ventilation air supply

8/7/2019 Ventilation Air Supply

1/64

CHAPTER 4 (VENTILATION AIR SUPPLY

401.0 General.This chapter contains requirements for ventilation airsupply and exhaust, evaporative cooling systems andmakeup-air requirements for direct-gas-fired heaters,industrial air heaters, and miscellaneous heaters.[OSHPD 1, 2, 3 & 4J See Sections 404.0 through 418.0.[SFMJ Air filters shall comply with all requirements ofPart 12, Title 24, Chapter 12-71, SFM Standard 12-71-1.

402.3 Mechanical Ventilation. Where naturalventilation is not permitted by this section or theBuilding Code, mechanical ventilation systems shallbe designed, constructed, and installed to provide amethod of supply air and exhaust air. The systemshall operate so that al l rooms and spaces ar econtinuously provided with the required ventilationrate while occupied.

Ra = outdoor airflow rate required per uni t area asdetermined from Table 4-1. [ASHRAE 62.1:6.2.2.1]

Rp = outdoor airflow rate required pe r person asdetermined from Table 4-1.

Az = zone floor area: the net occupiable floor area ofthe zone ft.2 (m2).

(Equation 4-1)Where:Vbz =RpPz + RaAz

403.0 Ventilation Rates. The design outdoor ai rintake f low rate for a venti la tion sys tem shall bedetermined in accordance with Sections 403.1through 403.6.403.1 Zone Calculations. Zone parameters shall bedetermined in accordance with Sections 403.1.1through 403.1.3. [ASHRAE 62.1:6.2.2]

403.1.1 Breathing Zone Outdoor Airflow. Thedesign outdoor airflow required in the breathingzone of the occupiable space or spaces in a zone,Le., the breathing zone outdoor airflow (Vbz), shallbe determined in accordance with Equation 4-1.[ASHRAE 62.1:6.2.2.1]

403.1.2 Zone Air Distribution Effectiveness.The zone air distribution effectiveness (Ez) shall bedetermined using Table 4-2. [ASHRAE62.1:6.2.2.2]403.1.3 Zone Outdoor Airflow. The design zoneoutdoor airflow (Voz), Le., the outdoor airflow that

pz = zone population: The largest number of peopleexpected to occupy the zone during typical usage..Ifthe number of people expected to occupy the zonefluctuates, pz shall be permitted to be estimated basedon averaging approaches described in Section 403.4. I fpz cannot be accurately predicted during design, itshall be estimated based on the zone floor area andthe default occupant density listed in Table 4-1.

402.0 Ventilation Air. [Not permitted for OSHPD 1, 2,3 &4]402.1 General Requirements. [Not permitted forOSHPD 1, 2, 3 & 4] All rooms and occupied spacesl is ted i n Table 4-1 shall be designed to haveventilation (outdoor) air for occupants in accordancewith this chapter. Ventilation air supply requirementsfor occupancies regulated by the California EnergyCommission are found in the California Energy Code.402.1.1 Construction Documents. The outdoorair ventilation rate and air distribution assumptions made in the design of the ventilation system

shall be clearly identified on the constructiondocuments.402.2 Natural Ventilation. Use of natural ventilationsystems designed in accordance with this sectionshall be permitted in lieu of or in conjunction withmechanical ventilation systems. [ASHRAE 62.1:5.1]

Exception: An engineered natural ventilationsystem when approved by the Authority HavingJurisdiction need no t meet the requirements of402.2.1 and 402.2.2. [ASHRAE 62.1:5.1]402.2.1 Location and Size of Openings.Naturally ventilated spaces shall be permanentlyopen to and within twenty-five (25) feet (8 m) ofoperable wal l or roof openings to the outdoors,the openable area of which is a minimum of 4percent of the net occupiable floor area. Wherethe op en in gs are covered with louvers orotherwise obstructed, openable area shall bebased on the free unobstructed area through theopening. Where interior spaces without directopenings to the outdoors are ventilated throughadjoining rooms, the opening between roomsshall be permanently unobstructed and have afree area of no t less than 8 percent of the area ofthe interior room nor less than 25 ft2 (2.3 m2).[ASHRAE 62.1:5.1.1]402.2.2 Control and Accessibility. The meansto open required operable openings shall bereadily accessible to bui ld ing occupantswhenever the space is occupied. [ASHRAE62.1:5.1.2]

43


2/64

403.1 - 405.0 2007 CALIFORNIA MECHANICAL CODEmust be provided to the zone by the supply ai rdistribution system, shall be determined inaccordance with Equation 4-2. [ASHRAE62.1:6.2.2.3]

Voz =Vbz/Ez (Equation 4-2)

where the system population (Ps) is the total populationin the area served by the system. Alternative methodsshall be permit ted to be used to account forpopulation diversity when calcUlating You, providedthat the resulting value is no less than that determinedby Equation 4-6. [ASHRAE 62.1:6.2.5.3]

403.2 Single-Zone Systems. When one air handlersupplies a mixture of outdoor air and recirculated airto only one zone, the outdoor air intake flow (Vot) shallbe determined in accordance with Equation 4-3.[ASHRAE 62.1:6.3]

403.4.4 Outdoor Air Intake. The design outdoorair intake flow (Vot) shal l be det ermined inaccordance with Equat ion 4-8. [ASHRAE62.1:6.2.5.4]

Vot =Voz (Equation4-3) Vot= Vou/Ev (Equation 4-8)

You =D all zones RpPz + all zones RaAz (Equation 4-6)

The occupancy diversity is defined as:D = Psiall zones pz (Equation 4-7)

Vpz is the primary airf low to the zone from the airhandler, including outdoor air and recirculatedreturn air. [ASHRAE 62.1:6.2.5.1]

The occupant diversity, D, shall be permitted to be usedto account for variations in occupancy within thezones served by the system. [ASHRAE 62.1:6.2.5.3]

(Equation 4-9)

404.0 Makeup Air.Makeup-air requirements for direct gas-fired heaters,industrial air heaters, and miscellaneous heaters arefotindin Chapters 5 and 9.

403.6 Dynamic Reset. The system shall bepermitted to be designed to vary the design outdoorair intake flow (Vot), or the space or zone airflow asoperating conditions change.403.7 Exhaust Ventilation. Exhaust airflow shall beprovided in accordance with the requirements inTable 4-4. Exhaust makeup ai r shall be permitted tobe any combination of outdoor air, recirculated air,and transfer air.

403.5 Design for Varying Operating Conditions.403.5.1 Variable Load Conditions. Ventilationsystems shall be designed to be capable ofproviding the required ventilation rates in thebreathing zone whenever the zones served bythe system are occupied, including all full andpart-load conditions. [ASHRAE 62.1:6.2.6.1]403.5.2 Short-Term Conditions. If it is knownthat peak occupancy will be of short duration orthe ventilation rate will be varied or interruptedfor a short period of time, the design shall bepermitted to be based on the average conditionsover a time period T determined by Equation 4-9.[ASHRAE 62: Section 6.2.6.2]:

T =3 vIVbz (4-9) IF

Vbz = the breathing zone outdoor airflow calculatedusing Equation 4-1 and the design value of the zonepopulation Pz, cfm (Lis).

where:T =averaging time period, (min)v = the volume of the zone for which averaging isbeing applied, ft.3 (m3).

(Equation 4-4)

(Equation 4-5)p =Voz/Vpz

403.4.2 System Ventilation Efficiency. Thesystem ventilation efficiency (Ev) shall bedetermined using Table 4-3 or Appendix A ofASHRAE 62.1. [ASHRAE 62.1:6.2.5.2]403.4.3 Uncorrected Outdoor Air Intake. Thedesign uncorrected outdoor air intake (Vou) shall bedetermined in accordance with Equation 4-6.[ASHRAE 62.1:6.2.5.3]

403.4 Multiple-Zone Recirculating Systems. Whenone air handler supplies a mixture of outdoor air andrecirculated return air to more than one zone, theoutdoor air intake flow (Vot) shall be determined inaccordance with Sections 403.4.1 through 403.4.4.[ASHRAE 62.1:6.2.5]403.4.1 Primary Outdoor Air Fraction. WhenTable 4-3 is used to determine system ventilationefficiency, the zone primary outdoor air fraction(Zp) shal l be determined in accordance withEquation 4-5. [ASHRAE 62.1:6.2.5.1]

403.3 100% Outdoor Air Systems. When one airhandler supplies only outdoor air to one or morezones, th e outdoor air intake flow (Vot) sha ll bedetermined in accordance with Equation 4-4.[ASHRAE 62.1:6.2.4]Vot = all zonesVoz

44


3/64

VENTILATION-AIR SUPPLY 405.0 - 407.1

405.4 Evaporative Cooling System for HealthCare facilities [For OSHPD 1, 2, 3 & 4] Directevaporative cooling systems where the air directly c o n t a c t ~

Per Table 4-2, the zone air distribution effectivenessis 1.0 since the system supplies cooling only from theceiling. Using th e r at es from Table 4-1 fo r ameeting/conference room, the minimum systemoutdoor air rate is calculated to be:

Example: Determine the outdoor air rate requiredfor a single zone AC unit serving an interior 2,000 ft.2meeting/conference room with a design occupancyof 100 people. The system supplies and returns airfrom the ceiling. '

406.0Reserved.Part I - Ventilation for Health Care Facilities [ForOSHPD 1,2,3 & 4]407.0 Ventilation System Details [For OSHPD 1, 2,3&4]407.1 General.407.1.1 AJI supply-air, return air, and exhaust-airsystems shall be mechanically operated and suchsystems for areas listed in Table 4-A shall be operated

continuously. Natural ventilation through windowsor other openings such as louvers will be consideredas supplemental to the required mechanicalventilation systems.Exception 1. Natural ventilation shall not beused in airborne infection isolation rooms andprotective environment rooms.Exception 2. The number of air changes may bereduced to 25 percent of the indicated value inTable 4-A, when the room is unoccupied, ifprovisions are made to ensure the following: (1)the number of air changes per hour indicated isreestablished whenever the space is occupied and(2) the pressure relationship with thesurrounding rooms is maintained when the airchanges per hour are reduced; In areas requiringno continuous directional control as identified inaccordance with Table 4-A, ventilation systemsmay be shut down when the space is unoccupiedand ventilation is not otherwise required.Ventilation shall not be reduced in roomsspecifically used for airborne infection control,such as waiting rooms, triage rooms, corridors,reception areas, areas adjacent to waiting areas,airborne infection isolation rooms, negativepressure exam room, negative pressure x-raytreatment rooms, and protective environmentrooms. All operating and delivery rooms shallmaintain aminimum of six air changes per hourof total air when not in use.

