WSR 04-07-192

PERMANENT RULES

BUILDING CODE COUNCIL


[ Filed March 24, 2004, 11:38 a.m. , effective July 1, 2004 ]

Date of Adoption: March 23, 2004.

Purpose: To amend the Washington State Ventilation and Indoor Air Quality Code (chapter 51-13 WAC) to update standards and codes referenced within the document.

Citation of Existing Rules Affected by this Order: Chapter 51-13 WAC, amending WAC 51-13-106, 51-13-201, 51-13-302, 51-13-303, 51-13-304, 51-13-402, 51-13-502, and 51-13-503.

Statutory Authority for Adoption: RCW 19.27.190 and 19.27.020.

Other Authority: Chapters 19.27 and 34.05 RCW.

Adopted under notice filed as WSR 04-03-033 on January 14, 2004.

Number of Sections Adopted in Order to Comply with Federal Statute: New 0, Amended 0, Repealed 0; Federal Rules or Standards: New 0, Amended 0, Repealed 0; or Recently Enacted State Statutes: New 0, Amended 8, Repealed 0.

Number of Sections Adopted at Request of a Nongovernmental Entity: New 0, Amended 0, Repealed 0.

Number of Sections Adopted on the Agency's Own Initiative: New 0, Amended 8, Repealed 0.

Number of Sections Adopted in Order to Clarify, Streamline, or Reform Agency Procedures: New 0, Amended 0, Repealed 0.

Number of Sections Adopted Using Negotiated Rule Making: New 0, Amended 0, Repealed 0; Pilot Rule Making: New 0, Amended 0, Repealed 0; or Other Alternative Rule Making: New 0, Amended 0, Repealed 0.
Effective Date of Rule: July 1, 2004.

March 23, 2004

Tim Nogler

for Stan Price

Council Chair

OTS-6581.3


AMENDATORY SECTION(Amending WSR 98-02-047, filed 1/5/98, effective 7/1/98)

WAC 51-13-106   Conflicts with other codes.  


106.1 Conflicts with Other Codes: In addition to the requirements of this Code, buildings must conform to the provisions of the State Building Code (chapter 19.27 RCW and chapters ((51-40, 51-42, 51-44 and 51-46)) 51-50, 51-52, 51-54 and 51-56 Washington Administrative Code). In case of conflicts between the ((Uniform)) International Building, Uniform Plumbing, ((Uniform)) International Mechanical, and ((Uniform)) International Fire Codes as adopted and amended in chapters ((51-40, 51-42, 51-44 and 51-46)) 51-50, 51-52, 51-54 and 51-56 Washington Administrative Code, the provisions of chapter 51-13 shall govern. This Code is not intended to abridge any safety or health requirements under any other applicable codes or ordinances.


Where, in any specific case, different sections of this Code specify different materials, methods of construction or other requirements, the most restrictive shall govern. Where there is a conflict between a general requirement and a specific requirement, the specific requirement shall be applicable.


Wherever in this Code reference is made to the appendix, the provisions of the appendix shall not apply unless specifically adopted.


106.2 Authority: Local legislative authorities are authorized and directed to enforce this Code. Local legislative authorities are authorized to promulgate, adopt, and issue those rules and regulations necessary for the effective and efficient administration of this Code.

[Statutory Authority: RCW 19.27.190 and 19.27.020. 98-02-047, 51-13-106, filed 1/5/98, effective 7/1/98. Statutory Authority: RCW 19.27.190. 95-01-128, 51-13-106, filed 12/21/94, effective 6/30/95; 91-01-102, 51-13-106, filed 12/18/90, effective 7/1/91.]


AMENDATORY SECTION(Amending WSR 95-01-128, filed 12/21/94, effective 6/30/95)

WAC 51-13-201   General.  


201.1 General: For the purposes of this Code, certain terms, phrases, words, and their derivatives shall be construed as specified in this section. Words used is the singular include the plural and the plural, the singular. Words used in the masculine gender include the feminine and feminine, the masculine.


Where terms are not defined in this section, the definitions shall be taken from Chapter 2 of the ((Uniform)) International Building Code.


Where terms are not defined in either this section or Chapter 2 of the ((Uniform)) International Building Code, ((they)) such terms shall have ((their ordinary)) ordinarily accepted meanings ((within)) such as the context ((with which they are used. Webster's Third International Dictionary of the English Language, Unabridged, copyrighted 1986, shall be considered as providing ordinarily accepted meanings)) implies.

