uniform mechanical code- 2009 chapter 11

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1101.0 Scope.Part I of this chapter covers refrigeration systems.Refrigeration systems, equipment, and devices,including the replacement of parts, alterations, andsubstitution of a different refrigerant, shall conformto the requirements of this chapter and other appli-cable provisions of this code.

Occupied spaces within refrigerated areas shallcomply with this chapter and the applicableportions of the Building Code.

Part II covers cooling towers.

Part I – Refrigeration Systems.

1102.0 General.Except as modified by this code, refrigeration systemsshall comply with ASHRAE 15. In addition, ammoniarefrigeration systems shall comply with IIAR 2.1102.1 Refrigerants. The refrigerant used shall be ofa type listed in Table 11-1 or as classified underSection 1103.0 as approved.

Exception: Lithium bromide absorption systemsusing water as the refrigerant.

1103.0 Refrigerant Classification.Refrigerants shall be classified in accordance withthe referenced standard for refrigerant designationand safety classification in Chapter 17.

1104.0 Classification of Refrigeration Systems.Refrigeration systems shall be classified according tothe degree of probability that a leakage of refrigerantcould enter a normally occupied area.1104.1 High-Probability System. Systems in whichthe basic design, or the location of components, issuch that a leakage of refrigerant from a failedconnection, seal, or component could enter the occu-pied space described in Section 1105.2.1104.2 Low-Probability System. Systems thatcannot be considered as high-probability system areclassified as low-probability systems. This classincludes systems whose joints and connections in therefrigerant circuit are effectively isolated from theoccupied space described in Section 1105.2.

1105.0 Requirements for Refrigerant andRefrigeration System Use.1105.1 System Selection. Refrigeration systemsshall be limited in application in accordance withTable 11-2 and the requirements of this section.

1105.2 Volume of Occupied Space. The quantity ofrefrigerant in a single, independent circuit of a high-probability system shall not exceed the amountsshown in Table 11-1 based on the volume of the occu-pied space. The volume of the smallest, enclosed,occupied space shall be used to determine thepermissible quantity of refrigerant in a system that islocated in serves, or passes through such space. Inaccordance to this Section, occupied space shallinclude those rooms that are occupied occasionallyfor short periods of time such as storage rooms,equipment rooms other than refrigeration machineryrooms, or any room which can be entered with a doorthat can be closed after entry.

Exceptions:(1) If the airflow to any enclosed space served

by a portion of an air-duct system cannot beshut off or reduced below one-quarter of itsmaximum, the cubical contents of the entirespace served by that portion of the air-ductsystem shall be used to determine thepermissible quantity of refrigerant in thesystem.

(2) Refrigerated process or storage areasmeeting the requirements of Section 1105.3.

1105.3 Refrigerated Process and Storage Areas.Refrigerant quantities in evaporators and pipingwithin rooms or spaces used exclusively forprocessing or storage of materials under refrigeratedconditions shall not be limited, provided that exitingis provided per the Building Code and that:

1105.3.1 The refrigerated room or space isequipped with a refrigerant vapor detection andalarm system complying with Section 1121.0.1105.3.2 The refrigerated room or space issealed from all other portions of the building byvapor-tight construction and tight-fitting,gasketed doors.

Exception: Adjoining refrigerated rooms.1105.3.3 Where the quantity of a Group A2, B2,A3 or B3 refrigerant, other than ammonia, in anindependent circuit would exceed 25% of thelower flammability limit if released to thesurrounding room, (1) electrical equipment shallcomply with the requirements of the electricalcode for Class I, Division 2, or (2) the refrigerantvapor detection system required by Section1105.3.1 shall automatically de-energize all elec-trical power within the space at vapor concentra-tions at or above 25% of the lower flammabilitylimit.

CHAPTER 11REFRIGERATION

1105.4 Refrigerant Purity. New and reclaimed refrig-erants are allowed to be used in refrigeration systemsin accordance with this section. When requested, theinstaller shall furnish a declaration identifying therefrigerant by standard “R” designation and statingthat it meets the requirements of Section 1105.4.1 or1105.4.2.

Exception: The refrigerant used shall meet thepurity specifications set by the manufacturer ofthe equipment in which it is used when thatspecification is different from Section 1105.4.1 or1105.4.2.1105.4.1 New and Reclaimed Refrigerants.New and reclaimed refrigerants shall meet thereferenced standard for refrigerant specificationsin Chapter 17.1105.4.2 Recovered Refrigerants. Reuse ofrecovered refrigerant that shows no sign ofcontamination is allowed, provided that it hasbeen filtered and dried with a listed or approvedrecovery machine, in equipment belonging tothe same owner as the equipment from which itwas removed. Recovered refrigerants shall notbe used in a different owner’s equipment unlessthe refrigerant has been analyzed and found tomeet the purity requirements of Section 1105.4.1.

1106.0 General Requirements.1106.1 Human Comfort. Cooling systems used forhuman comfort shall comply with the return-air andoutside-air provisions for furnaces in Sections 904.7and 904.8 of this code. Cooling equipment used forhuman comfort in dwelling units shall be sized tosatisfy the calculated loads determined in accordancewith the reference standards in Chapter 17 or otherapproved methods.1106.2 Supports and Anchorage. Supports andanchorage for refrigeration equipment and pipingshall be designed in accordance with the BuildingCode as Occupancy Category H hazardous facilities.Supports shall be noncombustible.

Exceptions:(1) Equipment containing Group A1 refrigerants

may be supported by the same materialspermitted for the building type.

(2) The use of approved vibration isolatorsspecifically designed for the normal, wind,and seismic loads to which they may besubject shall be permitted.

A compressor or portion of a condensing unitsupported from the ground shall rest on a concreteor other approved base extending not less than three(3) inches (76 mm) above the adjoining ground level.

1106.3 Access. An unobstructed readily accessibleopening and passageway not less than thirty-six (36)inches (914 mm) in width and six (6) feet (1829 mm)eight (8) inches (203 mm) in height shall be providedand maintained to the compressor, valves requiredby this chapter, or other portions of the systemrequiring routine maintenance.

Exceptions:(1) Refrigerant evaporators, suspended over-

head, may use portable means of access.(2) Air filters, brine control or stop valves, fan

motors or drives, and remotely de-energizedelectrical connections may be providedaccess by an unobstructed space not lessthan thirty (30) inches (762 mm) in depth,width, and height. When an access openingis immediately adjacent to these items andthe equipment can be serviced, repaired,and replaced from this opening, the dimen-sions may be reduced to twenty-two (22)inches (559 mm) by thirty (30) inches (762 mm)provided the largest piece of equipment canbe removed through the opening.

(3) Cooling equipment, using Group A1 refrig-erants or brine, located in an attic or furredspace may be provided an access by aminimum opening and passageway theretoof not less than twenty-two (22) inches (559mm) x thirty (30) inches (762 mm).

(4) Cooling or refrigeration equipment, usingGroup A1 or B1 refrigerants or brine,located on a roof or on an exterior wall of abuilding, may be provided access as forfurnaces in Section 904.10 of this code.