407.1.2 Fans serving exhaust systems shall belocated at the discharge end of the system. Theventilation rates shown in Table 4-A shall beconsidered as minimum acceptable rates and shallnot be construed as precluding the use of higherventilation rates if they are required to meetdesign conditions.

the wetted surface or spray shall be limited in healthfacilities to nonpatient areas such as laundry rooms, foodpreparation areas and boiler or machinery rooms. Similarrooms with high heating-producing equipment will beconsidered when specifically approved by the enforcingagency. The evaporative pads, shall be a synthetic type.Filters shall be required in accordance with Tables 4-B and4-C except utility rooms i.e;: boiler or machinery rooms.

=RpPz + RaAzEz= 5 x 100 + 0.06 x 2,000

1.0=620 cfm

Vat

405.0 Evaporative Cooling Systems.Evaporative cooling systems shall comply' witl.1 thischapter.Evaporative cooling systems shall be providedwith outside air as specified for cooling systems inthis code. .- .

Ali' ducts and fire dampers that are a portion of anevaporative cooling system shall complywith this code.405.1 Location.Evaporative cooling systems shall be installed soas to minimize the probability of damage from .anexternal source. .405.2 Access, Inspection, and Repair. Evaporativec;oolers shall be accessible for inspection, service, andreplacementwithout removingpermanent construction:405.3 Installation.An evaporative cooler supported by the buildingstructure shall be installed on a substantial level baseand shall be secuteddirectlyor indirectly to thebuilding structure by suitable means to preventdisplacement of the cooler.Modifications mflde to th e supportingframework of buildings as a result of the installationshall be in accordance with the requirements of theBuilding Code. Openings in exterior walls shall beflashed in an approved manner in accordance with. the requirements of the Building Code.

An evaporative cooler supported directly by theground shall be isolated from the ground by a levelconcrete slab extending not less than three (3) inches(76 mm) above the adjoining ground level.

An evaporative cooler supported on anaboveground platform shall be elevated at least six(6) inches (152mrn) above adjoining ground level.

)

45


4/64

407.2 - 407.5

407.1.3 Services/Systems and Utilities. SeeSection 313.2.407.2 O u t d o o r A ir In ta ke s a nd E x h a u s tOutlets.

407.2.1 Outdoor Ai r Intakes. Outdoor air intakesshall be located at least 25 feet (7.62 m) from exhaustoutlets ofventilating systems, combustion equipmentstacks, medical-surgical vacuum systems, coolingtowers and areas that may collect vehicular exhaust~ other noxious fumes. The bottom of outdoor airmtakes shall be located as high as practicable, but notless than 10 feet (3048 mm), above ground level. Ifinstalled through the roof, they shall be located 18inches (457 mm) above roof level or 3 feet (914 mm)above aflat roofwhere heavy snowfall is anticipated.Exceptions:1. These dimensions may be reduced if it isdemonstrated by the submission of details andcalculations that location of intakes with respect

to exhausts and their orientation, or the use ofspecial filters, provides equal performance.2. The requirements regarding the bottom ofoutdoor air intakes and installation through theroof do not apply to skilled nursing facilities,intermediate-care facilities or nonsensitive areasin correctional treatment centers.407.2.2 Exhaust Outlets. Exhaust outlets shallbe located a minimum of10 feet (3048 mm) aboveadjoining grade and 10 feet (3048 mm) fromdoors, occupied areas and operable windows.Exception: Airborne infection isolation roomsshall comply with Section 414.1.407.2.3 ReliefAir Discharge. Building relief airdischarge shall discharge at least 10 feet (3048mm) from any outside air intake.407.3 A ir Balance.407.3.1 The ventilation systems shall be designedand balanced to provide the general air balancerelationship to adjacent areas, shown in Table 4-A.The ventilation systems shall be balanced inaccordance with the latest edition of standardspublished by the Associated Air Balanced Council(AABC) or the National Environmental BalancingBureau (NEBB).407.3.2 Where the variation in static pressure dropacross filters is a significant portion of the totalpressure drop, static pressure or pressure differentialcontrols or constant volume devices may be requiredto e n s u ~ e the maintenance ofair balance relationshipsshown m Table 4-A regardless offilter loading.Exception: This section does not pertain to skillednursing facilities, intermediate-care facilities andnonsensitive areas in correctional treatment centersexcept for airborne infection isolation rooms and

46

2007 CALIFORNIA MECHANICAL CODE

protective environment rooms.407.4 Air Circulation.407.4.1 Air shall be introduced at the cleanestareas and removed at the dirtiest areas in order toreduce chances of airborne cross infection asfollows:407.4.1.1 Air supplied to operating rooms,cesarean operating rooms, cardiac catherizationlabs, cystoscopy rooms, delivery rooms andnurseries, shall be delivered at or near the ceilingof the area served, and all air removed from thearea shall be removed near floor level. At leasttwo exhaust or recirculation air inlets shall beused in all operating and delivery rooms andshall be located not less than 3 inches (76 mm)nor more than 8 inches (203 mm) above thefinished floor.Exception: For airborne infection isolationrooms and protective environment rooms, seeSection 414.0 and 415.0.407.4.1.2 Room supply air outlets and roomrecirculation and exhaust air inlets installed innonsensitive areas shall be located not less than 3inches (76 mm) above the floor.Exception: For airborne infection isolationrooms and protective environment rooms, seeSection 414.0 and 415.0.407.4.1.3 Corridors shall not be used to conveysupply, return or exhaust air to or from any roomif the corridor is required to be of fire resistiveconstruction per the California Building Code.Exception 1: Mechanically exhausted toiletrooms of50 square feet (4.7m2) or less and smallrooms of 30 square feet (2.79 m2) or less such asjanitor closets, housekeeping rooms, andelectrical or telephone closets opening directlyonto corridor.Exception 2: Air transfer caused by pressuredifferentials in rooms required to have a positiveor negative air balance by Table 4-A.407.4.1.4 No space above a ceiling may beutilized as an outside-air, supply-air, exhaustair or return-air plenum.Exception: Designs specifically approved bythe enforcing agency.407.4.1.5 Air from a patient room, exam room,treatment room shall not be transferred toanother similar room without first having passedthrough air filters as required b y Table 4-B orTable 4-C.407.4.1.6 Supply outlets and return andexhaust air inlets shall be located to preventshort-circuiting.407.5 Variable A ir Volume.401.5.1 Variable Air Volume Systems (VA V).Variable air volume .systems subjecting the patient to


5/64

)

~

VENTILATIONAIR SUPPLYa fluctuating air movement are not acceptable forairborne infection isolation rooms, protectiveenvironment rooms or those critically sensitive areaslisted in Table 315. For nonsensitive areas, variableair volume systems meeting the following criteria canbe considered:407.5.1.1 The VAV system shall comply withcode requirements for outside air, total air, andpressure relationship through the full range ofoperation from minimum to maximum.407.5.1.2 The central return or exhaust fanshall be controlled to accomplish the variable airvolume requirements of the individual roomsserved by the fan as described in Section407.5.1.3.407.5.1.3 Variable air volume for return orexhaust air shall be accomplished by utilizing anautomatic modulating damper in the return orexhaust air for each zone. The damper willmodulate from full open to minimum position inconjunction with the supply airVAV terminal b ~ x .

408.0 Filters [For OSHPD 1, 2, 3 &4J408. 1 General. Filter efficiencies shall be certified by themanufacturer and shall be based on ASHRAE Standard52.1-1992, Gravimetric and Dust-spot Procedures forTesting Air-Cleaning Devices Used in General Ventilationfor Removing Particulate Matter or ASHRAE Standard52.2-1999, Method of Testing General Ventilation AirCleaning Devices for Removal Efficiency by Particle Sizewhen specifically set forth in these standards.408. 1.1A filter gauge shall be installed across eachfilter bank serving central air systems. The gaugeshall be red lined or a filter alarm light installed tosignal when the recommended maximum staticpressure. drop has been reached.408.1.2 Central air-handling systems are defined asany unit requiring duct work on the supply or inletside that serve more than one room.408.1.3 Filter banks shall be visually inspected fortorn media and bypass in filter frames by means of aflashlight or equivalent, both with fans in operationand stopped. Tears in media and bypass in filterframes shall be eliminated in accordance with themanufacturer's directions and the requirements of theenforcing agency prior to commencing operation ofthe system.408.1.4 Central air-handling systems shall bemaintained in a reasonably clean condition duringconstruction and shall be cleaned as necessary priorto replacement of temporary filter used duringconstruction to ensure that clean air will be deliveredto the occupied spaces.408.1.5 Filter bank No.1 shall be located upstreamof the air-conditioning equipment. Filter bank No. 2a1id filter bank No. 3 shall be located downstream of. the supply fan and all cooling and humidification

407.5 - 408.3

equipment with efficiencies as indicated in Table 4-Bor Table 4-C.Exception: Dry steam-type humidifiers for local roomhumidity control may be installed in the supply airduct downstream of the final filter bank where designsare speCifically approved by the enforcing agency.408.1.6Filter bank No.2 and filter bank No.3 mediashall be rigid or supported (noncollapsing type) andshall operate on the principles of impingement,straining and diffusion.408.2 Filters for Hospitals.408.2.1 All air-ventilation systems shall complywith code requirements of this section and shall havefilter bank efficiencies as listed in Table 4-B.408.2.2 Noncentral recirculating air systemsproviding cooling to high heat producing equipmentlocated in nonsensitive areas shall have a filter with30 percent average efficiency based on ASHRAEStandard 52.1-1992 or a minimum efficiencyreporting value (MER V) of 8 based on ASHRAEStandard 52.2-1999. .408.2.3 Noncentral air systems serving any areasnot listed in Table 4-B shall be provided with filterarrangement and efficiency specifically approved bythe enforcing agency.408.2.4 Noncentral recirculating air handlingsystems, i.e., through-the-wall units, fan coil units,and heat pumps may be utilized for single patientrooms of one or more beds. Filtration for these unitsshall have a minimum weight arrestance value of 50percent, based on ASHRAE Standard 52.1-1992 or aminimum efficiency reporting value (MER V) of 1,based on ASHRAE Standard 52.2-1999. The airventilation system providing the minimum airchanges of outdoor air shall comply with Table 4-B.These units may be used as recirculating units only.All outdoor air requirements shall be met by aseparate central air handling systems.408.3 Filters for Skilled Nursing Facilities,Intermediate Care Facilities and CorrectionalTreatment Centers.408.3.1 The air ventilation systems shall complywith code requirements of this section for skillednursing facilities, intermediate care facilities andcorreCtional treatment centers and shall have filterbank efficiencies as listed in Table 4-C.408.3.2 Noncentral air systems serving singlepatient rooms of one or more beds shall comply withTable 4-C.408.3.3 Noncentral recirculating air-handlingsystems, i.e. through the wall units, may be utilizedfor each patient room with one or more beds.Filtration for 'these units shall have a minimumweight arrestance vqlue of 50 percent, based onASHRAE Standard 52.1-1992 or a minimumefficiency reporting value (MERV) ofl, based on

47


6/64

408.3 - 413.2

ASHRAE Standard 52.2-1999. The air ventilationsystem providing the minimum air changes ofoutdoor air shall comply with Table 4-C. These unitsmay be used as recirculating units only. All outdoorair requirements shall be met by a separate central airhandling system.401!.3.4 Airborne infection isolation rooms,protective environment rooms and sensitive areas incorrectional treatment centers shall comply withSection 408.2.408.4 Filters for Outpatient Facilities.408.4.1 The air ventilation systems shall complywith code requirements of this section for outpatientfacilities and shall have filter bank efficiencies aslisted in Table 4-B.408.4.2 Noncentral air systems serving individualrooms shall comply with Table 4-B.