[Statutory Authority: RCW 19.27.190. 95-01-128, 51-13-201, filed 12/21/94, effective 6/30/95; 91-01-102, 51-13-201, filed 12/18/90, effective 7/1/91.]


AMENDATORY SECTION(Amending WSR 01-02-099, filed 1/3/01, effective 7/1/01)

WAC 51-13-302   Mechanical ventilation criteria using performance or design methods for Group R Occupancies four stories and less.  


302.1 Applicability: Group R Occupancies four (4) stories and less as defined by the Washington State Building Code shall comply with either this section or Section 303.


302.1.1 Compliance by Calculations or Testing: Compliance with this section shall be demonstrated through engineering calculation or performance testing. Documentation of calculations or performance test results shall be submitted to the building official. Performance testing shall be conducted in accordance with recognized test methods.


302.1.2 Minimum Ventilation Performance: Each dwelling unit or guest room shall be equipped with source specific and whole house ventilation systems designed and installed to satisfy the ventilation requirements of this section.


All public corridors shall meet the ventilation requirements in section ((1203.3)) 1203 of the ((Uniform)) International Building Code.


302.2 Source Specific Ventilation Requirements.


302.2.1 Source Specific Ventilation: Source specific exhaust ventilation is required in each kitchen, bathroom, water closet, laundry room, indoor swimming pool, spa, and other rooms where excess water vapor or cooking odor is produced.


The minimum source specific ventilation effective exhaust capacity shall be not less than levels specified in Table 3-1.


302.2.2 Source Specific Ventilation Controls: Source specific ventilation systems shall be controlled by manual switches, dehumidistats, timers, or other approved means. Source specific ventilation system controls shall be readily accessible.


302.2.3 Source Specific Ventilation Ducts: Source specific ventilation ducts shall terminate outside the building. Exhaust ducts in systems which are designed to operate intermittently shall be equipped with back-draft dampers. All exhaust ducts in unconditioned spaces shall be insulated to a minimum of R-4. Terminal elements shall have at least the equivalent net free area of the duct work. Terminal elements for exhaust fan duct systems shall be screened or otherwise protected from entry by leaves or other material.


302.3 Requirements for Whole House Ventilation Systems.


302.3.1 Whole House Ventilation Systems: Each dwelling unit shall be equipped with a whole house ventilation system which shall be capable of providing the volume of outdoor air specified in Table 3-2 under normal operating conditions.


EXCEPTION: Maximum flow rates listed in Table 3-2 do not apply to heat recovery ventilation systems.

302.3.2 Whole House Ventilation System Controls: All ventilation system controls shall be readily accessible. Controls for whole house ventilation systems shall be capable of operating the ventilation system without energizing other energy-consuming appliances.


Intermittently operated whole house ventilation systems shall be constructed to have the capability for continuous operation, and shall have a manual control and an automatic control, such as a clock timer. At the time of final inspection, the automatic control timer shall be set to operate the whole house fan for at least eight hours a day. A label shall be affixed to the control that reads "Whole House Ventilation (see operating instructions)."


302.3.3 Fan Noise: Whole house fans located four feet or less from the interior grille shall have a sone rating of 1.5 or less measured at 0.1 inches water gauge. Manufacturer's noise ratings shall be determined as per HVI 915 (October 1995). Remotely mounted fans shall be acoustically isolated from the structural elements of the building and from attached duct work using insulated flexible duct or other approved material.


EXCEPTION: Whole house ventilation systems which are integrated with forced-air heating systems or heat-recovery ventilation systems are exempt from the sone rating requirements of this section.

302.3.4 Whole House Ventilation Ducts: All ducts shall terminate outside the building. Exhaust ducts in systems which are designed to operate intermittently shall be equipped with back-draft dampers. All exhaust ducts in unconditioned spaces shall be insulated to a minimum of R-4. All supply ducts in the conditioned space shall be insulated to a minimum of R-4.


302.3.5 Outdoor Air.


302.3.5.1 Outdoor Air Supply: A mechanical system shall supply outdoor air as required in Section 302.3.1. The mechanical system may consist of exhaust fans, supply fans, or both.


302.3.5.2 Outdoor Air Inlets: Inlets shall be screened or otherwise protected from entry by leaves or other material. Outdoor air inlets shall be located so as not to take air from the following areas:


a) Closer than ten feet from an appliance vent outlet, unless such vent outlet is three feet above the outdoor air inlet.


b) Where it will pick up objectionable odors, fumes, or flammable vapors.


c) A hazardous or unsanitary location.


d) A room or space having any fuel-burning appliances therein.


e) Closer than ten feet from a vent opening of a plumbing drainage system unless the vent opening is at least three feet above the air inlet.


f) Attic, crawl spaces, garages.


