYPE: CATEGORY I
APPLIANCE VENT CONNECTION: SINGLE-WALL METAL CONNECTORVENT CONNECTOR CAPACITY
SINGLE-WALL METAL VENT CONNECTOR DIAMETER – D (inch)3 4 5 6 7
APPLIANCE INPUT RATING LIMITS IN THOUSANDS OF BTU PER HOURVENTHEIGHT
H(feet)
CONNECTORRISER
(feet)
FAN NAT FAN NAT FAN NAT FAN NAT FAN NAT
Min Max Max Min Max Max Min Max Max Min Max Max Min Max Max
6 123
NANANA
NANANA
212834
NANANA
NANANA
395261
NANA134
NANA153
668497
179186193
191227258
100123142
231239247
271321365
140172202
8 123
NANANA
NANANA
212834
NANANA
NANANA
405262
NA137143
NA139156
688598
195202210
208240264
103125145
250258266
298343376
146177205
10 123
NANANA
NANANA
222934
NANA97
NANA102
415362
130136143
151150166
708699
202210217
225255277
106128147
267276284
316358389
151181207
15 123
NANANA
NANANA
233034
NA9296
NA103112
435463
129135141
151170185
7388101
199207215
271295315
112132151
268277286
376411439
161189213
20 123
NANANA
NANANA
233035
879196
99111119
455564
128134140
167185199
7690103
197205213
303325343
117136154
265274282
425455481
169195219
30 123
NANANA
NANANA
243135
869195
108119127
475765
126132138
187203216
8093105
193201209
347366381
124142160
259269277
492518540
183205229
50 123
NANANA
NANANA
243135
858994
113123131
506068
124130136
204218231
87100112
188196205
392408422
139158176
252262271
567588607
208230255
100 123
NANANA
NANANA
233034
848893
104115124
495967
122127133
200215228
89102115
182190199
410425438
151169188
243253262
617636654
232254279
COMMON VENT CAPACITYMINIMUM INTERNAL AREA OF MASONRY CHIMNEY FLUE (square inches)
12 19 28 38 50COMBINED APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR
VENTHEIGHT
H(feet)
FAN+FAN
FAN+NAT
NAT+NAT
FAN+FAN
FAN+NAT
NAT+NAT
FAN+FAN
FAN+NAT
NAT+NAT
FAN+FAN
FAN+NAT
NAT+NAT
FAN+FAN
FAN+NAT
NAT+NAT
681015203050100
NANANANANANANANA
NANANANANANANANA
25283136NANANANA
NANANANANANANANA
118128136NANANANANA
4552566674NANANA
NANANANANANANANA
176190205230247NANANA
718189105120135NANA
NANANANANANANANA
255276295335362398NANA
102118129150170195NANA
NANANANANANANANA
348380405400503558612NA
142162175210240275325NA
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
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120 2013 CALIFORNIA PLUMBING CODE
WATER HEATERS
TABLE 510.2(4)MASONRY CHIMNEY [NFPA 54: TABLE 13.2(d)] (continued)*
NUMBER OF APPLIANCES: TWO OR MOREAPPLIANCE TYPE: CATEGORY I
APPLIANCE VENT CONNECTION: SINGLE-WALL METAL CONNECTORVENT CONNECTOR CAPACITY
SINGLE-WALL METAL VENT CONNECTOR DIAMETER – D (inch)8 9 10
APPLIANCE INPUT RATING LIMITS IN THOUSANDS OF BTU PER HOURVENTHEIGHT
H(feet)
CONNECTORRISER
(feet)
FAN NAT FAN NAT FAN NAT
Min Max Max Min Max Max Min Max Max
6 123
292301309
366432491
200231269
362373381
474557634
252299348
499509519
594696793
316376437
8 123
313323332
407465509
207238274
387397407
530607663
263309356
529540551
672766838
331391450
10 123
333343352
434489530
213244279
410420430
571640694
273317363
558569580
727813880
343403459
15 123
349359368
502548586
225256289
445456466
646706755
291334378
623634646
808884945
366424479
20 123
345355365
569610644
235266298
439450461
734787831
306348391
614627639
9219861042
387443496
30 123
338348358
665699729
250282312
430442452
864908946
330372412
600613626
108911451193
421473524
50 123
328339349
778806831
287320351
417429440
102210581090
383425466
582596610
130213461386
492545597
100 123
315326337
875899921
328361392
402415427
118112101238
444488529
560575589
153715701604
580634687
COMMON VENT CAPACITYMINIMUM INTERNAL AREA OF MASONRY CHIMNEY FLUE (square inches)
63 78 113COMBINED APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR
