HCD DSA OSHPD Adopting Agency BSC SFM - IAPMO

1 592013 california MECHANICAL CODECALIFORNIA MECHANICAL code MATRIX ADOPTION TABLECHAPTER 4 VENTILATION AIR SUPPLY(Matrix Adoption Tables are non-regulatory, intended only as an aid to the user. See Chapter 1 for state Agency authority and building application.) Adopting AgencyBSCSFMHCDDSAOSHPDBSCCDPHAGRDWRCASL SLC121-ACACSSSS/CC1234 Adopt Entire ChapterXXAdopt Entire Chapter as amended(amended sections listed below)XXXXA dopt only those sections that arelisted ONLY602013 california MECHANICAL CODEREAD Applicability. This chapter contains requirements forventilation air supply,exhaust, and makeupair requirementsfor occupiablespaces within a building.[ OSHPD 1, 2, 3 & 4]See Sections through [SFM] Air filters shallcomply with all requirements of Part 12, Title 24, Chapter 12-71, SFM Standard Ventilation Air. [Not permitted for OSHPD 1, 2, 3 &4] General Requirements.[Not permitted for OSHPD 1,2, 3 & 4] Occupiablespaces listed in Table shall bedesigned to have ventilation (outdoor) air for occupants inaccordance with this chapter.

2 Ventilation air supply require-ments for occupancies regulated by the california EnergyCommission are found in the california Energy Construction outdoor airventilation rate and air distribution assumptions made inthe design of the ventilation system shall be clearly iden-tified on the construction Dwelling. Requirements for ventilation air ratefor single family dwellings shall be in accordance withthis chapter or ASHRAE Natural ventilation systems shallbe designed in accordance with this section and shall includemechanical ventilation systems designed in accordance withSection and Section Exceptions:(1) An engineered natural ventilation system whereapproved by the Authority Having Jurisdiction need notcomply with Section (2) A mechanical ventilation system is not required wherenatural ventilation openings comply with the require-ments of Section and are permanently open or havecontrols that prevent the openings from being closedduring occupancy.

3 (3) A mechanical ventilation system is not required wherethe zone is not served by heating or cooling equipment.[ASHRAE ] Location and Size of spaces shall be permanently open by way ofoperable wall openings directly to the outdoors, the open-able area of which is a minimum of 4 percent of the netoccupiable floor area. Where the openings are coveredwith louvers or otherwise obstructed, openable area shallbe based on the free unobstructed area through theopening. Where interior spaces without direct openingsto the outdoors are ventilated through adjoining rooms,the opening between rooms shall be permanently unob-structed and have a free area of not less than 8 percent ofthe area of the interior room nor less than 25 square feet( m2). [ASHRAE ] Control and means to openrequired operable openings shall be readily accessibleto building occupants where the space is shall be designed to coordinate operation of thenatural and mechanical ventilation systems.

4 [ ] Mechanical natural ventilation isnot permitted by this sectionor the building code , mechanicalventilation systems shall be designed, constructed, andinstalled to provide a method of supply air and exhaust ventilation systems shall include controls, manualor automatic, that enable the fan system to operate whereverthe spaces served are occupied. The system shall be designedto maintain minimum outdoor airflow as required by under any load Outdoor Air Intake outdoor-airintakes shall be covered with a screen having not less than 1 4inch ( mm) openings, and shall have not more than 1 2inch( mm) Weather air intakes thatare part of the mechanical ventilation system shall bedesigned to manage rain entrainment, to prevent rainintrusion, and manage water from snow in accordancewith ASHRAE Bathroom Exhaust Fans. [HCD 1 & HCD 2] Eachbathroom shall be mechanically ventilated in accordance withDivision of the california Green Building Standards code (CALG reen).

5 Ventilation Rates. [Not permitted for OSHPD 1, 2, 3& 4] design outdoor air intake flow rate for aventilation system shall be determined in accordance withSection through Section Zone parameters shall be deter-mined in accordance with Section through [ASHRAE ] Breathing Zone Outdoor designoutdoor airflow required in the breathing zone of theoccupiable space or spaces in a zone, , the breathingzone outdoor airflow(Vbz), shall be determined in accor-dance with Equation Vbz= Rp Pz+ Ra Az(Equation )Where:Az=zone floor area: the net occupiable floor area ofthe zone in square population: The largest number of peopleexpected to occupy the zone during typical california MECHANICAL CODECHAPTER 4 VENTILATION AIR SUPPLYREAD ONLY62 Where the number of people expected to occupythe zone fluctuates, Pzshall be permitted to beestimated based on averaging approachesdescribed in Section Where Pzcannot beaccurately predicted during design, it shall be esti-mated based on the zone floor area and the defaultoccupant density listed in Table airflow rate required per person as deter-mined from Table airflow rate required per unit area asdetermined from Table [ ] Zone Air Distribution zoneair distribution effectiveness (Ez) shall be determinedusing Table [ASHRAE ] Zone Outdoor design zoneoutdoor airflow (Voz), , the outdoor airflow that shallbe provided to the zone by the supply air distributionsystem, shall be determined in accordance with [ASHRAE ]Voz= Vbz/Ez(Equation )