302.3.5.3 Outdoor Air Distribution: Outdoor air shall be distributed to each habitable room by means such as individual inlets, separate duct systems, or a forced-air system. Where outdoor air supplies are separated from exhaust points by doors, provisions shall be made to ensure air flow by installation of distribution ducts, undercutting doors, installation of grilles, transoms, or similar means where permitted by the ((Uniform)) International Building Code. Doors shall be undercut to a minimum of one-half inch above the surface of the finish floor covering.


302.3.5.4 Doors and operable lites in windows are deemed not to meet the outdoor air supply intake requirements.


302.3.5.5 Individual Room Outdoor Air Inlets: Where provided, individual room outdoor air inlets shall:

a) Have controllable and secure openings;

b) Be sleeved or otherwise designed so as not to compromise the thermal properties of the wall or window in which they are placed.


302.3.5.6 Ventilation Integrated with Forced-Air Systems: Where outdoor air is provided by a forced-air system, the outdoor air connection to the return air stream shall be located upstream of the forced-air system blower and shall not be connected directly into a furnace cabinet to prevent thermal shock to the heat exchanger.

[Statutory Authority: RCW 19.27.190, 19.27.020. 01-02-099, 51-13-302, filed 1/3/01, effective 7/1/01. Statutory Authority: RCW 19.27.190. 95-01-128, 51-13-302, filed 12/21/94, effective 6/30/95. Statutory Authority: RCW 19.27.190(2) and 1992 c 132. 93-02-056, 51-13-302, filed 1/6/93, effective 7/1/93. Statutory Authority: RCW 19.27.190. 91-01-102, 51-13-302, filed 12/18/90, effective 7/1/91.]


AMENDATORY SECTION(Amending WSR 01-02-099, filed 1/3/01, effective 7/1/01)

WAC 51-13-303   Mechanical ventilation criteria using prescriptive methods for Group R Occupancies four stories and less.  


303.1 Applicability: Group R Occupancies 4 stories or less shall comply with this section or Section 302. This section establishes minimum prescriptive design requirements for intermittently operated systems. Continuously operated systems shall comply with Section 302. A system which meets the requirements of this section shall be deemed to satisfy the requirements of this chapter.


303.2 Minimum Ventilation Performance: Each dwelling unit or guest room shall be equipped with source specific and whole house ventilation systems designed and installed to satisfy the ventilation requirements of this section. All public corridors shall meet the ventilation requirements in Section ((1203.3)) 1203 of the ((Uniform)) International Building Code.


303.3 Source Specific Exhaust Ventilation Requirements.


303.3.1 Source Specific Ventilation: Source specific exhaust ventilation is required in each kitchen, bathroom, water closet, laundry room, indoor swimming pool, spa, and other rooms where excess water vapor or cooking odor is produced. The minimum source specific ventilation effective exhaust capacity shall be not less than levels specified in Table 3-1.


303.3.2 Source Specific Exhaust Fans: Exhaust fans providing source specific ventilation shall have a minimum fan flow rating not less than 50 cfm at 0.25 inches water gauge for bathrooms, laundries, or similar rooms and 100 cfm at 0.25 inches water gauge for kitchens. Manufacturers' fan flow ratings shall be determined as per HVI 916 (April 1995) or AMCA 210.


EXCEPTION: Where a range hood or down draft exhaust fan is used to satisfy the source specific ventilation requirements for kitchens, the range hood or down draft exhaust shall not be less than 100 cfm at 0.10 inches water gauge.

303.3.3 Source Specific Ventilation Controls: Source specific ventilation systems shall be controlled by manual switches, dehumidistats, timers, or other approved means. Source specific ventilation system controls shall be readily accessible.


303.3.4 Source Specific Ventilation Ducts: Source specific ventilation ducts shall terminate outside the building. Exhaust ducts shall be equipped with back-draft dampers. All exhaust ducts in unconditioned spaces shall be insulated to a minimum of R-4. Terminal elements shall have at least the equivalent net free area of the duct work. Terminal elements for exhaust fan duct systems shall be screened or otherwise protected from entry by leaves or other material.