409.0 DUCTS [FOR OSHPD 1, 2, 3 & 4J409.1 Ducts which penetrate construction, intended forX-ray or other radiation protection, shall not impair theeffectiveness of the protection.409.2 Duct linings and their use shall meet therequirements ofChapter 6, California Mechanical Code.409.3 Cold-air ducts shall be insulated wherevernecessary or to prevent condensation problems.409.4 The anchorage and supporting structural elementsfor airducts shall be designed to withstand the lateralforces as required by the California Building Code, Title24, Part 2.410.0 Laboratories [For OSHPD 1,2,3 & 4J410.1 The minimum amount ofoutdoor air in laboratoriesshall be provided in accordance with Table 4-A. A filterwith 90 percent average efficiency based on ASHRAEStandard 52.1-1992 or a minimum efficiency reportingvalue (MERV) of 14, based on ASHRAE Standard 52.21999 shall be installed in the air-supply system at itsentrance to the media transfer room.410.2 Laboratory hoods for general use shall have aminimum average face velocity of 75 feet per minute (380m/s). Hoods in which infectious or highly radioactivematerials are processed shall have a face velocity of 100feet per minute (510 m/s). Bacteriological safety cabinetsused for processing infectious materials shall have anaverage face velocity of 50 to 70 feet per minute (255 m/sto 355 m/s) and shall be equipped with a means fordisinfection.410.3 Laboratory hoods shall not be connected to thegeneral building exhaust system. Hoods in whichinfectious, incompatible or highly radioactive materials areprocessed each shall have an independent exhaust systemwith the fan installed at .the discharge point of the system.Duct systems serving laboratory hoods shall beconstructed of stainless steel of a type which will resistcorrosion by materials normally handled. Duct systemsserving laboratory hoods used for purposes other than

48


those needed for routine diagnostic laboratory proceduresand in which highly radioactive materials or a significantvolume of highly oxidizing agents are used shall beconstructed of USS 18-8 stainless steel or the equivalentfor a minimum distance of 10 feet (3048 mm) from thehood. Such ducts shall be equipped with wash downfacilities and shall be consistent with fire safetyrequirements. Fire dampers and smoke dampers shall notbe installed in laboratory hood exhaust systems.410.4 The exhaust from all laboratory hoods in whichinfectious or radioactive materials are processed shall beequipped with filters having a 99 percent efficiency based onthe DOP (dioctylphthalate) test method or a minimumefficiency reporting value (MERV) of 15, based onASHRAE Standard 52.2-1999. Filter frames shall bedurable and carefully dimensioned, and shall provide anairtight fit with the enclosing duct work. All joints betweenfilter segments and the enclosing duct work shall be gasketedor sealed to provide apositive seal against air leakage.411.0 Kitchen and Dining Areas [For OSHPD 1,2,3&4J411.1 The air from dining areas may be used to ventilatethe food preparation areas only after it has passed throughafilter with at least an 80 percent average efficiency basedon ASHRAE Standard 52.1-1992 or a minimumefficiency reporting value (MERV) of 13, based onASHRAE Standard 52.2-1999.Exception: For skilled nursing facilities,intermediate care facilities and correctional treatmentcenters, the air from dining area may be used toventilate food preparation areas only after it haspassed through a filter with a 50 percent averageefficiency based on ASHRAE Standard 52.1-192 or aminimumefficiency reporting value (MERV) of 10,based on ASHRAE Standard 52.2-1999.412.0 Boiler, Mechanical and Electrical Rooms[For OSHPD 1, 2, 3 &4J412.1 Boiler, heater and electrical equipment rooms shallbe provided with outdoor air so as to maintain combustionrates ofequipment and temperatures in the rooms and inadjoining areas as rated in this chapter.412.2Floor surfaces in occupied spaces above such roomsshould not exceed a temperature of 85 OF (29.4 C), andsuitable insulation may be required.413.0 Odorous Rooms [For OSHPD 1, 2, 3 &4J413.1 Rooms in areas where excessive heat or moisture isgenerated, where objectional odors or dust are present, orwhere flammable or toxic gases may accumulate, whichare used by health facility personnel or patients, shall beprovided with exhaust ventilation to change the air aminimum of ten times per hour.413.2 Kitchen; morgues and laundries located inside ahospital building or skilled nursing facility in whichpatients are accommodated, or treated, shall be ventilated


7/64

VENTILATION-AIR SUPPLY 413.2-416.3

/

)

with exhaust systems which will provide a minimum often air changes per hour and prevent odors from enteringpatient areas.414.0 Airborne Infection Isolations Rooms [ForOSHPD 1,2,3 & 4J414.1 Exhaust Systems. A separate, dedicated exhaustsystem shall be provided for airborne infection isolationrooms. The dedicated system may serve more than oneairborne infection isolation room, adjoining toilet roomand anteroom. The exhaust ducts shall be identified byappropriate labeling with the words "Caution AirborneInfection Isolation Rooms Exhaust" or similarterminology. Such labeling shall be in a manner which isnot readily removable and shall appear on the exhaustduct at intervals of not more than 20 feet (6096 mm) andat least once near each room and each story traversed bythe exhaust system. Exhaust fans shall comply withSection 407.1.2. The discharge from exhaust fans shall belocated a ~ o v e the roof and shall be located a minimum of25 feet (7620 mm) from areas that may be occupied, doors,operable windows, outdoor air intakes, or other openingsinto the building. The exhaust fan discharge shall belabeled in a manner which readily identifies theprecautions which should be observed. To ensure, that theairborne contaminates do not reenter the building, one ofthe following shall be provided:

414. 1. 1 Exhaust discharge from fan, shall extend atleast 7 feet (2134 mm) above the roof and dischargevertically upward. Self-draining stacks or equivalentshall be used for rain protection. Rain caps which divertthe exhaust toward the roofshall be prohibited; or414.1.2 Exhaust shall discharge above roof level andthrough an accessible HEPA filter. The HEPA filtershall be located upstream of the exhaust fan and havea minimum efficiency of99.97 percent based on theDOP method in accordance with Mil-Std. 282 or aminimulrl efficiency reporting value (MERV) of 17,based on ASHRAE Standard 52.2 1999. Filter gageshall be installed across' thefilter. For maintenance ofair balance relationship,see Section 407.3.2. The 25foot (7620 mm) dimension required by Section 414.1may be reduced when a 99.97 percent HEPAfilter or

a ~ m i n i m u m efficiency reporting value (MERV) of 17,iJased on ASHRAE Standard 52.2 1999 is used andthe reduced dimension is specifically approved by the, enforcing agency. ,414.2 Air Distribution. The supply outlets and exhaustinlets shall be located to provide airflow patterns thatprevent stagnation of the air and eliminate shortcircuiting of the supply to the exhaust, and minimizeexposure of health care workers to airborne infectiousparticles. Supply-air outlets shall be located at or near theceiling and at the end of the airborne infection isolationroom which is opposite >the head of the bed; Exhaust

registers shall be located on the wall behind the patient'shead, or as close to that wall as practical and shall belocated not less than 3 inches (76 mm) nor more than 24inches (610 mm) above the finished floor.Exception: For correctional treatment centers, thelocation and design of the supply outlets an exhaust orreturn inlets shall not compromise the safety, securityand protection ofstaff, inmates and property.

415.0 Protective Environment Rooms [ForOSHPD 1,2,3 & 4J415.1 Air Distribution. The supply outlets and exhaustand return inlets shall be located to provide airflow ,patternsthat prevent stagnation of the air and eliminate shortcircuiting of the supply to the exhaust or return. Supply airshall be delivered at or near the ceiling and near thepatient's bed. All exhaust or return registers shall be locatednear the entrance to the protective environment room andnot less than 3 inches (76 mm) nor more than 8 inches (203mm) above the finished floor.Exception: For correctional treatment centers, thelocation and design of the supply outlets and exhaustor return inlets shall not compromise the safety,security and protection of staff, inmates and property.416.0 Alarms - Airborne Infection IsolationRooms and Protective Environment Rooms[OSHPD 1, 2, 3 & 4J416.1 An alarm system which is based on static pressurecontrol, volumetric control, or directional flowmeasurement shall be provided for each isolation room. Thealarm system shall consist of a display monitor located onthe corridor wall near the door to the room and a visual andaudible alarm which annunciates at the room and at anurses' station or other suitable location that will provideresponsible surveillance. A time delay shall be provided toallow for routine openings of doors. The alarm shallannunciate when the supply, return, or exhaust fans areinterrupted and when one of the following conditions is notbeing metduring closed door conditions:1. When the minimum air quantity difference of 75cfm (35.4 Lis) required by Table 4-A is not beingmaintained; or2. When a minimum pressure differential of 0.001

inch (0.003 kPa) ofwater and aminimum inward(outward for protective environment rooms) airvelocity of 100 feet per minute (0.508 m/s) is notbeing maintained at the air transfer openingrequired by Table 4-A. '416.2Other acceptable alarm systems will be allowed whendesigns are specifically approved by the enforcing agency.416.3 [For OSHPD 4J For correctional treatmentcenters, the alarm system shall,not create fcilse alarms orsecurity hazards., ' ,"