1106.4 Illumination and Service Receptacles. Inaddition to the requirements of Section 309.0, perma-nent lighting fixtures shall be installed for all equip-ment required by this code to be accessible or readilyaccessible. Such fixtures shall provide sufficient illumi-nation to safely perform the required tasks for whichaccess is provided. Control of the illumination sourceshall be provided at the access entrance.

Exceptions:(1) Lighting fixtures may be omitted when the

fixed lighting of the building will providethe required illumination.

(2) Equipment located on the roof or on the exte-rior walls of a building.

1106.5 Protection from Mechanical Damage.Refrigeration systems and portions thereof shall notbe located in an elevator shaft, dumbwaiter shaft, or ashaft having moving objects therein, nor in a locationwhere they will be subject to mechanical damage.

UNIFORM MECHANICAL CODE

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1105.4 – 1106.5

1106.6 Electrical. Electrically energized componentsof refrigeration systems shall conform to theElectrical Code.1106.7 Ventilation of Rooms ContainingCondensing Units. Rooms or spaces other than arefrigeration machinery room complying with therequirements of this chapter in which any refrig-erant-containing portion of a condensing unit islocated shall be provided with one of the followingmeans of ventilation:

1106.7.1 Permanent gravity ventilation open-ings of not less than two (2) square feet (0.19 m2)net free area opening directly to the outside ofthe building or extending to the outside of thebuilding by continuous ducts.1106.7.2 A mechanical exhaust system arrangedto provide a complete change of air in such roomor space at least every 20 minutes and todischarge to the outside of the building.

Exceptions:(1) A condensing unit in a room or space if

the cubical content exceeds 1,000 cubicfeet per horsepower (38.50 m3/kW) ofthe unit.

(2) A condensing unit in a room or spacethat has permanent gravity ventilationhaving an area of two (2) square feet(0.19 m2) or more to other rooms oropenings exceeding 1,000 cubic feet perhorsepower (38.50 m3/kW).

1106.8 Prohibited Locations. Refrigeration systemsor portions thereof shall not be located within arequired exit enclosure. Refrigeration compressorsexceeding five (5) horsepower (3.68 kW) rating shallbe located at least ten (10) feet (3,048 mm) from anexit opening in a Group A; Group B; Group E; GroupF; Group I; Group R, Division 1; or Group SOccupancy, unless separated by a one-hour fire-resistive occupancy separation.1106.9 Condensation Control. Piping and fittingsthat convey brine, refrigerant, or coolants thatduring normal operation could reach a surfacetemperature below the dew point of thesurrounding air and that are located in spaces orareas where condensation could cause a hazard tothe building occupants or damage to the structure orelectrical or other equipment shall be protected toprevent such an occurrence.1106.10 Condensate. Condensate from air-cooling coils shall be collected and drained to anapproved location. Drain pans and coils shall bearranged to allow thorough drainage and accessfor cleaning. Where temperatures can drop belowfreezing, heat tracing and insulation of condensatedrains shall be installed.

1106.11 Defrost. When defrost cycles are requiredfor portions of the system, provisions shall be madefor collection and disposal of the defrost liquid in asafe and sanitary manner.1106.12 Overflows. Where condensate or defrostliquids are generated in an attic or furred space andstructural damage may result from overflow, provi-sions for overflow shall be provided.1106.13 Condensate, Defrost, and OverflowDisposal. Disposal of condensate, defrost, or over-flow discharges shall comply with Section 310.0.

1107.0 Refrigeration Machinery Rooms.1107.1 When Required. Refrigeration systems shallbe provided with a refrigeration machinery roomwhen any of the following conditions exist:

1107.1.1 The quantity of refrigerant in a single,independent refrigerant circuit of a systemexceeds Table 11-1 amounts.1107.1.2 Direct- and indirect-fired absorptionequipment is used.

Exceptions: Direct and indirect-fired lithiumbromide absorption systems using water asthe refrigerant.

1107.1.3 An A1 system having an aggregatecombined compressor horsepower of 100 (73.55kW) or more is used.1107.1.4 The system contains other than a GroupA1 refrigerant.

Exceptions:(1) Lithium bromide absorption systems

using water as the refrigerant.(2) Ammonia-water absorption unit

systems installed outdoors, providedthat the quantity of refrigerant in asingle system does not exceed Table 11-1amounts and the discharge is shieldedand dispersed.

(3) Systems containing less than 300pounds (136 kg) of refrigerant R-123and located in an approved exteriorlocation.

(4) Systems containing less than 35 pounds(16 kg) of refrigerant R-717 and locatedin an approved exterior location.

Refrigeration machinery rooms shall house allrefrigerant-containing portions of the systemother than the piping and evaporators permittedby Section 1105.3, discharge piping required ofthis chapter, and cooling towers regulated byPart II of this chapter, and their essential piping.

1107.2 Dimensions. Refrigeration machinery roomsshall be of such dimensions that all system parts are

REFRIGERATION 1106.6 – 1107.2

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readily accessible with adequate space for mainte-nance and operations. An unobstructed walkingspace at least three (3) feet (914 mm) in width and six(6) feet eight (8) inches (2,032 mm) in height shall bemaintained throughout, allowing free access to atleast two sides of all moving machinery andapproaching each stop valve. Access to refrigerationmachinery rooms shall be restricted to authorizedpersonnel and posted with a permanent sign.1107.3 Exits. Exits shall comply with the BuildingCode for special hazards.1107.4 Refrigerant-Vapor Alarms. Machineryrooms shall have approved refrigerant-vapor detec-tors located in an area where refrigerant from a leakis likely to concentrate and that will activate visualand audible alarms. Alarms shall be activated at avalue not greater than one-half the immediatelydangerous to life or health (IDLH), or measurementconsistent therewith; the PEL, or measurementconsistent therewith; or 25 percent of the LFL,whichever is less.1107.5 Separation. Refrigeration machinery roomsshall be separated from other portions of thebuilding, as required in the special hazards provi-sions of the Building Code. Penetrations shall besealed to inhibit the passage of refrigerant vapor.1107.6 Combustion Air and Return Air. Combustionair or return air shall not be taken from or through arefrigeration machinery room.

Exceptions:(1) Refrigeration machinery rooms used exclu-

sively for direct-fired absorption equipment.(2) Direct-vented combustion equipment.

1107.7 Special Requirements. Open flames ordevices having an exposed surface exceeding 800°F(427°C) are prohibited in refrigeration machineryrooms.

Exceptions:(1) Momentary temperature excursions such as

electrical contacts in A1 and B1 systems.(2) Refrigeration machinery rooms used exclu-

sively for direct-fired absorption equipment.

1108.0 Refrigeration Machinery Room Ventilation.1108.1 General. Refrigeration machinery rooms shallbe provided with a continuous source of outside airfor ventilation and removal of rejected heat.1108.2 Refrigeration Machinery Rooms. Refrigerationmachinery rooms shall be provided with dedicated

mechanical exhaust systems. The exhaust systemsshall have the capacity to achieve each of thefollowing:

1108.2.1 Continuously maintain the refrigerationmachinery room at 0.05 inch (12.44 Pa) watergauge negative relative to adjacent spaces calcu-lated by:

Exception: Refrigeration machinery roomslocated in entirely detached structures andmore than twenty (20) feet (6,096 mm) fromproperty lines or openings into buildings.