303.4 Prescriptive Whole House Ventilation Systems: Whole house ventilation shall be provided by a system that meets the requirements of either Section 303.3.1, 303.3.2, 303.3.3, or 303.3.4. A system which meets all of the requirements of one of these sections shall be deemed to satisfy the requirements for a whole house ventilation system.


303.4.1 Intermittent Whole House Ventilation Using Exhaust Fans: This section establishes minimum prescriptive requirements for intermittent whole house ventilation systems using exhaust fans. A system which meets all the requirements of this section shall be deemed to satisfy the requirements for a whole house ventilation system.


303.4.1.1 Whole House Ventilation Fans: Exhaust fans providing whole house ventilation shall have a flow rating at 0.25 inches water gauge as specified in Table 3-2. Manufacturers' fan flow ratings shall be determined according to HVI 916 (April 1995) or AMCA 210.


303.4.1.2 Fan Noise: Whole house fans located four feet or less from the interior grille shall have a sone rating of 1.5 or less measured at 0.1 inches water gauge. Manufacturer's noise ratings shall be determined as per HVI 915 (October 1995). Remotely mounted fans shall be acoustically isolated from the structural elements of the building and from attached duct work using insulated flexible duct or other approved material.


303.4.1.3 Fan Controls: The whole house ventilation fan shall be controlled by a 24-hour clock timer with the capability of continuous operation, manual and automatic control. The 24-hour timer shall be readily accessible. The 24-hour timer shall be capable of operating the whole house ventilation fan without energizing other energy-consuming appliances. At the time of final inspection, the automatic control timer shall be set to operate the whole house fan for at least eight hours a day. A label shall be affixed to the control that reads "Whole House Ventilation (see operating instructions)."


303.4.1.4 Exhaust Ducts: All exhaust ducts shall terminate outside the building. Exhaust ducts shall be equipped with back-draft dampers. All exhaust ducts in unconditioned spaces shall be insulated to a minimum of R-4.


303.4.1.5 Outdoor Air Inlets: Outdoor air shall be distributed to each habitable room by individual outdoor air inlets. Where outdoor air supplies are separated from exhaust points by doors, provisions shall be made to ensure air flow by installation of distribution ducts, undercutting doors, installation of grilles, transoms, or similar means where permitted by the ((Uniform)) International Building Code. Doors shall be undercut to a minimum of one-half inch above the surface of the finish floor covering.


Individual room outdoor air inlets shall:

a. Have controllable and secure openings;

b. Be sleeved or otherwise designed so as not to compromise the thermal properties of the wall or window in which they are placed;

c. Provide not less than four square inches of net free area of opening for each habitable space. Any inlet or combination of inlets which provide 10 cfm at 10 Pascals as determined by the Home Ventilating Institute Air Flow Test Standard (HVI 901 (November 1996)) are deemed equivalent to four square inches net free area.


Inlets shall be screened or otherwise protected from entry by leaves or other material. Outdoor air inlets shall be located so as not to take air from the following areas:

a. Closer than 10 feet from an appliance vent outlet, unless such vent outlet is 3 feet above the outdoor air inlet.

b. Where it will pick up objectionable odors, fumes or flammable vapors.

c. A hazardous or unsanitary location.

d. A room or space having any fuel-burning appliances therein.

e. Closer than 10 feet from a vent opening of a plumbing drainage system unless the vent opening is at least 3 feet above the air inlet.

f. Attic, crawl spaces, or garages.


EXCEPTION: Exhaust only ventilation systems do not require outdoor air inlets if the home has a ducted forced air heating system that communicates with all habitable rooms and the interior doors are undercut to a minimum of one-half inch above the surface of the finish floor covering.

303.4.2 Prescriptive Requirements for Intermittent Whole House Ventilation Integrated with a Forced-Air System: This section establishes minimum prescriptive requirements for intermittent whole house ventilation systems integrated with forced-air ventilation systems. A system which meets all the requirements of this section shall be deemed to satisfy the requirements for a whole house ventilation system.