6 Single-Zone one air handler suppliesa mixture of outdoor air and recirculated air to only one zone,the outdoor air intake flow (Vot) shall be determined in accor-dance with Equation [ASHRAE ]Vot= Voz(Equation ) One Hundred Percent Outdoor Air air handler supplies only outdoor air to one or morezones, the outdoor air intake flow (Vot) shall be determined inaccordance with Equation [ASHRAE ]Vot= all zonesVoz(Equation ) Multiple-Zone Recirculating one airhandler supplies a mixture of outdoor air and recirculatedreturn air to more than one zone, the outdoor air intake flow(Vot) shall be determined in accordance with Section Section [ASHRAE ] Primary Outdoor Air primaryoutdoor air fraction(Zpz) shall be determined for venti-lation zones in accordance with Equation [ASHRAE ]Zpz= Voz/Vpz(Equation )Vpzis the primary airflow to the ventilation zone fromthe air handler, including outdoor air and recirculatedreturn air.

7 [ASHRAE ] System Ventilation systemventilation efficiency(Ev) shall be determined in or [ASHRAE ] Uncorrected Outdoor Air designuncorrected outdoor air intake(Vou) shall be determinedin accordance with Equation (1).[Equation (1)]Vou= D all zones(Rp Pz)+ all zones(Ra Az)The occupant diversity, D, shall be permitted to beused to account for variations in occupancy within thezones served by the system. The occupancy diversity is determined in accordancewith Equation (2).D = Ps/ all zonesPz[Equation (2)]Where the system population (Ps) is the total populationin the area served by the system. Alternative methodsshall be permitted to be used to account for populationdiversity where calculating Vou, provided that theresulting value is no less than that determined by Equa-tion (1). [ASHRAE ] Outdoor Air design outdoor airintake flow (Vot) shall be determined in accordance withEquation [ASHRAE ]Vot= Vou/Ev(Equation ) Design for Varying Operating Conditions.

8 Ventila-tion systems shall be designed to be capable of providing therequired ventilation rates in the breathing zone where thezones served by the system are occupied, including all fulland part-load conditions. [ASHRAE ] Short-Term it is known thatpeak occupancy will be of short duration or the ventila-tion rate will be varied or interrupted for a short period oftime, the design shall be permitted to be based on theaverage conditions over a time period (T) determined inaccordance with Equation (Equation )Acceptable design adjustments based on thisoptional provision shall be in accordance with thefollowing:(1) Zones with fluctuating occupancy: The zone popu-lation (Pz) shall be averaged over time (T).(2) Zones with intermittent interruption of supply air:The average outdoor airflow supplied to thebreathing zone over time (T) shall be not less thanthe breathing zone outdoor airflow (Vbz) calculatedusing Equation (3) Systems with intermittent closure of the outdoor airintake: The average outdoor air intake over time (T)2013 california MECHANICAL CODEVENTILATION AIR SUPPLYREAD ONLY63 VENTILATION AIR SUPPLY shall be not less than the minimum outdoor airintake (Vot) calculated using Equation , Equa-tion , or Equation :T=averaging time period, volume of the zone for which averaging isbeing applied, cubic foot (ft3).

9 Vbz= the breathing zone outdoor airflow shall be deter-mined in accordance with Equation anddesign value of the zone population Pz, cfm.[ASHRAE ] Exhaust airflow shall beprovided in accordance with the requirements in Table makeup air shall be permitted to be a combinationof outdoor air, recirculated air, and transfer Dynamic system shall be permitted to bedesigned to vary the design outdoor air intake flow(Vot), orthe space or zone airflow, and the exhaust air flow as oper-ating conditions change. [ASHRAE ] Exhaust Ventilation for Enclosed Parking airflow for enclosed parking garages shall beprovided in accordance with the requirements in Table this section. Exhaust makeup air shall be permitted to beany combination of outdoor air or transfer air. Exhaustsystems shall operate :(1) Mechanical ventilation systems used for enclosedparking garages shall be permitted to operate intermit-tently where the system is arranged to operate automat-ically upon detection of vehicle operation or thepresence of occupants by approved automatic detectiondevices.

10 (2) Automatic carbon monoxide sensing devices may beemployed to modulate the ventilation system to notexceed a maximum average concentration of carbonmonoxide of 50 parts per million during any eight-hourperiod, with a maximum concentration not greater than200 parts per million for a period not exceeding onehour. Automatic carbon monoxide sensing devicesemployed to modulate parking garage ventilationsystems shall be approved pursuant to the requirementsin Section Alternative Exhaust Ventilation for EnclosedParking Garages. Minimum Exhaust Rate. In lieu of theexhaust rates in Table , ventilation systemsshall be capable of providing 14,000 cfm (6608 L/s)of exhaust air for each operating vehicle. Numberof operating vehicles shall be determined based percent of all parking spaces (and not less thanone vehicle). Exhaust Inlet Distribution. To ensureproper exhaust of contaminated air and fumes fromparking garages, exhaust systems utilizing multipleexhaust inlets shall be designed so that exhaustinlets are distributed in such a manner that noportion of the parking garage is more than 50 feet(15,240 mm) from an exhaust inlet.