1108.2.2 Continuously provide 0.5 cubic footper minute of airflow per gross square foot (2.54L/s/m2) of floor area within the refrigerationmachinery rooms as calculated by:

1108.2.3 Limit the temperature rise within therefrigeration machinery room to a maximum of104°F (40°C) as calculated by:

1108.2.4 Provide emergency purge of escapingrefrigerant as calculated by:

WHERE:q = Btu/h of all heat-producing equipment.Q = air-flow rate, cubic feet per minute (cfm).∆p = pressure difference, inches water gauge.Ae = equivalent leakage area, square feet (see

the Building Code).Agf = gross floor area, square feet.∆T = temperature difference between

machinery room and supply air (°F).G = refrigerant mass in largest system, lbs.

1108.3 Distribution of Ventilation. Exhaust inlets orpermanent openings shall be located to provideventilation throughout the entire refrigerationmachinery room.

Q = 2610Ae √∆p (Equation 11-1)

Q = 0.5Agf (Equation 11-2)

Q = ∑q / 1.08 ∆ T (Equation 11-3)

Q = 100 √G (Equation 11-4)


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1107.2 – 1108.3

1108.4 Intermittent Control of the VentilationSystems. Fans providing refrigeration machineryroom temperature control or automatic response torefrigerant gas in order to maintain concentrationsbelow the PEL may be automatically controlled toprovide intermittent ventilation as conditions require.1108.5 Emergency Control of the VentilationSystems. Fans providing emergency purge ventila-tion for refrigerant escape shall have a clearly identi-fied switch of the break-glass type providing “on”only control immediately adjacent to and outside ofeach refrigerant machinery room exit. For other thanammonia, purge fans shall also respond automati-cally to the refrigerant concentration detectionsystem set to activate the ventilation system at nomore than 25 percent of the LFL, or 50 percent of theIDLH, or a measure equivalent thereto, whichever isless. For ammonia, purge fans shall also respondautomatically to the refrigerant concentration detec-tion system set to activate the ventilation system atno more than 1,000 parts per million. An emergencypurge control shall be provided with a manual resetonly.1108.6 Central Control of Ventilation Systems.Mechanical ventilation systems shall have switchesto control power to each fan. The switches shall bekey operated or within a locked, glass-covered enclo-sure at an approved location adjacent to and outsideof the principal entrance to the machinery room.Necessary keys shall be located in a single approvedlocation. Switches controlling fans providing contin-uous ventilation shall be of the two-position, on-offtype. Switches controlling fans providing intermit-tent or emergency ventilation shall be of the three-position, automatic on-off type. Switches shall belabeled identifying both the function and the specificfan controlled. Two colored and labeled indicatorlamps responding to the differential pressure createdby airflow shall be provided for each switch. Onelamp shall indicate flow; the other shall indicate noflow.1108.7 Ventilation Discharge. Exhaust frommechanical ventilation systems shall be dischargedat least twenty (20) feet (6,096 mm) from a propertyline or openings into buildings. Discharges capableof exceeding 25 percent of the LFL, or 50 percent ofthe IDLH, shall be equipped with approved treat-ment systems to reduce the discharge concentrationsto these values or lower.

Exception:(1) When an approved engineering analysis of

plume dispersion demonstrates that thelimiting values will not be exceeded at theproperty line.

(2) A treatment system is not required for venti-lation provided for an ammonia refrigera-tion system.

1108.8 Fans. Fans and associated equipmentintended to operate the emergency purge of otherthan Group A1 or Group B1 refrigerants shall meetthe requirements for a Class I, Division 1 hazardouslocation as specified in the Electrical Code.1108.9 Ventilation Intake. Makeup air intakes toreplace the exhaust air shall be provided to therefrigeration machinery room directly from outsidethe building. Intakes shall be located as required byother sections of the code and fitted with backdraftdampers or similar approved flow-control means toprevent reverse flow. Distribution of makeup airshall be arranged to provide thorough mixing withinthe refrigeration machinery room to prevent shortcircuiting of the makeup air directly to the exhaust.

1109.0 Refrigeration Machinery Room Equipmentand Controls.1109.1 General. Equipment, piping, ducts, vents, orsimilar devices that are not essential for the refrigera-tion process, maintenance of the equipment, or forthe illumination, ventilation, or fire protection of theroom shall not be placed in or pass through a refrig-eration machinery room.

Equipment essential to the refrigeration processoften includes, but is not always limited to, thefollowing:

1109.1.1 Refrigeration compressors.1109.1.2 Condensing units.1109.1.3 Pumps, associated piping, and automaticcontrol valves for refrigerant, condenser water,and brine or chilled water.1109.1.4 Refrigeration control devices andpanels.1109.1.5 Machinery room ventilation equipment(see Section 1108.0).1109.1.6 Cooling towers or portions thereof (seeChapter 11, Part II).1109.1.7 Refrigerant receivers and accumulators.1109.1.8 Refrigerant vapor-detection and alarmsystems (see Section 1121.0).1109.1.9 Machinery room fire sprinkler systemexclusive of its shutoff valves.1109.1.10 Machinery room lighting and servicereceptacles.1109.1.11 Motor control centers and electricalpanels for machinery room systems.

1109.2 Electrical. Electrical equipment and installa-tions shall comply with the Electrical Code. Therefrigeration machinery room shall not be requiredto be a hazardous (classified) location except asprovided in Section 1108.8.


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1109.3 Storage. Storage of materials in a refrigera-tion machinery room shall be as permitted in the FireCode.1109.4 Emergency Control. A clearly identifiedswitch of the break-glass type providing “off”-onlycontrol of electrically energized equipment anddevices within the refrigeration machinery roomshall be provided immediately adjacent to andoutside of each refrigeration machinery room exit. Inaddition, emergency shutoff shall also be automati-cally activated when the concentration of refrigerantvapor exceeds 25 percent of the LFL.

1110.0 Refrigeration Piping, Containers, andValves.1110.1 General. Materials used in the constructionand installation of refrigeration systems shall be suit-able for the refrigerant, refrigerant oil, or brine in thesystem. Material or equipment that will deterioratedue to the chemical action of the refrigerant, the oil,or combination of both, shall not be installed.1110.2 Nonferrous Materials. Copper and brassrefrigeration piping, valves, fittings, and relatedparts used in the construction and installation ofrefrigeration systems shall be approved for theintended use.1110.3 Ferrous Materials. Iron and steel refrigerationpiping, valves, fittings, and related parts shall beapproved for the intended use. Pipe more than two(2) inches (50 mm) iron pipe size shall be electric-resistance welded or seamless pipe.

1111.0 Erection of Refrigerant Piping.1111.1 General. Piping and tubing shall be installedso as to prevent vibration and strains at joints andconnections.1111.2 Support. In addition to the requirements ofSection 1106.2, piping and tubing shall be securelyfastened to a permanent support within six (6) feet(1,829 mm) following the first bend in such tubingfrom the compressor and within two (2) feet (610mm) of each subsequent bend or angle. Piping andtubing shall be supported at points not more thanfifteen (15) feet (4,572 mm) apart.1111.3 Protection from Damage. Refrigerantpiping and tubing shall be installed so that it is notsubject to damage from an external source. Softannealed copper tubing shall not be larger than 1-3/8 inch (35 mm) nominal size. Mechanical jointsshall not be made on tubing larger than 3/4 inch (20mm) nominal size. Soft annealed copper tubingconveying refrigerant shall be enclosed in iron orsteel piping and fittings, or in conduit, molding, orraceway that will properly protect the tubing againstmechanical injury from an exterior source.