303.4.2.1 Integrated Whole House Ventilation Systems: Integrated Whole House Ventilation Systems shall provide outdoor air at the rates specified in Table 3-2. Integrated Forced-Air Ventilation Systems shall distribute outdoor air to each habitable room through the forced-air system ducts. Integrated Forced-Air Ventilation Systems shall have an outdoor air inlet duct connecting a terminal element on the outside of the building to the return air plenum of the forced-air system, at a point within four (4) feet upstream of the air handler. The outdoor air inlet duct connection to the return air stream shall be located upstream of the forced-air system blower and shall not be connected directly into a furnace cabinet to prevent thermal shock to the heat exchanger. The outdoor air inlet duct shall be prescriptively sized in accordance with Table 3-5. The system will be equipped with one of the following:

1. A motorized damper connected to the automatic ventilation control as specified in Section 303.3.2.2; or

2. A damper installed and set to meet minimum flow rates as specified in Table 3-2, by either field testing or following manufacturer's installation instructions based on site conditions; or

3. An automatic flow regulated device with field measured or field calculated minimum negative pressure of 0.07 inches water gauge at the point where the outside air duct is connected to the return air plenum.


303.4.2.2 Ventilation Controls: The whole house ventilation system shall be controlled by a 24-hour clock timer with the capability of continuous operation, manual and automatic control. This control will control the forced air system blower and if applicable the automatic damper. The 24-hour timer shall be readily accessible. The 24-hour timer shall be capable of operating the whole house ventilation system without energizing other energy-consuming appliances. At the time of final inspection, the automatic control timer shall be set to operate the whole house system for at least eight hours a day. A label shall be affixed to the control that reads "Whole House Ventilation (see operating instructions)."


303.4.2.3 Ventilation Duct Insulation: All supply ducts in the conditioned space shall be insulated to a minimum of R-4.


303.4.2.4 Outdoor Air Inlets: Inlets shall be screened or otherwise protected from entry by leaves or other material. Outdoor air inlets shall be located so as not to take air from the following areas:

a. Closer than 10 feet from an appliance vent outlet, unless such vent outlet is 3 feet above the outdoor air inlet.

b. Where it will pick up objectionable odors, fumes or flammable vapors.

c. A hazardous or unsanitary location.

d. A room or space having any fuel-burning appliances therein.

e. Closer than 10 feet from a vent opening of a plumbing drainage system unless the vent opening is at least 3 feet above the air inlet.

f. Attic, crawl spaces, or garages.


303.4.3 Prescriptive Requirements for Intermittent Whole House Ventilation Using a Supply Fan: This section establishes minimum prescriptive requirements for intermittent whole house ventilation systems using an inline supply fan. A system which meets all the requirements of this section shall be deemed to satisfy the requirements for a whole house ventilation system.


303.4.3.1 Outdoor Air: Supply Fan Ventilation Systems shall distribute outdoor air to each habitable room through the forced-air system ducts or through dedicated ducts to each habitable room. Supply fans shall have the capacity to provide the amount of outdoor air specified in Table 3-2 at 0.4 inches water gauge as per HVI 916 (April 1995). The outdoor air must be filtered before it is delivered to habitable rooms. The filter may be located at the intake device, inline with the fan, or, in the case of a connection to the return plenum of the airhandler, using the furnace filter. An outdoor air inlet shall be connected to either the supply or return air stream.


303.4.3.2 Ducts: An outdoor air inlet duct connection to the supply air stream shall be located downstream of the forced-air system blower. An outdoor air inlet duct connection to the return air stream shall be located at least four feet upstream of the forced-air system blower and its filter. Neither type of duct shall be connected directly into a furnace cabinet to prevent thermal shock to the heat exchanger. The outdoor air inlet duct shall be prescriptively sized in accordance with Table 3-6. The terminal element on the outside of the building shall be sized two inches in diameter larger than the outdoor air inlet duct.


303.4.3.3 Dampers: The system shall be equipped with a back-draft damper and one of the following:

1. A calibrated manual volume damper installed and set to meet the measured flow rates specified in Table 3-2 by field testing with a pressure gauge and/or following manufacturer's installation instructions, or

2. A manual volume damper installed and set to meet the measured flow rates specified in Table 3-2 by field testing with a flow hood or a flow measuring station; or

3. An automatic flow-regulating device sized to the specified flow rates in Table 3-2 which provides constant flow over a pressure range of 0.2 to 0.6 inches water gauge.


303.4.3.4 Ventilation Controls: The whole house ventilation system shall be controlled by a 24 hour clock timer with the capability of continuous operation, manual and automatic control. This control will control the inline supply fan. The 24-hour timer shall be readily accessible. The 24 hour timer shall be capable of operating the whole house ventilation system without energizing other energy-consuming appliances. At the time of final inspection, the automatic control timer shall be set to operate the whole house system for at least eight hours a day. A label shall be affixed to the control that reads "Whole House Ventilation (see operating instructions)."