VENTHEIGHT
H(feet)
FAN+FAN
FAN+NAT
NAT+NAT
FAN+FAN
FAN+NAT
NAT+NAT
FAN+FAN
FAN+NAT
NAT+NAT
681015203050100
NANANA677765808NANA
455497532602661739821NA
187217234280321377456494
NANA77186694710521152NA
5796336807728499571076NA
245277300360415490600663
NA1136121613591495168218792006
846928100011391264144716721885
NA4054505406407409101046
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
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1212013 CALIFORNIA PLUMBING CODE
WATER HEATERS
TABLE 510.2(5)SINGLE-WALL METAL PIPE OR TYPE B ASBESTOS-CEMENT VENT [NFPA 54: TABLE 13.2(e)]*
TABLE 510.2(6)EXTERIOR MASONRY CHIMNEY [NFPA 54-12: TABLE 13.2(f)]*
NUMBER OF APPLIANCES: TWO OR MOREAPPLIANCE TYPE: DRAFT HOOD-EQUIPMENT
APPLIANCE VENT CONNECTION: DIRECT TO PIPE OR VENTVENT CONNECTOR CAPACITY
VENT CONNECTOR DIAMETER – D (inch)TOTAL VENT HEIGHT
H(feet)
CONNECTOR RISER
(feet)
3 4 5 6 7 8
APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR
6-8123
212834
405361
688698
102124147
146178204
205235275
15123
233035
445664
7792102
117134155
179194216
240265298
30and up
123
253136
495868
8497107
129145164
190211232
270295321
COMMON VENT CAPACITYCOMMON VENT DIAMETER – D (inch)
TOTAL VENT HEIGHT
H(feet)
4 5 6 7 8 10 12
COMBINED APPLIANCE INPUT RATING IN THOUSANDS OF BTU PER HOUR
681015203050
4855597180NANA
788995115129147NA
111128136168186215NA
155175190228260300360
205234250305340400490
320365395480550650810
NA5055606907909401190
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
NUMBER OF APPLIANCES: TWO OR MOREAPPLIANCE TYPE: NAT + NAT
APPLIANCE VENT CONNECTION: TYPE B DOUBLE-WALL CONNECTORCOMBINED APPLIANCE MAXIMUM INPUT RATING IN THOUSANDS OF BTU PER HOUR
VENT HEIGHTH
(feet)
INTERNAL AREA OF CHIMNEY (square inches)
12 19 28 38 50 63 78 113681015203050100
252831NANANANANA
46535667NANANANA
718290106NANANANA
103119131152NANANANA
143163177212NANANANA
188218236283325NANANA
246278302365419496NANA
NA408454546648749922NA
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
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122 2013 CALIFORNIA PLUMBING CODE
WATER HEATERS
TABLE 510.2(7)EXTERIOR MASONRY CHIMNEY [NFPA 54-12: TABLE 13.2(g)]1, 2
NUMBER OF APPLIANCES: TWO OR MOREAPPLIANCE TYPE: NAT + NAT
APPLIANCE VENT CONNECTION: TYPE B DOUBLE-WALL CONNECTORMINIMUM ALLOWABLE INPUT RATING OF SPACE-HEATING APPLIANCE IN THOUSANDS OF BTU PER HOUR
VENT HEIGHTH
(feet)
INTERNAL AREA OF CHIMNEY (square inches)
12 19 28 38 50 63 78 113
Local 99% winter design temperature: 37°F or greater681015203050100
000
NANANANANA
0000
NANANANA
0000
NANANANA
0000
NANANANA
0000
NANANANA
0000
184393NANA
00000
334NANA
NA00000
579NA
Local 99% winter design temperature: 27°F to 36°F681015203050100
000
NANANANANA
0051NANANANANA
6882NANANANANANA
NANANANANANANANA
NANANANANANANANA
180187201253307NANANA
212214225274330445NANA
NA263265305362485763NA
Local 99% winter design temperature: 17°F to 26°F681015203050100
NANANANANANANANA
NANANANANANANANA
NANANANANANANANA
NANANANANANANANA
NANANANANANANANA
NANANANANANANANA
NA264278331387NANANA
NA352358398457581862NA
Local 99% winter design temperature: 5°F to 16°F681015203050100
NANANANANANANANA
NANANANANANANANA
NANANANANANANANA
NANANANANANANANA
NANANANANANANANA
NANANANANANANANA
NANANANANANANANA
NANA430485547682NANA
Local 99% winter design temperature: 4°F or lowerNot recommended for any vent configurations
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2, °C = (°F-32)/1.8Notes:1 See Figure 510.1.2(6) for a map showing local 99 percent winter design temperatures in the United States.2 NA: Not applicable.