Exceptions:(1) Tubing entirely within or tubing within five

(5) feet (1,524 mm) of a refrigerant compressorwhen so located that it is not subject toexternal injury.

(2) Copper tubing serving a dwelling unit,when such tubing contains Group A1 refrig-erant and is placed in locations not subjectto damage from an external source.

1111.4 Visual Inspection. Refrigerant piping andjoints shall be exposed to view for visual inspectionand acceptance by the Authority Having Jurisdictionprior to being covered or enclosed.

Exception: Copper tubing enclosed in iron orsteel piping conduit, molding, or raceway,provided there are no fittings or joints concealedtherein.

1111.5 Prohibited Locations. Refrigerant pipingshall not be located within a required exit.1111.6 Underground Piping. Refrigerant pipingplaced underground shall be protected against corro-sion.1111.7 Joints. Iron or steel pipe joints shall be ofapproved threaded, flanged, or welded types.Exposed threads shall be tinned or coated with anapproved corrosion inhibitor. Copper or brass pipejoints of iron pipe size shall be of approved threaded,flanged, or brazed types. Copper tubing joints andconnections shall be approved flared, lapped,swaged, or brazed joints.1111.8 Identification. Piping shall meet the refer-ence standard for identification. The type of refrig-erant, function, and pressure shall be indicated.

1112.0 Refrigerant Control Valves.1112.1 Location. Stop valves shall be installed in therefrigerant piping of a refrigeration system at thefollowing locations:

1112.1.1 At the inlet and outlet of a positive-displacement-type compressor, compressor unit,or condensing unit.1112.1.2 At the refrigerant outlet from a liquidreceiver.1112.1.3 At the refrigerant inlet of a pressurevessel containing liquid refrigerant and havingan internal gross volume exceeding three (3)cubic feet (108 m3).

Exceptions:(1) Systems with nonpositive-displacement

compressors.(2) Systems having a pump-out receiver for

storage of the charge.(3) Systems containing less than 110

pounds (49.9 kg) of Group A1 refrigerant.


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1109.3 – 1112.1

(4) Self-contained systems that do not requirea stop valve at the inlet of the receiver.

1112.2 Support. Stop valves installed in copperrefrigerant lines of 3/4 inch (20 mm) or less outsidediameter shall be securely supported independentlyof the tubing or piping.1112.3 Access. Stop valves required by this sectionshall be readily accessible from the refrigerationmachinery room floor or a level platform.1112.4 Identification. Stop valves shall be identifiedby tagging in accordance with the reference standardfor identification. A valve chart shall be mountedunder glass at an approved location near the prin-cipal entrance to a refrigeration machinery room.

1113.0 Pressure-Limiting Devices.1113.1 When Required. Pressure-limiting devicesshall be provided on all systems operating aboveatmospheric pressure.

Exception: Factory-sealed systems containingless than twenty-two (22) pounds (9.98 kg) ofGroup A1 refrigerant listed by an approvedagency.

1113.2 Setting. The maximum setting to which apressure-limiting device may be set by use of theadjusting means provided shall not exceed the designpressure of the high side of a system not protected bya pressure-relief device or 90 percent of the pressuresetting of the pressure-relief device installed on thehigh side of a system.

Exception: In systems using other than positive-displacement compressors that are protected bya pressure-relief device, the setting may be thedesign pressure of the high side of the system,provided the pressure-relief device is located inthe low side, subject only to low-side pressure,and there is a permanent, unvalved relief pathbetween the high side and the low side of thesystem.

1113.3 Connection. Pressure-limiting devices shallbe connected between the pressure-imposingelement and stop valve on the discharge sidewithout intervening stop valves in the line leading tothe pressure-limiting device.1113.4 Operation. When the system is protectedby a pressure-relief device, the pressure-limitingdevice shall stop the action of the pressure-imposing element at a pressure not more than 90percent of the setting of the pressure-relief device.

1114.0 Pressure-Relief Devices.1114.1 General. Refrigeration systems shall beprotected by a pressure-relief device or other meansdesigned to safely relieve pressure due to fire orabnormal conditions.

1114.2 Positive-Displacement Compressor. Apositive-displacement compressor shall be equippedby the manufacturer with a pressure-relief device ofadequate size and pressure setting to preventrupture of the compressor or other componentlocated between the compressor and the stop valveon the discharge side.1114.3 Liquid-Containing Portions of Systems.Liquid-containing portions of systems, includingpiping, that can be isolated from pressure-reliefdevices required elsewhere and that can developpressures exceeding their working design pressuresdue to temperature rise, shall be protected by theinstallation of pressure-relief devices.1114.4 Evaporators. Evaporators located withineighteen (18) inches (457 mm) of a heating element orcoil shall be fitted with a pressure-relief device.

Exceptions:(1) Self-contained equipment.(2) Factory-built coil assemblies specifically

designed for installation on the discharge offorced-air heating units.

(3) If the connected and unvalved volume of thelow side of the system meets the following:V1 > [W1 – (V2 – V1) /Vgt ] Vgc

(Equation 11-5)WHERE:V1 = low-side volume, cubic feet.V2 = total volume of system, cubic feet.W1 = total weight of refrigerant in system,

pounds.Vgt = specific volume of refrigerant vapor at

110°F (43°C), cubic feet per pound.Vgc = specific volume at critical temperature

and pressure, cubic feet per pound.(4) Reheat coils using the refrigerant for heat

recovery.1114.5 Actuation. Pressure-relief devices shall bedirect-pressure actuated. Each part of a refrigerationsystem that can be valved off and that contains oneor more pressure vessels having internal diametersgreater than six (6) inches (150 mm) and containingliquid refrigerant shall be protected by a pressure-relief device.1114.6 Stop Valves Prohibited. Stop valves shallnot be located between a pressure-relief device andthe portion of the system protected thereby.1114.7 Location. Pressure-relief devices shall beconnected as nearly as practical to the portion of thesystem protected thereby, above the liquid refrigerantlevel, and accessible for inspection and repair.

Exception: Fusible plugs on the high side maybe located above or below the liquid refrigerantlevel.


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1114.8 Materials. Seats and discs of pressure-reliefdevices shall be constructed of suitable material toresist corrosion or other chemical action caused by therefrigerant. Seats and discs of cast iron are prohibited.

1115.0 Pressure-Relief Device Settings.1115.1 Pressure-Relief Valve Setting. Pressure-reliefvalves shall actuate at a pressure not exceeding thedesign pressure of the parts of the system protected.1115.2 Rupture Member Setting. Rupture membersused in lieu of, or in series with, a relief valve shallhave a nominal rated rupture pressure not exceedingthe design pressure of the parts of the systemprotected. Rupture members installed ahead of reliefvalves need not be larger, but shall not be smaller,than the relief-valve inlet.