303.4.3.5 Ventilation Duct Insulation: All supply ducts in the conditioned space shall be insulated to a minimum of R-4.


303.4.3.6 Outdoor Air Inlets: Inlets shall be screened or otherwise protected from entry by leaves or other material. Outdoor air inlets shall be located so as not to take air from the following areas:

a. Closer than 10 feet from an appliance vent outlet, unless such vent outlet is 3 feet above the outdoor air inlet.

b. Where it will pick up objectionable odors, fumes or flammable vapors.

c. A hazardous or unsanitary location.

d. A room or space having any fuel-burning appliances therein.

e. Closer than 10 feet from a vent opening of a plumbing drainage system unless the vent opening is at least 3 feet above the air inlet.

f. Attic, crawl spaces, or garages.


303.4.4 Prescriptive Requirements for Intermittent Whole House Ventilation Using a Heat Recovery Ventilation System: This section establishes minimum prescriptive requirements for intermittent whole house ventilation using a heat recovery ventilation system.


303.4.4.1 Heat Recovery Ventilation Systems: All duct work in heat recovery ventilation systems shall be not less than six inch diameter. Balancing dampers shall be installed on the inlet and exhaust side. Flow measurement grids shall be installed on the supply and return. System minimum flow rating shall be not less than that specified in Table 3-2. Maximum flow rates in Table 3-2 do not apply to heat recovery ventilation systems.


303.4.4.2 Ventilation Controls: The whole house ventilation system shall be controlled by a 24 hour clock timer with the capability of continuous operation, manual and automatic control. This control will control the inline supply fan. The 24-hour timer shall be readily accessible. The 24 hour timer shall be capable of operating the whole house ventilation system without energizing other energy-consuming appliances. At the time of final inspection, the automatic control timer shall be set to operate the whole house system for at least eight hours a day. A label shall be affixed to the control that reads "Whole House Ventilation (see operating instructions)."


303.4.4.3 Ventilation Duct Insulation: All supply ducts in the conditioned space installed upstream of the heat exchanger shall be insulated to a minimum of R-4.


303.4.4.4 Outdoor Air Inlets: Inlets shall be screened or otherwise protected from entry by leaves or other material. Outdoor air inlets shall be located so as not to take air from the following areas:

a. Closer than 10 feet from an appliance vent outlet, unless such vent outlet is 3 feet above the outdoor air inlet.

b. Where it will pick up objectionable odors, fumes or flammable vapors.

c. A hazardous or unsanitary location.

d. A room or space having any fuel-burning appliances therein.

e. Closer than 10 feet from a vent opening of a plumbing drainage system unless the vent opening is at least 3 feet above the air inlet.

f. Attic, crawl spaces, or garages.

[Statutory Authority: RCW 19.27.190, 19.27.020. 01-02-099, 51-13-303, filed 1/3/01, effective 7/1/01. Statutory Authority: RCW 19.27.190(2) and 1992 c 132. 93-02-056, 51-13-303, filed 1/6/93, effective 7/1/93. Statutory Authority: RCW 19.27.190. 91-01-102, 51-13-303, filed 12/18/90, effective 7/1/91.]


AMENDATORY SECTION(Amending WSR 01-02-099, filed 1/3/01, effective 7/1/01)

WAC 51-13-304   Mechanical ventilation criteria and minimum ventilation performance for all other occupancies not covered in sections 302 and 303.  


304.1 Ventilation: The minimum requirements for operable area to provide natural ventilation are specified in the ((Uniform)) International Building Code (((UBC))) (IBC) as adopted by the state of Washington.


Where a mechanical ventilation system is installed, the mechanical ventilation system shall be capable of supplying ventilation air to each zone with the minimum outdoor air quantities specified in Table 3-4.


EXCEPTION: Where occupancy density is known and documented in the plans, the outside air rate may be based on the design occupant density. Under no circumstance shall the occupancies used result in outside air less than one-half that resulting from application of Table 3-4 estimated maximum occupancy values.

The outdoor air shall be ducted in a fully enclosed path directly to every air handling unit in each zone not provided with sufficient operable area for natural ventilation.


EXCEPTION: Ducts may terminate within 12 inches of the intake to an HVAC unit provided they are physically fastened so that the outside air duct is directed into the unit intake.