49


8/64

416.4- 418.5

416.4 Prior to acceptance of the rooms, the alarm systemshall be tested and operated to demonstrate to the owner ordesignated representative that the installation andperformance of the system conforms to design intent.417.0 Testing Airborne Infection Isolation Roomsand Protective Environment Room [For OSHPD 1,2, 3 &4J Prior to acceptance of the rooms, all mechanicalsystems shall be tested, balanced and ...operated todemonstrate to the owner or designated representative thatthe installation and performance of the systems conform todesign intent. All testing and balancing shall be performedby a qualified independent agency certified by theAssociated Air Balance Council (AABC) or the NationalEnvironmental Balancing Bureau (NEBB). Test resultsshall be documented for maintenance files.418.0 Design Requirements for Ethylene Oxide(ETO) Sterilization Areas [For OSHPD 1,2,3 &4J418.1 Air Changes. The ETO sterilization equipmentroom shall be provided with minimum air changes per hourper Table 4-A and be maintained at anegative air balance.418.2 Exhaust Requirements.418.2.1 All air from the ETO sterilizer equipmentroom shall be exhausted to the outside by a dedicatedsystem or other approved method.418.2.2 The exhaust fan for the dedicated system shallbe located at the discharge point of the system andidentified as ETO Equipment Room Exhaust.418.2.3 Discharge Point. The discharge point shall

be a minimum of 25 feet (7620 mm) away from anyoutside intake, operable window or personnel passage.418.3 Ventilation Requirements.418.3.1 Aeration units. The aeration units shall beventilated through a nonrecirculating dedicatedventilation exhaust system.418.3.2 Capture box. When the drain is not locatedin the ETO sterilizer equipment room, ventilation isrequired by a capture box.418.3.3 Cylinder change. When not located in theETO sterilizer equipment room, exhaust during cylinderchange is required by installing a hood that is part ofadedicated ventilation exhaust system, positioned no morethan 1 foot (305 mm) above or behind the point where thechange ofcylinders takes place.418.3.4 Sterilizer relief valve. The ventilation ofsterilizer reliefvalve is required through a pipe connectedto the outlet of the relief valve exhausted directly to theoutdoors at apoint high enough to be away from passersby, and not near any windows that open, nor near anyair-conditioning or ventilation air intakes.418.3.5 Ventilation of sterilizer door area. Thesystem shall be designed to capture the ETO when thedoor is opened following the completion of thesterilization process. A hood or canopy closed on each

50


end should be installed over the sterilization door. Ahood or canopy shall be connected to a dedicatedexhaust ventilation system.418.4 Gas Valves. Installation ofgas line hand valves atthe c o n n ~ c t i o n to the supply cylinders are required tominimize leakage during cylinder change.418.5 Alarm Systems. An Audible an visual alarmsystem shall be installed to alert sterilizer operating personnelif the air flow falls below design cubitfeet perminute(L/S).


9/64

VENTILATION-AIR SUPPLY

TABLE 4-A - PRESSURERELATIONSHIP AND VENTILATION REQUIREMENTS FORGENERAL ACUTECARE HOSPITALS, SKILLEDNURSING FACILITIES,INTERMEDIATE CARE FACILITIES, CORRECTIONAL .

Table 4-A

/

TREATMENT CENTERS, OUTPATIENTS FACILITIES AND LICENSED CLINICSA B C D E FCONDITIONED AIR NOT ALL AIRAIRBALANCE MINIMUM 100% O.S.A EXHAUSTERELATlONSHIP AIR Minimum Air Minimum DTO CHANGES Changes of Total Ai r DIRECTLYADJACENT IF 100% OutdoorAir Changes per TOArea Designation AREAS" O.S.A. per hour hour OUTDOORS

Operating room, cardiac cath lab and P' 12 5 20cystoscopyPatient holding preparation' E 6 2 6Delivery room, cesarean operating room P 12 5 20Newborn/well baby nursery P 6 2 6Post anesthesia care unit E 6 2 6 . YesIntensive care service spaces, P 6 2 6Acute respiratory - care service spaces,Burn service spaces, Coronary-care service Spaces, Pediatricintensive - care service spaces'Newborn intensive care P 6 2 6Emergencydepartment:'

Waiting area N 12 2 12 Yes'Operating room P 12 5 20Treatment room E 6 2 6Trauma room' P 12 5 20Triage N 12 2 12 Yes

Patient room E 2 2 6Patient area corridor E 2 2 4Labor/delivery/recovery room, Labor/ E 2 2 6deliverylrecovery/postpartum roomAirborne infection isolation room N4 12 2 12 YesAirbone infection isolation anteroom p4 10 2 10 YesProtective environment room p' 15 2 15Protective environment anteroom N" 15 2 15Treatment, and examination rooms E 6 2 6Bronchoscopy and endoscopy N 12 2 12 YesSpecial purpose room (SNF & ICF only) E 6 2 6 Yes

51


10/64

Table 4-A cant. 2007 CALIFORNIAMECHANICAL CODE

A B C D E FCONDITIONEDAIR NOT ALL AIRAIRBALANCE MINIMUM 100% O.S.A EXHAUSTERELATIONSHIP AIR Minimum Ai r Minimum D

TO CHANGES Changes of TotalAir DIRECTLYADJACENT IF 100% OutdoorAi r Changes pe r TO

Area Designation AREAS" O.S.A. pe r hour hour OUTDOORS

Radiological/Imaging:Angiography Room P 12 5 15X-ray (diagnostic and treatment) E 6 2 6CTScan E 6 2 6MRlroom E 6 2 6Fluoroscopy Room N 6 2 6 YesDarkRoom N 12 2 12 YesNegative-pressure x-ray room N 12 2 12 YesUltra. sound room E 6 2 6Gamma camera E 6 2 6Waiting area N 12 2 12 Yes

Bedpan room N 10 YesBathroom N 10 YesJanitors' closet, Housekeeping r oom N 10 YesSterilizer equipment room N 10 YesSub sterile room E 10 2 10 YesLinen and trash chute rooms N 10 YesFoodpreparation centers E 10 2 10 YesDining room E 10 2 10Dishwashing room N 10 YesDietary day storage E 2Laundry, general (clean and dirty) E 10 2 10 YesSoiled linen sorting and storage N 10 YesClean linen storage P 2 2 2Anesthesia storage E 8 8 YesCentralmedical and surgicalsupply:Soiled or decontamination room N 4 2 4 YesClean workroom P 4 2 4Unsterile supply E 2 2 2Pharmacy/medicine room P 2 2 4LaboratoryGeneral N 6 2 6Biochemistry P 6 2 6Cytology N 6 2 6 YesGlass washing N 10 2 10 YesHistology N 6 2 6 YesMicrobiology N 6 2 6 YesNuclear medicine N 6 2 6 YesPathology N 6 2 6 YesSerology P 6 2 6Sterilizing N 10 2 10 YesMedia transfer P 4 2 4

52


11/64

VENTILATION-AIR SUPPLY Table 4-A cont.

A B C D E FCONDITIONED AIR NOT ALL AIRAIRBALANCE MINIMUM 100% O.S.A EXHAUSTERELATIONSHIP AIR Minimum Air Minimum DTO CHANGES Changes of Total Ai r DIRECTLYADJACENT IF 100% OutdoorAir Changesper TOArea Designation AREAS" O.S.A. per hour hour OUTDOORS

Infectious disease and virus N 6 2 6 YesBacteriology N 6 2 6 YesNegative-pressure treatment/exam room N 12 2 12 YesPhysical therapyandhydrotherapy N 6 2 6Soiled workroom (utility room) N 4 2 10 YesClean workroom P 4 2 6Autopsy N 12 2 12 YesToilet room N 10 Yes.

Shower room N 10 YesWaiting area primary care clinic N 10 2 10 Yes'P =Positive E=Equal N=Negative1 The pressure relationship of the entire emergency department shall be negative to otheradjacent areas.2 Airmay be recirculated if a high-efficiencyparticulate air (HEPA) filter with a minimum efficiencyof 99.97percent or a minimumefficiency reporting value (MERV) of 17 is installed in the return air duct which serves the waiting area.3 The term "trauma room" as used here is the operating room space in the emergencydepartment or other trauma reception areathat is used for emergency surgery. The first aid room and/pr "emergency room" used for initial treatment of accident victims maybe ventilatedas noted for the "treatment rooms. " .4 The anteroom shall have positive air pressure in relation to the airborne infection isolation room. A door louver, transfergrille, orother acceptable means shall be provided to allow for airflow from the anteroom to the airborne infection isolation room. Theairborne infection isolation room shall have negative pressure in relation to the anteroom, and the adjoining toilet room shall havenegativepressure in relation to the airborne infection isolation room. Negative pressure shall be achievedby balancing theexhaust cfm to no less than 75 cfm (35.4Us) greater than the supply cfm for each airborne infection isolation room the anteroomserves. The overall area consisting of the anteroom, airborne infection isolation room, and adjoining toilet room shall have anequal air balance in relation to the corridor.Except ion: Forcorrectional treatment centers, the location and design of the air transfer device shall not compromise thesafety, security and protection of staff, inmates, and property.5 Positive-pressure shallbe achievedby balancing the supply cfm to not less than 75 cfm (35.4 Us) greater than the exhaust andreturn cfm for each protective environment room the anteroom serves,6 The anteroom shall have negative air pressure in relation to the protective environment room. A door louver, transfergrille, orother acceptablemeans shall be provided to allow for airflow from the protective environment room to the anteroom. Theprotective environment room shallhavepositive-pressure in relation to the anteroom andadjoining toilet room. Positive pressureshall be achievedby balancing the supply cfm to not less than 75 cfm (35.4 Us) greater than the exhaust and return cfm. Theoverall area consisting of the anteroom, protective environment room, andadjoining toilet room shall have an equal air balance inrelation to the corridor.Exception: For correctional treatment centers, the location and design of the air transfer device shall not compromise thesafety, security, andprotection of staff, inmates, and property.7 Cystoscopymay have equal air balance relationship to adjacent areas when approvedby AuthorityHaving Jurisdiction.

8 For operating rooms, cardiac catheterization labs, angiography rooms, cystoscopy rooms, delivery rooms, cesarean operatingrooms, newborn intensive care, intensive care units, and nurseries provide approximately 15% excess supplyair to the room or asufficient quantity of excess supply air to maintain an appropriate positive air balance based on the room tightness andnumber ofdoors. For all rooms not listed in this footnote or not listed in Table 315 requiring eithera positive or negative air balance, provideapproximately 10% differential cfm between supplyand return/exhaustairflow but not less than 25 cfm differential shall beprovidedregardless of room size. Room function, size, and tightnessmay be considered when determining the differential airflowrequired.9 Intensive care patient rooms, which contain a modular toilet/ sink combination unitwithin the room, shall be provided with aminimum of 75 cfm of exhaust directly over the modular toilet/sinkcombination unit.