1116.0 Marking of Pressure-Relief Devices.1116.1 Pressure-Relief Valves. Pressure-reliefvalves for refrigerant-containing components shallbe set and sealed by the manufacturer or by anapproved assembler. Pressure-relief valves shall bemarked by the manufacturer with the data requiredto show compliance with this chapter.

Exception: Relief valves for systems with designpressures of fifteen (15) psig (103.35 kPa) or lessmay be marked by the manufacturer with pres-sure-setting capacity.

1116.2 Rupture Members. Rupture members forrefrigerant pressure vessels shall be marked with thedata required to show compliance with this chapter.1116.3 Fusible Plugs. Fusible plugs shall bemarked with the melting temperatures in °F (°C) toshow compliance with this chapter.

1117.0 Overpressure Protection.1117.1 General. Pressure vessels shall be provided withover-pressure protection as required by this section.1117.2 Type of Protection. Pressure vessels withthree (3) cubic feet (0.085 m3) internal gross volumeor less may use a single pressure-relief device or afusible plug. Pressure vessels over three (3) cubic feet(0.085 m3) but less than ten (10) cubic feet (0.283 m3)internal gross volume may use a single pressure-relief device but not a fusible plug. Pressure vesselsof ten (10) cubic feet (0.283 m3) or more internal grossvolume shall use a single rupture member or dualpressure-relief valve.1117.3 Three-Way Valve Required. When dualpressure-relief valves are used, they shall be installedwith a three-way valve to allow testing or repair.

Exception: A single relief valve of the requiredrelieving capacity may be used on low-side pres-sure vessels of ten (10) cubic feet (0.283 m3) or

more when meeting the requirements of Section1117.8, Exception 2.

1117.4 Parallel Pressure-Relief Devices. Two ormore pressure-relief devices in parallel to obtain therequired capacity shall be considered as one pres-sure-relief device. The discharge capacity shall be thesum of the capacities required for each pressurevessel being protected.1117.5 Discharge Capacity. The minimum requireddischarge capacity of pressure-relief devices for eachpressure vessel shall be determined by the following:

C =ƒDL (Equation 11-6)

WHERE:C = minimum required discharge capacity of the

relief device in pounds of air per minute.D = outside diameter of vessel, feet.L = length of vessel, feet.f = factor dependent upon type of refrigerant

from Table 11-3.

1117.6 Rating of Pressure-Relief Valves. Pressure-relief valves shall be of approved types and capaci-ties. The rated discharge capacity of a pressure-reliefvalve shall be expressed in pounds of air per minute.Pipe and fittings between the pressure-relief valveand the parts of the system it protects shall have atleast the area of the pressure-relief valve inlet.1117.7 Rating of Rupture Members and FusiblePlugs. The rated discharge capacity of a rupturemember or fusible plug discharging to atmosphereunder critical flow conditions in pounds of air perminute shall be determined by the followingformulas:

C = 0.8P1d2 (Equation 11-7)

d = 1.12 √C / P1 (Equation 11-8)

WHERE:C = rated discharge capacity of air, pounds per

minute.d = smallest internal diameter of the inlet pipe,

retaining flanges, fusible plug, rupture member,inches.

For rupture members:P1 = (rated pressure psig x 1.1) + 14.7 (Equation 11-9)For fusible plugs:P1 = absolute saturation pressure, corresponding to

the stamped temperature melting point of thefusible plug or the critical pressure of the refrig-erant used, whichever is smaller, psia.


172

1114.8 – 1117.7

1117.8 Discharge Location. Pressure-relief devicesshall discharge to the atmosphere unless otherwiseprohibited by this chapter at a location at least fifteen(15) feet (4,572 mm) above the adjoining grade leveland at least twenty (20) feet (6,096 mm) from anopening into a building. The discharge terminationshall be fitted with an approved diffuser directed toprevent spray of discharged refrigerant on personnelor entry of foreign material or water into thedischarge piping. Discharge piping connected to thedischarge side of a fusible plug or rupture membershall have provisions to prevent internal plugging ofthe pipe caused by the fusible plug or rupture-member function.

Exceptions:(1) Systems containing less than 110 pounds

(49.9 kg) of a Group A1 refrigerant.(2) A pressure-relief valve may discharge into

the low side of the system if the pressure-relief valve is of a type not affected by backpressure, provided the low side is equippedwith pressure-relief devices of equalrelieving capacity. The low-side pressure-relief device shall be set and discharged asrequired by this section. Fusible plugs orrupture members shall not be used for pres-sure relief into the low side.

1118.0 Discharge Piping.The area of the discharge pipe from the pressure-relief device or fusible plug shall be at least as largeas the outlet area of the pressure-relief device orfusible plug. A discharge pipe accepting dischargefrom more than one relief device or fusible plug shallbe sized and have a maximum length of the commondischarge not less than that required by the sum ofthe rated capacities of all relief valves discharginginto the header at the lowest pressure setting of anyof the relief valves discharging into the header.

The maximum length of the discharge pipingpermitted to be installed on the outlet of a pressure-relief device shall be determined by:

L = 9 P2 d5 / 16C2 (Equation 11-10)

WHERE:C = minimum required discharge capacity, pounds

of air per minute.d = internal diameter of pipe, inches.L = length of discharge pipe, feet.For relief valves and rupture disks:P = (rated pressure psig x 1.1) + 14.7(Equation 11-11)

For fusible plugs P=P1 where:P1 = absolute saturation pressure corresponding to

the stamped temperature melting point of thefusible plug or the critical pressure of the refrig-erant used, whichever is smaller, psia.

1119.0 Special Discharge Requirements.1119.1 General. Systems containing other thanGroup A1 or B1 refrigerants shall discharge to atmo-sphere only through an approved flaring device.

Exceptions:(1) Ammonia systems complying with Section

1120.0.(2) Ammonia absorption systems serving a

single dwelling unit.(3) When the Authority Having Jurisdiction

determines upon review of a rational engi-neering analysis that significant fire, health,or environmental hazard would not resultfrom the proposed atmospheric release.

(4) Lithium bromide absorption system usingwater as the refrigerant.

1119.2 Design Requirements. Flaring devices shallbe designed to incinerate the entire discharge. Theproducts of refrigerant incineration shall not posehealth or environmental hazards. Incineration shallbe automatic upon initiation of discharge, shall bedesigned to prevent blow-back, and shall not exposestructures or materials to threat of fire. Standby fuel,such as LPG, and standby power shall have thecapacity to operate for 1.5 times the required time forcomplete incineration of the charge.1119.3 Testing. Flaring systems shall be tested todemonstrate their safety and effectiveness. A reportfrom an approved agency shall be submitted detailingthe emission products from the system as installed.

1120.0 Ammonia Discharge.Ammonia shall discharge into a tank of water thatshall be used for no purpose except ammonia absorp-tion. At least one (1) gallon (3.785 L) of fresh watershall be provided for each pound (454 g) of ammoniathat will be released in one (1) hour from the largestrelief device connected to the discharge pipe. Thewater used shall be prevented from freezing withoutthe use of salt or chemicals. The tank shall be substan-tially constructed of not less than 1/8 inch (3.2 mm)or No. 10 MSG steel. The horizontal dimensions ofthe tank shall be equal to or less than one-half theheight. The tank shall have a hinged cover or, if of theenclosed type, shall have a vent hole at the top. Pipeconnections shall be through the top of the tank. Thedischarge pipe from the pressure-relief valves shalldischarge ammonia in the center of the tank near thebottom but not more than thirty (30) feet (9,144 mm)below the surface of the water.