In all parking garages, other than open parking garages as defined in ((UBC 311.9)) IBC 406.3, used for storing or handling of automobiles operating under their own power and on all loading platforms in bus terminals, ventilation shall be provided at 1.5 cfm per square foot of gross floor area. The building official may approve an alternate ventilation system designed to exhaust a minimum fourteen thousand cfm for each operating vehicle. Such system shall be based on the anticipated instantaneous movement rate of vehicles but not less than 2.5 percent (or one vehicle) of the garage capacity. Automatic carbon monoxide sensing systems may be submitted for approval.


In all buildings used for the repair of automobiles, each repair stall shall be equipped with an exhaust extension duct, extending to the outside of the building, which if over ten feet in length, shall mechanically exhaust three hundred cfm. Connecting offices and waiting rooms shall be supplied with conditioned air under positive pressure.


Combustion air requirements shall conform to the requirements of Chapter 7 of the ((UMC)) International Mechanical Code (IMC).


Mechanical refrigerating equipment and rooms storing refrigerants shall conform to the requirements of Chapter 11 of the ((UMC)) IMC.


304.2 Alternate Systems: Alternate systems designed in accordance with ASHRAE Standard 62.1.1999 shall be permitted.

TABLE 3-1
Minimum Source Specific Ventilation Capacity
Requirements


Bathrooms Kitchens
Intermittently operating 50 cfm 100 cfm
Continuous operation 20 cfm 25 cfm


TABLE 3-2
Ventilation Rates For All Group R Occupancies four (4) stories and less*
Minimum and Maximum Ventilation Rates: Cubic Feet Per Minute (CFM)

Floor

Area, ft2

Bedrooms
2 or less 3 4 5 6 7 8
Min. Max. Min. Max. Min. Max. Min. Max. Min. Max. Min. Max. Min. Max.
<500 50 75 65 98 80 120 95 143 110 165 125 188 140 210
501-1000 55 83 70 105 85 128 100 150 115 173 130 195 145 218
1001-1500 60 90 75 113 90 135 105 158 120 180 135 203 150 225
1501-2000 65 98 80 120 95 143 110 165 125 188 140 210 155 233
2001-2500 70 105 85 128 100 150 115 173 130 195 145 218 160 240
2501-3000 75 113 90 135 105 158 120 180 135 203 150 225 165 248
3001-3500 80 120 95 143 110 165 125 188 140 210 155 233 170 255
3501-4000 85 128 100 150 115 173 130 195 145 218 160 240 175 263
4001-5000 95 143 110 165 125 188 140 210 155 233 170 255 185 278
5001-6000 105 158 120 180 135 203 150 225 165 248 180 270 195 293
6001-7000 115 173 130 195 145 218 160 240 175 263 190 285 205 308
7001-8000 125 188 140 210 155 233 170 255 185 278 200 300 215 323
8001-9000 135 203 150 225 165 248 180 270 195 293 210 315 225 338
>9000 145 218 160 240 175 263 190 285 205 308 220 330 235 353
*For residences that exceed 8 bedrooms, increase the minimum requirement listed for 8 bedrooms by an additional 15 CFM per bedroom. The maximum CFM is equal to 1.5 times the minimum.

TABLE 3-3
Prescriptive Exhaust Duct Sizing


Fan Tested

CFM @

0.25 W.G.

Minimum

Flex

Diameter

Maximum

Length

Feet

Minimum

Smooth

Diameter

Maximum

Length

Feet

Maximum

Elbows1

50 4 inch 25 4 inch 70 3
50 5 inch 90 5 inch 100 3
50 6 inch No Limit 6 inch No Limit 3
80 4 inch2 NA 4 inch 20 3
80 5 inch 15 5 inch 100 3
80 6 inch 90 6 inch No Limit 3
100 5 inch2 NA 5 inch 50 3
100 6 inch 45 6 inch No Limit 3
125 6 inch 15 6 inch No Limit 3
125 7 inch 70 7 inch No Limit 3

1. For each additional elbow subtract 10 feet from length.
2. Flex ducts of this diameter are not permitted with fans of this size.