53


12/64

Table 4-8 - Table 4-C 2007 CALIFORNIA MECHANICAL CODETABLE 4-B - Filter Efficiencies for Central Ventilation andAir-Conditioning Systemsin General Acute Care Hospitals, AcutePsychiatric Hospitals, Outpatient Facilities and Licensed Clinics. 1

FilterEfficiency % Filter Bank(Minimum efficiency reportingArea Designation Minimum Number of Filter Banks value MERV)5No. 11 No. 21 No. 31Orthopedic operating room, 30% 90% 99.97%3bone marrow transplantoperating room, organ transplant 3operating room (8) (14) (17)Protective environment rooms 3 30% 90% 99.97%4

(8) (14) (17)Angiography; cardiac cath labs; 2 30% 90%operating rooms; delivery roomsnurseries; patient care, treatment,cystoscopy, cesarean operating room, (8) (14)diagnostic and related areas; airborneinfection isolation rooms; areasproviding directpatient service or cleansupplies such as sterile and cleanprocessesLaboratories 2 30% 80%

(8) (13)Administrative, med staff support areas, 1 30%bulk storage, soiled holding areas,food preparation areas and laundries (8)1Based on ASHRAEStandard 52.1-1992orASHRAEStandard52.2-1999.2 Based on DOP test in accordance With MIL-STD-282 or based on ASHRAEStandard52.2-1999.3 HEPA filters at air outletor otherlocationswhen approvedby the AuthorityHaving Jurisdiction.4 HEPA filter located in the supplyduct which serves the positive-pressure isolation room or rooms may serve more than one supplyoutletandmorethan one positive-pressure isolation room. HEPA filter ora filter with minimum efficiency reporting value (MERV) of 17 installation shallbe designedand equipped to permit safe removal, disposal and replacement of filters.5 The numbers in parentheses representMER V rating based on ASHRAEStandard 52.2-1999.

TABLE 4-C - Filter Efficiencies for Central Ventilation andAir-Conditioning Systemsin SkilledNursing Facilities and Intermediate Care Facilities and Correctional Treatment Centers.1FilterEfficiency % Filter Bank(Minimum efficiency reportingArea Designation Minimum Number of Filter Banks valueMERVysNo. 11 No. 21

Al l areas for inpatientcare, treatment 2 30% 80%and/or diagnosis, and those areasproviding direct service orcleaning supplies (8) (13)Administrative, bulk storage, soiled 1 30%2holding, laundries and foodprep areas (8)1Based on ASHRAEStandard52.1-1992orASHRAEStandard52.2-1999.2 Filters are not required forevaporative coolers serving laundries and food preparation areas.3 The numbers in parentheses represent MERV rating based on ASHRAE 52.2-1999.

54


13/64

VENTILATION-AIR SUPPLY Table 4-1

TABLE 41 MINIMUM VENTILATION RATES IN BREATHING ZONE 2,3[ASHRAE 62.1 :Table 6-1]

Note: Ventilation air supply requirements for occupancies regulated by theCalifornia Energy Commission are found in the California Energy Code.Occupancy People Outdoor Area Outdoor Default OccupantCategory6 Air Rate Rp AirRateRA Density4(cfmlperson) (cfmlftZ) (peoplel1,OOO ftZ)Correctional FacilitiesCell 5 0.12 25Dayroom 5 0.06 30Guard stations 5 0.06 15Booking/waiting 7.5 0.06 50) Educational FacilitiesDay care (through age 4) 10 0.18 25Classrooms (ages 5-8) 10 0.12 25Classrooms (age 9 plus) 10 0.12 35Lecture classroom 7.5 0.06 65Lecture hall (fixed seats) 7.5 0.06 150Art classroom 10 0.18 20Science laboratories E 10 0.18 25Wood/metal shop 10 0.18 20Computer lab 10 0.12 25Media center A 10 0.12 25Music/theater/ dance 10 0.06 35Multi-use assembly 7.5 0.06 100University/College LaboratoriesFood and Beverage ServiceRestaurant dining rooms 7.5 0.18 70Cafeteria/fast food dining 7.5 0.18 100Bars, cocktail lounges 7.5 0.18 100GeneralConference/meeting 5 0.06 50Corridors 0.06Storage rooms B 0.12Hotels, Motels, Resorts,DormitoriesBedroom/livillg room 5 0.06 10Barracks sleeping areas 5 0.06 20) Lobbies/ pre-function 7.5 0.06 30Multipurpose assembly 5 0.06 120Office BuildingsOffice space 5 0.06 5Reception areas 5 0.06 30Telephone/data entry 5 0.06 60Main entry lobbies 5 0.06 10Miscellaneous spacesBankvaults/safe deposit 5 0.06 5Computer (not printing) 5 0.06 4Pharmacy (prep. area) 5 0.18 10Photo studios 5 0.12 10Shipping/receiving B 0.12

55


14/64

Table 4-1 cont. 2007 CALIFORNIA MECHANICAL CODE

TABLE 4-1 MINIMUM VENTILATION RATES IN BREATHING ZONE 2,3 (continued)[ASHRAE 62.1 :Table 6-1]TransportationwaitingWarehouses BPublic Assembly SpacesAuditorium seating areaPlaces of religious worshipCourtroomsLegislative chambersLibrariesLobbiesMuseums (children's)Museums/galleriesRetailSales (except as below)Mall common areasBarbershopBeauty and nail salonsPet shops (animal areas)SupermarketCoin-operated laundriesSports and EntertainmentSports arena (play area)Gym, stadium (play area)Spectator areasSwimming (pool & deck) CDisco/ dance floorsHealth club / aerobics roomHealth club/weight roomsBowling alley (seating)Gambling casinosGame arcadesStages, studios D

7.5

5555557.57.5

7.57.57.5207.57.57.5

7.5202020107.57.510

0.060.06

0.060.060.060.060.120.060.120.06

0.120.060.060.120.180.060.06

0.300.300.060.480.060.060.060.120.180.180.06

100

1501207050101504040

1540252510820

301501004010401202070

GENERAL NOTES FORTABLE 4.12 Smoking: This table applies to no-smoking areas. Rates for smoking-permitted spacesmust be determined using othermethods.3 Air Density: Volumetric airflow rates arebased on an air density of 1.2 kgda/m3 (O.075Ibda/ft3),which corresponds to

dry air at a barometric pressure of 101.3 kPa (1 atm) and an air temperature of 21C (70 OF). Rates shall be permitted to beadjusted for actual density bu t such adjustment is not required for compliancewith this chapter.4 DefaultOccupant Density: The default occupant density shall be used when actual occupant density is not known.6 Unlisted Occupancies: If the occupancycategory for a proposed space or zone is not listed, the requirements for thelisted occupancy category that is most similar in terms of occupant density, activities, and building construction shall beused.

ITEM-SPECIFIC NOTES FORTABLE 4.1A For high school and college libraries, use values shown for Public Spaces - Library.B Ratemay not be sufficientwhen stored materials include those having potentiallyharmful emissions.C Rate does no t allow for humidity control. Additional ventilation or dehumidificationmaybe required to removemoisture.D Rate does no t include special exhaust for stage effects, e.g., dry ice vapors, smoke.E No class of air has been established for this occupancy category.

56


15/64

- - - - - - - - - - - - - - - - - - - - - - - - ~ ~ - - - - - - - - - - - - - - -

Ceiling supply of cool air 1.0Ceiling supply ofwarm air and floor return 1.0

VENTILATION-AIR SUPPLY

TABLE 42Zone Air Distribution Effectiveness[ASHRAE 62.1 :Table 6-2]

AirDistribution Configuration

Table 4-2 & Table 4-3

Ez

Ceiling supply ofwarm air at least 15F (8C) above space temperature 0.8and ceiling return.Ceiling supply ofwarm air less than 15F (8C) above space 1.0temperature and ceiling return provided that the 150 pm (0.8 m/ s)supply air jet reaches to within 4.5 ft. (1.4 m) of floor level.Floor supply of cool air and ceiling return provided that the 150 pm 1.0(0.8 m/ s) supply jet reaches at least 4.5 ft. (1.4 m) above the floor.Floor supply of cool air and ceiling return, provided low velocity 1.2displacement ventilation achieves unidirectional flow and thermalstratification.Floor supply ofwarm air and floor return 1.0Floor supply ofwarm air and ceiling return 0.7Makeup supply drawn in on the opposite side of the room from the 0.8exhaust or return.Makeup supply drawn in near to the exhaust or return location 0.5Notes for Table 4-21. "Cool air" is air cooler than space temperature.2. "Warm air" is air warmer than space temperature.3. "Ceiling" includes any point above thebreathingzone.4. "Floor" includes any point below the breathing zone.5. As an alternative to using the a b o v ~ values, determine Ez in accordance withASHRAE Standard 129 for all airdistribution.configurations except unidirectional flow.

TABLE 4-3System Ventilation Efficiency. .[ASHRAE 62.1 :Table 6-3]Max (Zp).


16/64

Table 44 2007 CALIFORNIA MECHANICAL CODE

TABLE 44 Minimum Exhaust Rates[ASHRAE 62.1 :Table6-4]

Occupancy Category

Ar t classroomsAuto repair rooms 1BarbershopBeauty and nail salonsCell with toiletDarkroomsArena 2Kitchen - commercialKitchenettesLocker roomsLockerI dressing roomsParking garages 3Janitor, trash, recyclePet shops (animal areas)Copy, printing roomsScience lab classroomsToilets- public 4Toilet - private 5Woodwork shop I classroom

Exhaust Ratecfm/unit

50/7025/50

Exhaust Ratecfm/ft2

0.701.500.500.601.001.000.500.700.300.500.250.751.000.900.501.00

0.50

Exhaust RateLis-unit

25/3512.5/25

Exhaust RateL/s-m23.57.52.53.05.05.02.53.51.52.51.253.75.04.52.55.0

2.5Notes For Table 4-41 Standswhere engines are run shall have exhaust systems that directly connect to the engine exhaust and prevent escapeof fumes.2 The rates do not include exhaust from vehicles or equipment with internal combustion engines.3 Exhaust not required i f two or more sides comprisewalls that are at least 50% open to the outside.4 Rate is per water closetor urinal. Provide the higher rate where periods of heavy use are expected to occur, e.g., toilets intheatres, schools, and sports facilities.5 Rate is for a toiletroom intended to be occupied by one person at a time. For continuous system operationduring normalhours of use, the lowerratemaybe used. Otherwise use the higher rate.