173

Exception: An ammonia-water absorption unitsystem installed outdoors serving a dwellingunit, provided the discharge is shielded anddispersed.

1121.0 Detection and Alarm Systems.1121.1 General. When required by this chapter,approved refrigerant-vapor detection and alarmsystems shall utilize alarm signaling devicesproviding a sound pressure level of at least 15 dBabove the operating ambient noise sound pressurelevel of the space in that they are installed andproviding an approved, distinctive visual alarm.Alarms shall be activated within the space and asrequired in Section 1121.3 whenever the refrigerantvapor OEL is exceeded.1121.2 Power and Supervision. Detection andalarm systems shall be powered and supervised asrequired for fire alarm systems in the Fire Code.1121.3 Annunciation. Detection and alarm systemsshall be annunciated for all refrigerants at anapproved location in accordance with the Fire Code.1121.4 Installation, Maintenance, and Testing.Detection and alarm systems shall be installed, main-tained, and tested in accordance with the Fire Code.

1122.0 Emergency Pressure Control System.When required by the fire code, an emergency pres-sure control system shall be installed in accordancewith applicable fire code requirements.

1123.0 Equipment Identification.In addition to labels required elsewhere in this code,a refrigeration system shall be provided with labelscomplying with the requirements of this section.1123.1 A condenser, receiver, absorber, accumulator,and similar equipment having an internal volume ofmore than three (3) cubic feet (0.085 m3) andcontaining refrigerant shall be equipped with apermanent label setting forth the type of refrigerantin such vessel.1123.2 In a refrigeration machinery room and for adirect refrigerating system of more than ten (10)horsepower (7.457 kW), there shall be a permanentsign at an approved location giving the followinginformation:

1123.2.1 Name of contractor installing theequipment.1123.2.2 Name and number designation of refrig-erant in system.1123.2.3 Pounds of refrigerant in system.

1124.0 Testing of Refrigeration Equipment.1124.1 Factory Tests. Refrigerant-containing partsof units shall be tested and proved tight by themanufacturer at the design pressure for which theyare rated. The test pressure applied to the high sideof each factory-assembled refrigeration system shallbe equal to the design pressure of the high side. Thetest pressure applied to the low side of each factory-assembled refrigeration system shall be equal to thedesign pressure of the low side.

Exception: Units with a design pressure offifteen (15) psig (103.42 kPa) or less shall betested at a pressure not less than 1.33 times thedesign pressure.

1124.2 Field Tests. Refrigerant-containing parts of asystem that is field-erected shall be tested andproved tight to the Authority Having Jurisdictionafter complete installation and before operation. Thehigh and low sides of each system shall be tested andproved tight at not less than the lower of the pres-sure in Table 11-4 or the setting of the pressure-reliefdevice.

Exceptions:(1) Compressors, condensers, evaporators,

coded pressure vessels, safety devices, pres-sure gauges, control mechanisms, andsystems that are factory tested.

(2) Refrigeration systems containing Group R-22, not exceeding five (5) tons of refrigerationcapacity (17.58 kW), and field-piped usingapproved, factory-charged line sets may beproved tight by observing retention of pres-sure on a set of charging gauges and soapingconnections while the system is operating.

1124.3 Test Medium. Oxygen, flammable orcombustible gases, or gas mixtures shall not be usedfor leak testing. The means used to build up the testpressure shall have either a pressure-limiting deviceor a pressure-reducing device with a pressure-reliefdevice and a gauge on the outlet side. The pressure-relief device shall be set above the test pressure butlow enough to prevent permanent deformation ofsystem components.1124.4 Declaration. A dated declaration of test shallbe provided for systems containing fifty-five (55)pounds (24.95 kg) or more of refrigerant. The decla-ration shall give the name and number designationof the refrigerant and the field test pressure appliedto the high side and the low side of the system. Thedeclaration of test shall be signed by the installer.1124.5 Brine Systems. Brine-containing portions ofa system shall be tested at 1.5 times the design pres-sure of the system using brine as the test fluid.


174

1120.0 – 1124.5

1125.0 Maintenance and Operation.Refrigeration systems shall be operated and main-tained as required by the Fire Code.

1126.0 Storage of Refrigerants and Refrigerant Oils.Refrigerants and refrigerant oils not charged withinthe refrigeration system shall be stored as requiredby the Fire Code.

Part II – Cooling Towers.

1127.0 General.Cooling towers, evaporative condensers, and fluidcoolers shall be readily accessible. When located onroofs, such equipment having combustible exteriorsurfaces shall be protected with an approved auto-matic fire-extinguishing system.

1128.0 Support and Anchorage.Cooling towers, evaporative condensers, and fluidcoolers shall be supported on noncombustible gril-lage designed in accordance with the Building Code.Seismic restraints shall be as required by theBuilding Code.

1129.0 Drainage.Drains, overflows, and blow-down provisions shallhave an indirect connection to an approved disposallocation. Discharge of chemical waste shall be asapproved by the appropriate regulatory authority.

1130.0 Chemical Treatment Systems.Chemical treatment systems shall comply with theFire Code. When chemicals used present a contacthazard to personnel, approved emergency eye-washand shower facilities shall be installed.

1131.0 Location.Cooling towers, evaporative condensers, and fluidcoolers shall be located such that their plumes cannotenter occupied spaces. Plume discharges shall be atleast twenty-five (25) feet (7,620 mm) away from anyventilation inlet to a building. Location on the prop-erty shall be as required for buildings by theBuilding Code.

1132.0 Electrical.Electrical systems shall be in accordance with theElectrical Code. Equipment shall be provided with avibration switch to shut off fans operating withexcessive vibration. In climates commonly subject to

electrical storms, lightning protection shall beprovided on roof-mounted equipment.

1133.0 Refrigerants and Hazardous Fluids.Equipment containing refrigerants as a part of aclosed-cycle refrigeration system shall comply withPart I of this chapter. Equipment containing otherfluids that are flammable, combustible, or hazardousshall comply with the Fire Code.