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1232013 CALIFORNIA PLUMBING CODE
WATER HEATERS
TABLE 510.2(8)EXTERIOR MASONRY CHIMNEY [NFPA 54-12: TABLE 13.2(h)]*
NUMBER OF APPLIANCES: TWO OR MOREAPPLIANCE TYPE: FAN + NAT
APPLIANCE VENT CONNECTION: TYPE B DOUBLE-WALL CONNECTORCOMBINED APPLIANCE MAXIMUM INPUT RATING IN THOUSANDS OF BTU PER HOUR
VENT HEIGHTH
(feet)
INTERNAL AREA OF CHIMNEY (square inches)
12 19 28 38 50 63 78 113
681015203050100
748084NANANANANA
119130138152NANANANA
178193207233250NANANA
257279299334368404NANA
351384409467508564NANA
458501538611668747831NA
5826366867818589691089NA
853937101011561286147316921921
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2
* NA: Not applicable.
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124 2013 CALIFORNIA PLUMBING CODE
WATER HEATERS
TABLE 510.2(9)EXTERIOR MASONRY CHIMNEY [NFPA 54-12: TABLE 13.2(i)]1, 2
NUMBER OF APPLIANCES: TWO OR MOREAPPLIANCE TYPE: FAN + NAT
APPLIANCE VENT CONNECTION: TYPE B DOUBLE-WALL CONNECTORMINIMUM ALLOWABLE INPUT RATING OF SPACE-HEATING APPLIANCE IN THOUSANDS OF BTU PER HOUR
VENT HEIGHTH
(feet)
INTERNAL AREA OF CHIMNEY (square inches)12 19 28 38 50 63 78 113
Local 99% winter design temperature: 37°F or greater681015203050100
000
NANANANANA
0000
NANANANA
0000
123NANANA
0000
190334NANA
0000
249398NANA
0000
184393714NA
00000
334707NA
000000
5791600
Local 99% winter design temperature: 27°F to 36°F681015203050100
000
NANANANANA
0051111NANANANA
688297142187NANANA
116127141183230330NANA
156167183233284319NANA
180187201253307419672NA
212214225274330445705NA
2662632653053624857631554
Local 99% winter design temperature: 17°F to 26°F681015203050100
052NANANANANANA
557490NANANANANA
99111125167212NANANA
141154169212258362NANA
182197214263316429NANA
215226245296352470723NA
259264278331387507766NA
3493523583984575818621669
Local 99% winter design temperature: 5°F to 16°F681015203050100
NANANANANANANANA
7894111NANANANANA
121135149193NANANANA
166182198247293377NANA
214230250305360450NANA
252269289346408531797NA
301312331393450580853NA
4164234304855476829721833
Local 99% winter design temperature: -10°F to 4°F681015203050100
NANANANANANANANA
NANANANANANANANA
145159175NANANANANA
196213231283333NANANA
249269292351408NANANA
296320339404468603NANA
349371397457528667955NA
4844945135866508051003NA
Local 99% winter design temperature: -11°F or lowerNot recommended for any vent configurations
For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1000 British thermal units per hour = 0.293 kW, 1 square inch = 0.000645 m2, °C = (°F-32)/1.8Notes:1 See Figure 510.1.2(6) for a map showing local 99 percent winter design temperatures in the United States.2 NA: Not applicable.
READ ONLY