58


17/64

CHAPTER 5EXHAUST SYSTEMS

Note: Portions of this chapter have been reproduced in their entirety from NFPA 96-1999.501.0 Scope.This chapter includes requirements for environmentalai r ducts, product-conveying systems, andcommercial hoods and kitchen ventilation.Part I - Environmental Air Ducts and Product

Conveying Systems

502.0 Definitions.For the purposes of this chapter , the followingdefinitions apply:ACCESS PANEL. A closure device used to cover anopening into a duct, an enclosure, equipment, or anappurtenance.AIR INTAKES. An opening in a building's envelopewhose purpose is to allow outside air to be drawninto the structure to replace inside ai r that isremoved by exhaust systems or to improve thequality of the inside air by providing a source of airhaving a lower concentration of odors, suspendedparticles, or heating content.AIR POLLUTION CONTROL DEVICES. Equipmentand devices used for the purpose of c leaning airpassing through them or by them in such a manner asto reduce or remove the impurities contained therein.APPURTENANCE. An accessory or a subordinatepart that enables the primary device to perform orimprove its intended function.AUTOMATIC. That which provides a functionwithout the necessity of human intervention. [NFPA96: 3.3.6]BAFFLE PLATE. An object placed in or near anappliance to change the direction or retard the flowof air, air-fuel mixtures, or flue gases.CERTIFIED. A formally stated recognition andapproval of an acceptable level of competency,acceptable to the Authority Having Jurisdiction.[NFPA 96 3.3.9]CLASSIFIED. See Listed.CLEARLY IDENTIFIED. Capable of beingrecognized by a person of normal vision withoutcausing uncertainty and indecisiveness about thelocation or operating process of the identified item.CLOSED COMBUSTIBLE CONSTRUCTION.Combustible building construction, including walls,

structural framing, roofs, roof ceilings, floors, andfloor-ceiling assemblies continuously enclosing agrease duct on four sides where one or more sidesrequire protection per Section 507.2.COMBUSTIBLE MATERIAL. Material subject to anincrease in combustibility or flame-spread ratingbeyond the limits established in the definition ofLimited-Combustible Material.COMMERCIAL FOOD HEAT-PROCESSINGEQUIPMENT. Equipment used in a foodestablishment for heat-processing food or utensilsand that produces grease vapors, s team, fumes,smoke, or odors that are required to be removedthrough a local exhaust ventilation system.COMPENSATING HOOD. A hood that has anoutside-air supply with ai r delivered below orwithin the hood. When makeup air is diffuseddirectly into the exhaust within the hood cavity, itbecomes a short-circuit hood.CONCEALED SPACES. That portion(s) of a buildingbehind walls, over suspended ceilings, in pipe chases,attics, and elsewhere whose size might normallyrange from 1-3/4 inch (44.45 mm) stud spaces toeight (8) foot (2.44 m) interstitial truss spaces and thatmight contain combustible materials such as buildingstructural members, thermal and/ or electricalinsulation, and ducting. Such spaces have sometimesbeen used as HVAC plenum chambers.CONTINUOUS ENCLOSURE. A recognized architectural or mechanical component of a building having afire resistance rating as required for the structure andwhose purpose is to enclose the vapor removal ductfor its full length to its termination point outside thestructure without any portion of the enclosure havinga fire resistance rating less than the required value.CONTINUOUS WELD. A metal-joining method thatproduces a product without visible interruption orvariation in quality. For the purpose of the definition,it specifically includes the exhaust compartment ofhoods and welded joints of exhaust ducts, yetspecifically does not include filter support frames orappendages inside hoods.COOKING APPLIANCE FLUE OUTLET. Theopening or openings in a cooking device wherevapors, combustion gases, or both leave the cookingdevice. There might or might not be ductworkattached to this opening.

59


18/64

502.0

DAMPER. A valve o r plate within a duct or it sterminal components for controlling draft or the flowof gases, including air.DETECTION DEVICES. Electrical, pneumatic,thermal, mechanical, or optical sensing instruments,or subcomponents of such instruments, whosepurpose is to cause an automatic action upon theoccurrence of some preselected event. In the contextof this document, the event in question could beexcessive temperature or flame, and the action couldbe the operation of a fire-extinguishing system.DIPS. Depression or cuplike places in horizontalduct runs in which liquids could accumulate.DISCHARGE. The final portion of a duct or p ipewhere the product being conveyed is emptied orreleased from confinement; the termination point ofthe pipe or duct.EASILY ACCESSIBLE. See Accessible, Readily inSection 203.0, Chapter 2.ENVIRONMENTAL AIR DUCT. Ducting used forconveying air at temperatures not exceeding 250F(121OC) to or from occupied areas of any occupancythrough other than hea ting or air-conditioningsystems, such as ventilation for human usage,domestic kitchen range exhaust, bathroom exhaustducts, and domestic-type clothes dryer exhaust ducts.FACTORY-BUILT GREASE ENCLOSURES. A listedfactory-built grease duct enclosure system evaluatedfor reduced clearances to combustibles, and as analternative to a ductwith its fire-rated enclosure.FIELD-APPLIED GREASE DUCT E(\,jCLOSURES.A listed system evaluated for reduced clearances tocombustibles, and as an alternative to a duct with itsfire-rated enclosure. -FLAMMABLE VAPOR OR FUMES. The concentration of flammable constituents in air that exceedstwenty-five percent (25%) of its lower flammabilitylimit (LFL).FIRE BARRIER WALL. A wall assembly complyingwith the requirements of NFPA 221, Standard forFire Walls and Fire Barrier Walls, having a fireresistance rating of four (4) hours.FIRE PARTITION. An interior wall or parti tion of abuilding that separates two areas and serves to restrictthe spread of fire but does not qualify as a fire wall.FIRE RESISTANCE RATING. A relat ive value inminutes or hours assigned to materials or assembliesthat have withstood a fire exposure as established inaccordance with NFPA 251, Standard Methods ofTests of Fi re Endurance of Building Constructionand Materials.

60


FUME INCINERATORS. Devices utilizing intenseheat or fire to break down and/ or oxidize vaporsand odors contained in gases or air being exhaustedinto the atmosphere.FUSIBLE LINK. A form of fixed-temperature heatdetecting device sometimes employed to restrain theoperation of an electrical or mechanical control untilits designed temperature is reached. Such devices areto be replaced following each operation.GREASE. Rendered animal fat, vegetable shortening,and other such oily matter used for the purposes ofand resulting from cooking and/or preparing foods.Grease might be liberated and entrainedwith exhaustair or might be visible as a liquid or solid.GREASE DUCTS. A containment system fo r thetransportation of air and grease vapors that is designedand installed to reduce the possibil ity of theaccumulation of combustible condensation and theocCllIrence of damage if a fire occurs w i the system.GREASE FILTER. A removable component of thegrease removal system designed to capture greaseand direct it to a safe collection point before it entersa duct system. Filters are expected to minimize theprojection of flames downstream when attacked byflame on the upstream s ide and are expected tomaintain their strength, shape, and integrity whenexposed to the anticipated rough handling, cleaning,and service found in the field.GREASE FILTER, MESH-TYPE. A general-purposeair filter designed to collect and retain lint and greasefrom the air passing through it. This type of filter isnot tested, listed, or acceptable for commercialcooking operations due to the increased fire hazard.GREASE REMOVAL DEVICES. A system ofcomponents designed for and intended to processvapors, gases, and/ or air as it is drawn through suchdevices by collecting the airborne grease particlesand concentrating them for further: action at somefuture time, leaving the exiting air with a loweramount of combustible matter.GREASETIGHT. Constructed and performing insuch a manner as not to permi t the passage of anygrease under normal cooking conditions.HIGH BROILER. SeeUpright Broiler.HIGH LIMIT CONTROL. An operating deviceinstalled in and serving as an integral component ofa deep-fat fryer. It s purpose is the secondarylimitation of t e m p e r a t u r ~ allowed by the cookingoperation and, i f that temperature is exceeded, theautomatic interruption of the thermal energy input.HOOD. An air-intake device connected to a mechanicalexhaust system for collecting and removing grease,


19/64

.. _ - - - - - ~ ~ ~ ~ ~ -

EXHAUST SYSTEMS 502.0

j

)

vapors, fumes, smoke, steam, heat, or odors fromcommercial food heat-processing equipment.Fixed Baffle. A l isted unitary exhaust hooddesign where the grease removal device is anonremovable assembly that con ta in s anintegral fire-activated water-wash fireextinguishing system listed for this purpose.Type I is a kitchen hood for collecting andremoving grease and smoke.Type II is a geiteral ki tchen hood for collectingand removing steam, vapor, heat, or odors.

INTERCONNECTED. Mutually assembled toanother component in such a manner tha t theoperation of one directly affects the other or that thecontents of one specific duct system are allowed toencounter or contact the products being moved byanother duct system.LABELED. Equipment or materials to which hasbeen attached a label, symbol, or other identifyingmark of an organization that is accep table to theAuthority Having Jurisdiction and concerned withproduct evaluation, that maintains periodicinspection of production of labeled equipment ormaterials, and by whose labeling the manufacturerii:ldicah;?s compliance with appropriate standards orperformance in a specified manner.LIMITED-COMBUSTIBLE MATERIAL. A buildingconstruction material that does not comply with thedefinition of noncombustible'material, that, in theform in which i t is used, has a potentia l heat valuenot exceeding 3,500 Btu/lb. (8141 kJ /kg)(see NFPA259, Standard Test Method for Potential Heat of .Building Materials), and that complies with either ofthe following (A) or (B). Materials subject to anincrease in combustibility or flame-spread ratingbeyond the limits herein established through theeffects of age, moisture, or other atmosphericconditions shall be considered combustible.

(A) Materials having a structural base ofnoncombustible material, with a surfacingno t exceeding a thickness of 1/8 inch (3.2mm), and with a flame-spread rating no tgreater than fifty (50),

(B) Materials in the form and thickness used,other thim as described in (A), having neithera flame-spread rating greater than twentyfive (25) nor evidence of continuedprogressive combustion and of such composition thatsurfaces tha t would be exposed by cuttingthrough the material on any plane wouldhave neither a flame-spread rating greaterthan twenty-five (25) no r evidence of,continued progressive combustion.