175

TABLE 11-1Refrigerant Groups1, Properties2, and Allowable Quantities3

[ASHRAE 34: Table 1]


176

Table 11-1

ASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAE

Refrig-erant

ChemicalFormula

Chemical Name4

(Composition for Blends)SafetyGroup1 OEL5 (ppm) IDLH6 (ppm)

Pounds per 1000cf of Space7

R-11 CCl3F Trichlorofluoromethane A1 C10008 2,000 0.39

R-12 CCl2F2 Dichlorodifluoromethane A1 1,000 15,000 5.6

R-13 CClF3 Chlorotrifluoromethane A1 1,00010 67,000

R-13B1 CBrF3 Bromotrifluoromethane A1 1,000 40,000

R-14 CF4 Tetrafluoromethane (carbontetrafluoride)

A1 1,00010 67,000 25

R-21 CHCl2F Dichlorofluoromethane B1 1014 5,000

R-22 CHClF2 Chlorodifluoromethane A1 1,00014 42,00011 13

R-23 CHF3 Trifluoromethane A1 1,00010 7.3

R-30 CH2Cl2 Dichloromethane (methylene chlo-ride)

B2 C10008 2,300

R-32 CH2F2 Difluoromethane (methylene fluo-ride)

A2 1,00013 4.8

R-40 CH3Cl Chloromethane (methyl chloride) B2 100 2,000

R-50 CH4 Methane A3 1,00010

R-113 CCl2FCClF2 1,1,2-trichloro-1, 2, 2 -trifluo-roethane

A1 1,000 2,000 1.2

R-114 CClF2CClF2 1,2-dichloro-1,1,2,2 -tetraflouroethane

A1 1,000 15,000 8.7

R-115 CClF2CF3 Chloropentafluoroethane A1 1,00014 47

R-116 CF3CF3 Hexafluoroethane A1 1,00010 34

R-123 CHCl2CF3 2,2-dichloro-1,1,1, -trifluoroethane B1 5013 4,00011 3.5

R-124 CHClFCF3 2-chloro-1,1,1,2 –tetrafluoroethane A1 1,00013 3.5

R-125 CHF2CF3 Pentafluoroethane A1 1,00013 23

R-134a CH2FCF3 1,1,1,2-tetrafluoroethane A1 1,00013 50,00011 13

R-141b CH3CCl2F 1,1-dichloro-1-fluoroethane A1 50013 0.78

R-142b CH3CClF2 1-chloro-1,1-difluoroethane A2 1,00013 5.1

R-143a CH3CF3 1,1,1-trifluoroethane A2 100013 4.5

R-152a CH3CHF2 1,1-difluoroethane A2 1,00013 2.0

R-170 CH3CH3 Ethane A3 1,000 6,400 0.54

R-E170 CH3OCH3 Dimethyl ether A3 1,00010 1.0

R-218 CF3CF2CF3 Octafluoropropane A1 1,000 43

R-227ea CF3CHFCF3 1,1,1,2,3,3,3-heptafluoropropane A1 1,000 36

R-236fa CF3CH2CF3 1,1,1,3,3,3-hexafluoropropane A1 1,00013 21

R-245fa CHF2CH2CF3 1,1,1,3,3-pentafluoropropane B1 30013 12

R-290 CH3CH2CH3 Propane A3 1,000 2,100 0.56

R-C318 -(CF2)4- Octafluorocyclobutane A1 1,00010 41

R-400 zeotrope R-12/114 (50/50) A1 1,00010 10

R-400 zeotrope R-12/114 (60/40) A1 1,000 11

R-401A zeotrope R-22/152a/124 (53.0/13.0/34.0) A1 1,00010 6.6

REFRIGERATION Table 11-1 continued

177

ASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAE

Refrig-erant

ChemicalFormula

Chemical Name4



R-401B zeotrope R-22/152a/124 (61.0/11.0/28.0) A1 1,00010 7.2

R-401C zeotrope R-22/152a/124 (33.0/15.0/52.0) A1 1,00010 5.2

R-402A zeotrope R-125/290/22 (60.0/2.0/38.0) A1 1,00010 8.5

R-402B zeotrope R-125/290/22 (38.0/2.0/60.0) A1 1,00010 15

R-403A zeotrope R-290/22/218 (5.0/75.0/20.0) A1 1,00010 7.6

R-403B zeotrope R-290/22/218 (5.0/56.0/39.0) A1 1,00010 18

R-404A zeotrope R-125/143a/134a (44.0/52.0/4.0) A1 1,00010 31

R-405A zeotrope R-22/152a/142b/C318(45.0/7.0/5.5/42.5)

1,00010 16

R-406A zeotrope R-22/600a/142b (55.0/4.0/41.0) A2 1,00010 4.7

R-407A zeotrope R-32/125/134a (20.0/40.0/40.0) A1 1,00010 18

R-407B zeotrope R-32/125/134a (10.0/70.0/20.0) A1 1,00010 20

R-407C zeotrope R-32/125/134a (23.0/25.0/52.0) A1 1,00010 17

R-407D zeotrope R-32/125/134a (15.0/15.0/70.0) A1 1,00010 15

R-407E zeotrope R-32/125/134a (25.0/15.0/60.0) A1 1,00010 16

R-408A zeotrope R-125/143a/22 (7.0/46.0/47.0) A1 1,00010 21

R-409A zeotrope R-22/124/142b (60.0/25.0/15.0) A1 1,00010 7.1

R-409B zeotrope R-22/124/142b (65.0/25.0/10.0) A1 1,00010 7.3

R-410A zeotrope R-32/125 (50.0/50.0) A1 1,00010 25

R-410B zoetrope R-32.125 (45.0/55.0) A1 1,00010 24

R-411A zeotrope R-1270/22/152a (1.5/87.5/11.0) A2 99010 2.9

R-411B zeotrope R-1270/22/152a (3.0/94.0/3.0) A2 98010 2.8R-412A zeotrope R-22/218/143b (70.0/5.0/25.0) A2 1,00010 5.1R-413A zeotrope R-218/134a/600a (9.0/88.0/3.0) A2 1,000 5.8R-414A zeotrope R-22/124/600a/142b

(51.0/28.5/4.0/16.5)A1 1,00010 6.4

R-414B zeotrope R-22/124/600a/142b(50.0/39.0/1.5/9.5)

A1 1,000 6.0

R-415A zeotrope R-22/152a (82.0/18.0) A2 1,000 12

R-415B zeotrope R-22/152a (25.0/75.0) A2 1,000 9.3

R-416A zeotrope R-134a/124/600 (59.0/39.5/1.5) A1 1,000 3.9

R-417A zeotrope R-125/134a/600 (46.6/50.0/3.4) A1 1,000 3.5

R-418A zeotrope R-290/22/152a (1.5/96.0/2.5) A2 1,000 13

R-419A zeotrope R-125/134a/E170 (77.0/19.0/4.0) A2 1,000 19

R-420A zeotrope R-134a/142b (88.0/12.0) A1 1,000 12

R-421A zeotrope R-125/134a (58.0/42.0) A1 1,000 17

R-421B zeotrope R-125/134a (85.0/15.0) A1 1,000 21

TABLE 11-1Refrigerant Groups1, Properties2, and Allowable Quantities3 (continued)



178

Table 11-1 continued

ASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAE

Refrig-erant

ChemicalFormula

Chemical Name4



R-422A zeotrope R-125/134a/600a (85.1/11.5/3.4) A1 1,000 18

R-422B zeotrope R-125/134a/600a (55.0/42.0/3.0) A1 1,000 16

R-422C zeotrope R-125/134a/600a (82.0/15.0/3.0) A1 1,000 18

R-422D zoetrope R-125/134a/600a (65.1/31.5/3.4) A1 1,000 16

R-423A zeotrope R-134a/227ea (52.5/47.5) A1 1,000 19

R425A zeotrope R-32/134a/227ea (18.5/69.5/12.0) A1 1,000 16R426A zoetrope R-125/134a/600/601a