L1QUIDTIGHT. Constructed and performing in such amanner as not to permitthe passage of any liquid at anytemperature.~ I S T E D . Equipment, materials, or services included~ a l is t published by an organiza tion that i sacceptable to the Authority Having Jurisdiction andconcerned with evaluation of products or services,that maintains periodic inspection of production oflisted equipment ormaterials or periodic evaluationof services, and whose listing states that th eequipment,'material, or service meets identifiedstandards or has been tested and found suitable for aspecified purpose.NONCOMBUSTIBLE MATERIAL. A material that,in the form i n whi ch it is u se d a nd under th econditions anticipated, will not ignite, burn, supportcombustion, or release flammable vapors whensubjected to fire or heat. Materials that are reportedas passing ASTM E 136, Standard Test Method forBehavior of Materials in a Vertical Tube Furnace at750C, shall be considered noncombustible materials.OPEN ,COMBUSTIBLE CONSTRUCTION. Combustiblebuilding constructions including wall, structuralframing, roof, roof ceiling, floor, and floor ceiling'assemblies adjacent to a greas e duc t on three o rfewer s ides where one or more s ides requireprotection per Section 507.2.PITCHED. To be fixed or set at a desired angle orinclination.PRODUCT-CONVEYING DUCT. Ducting used forconveying solid particulates, such as refuse, dust,fumes, and smoke; liquid particulate matter, such asspray residu'e, mists, and fogs; vapors, such asyapors from flammable or corrosive liquids; noxiousand toxic gases; and air at temperatures exceeding250 0P (121C). ' 'QUALIFIED. A competent and capable person orcompany that has met the requirements and trainingfor a given field acceptable to the Authority HavingJurisdiction. [NPPA 96: 3.3.37]RECIRCULATING SYSTEMS. Systems for control ofsmoke or grease-laden vapors from commercialcooking equipment that do not exhaust to the outside.REMOVABLE. Capab le o f being transferred toanother location with a limited application of effortand tools.REPLACEMENT AIR. See Air, Makeup in Section203.0, Chapter 2.SALAMANDER BROILER. See Upright Broiler.SHALL. Indicates a mandatory requirement.SINGLE HAZARD AREA. As considered in theapplicable e x t i n g u i ~ h i n g system' standard (see

61


20/64

502.0 - 503.2

Section 513.2) or as determined by the AuthorityHaving Jurisdiction.SOLID COOKING FUEL. Any sol id , organic ,consumable fuel such as briquettes, mesquite,hardwood, or charcoal.SOLID-FUEL COOKING EQUIPMENT. Cookingequipment that is fired with solid cooking fuel. Thisequipment includes ovens, tandoori charcoal pots,grills, broilers, rotisseries, barbecue pits, or any othertype of cooking equipment that derives all or part ofits heat source from the burning ofsolid cooking fuel.SOLVENT. A substance (usually liquid) capable ofdisso lv ing or d ispe rs ing another substance; achemical compound designed and used to convertsolidified grease into a liquid or semiliquid state inorder to facilitate a cleaningoperation.SPARK ARRESTER. A device or method thatminimizes the passage of airborne spa rks andembers into a plenum, duct, and flue.STANDARD. A document, the main text of whichcontains only mandatory provisions using the word"shall" to indicate requirements and that is in a formgenerally suitable for mandatory reference by anotherstandard or code or for adoption into law.Nonmandatory provisions shall be located in anappendix, footnote, or fine-print note and are not to beconsidered a part of the requirements of a standard.TERMINATION. The final or intended end portion ofa duct system that is designed and functions to fulfillthe obligations of the system in a satisfactorymanner.THERMAL RECOVERY UNIT. A device or series ofdevices whose purpose is to reclaim only the heatcontent of air, vapors, gases, or fluids that are beingexpelled through the exhaust system and to transferthe thermal energy so reclaimed to a locationwhereby a useful purpose can be served.TRAINED. A person who has become proficient inperforming a skil l reliably and safely throughinstruction and practice/ field experience acceptableto the Authority Having Jurisdiction. [NFPA 963.3.47]TRAP. A cuplike or U-shaped configuration locatedon the inside of a duct system component whereliquids can accumulate.UPRIGHT BROILER. An appliance u sed in thepreparation of food whereby foods are exposed tointense radiant heat, and perhaps to convective heat,with the food and the radiant source not l imited to ahorizontal mode.502.1 Product-Conveying Ducts - Classification.Product -conveying duc ts sha ll be classifiedaccording to their use, as follows:

62

2007 CALIFORNIA MECHANICAL CODEClass 1. Ducts conveying nonabrasives, such assmoke, spray, mists, fogs, noncorrosive fumesand gases, light fine dusts, or powders.Class 2. Ducts conveying moderately abrasiveparticulate in l ight concentrations, such assawdust a nd gra in du st, and buffing andpolishing dust.Class 3. Ducts conveying Class 2 materials inhigh concentrations and highly abrasivematerials in low concentrations, such asmanganese, steel chips, and coke.Class 4. Ducts conveying highly abrasivematerial in high concentrations.Class 5. Ducts conveying corrosives, such asacid vapors.

503.0 Motors, Fans, and Filters.503.1 General. Motors and fans shall be sized toprovide the required air movement. Motors in areasthat contain flammable vapors or dusts shall be of atype approved for such environments. A manuallyoperated remote control installed at an approvedlocation shall be provided to shut off fans or blowersin flammable vapor or dust systems. Electricalequipment used in operations that generate explosiveor flammable vapors, fumes, o r dus ts shall beinterlocked with the ventilation system so that theequipment cannot be operated unless the ventilationfans are in operation. Motors for fans used to conveyflammable vapors or dusts shall be located outsidethe duct or shall be protected with approved shieldsand dustproofing. Motors and fans shall be accessiblefor servicing andmaintenance.503.2 Fans. Parts of fans in contact with explosive orflammable vapors, fumes, or dus ts shall be ofnonferrous or nonsparking materials or their casingshall be lined or constructed of such material. Whenthe size and hardness of materials passing through afan could produce a spark, both the fan and thecasing shall be of nonsparking materials. When fansare required to be spark-resistant, their bearingsshall not be within the airstream, and all parts of thefan shall be grounded. Fans in systems handlingmaterials that are likely to clog the blades, and fansin buffing or woodworking exhaust systems, shall beof the radial-blade or tube-axial type.

Equipment used to exhaust explosive orflammable vapors, fumes, or dusts shall bear anidentification plate stating the ventilation rate forwhich the systemwas designed.

Fans located in systems conveying corrosivesshall be ofmaterials that are resistant to the corrosiveor shall be coated with corrosion-resistantmaterials.


21/64

J

EXHAUST SYSTEMS

503.3 Air filters shall be listed units. Liquid adhesivecoatings used on filters shall have a f lash point of350F (177C) or higher, as determined by the FireCode standards.~ 0 4 . 0 Environmental Air Ducts.504.1 Makeup and Exhaust-Air Ducts. Environmental air ducts not regulated by other provisions ofthis code shall comply with this section. Ducts shallbe substantially airtight and shall comply with theprovisions of Chapter 6. Exhaust ducts shall no textend into or through ducts or plenums. Exhaustducts shall terminate outside the building and shallbe equipped with back-draft dampers. [For OSHPD1, 2 & 4J Exception: Back-draft dampers are not requiredwhen the exhaust fan must operate continuously.Environmental air ducts that have an alternatefunction as a, part of an approved smoke-controlsystem do not r equire d esign as Class 1product-co:p.veying ducts.504.2 Domestic Range Vents. Ducts used for domestickitchen range ventilation shall be of metal and shallhave smooth interior surfaces. Ducts for domestic rangehoods shall only serve cooking appliances.

Exception: Ducts for domes ti c k it chendowndraft grill-range ventilation installed undera concrete s lab floor may be of approvedSchedule 40 PVC provided:(1) The under-floor trench in which the duct isinstalled shall be completely backfilled with

Eland or gravel.(2) Not more than one (1) inch (25.4 mm) of six

(6) inch diameter (152 mm) PVC couplingmay protrude above the concrete floor surface.

(3) PVC pipe joints shall be solvent cemented toprovided an air and grease-tight duct.(4) The duct s ha ll t erminat e above g rade

outside the building and shall be equippedwith a back-draft damper.504.3 Clothes Dryers.

504.3.1 Moisture Exhaust Ducts. Moistureexhaust ducts 'shall terminate on the outside ofthe building and shall be equipped with a backdraft damper. Screens shall not be installed at theduct termination. Ducts for exhausting clothesdryers shall not be connected or installed withsheet metal screws or other fasteners that willobstruct the flow. Clothes dryer moisture exhaustducts shall not be connected to a gas ventconnector, gas vent; or chimney, and shall onlyserve clothes dryers. Clothes dryer moisture

503.3- 504.5exhaust ducts shall no t extend into or throughducts or plenums.504.3.2 Domestic Clothes Dryers. When acompartment or space for a domestic clothesdryer is provided, a minimum four (4) inchdiameter (102 mm) moisture exhaust duct ofa pp roved mate ria l sha ll be installed inaccordancewith this section and Section 504.0.

When a closet is designed for the installationof a clothes dryer, a minimum opening of 100square inches (64,516 mm2) formakeup air shall beprovided in the door orby other approvedmeans.

504.3.2.1 Domestic Dryer Vents. Domesticclothes dryer moisture exhaust ducts shallbe of metal and shall have smooth interiorsurfaces.

Exception: Listed clothes dryer transitionducts not more than six (6) feet (1,829 mm)in length may be used in connectionwith domestic dryer exhausts.

Flexible clothes dryer transit ionducts shall not be concealed withinconstruction.

504.3.2.2 Length Limitation. Unlessotherwise permitted or required by the dryermanufacturer's installation instructions andapproved by the Authority HavingJurisdiction, domes ti c d ryer moi stur eexhaust ducts shall not exceed a totalcombined horizontal and vertical length offourteen (14) feet (4,263 mm), including two(2) 90 degree (1.57 rad) elbows. Two (2) feet(610 mm) shall be deduc ted for each 90degree (1.57 rad) elbow in excess of two.

504.3.3 Commercial Clothes Dryers. Commercial dryer exhaust ducts shall be installed inaccordance with their listings. The installation ofcommercial clothes dryer exhaust ducts shallcomply with the appliance manufacturer'sinstallation instructions.

504.4 Heat (Energy) Recovery Ventilators.504.4.1 Heat (energy) recovery ventilators shallbe installed in accordance with their listings andcomply with the appliance manufacturer'sinstallation instructions. Heat (energy) recoveryvent'ilator ducts shall comply with theprovisions of Chapter 6.

504.5 Termination of Environmental Air Ducts.Environmental air duct exhaust: three (3) feet (914mm)rom property line; three (3) feet (914 mm) fromopenings into the buildfug.