(5.1/93.0/1.3/0.6)A1 990 5.2

R427A zoetrope R-32/125/143a/134a(15.0/25.0/10.0/50.0)

A1 1,000 18

R428A zoetrope R-125/143a/290/600a(77.5/20.0/0.6/1.9)

A1 1,000 23

R-429A zeotrope R-E170/152a/600a(60.0/10.0/30.0)

A3 1,000 0.81

R-430A zeotrope R-152a/600a (76.0/24.0) A3 1,000 1.3R-431A zeotrope R-290/152a (71.0/29.0) A3 1,000 0.69R-432A zeotrope R-1270/E170 (80.0/20.0) A3 710 0.13R-433A zeotrope R-1270/290 (30.0/70.0) A3 880 0.34R-434A zeotrope R-125/143a/134a/600a

(63.2/18.0/16.0/2.8)A1 1,000 20

R-435A zeotrope R-E170/152a (80.0/20.0) A3 1,000 1.1R-436A zeotrope R-290/600a (56.0/44.0) A3 1,000 0.5R-436B zeotrope R-290/600a (52.0/48.0) A3 1,000 0.5R-437A zeotrope R-125/134a/600/601

(19.5/78.5/1.4/0.6)A1 990 5

R-500 azeotrope R-12/152a (73.8/26.2) A1 1,00010 47,00011 7.6R-501 azeotrope R-22/12 (75.0/25.0) A1 1,000 13R-502 azeotrope R-22/115(48.8/51.2) A1 1,00010 65,00011 21R-503 azeotrope R-23/13 (40.1/59.9) 1,000 67,000R-504 azeotrope R-32/115 (48.2/51.8) 1,000 29R-507A azeotrope R-125/143a (50.0/50.0) A1 1,00010 32R-508A azeotrope R-23/116 (39.0/61.0) A1 1,00010 14R-508B azeotrope R-23/116 (46.0/54.0) A1 1,00010 13R509A azeotrope R-22/218 (44.0/56.0) A1 1,00010 24R-510A azeotrope R-E170/600a (88.0/12.0) A3 1,000 0.87R-600 CH3CH2CH2C

H3

butane A3 1,000 3,400 0.1

R-600a CH(CH3)2CH3 isobutane (2-methyl propane) A3 1,000 3,400 0.6R-601 CH3CH2CH2C

H2CH3

pentane A3 600 0.2

R-601a (CH3)2CHCH2CH3

2-methylbutane (isopentane) A3 600 0.2



REFRIGERATION Table 11-1 continued

179

ASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAEASHRAE

Refrig-erant

ChemicalFormula

Chemical Name4



R-611 HCOOCH3 methyl formate B2 100

R-702 H2 hydrogen A3

R-704 He helium A1

R-717 NH3 ammonia B2 5012 300 0.014

R-718 H2O water A1 footnote15

R-720 Ne Neon A1

R-728 N2 nitrogen A1

R-740 Ar argon A1

R-744 CO2 carbon dioxide A1 5,000 40,000 4.5

R-764 SO2 sulfur dioxide B1 5 100

R-1150 CH2=CH2 ethene (ethylene) A3 200 5,200 0.38

R-1270 CH3CH=CH2 propene (propylene) A3 500 3,400 0.1

Notes:1 Refrigerant safety group designation is in accordance with Section 1103.0.2 Refrigerant properties are those needed for this chapter.3 Allowable quantities are for high-probability systems under Section 1104.0 only.4 Chemical name shown is the preferred name. The popular name is shown in parenthesis.5 OEL is the Occupational Exposure Limit. The value shown is the PEL designated in 29 CFR 1910.1000 unless otherwise indicated.6 IDLH is that designated by NIOSH unless otherwise designated. If no value is shown, use the value listed under pounds per

1000cf of Space. Use the following formula to convert from pounds per 1000cf of Space to ppm. ppm = pounds per 1000cf ofspace/(0.000002557 x M), where M equals the molar mass of the refrigerant in g/mole.

7 Pounds of refrigerant in a high-probability system per 1000 cubic feet (28.3 kg/m3) of occupied space. See Section 1104.0. Thiscolumn does not apply to refrigerant machinery rooms or areas covered by Section 1107.0. If no value is listed use zero (0) unlesssufficient data can be provided to determine the value as described in Section 7 of ASHRAE Standard 34-2007.

8The OEL value shown is the TLV-C recommended by ACGIH.

9 The IDLH value shown is reduced from that designated by NIOSH in light of cardiac sensitization potential.10 A PEL has not yet been established; the value given was determined in a consistent manner.11 An IDLH has not yet been established; the value given was determined in a consistent manner.12 OSHA PEL is 50 ppm; ACGIH TLV-TWA is 25 ppm.13 The OEL value shown is the WEEL recommended by AIHA14 The OEL value show is the ACGIH TLV-TWA15 Quantity is unlimited when R-718 (water) is used as the refrigerant.1 lb. = 0.454 kg, 1 ft3 = 0.0283 m3



TABLE 11-2Permissible Refrigeration Systems1

Occupancy Group High-Probability Low-Probability Machineryand Division System System Room

A–1 Group A1 only Any AnyA–2.1 Group A1 only Any AnyA–3 Group A1 only Any AnyA–4 Group A1 only Any Any

B Group A1 only2 Any AnyE–1 Group A1 only Any AnyE–2 Group A1 only Any AnyE–3 Group A1 only Any AnyF-1 Group A1 only2 Any AnyF-2 Any2 Any AnyH–1 Any Any AnyH–2 Any Any AnyH–3 Any Any AnyH–4 Group A1 only Any AnyH–5 Group A1 only Any AnyH–6 Group A1 only Any AnyH–7 Any Any AnyI–1.1 None Any AnyI–1.2 Group A1 only Any AnyI-2 Group A1 only Any AnyI-3 None Any AnyM Group A1 only2 Any Any

R–1 Group A1 only Any AnyR–2 Group A1 only Any AnyR–3 Group A1 only Any AnyS-1 Group A1 only2 Any AnyS-2 Any2 Any AnyS-3 Group A1 only Any AnyS-4 Group A1 only Any AnyS-5 Group A1 only Any AnyU-1 Any Any Any


180

Table 11-2

Notes:1 See Section 1105.0.2 Any refrigerant may be used within a high-probability system when the room or space complies with Section 1105.3.

TABLE 11-3Value of Factor Dependent for Equation 11–6

Refrigerant Number f11 1.012 1.622 1.6113 1.0114 1.6115 2.5123 1.0134a 1.6152a 1.0500 1.6502 2.5717 0.5744 1.0

TABLE 11-4Field Leak Test Pressures in psig (kPa)

Refrigerant High Side High SideNumber Water Cooled Air Cooled Low Side

11 15 35 1512 140 220 14022 230 360 230

113 15 15 15114 40 80 40115 275 340 275123 15 30 15

134a 150 250 150152a 130 220 130500 165 265 165502 250 385 250717 235 390 235744* N/A N/A N/A

Note: psig x 6.89476 = kPa, N/A—Not applicable.*Special design required; test pressures typically exceed 1,000 psig (6890 kPa).

REFRIGERATION Table 11-3 – Table 11-4

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uniform mechanical code- 2009 chapter 11

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