63


22/64

504.6 - Table 5-1504.6 Gypsum Wallboard Ducts. Bathroom andlaundry room exhaust ducts may be of gypsumwallboard subject to the limitations of Section 602.1.505.0 Design of Product-Conveying VentilationSystems.505.1 General. A mechanical ventilation or exhaustsystem shall be installed to control, capture, andremove emissions generated from product use orhandling when requi red by the Building Code orFire Code a nd when such emiss ions resul t in ahazard to life or property. The design of the systemshall be such that the emissions are confined to thearea in which they are generated by air currents,hoods, or enclosures and shall be exhausted by aduct system to a safe location or treated by removingcontaminants. Ducts conveying explosives orflammable vapors, fumes, or dusts shall extenddirectly to th e exterior of the building withoutentering other spaces and shall not extend into orthrough ducts and plenums.

Exception: Ducts conveying vapor or fumeshaving flammable constituents less than 25percent of their lower flammability limit (LFL)may pass through other spaces.505.1.1 Incompatible materials shall no t beconveyed in the same system.505.1.2 In systems conveying flammablevapors, gases, or mists, the concentration shallnot exceed 29 percent of the lower flammabilitylimit (LFL).

Exception: Higher concentrations shall bepermitted if the exhaust system is designedand pro tected in accordance with the

2007 CALIFORNIA MECHANICAL CODEStandard on Explosion Prevention Systemsin Chapter 17, using one or more of thefollowing techniques:(a) Combustible concentration reduction(b) Oxidant concentration reduction(c) Deflagration suppression(d) Deflagration presSUre containmentSeparate and distinct systems shall be provided forincompatiblematerials.

Contaminated air shall not be recirculated tooccupied areas unless contaminants have beenremoved. Air contaminated with explosive orflammable vapors, fumes, or dusts; flammable or toxicgases; or radioactivematerial shall not be recirculated.505.2 Minimum Velocities and Circulation. Thevelocity and circulation of air in work areas shall besuch that contaminants are captured by an airstreamat the area where the emissions are generated andconveyed into a product-conveying duct system.Mixtures within work areas where contaminants aregenerated shall be diluted below 25 percent of theirlower explosive limit or lower flammability limitwith air tha t does not contain other contaminants.The velocity of air within the duct shall be not lessthan set forth in Table 5-1.

Systems for removal of vapors, gases, and smokeshall be designed by the constant velocity or equalfriction methods. Systems conveying particulate mattershall be designed employing the constant velocitymethod. Systems conveying explosive or radioactivematerials shall be prebalanced through duct sizing.Other systems may be designed with balancing devicessuch as dampers. Dampers provided to balance airflowshall be provided with securely fixed minimumposition blocking devices to prevent restricting flowbelow the required volume or velocity.

TABLE 5-1Minimum Conveying Velocities

Feet per Minute (m/s)Vapors, gases, smoke, fumes Any

Fine light dusts, such as cotton, lint, and wood flour (100 mesh and under) 2,000 (10.2)Dry dusts; powders, such as fine rubber molding power, soap dust 2,5001 (12.7)'Industrial dustsAverage dusts, such as sawdust, grinding dust, coal dust 3,500 (17.8)Heavy dusts, such as metal turnings, lead dusts 4,000 (20.3)Moist dusts and chips, such as lead dust with chips, sticky buffing lint,quick-lime dust 4,500 (22.9)Note:'The velocity for aluminum and magnesium powder shall be not less than 4,000 feet per minute (20.3 m/s).

64


23/64

j

EXHAUST SYSTEMS

505.;3 Makeup Air. Makeup air shall be provided toreplenish air exhausted by the ventilation system.Makeup-ai r in takes shall be located so as to avoidrecirculation of contaminated air within enclosures.505.4 Hoods and Enclosures. Hoods andenclosures shall be used when con taminant soriginate in a concentrated area. The design of thehood or enclosure shall be such that air currentscreated by the exhaust systems will capture thecontaminants and transport them direc tl y to theexhaust duct. The volume of air shall be sufficient todilute explosive or flammable vapors, fumes, ordusts as set forth in Section 505.2. Hoods of steelshall have a base metal thickness not less than 0.027inch (0.69 mm) (No. 22 gauge) for Class 1 and Class 5metal duct systems; 0.033 inch (0.84 mm) (No. 20gauge) for hoods serving a Class 2 duct system; 0.044inch (1.12 mm) (No. 18 gauge) for hoods serving aClass 3 duct system; and 0.068 inch (1.73 mm) (No.14gauge) for hoods serving a Class 4 duct system.Approved nonmetallic hoods and duct systemsmay be used for Class 5 corrosive systems when thecorrosive mixture is nonflammable. Metal hoodsused with Class 5 duct systems shall be protectedwith suitable corrosion-resistant material. Edges ofhoods shall be rounded. The minimum clearancebetween hoods and combustible construction shallbe the clearance required by the duct system.505.12 Pharmacies - Compounding Area ofParenteral Solutions. lCA - Board of Pharmacy]The pharmacy shall have a designated area for thepreparation ofsterile products for dispensing which shall:

1. Be v e n t i l a t e ~ in a manner not interfering withlaminar air flow.Note: For additional pharmacy building standardrequirements, see Chapter 12, California BuildingCode.505.12.1 Pharmacies -laminar flow biologicalsafety cabinet. lCA - Board of Pharmacy] Inall pharmacies preparing parenteral cytotoxic agents,all compounding shall be conducted within a certifiedClass I I Type A or Class II Type B vertical laminarairflow hood with bag in - bag out design. Thepharmacy must ensure that contaminated air plenumsthat are under positive air pressure are leak tight.Note: For additional pharmacy building standardrequirements, seeChapter 12, California Building Code.

506.0 Product-Conveying Ducts.506.1 Materials. Materials used in product conveying duct systems shall be suitable for theintended use and shall be ofmetal.

Exceptions:(1) Asbestos-cement,concrete, clay, or ceramic

505.3 - 506.2materials may be used when it is shown thatthese materials will be equivalent to metalducts installed in accordance with thischapter.

(2) Ducts serving a Class 5 sys tem may beconstructed of approved nonmetallicmaterial when the corrosive characteristicsof the mater ia l being conveyed make ametal system unsuitable a nd wheh themixture being conveyed is nonflammable.Approved nonmetallic material shall beeither a listed product haVing a flame-spreadindex of twenty-five (25) or less and a smokedeveloped rating of fifty (50) or less on bothinside and outside surfaces without evidenceof continued progressive combustion, orshall have a flame-spread index of twentyfive (25) or less and shall be installed withan automatic fire-sprinkler protection systeminside the duct.

(3) Ducts u se d in central vacuum cleaningIystems within a dwelling unit shall beconstructed of materials in compliance withth e applicable standards referenced inChapter 17. Penetrations of fire walls orfloor-ceiling or roof-ceiling assemblies shallcomply with the BuildingCode.Copper or ferrous pipes o r condu it sextending from within the separat ionbetween a garage and dwelling unit to thecentral vacuuming unit may be used.

Aluminum ducts shall no t be used in systemsconveying flammable vapors, fumes, or explosivedusts, nor in Class 2, 3, or 4 systems. Galvanizedsteel and aluminum ducts shall not be used when thetemperature of the material being conveyed exceeds400 0P (205C).Metal ducts used in Class 5 systems that arenot resistant to the corrosiveness of the product shall

be protected with appropriate corrosion-resistantmaterial.506.2 Construction. Ducts used for conveyingproducts shall be of substantial airtight constructionand shall no t have openings o ther than thoserequired fo r operation and maintenance of thesystem. Ducts constructed of steel shall comply withTable 5-5 or 5-6.

Exceptions:(1) Class 1 product-conveying ducts thatoperate at less than four (4) inches water

column (995.6 Pa) negative pressure andconvey noncorrosive, nonflammable, andnonexplosive materials at temperatures not

65


24/64

506.2 - 506.7

exceeding 250F (121C) may be constructedin accordance with Tables 6-1, 6-2, 6-3, 6-4,6-5, 6-7, 6-8, or, with prior approval, UMCStandardNo. 6-2.

(2) Ducts used in central vacuuming systemswithin a dwelling unit shall be constructedof materials in compliance with th eapplicable standards referenced in Chapter17. Penetrations of fire-resistive walls, orfloor-ceiling or roof-ceiling assemblies shallcomply with the Building Code. Copper orferrous pipes or conduit extending fromwithin the separation between a garage anddwelling unit to the central vacuum unitmaybe used.

The use of rectangular duc ts conveyingparticulates sha ll be subject to approva l of th ebuilding official. The design of rectangular ductsshall consider the adhesiveness and buildup ofproducts being conveyed within the duct.Aluminum construction may be used in Class 1duct systems only. The thickness of aluminum ductssha ll be at least two Brown and Sharpe gaugesthicker than the gauges required for steel ducts setforth in Tables 5-5 and 5-6.506.3 Fittings. Fittings in Class 2, 3, and 4 systemsshall be not less than two gauges thicker than thethickness required for straight runs. Flexible metallicduct may be used for connecting ductwork tovibrating equipment. Duct systems subject to widetemperature fluctuations shall be provided withexpansion joints.

Branches shall connect to main ducts at the largeend of transitions at an angle not exceeding fortyfive (45) degrees (0.79 rad).

Except for ducts used to convey noncorrosivevapors with no particulate, accessible cleanouts shallbe provided at ten (10) foot (3,048 mm) intervals andat changes in direction. Access openings shall also beprovided for access to spr inkler s and otherequipment within the duct that require servicing.506.4 Explos ion Venting . Ducts conveyingexplosive dusts shall have explosion vents, openingsprotected by antiflashback swing valves, or rupturediaphragms. Openings to relieve explosive forcesshall be located outside the building. When reliefdevices cannot provide sufficient pressure relief,ductwork shall be designed to withstand an internalpressure of not less than 100 pounds per square inch(689 kPa).

If a room or building contains a dust explosionhazard that is external to protected equipment, asdefined in 2.2.3.1 of NFPA 654, such areas shall be

66


provided with deflagration venting to a safe outsidelocation.506.5 Supports. Spacing of supports for ducts shallnot exceed tWelve (12) feet (3,658 mm) for eight (8)inch (203 mm) ducts nor twenty (20) feet (6,096 mm)for larger ducts, unless justified by the design.

506.5.1 Duct supports shall be designed tocarry the weight of the duct half filled withmaterial. Where sprinkler protection is providedin the duct, the hanger's design shall include theweight of the duct half filled with water or withthe material being conveyed, whichever has thehigher density. Loads shall not b e placed onconnecting equipment.

Exception: Where adequate drainage isprovided, the weight of the water shall notrequire consideration.506.5.2 Hangers and supports exposed tocorrosive atmospheres shall be Type 316 S5 orequivalent.506.5.3 To avoid vibration and stress on theduct, hangers and supports shall be securelyfastened to the building or structure.506.5.4 Hangers and supports shall be designedto allow for expansion and contraction. [NFPA91:2.