TABLE 3-4
Outdoor air requirements for ventilation1
Occupancies not subject to sections 302 and 303


Application Estimated

Maximum2

Occupancy

P/1000 ft2 or

100 m2

Outdoor Air

Requirements

cfm/person

Dry Cleaners, Laundries3
Commercial laundry 10 25
Commercial dry cleaner 30 30
Storage, pick up 30 35
Coin-operated laundries 20 15
Coin-operated dry cleaner 20 15
Dwelling Units In Buildings Greater Than Four Stories or Attached to I-

Occupancy Facilities

Bedroom & living area24 15
Food and Beverage Service
Dining rooms 70 20
Cafeteria, fast food 100 20
Bars, cocktail lounges4 100 30
Kitchens (cooking)23 20 15
Garages, Repair, Service Stations
Enclosed parking garage5 1.50 cfm/ft.sq.
Auto repair rooms 1.50 cfm/ft.sq.
Hotels, Motels, Resorts, Congregate Residences with More Than Four

Stories6

Bedrooms 30 cfm/room
Living Rooms 30 cfm/room
Bath7 35 cfm/room
Lobbies 30 15
Conference rooms 50 20
Assembly rooms 120 15
Gambling casinos4 120 30
Offices
Office space9 7 20
Reception area 60 15
Telecommunication

centers and data

entry areas

60 20
Conference rooms 50 20
Public Spaces
Corridors and utilities 0.05 cfm/ft.sq.
Public restroom, cfm/wc

or urinal10

50
Lockers and dressing rooms 0.50 cfm/ft.sq.
Smoking lounge11 70 60
Elevators12 1.0 cfm/ft.sq.
Retail Stores, Sales Floors, and Show Room Floors
Basement and street 30 0.30 cfm/ft.sq.
Upper floors 20 0.20 cfm/ft.sq.
Storage rooms 15 0.15 cfm/ft.sq.
Dressing rooms 0.20 cfm/ft.sq.
Malls and arcades 20 0.20 cfm/ft.sq.
Shipping and receiving 10 0.15 cfm/ft.sq.
Smoking lounge11 70 60
Warehouses 5 0.05 cfm/ft.sq.
Speciality Shops
Barber 25 15
Beauty 25 25
Reducing salons 20 15
Florists13 8 15
Clothiers, furniture 0.30 cfm/ft.sq.
Hardware, drugs, fabric 8 15
Supermarkets 8 15
Pet shops 1.00 cfm/ft.sq.
Sports and Amusement14
Spectator areas 150 15
Game rooms 70 25
Ice arenas (playing areas) 0.50 cfm/ft.sq.
Swimming Pools (pool

and deck area)15

0.50 cfm/ft.sq.
Playing floor (gymnasium) 30 20
Ballrooms and discos 100 25
Bowling alleys (seating areas) 70 25
Theaters16
Ticket booths 60 20
Lobbies 150 20
Auditorium 150 20
Stages, studios 70 15
Transportation17
Waiting rooms 100 15
Platforms 100 15
Vehicles 150 15
Workrooms
Meat processing18 10 15
Photo studios 10 15
Darkrooms 10 0.50 cfm/ft.sq.
Pharmacy 20 15
Bank vaults 5 15
Duplicating, printing19 0.50 cfm/ft.sq.
INSTITUTIONAL FACILITIES
Education
Classroom 50 15
Laboratories20 30 20
Training shop 30 20
Music rooms 50 15
Libraries 20 15
Locker rooms 0.50 cfm/ft.sq.
Corridors 0.10 cfm/ft.sq.
Auditoriums 150 15
Smoking lounges11 70 60
Hospitals, Nursing and Convalescent Homes
Patient rooms21 10 25
Medical procedure 20 15
Operating rooms 20 30
Recovery and ICU 20 15
Autopsy rooms22 0.50 cfm/ft.sq.
Physical Therapy 20 15
Correctional Facilities
Cells 20 20
Dining halls 100 15
Guard station 40 15

1. Derived from ASHRAE Standard 62-1989.
2. Net occupiable space.
3. Dry-cleaning process may require more air.
4. Supplementary smoke-removal equipment may be required.
5. Distribution among people must consider worker location and concentration of running engine; stands where engines are run must incorporate systems for positive engine exhaust withdrawal. Contaminant sensors may be used to control ventilation.
6. Independent of room size.
7. Installed capacity for intermittent use.
8. See also food and beverage service, merchandising, barber and beauty shops, garages.
9. Some office equipment may require local exhaust.
10. Mechanical exhaust with no recirculation is recommended.
11. Normally supplied by transfer air, local mechanical exhaust; with no recirculation recommended.
12. Normally supplied by transfer air.
13. Ventilation to optimize plant growth may dictate requirements.
14. When internal combustion engines are operated for maintenance of playing surfaces, increased ventilation rates may be required.
15. Higher values may be required for humidity control.
16. Special ventilation will be needed to eliminate special stage effects.
17. Ventilation within vehicles may require special considerations.
18. Spaces maintained at low temperatures (-10F. to+ 50F.) are not covered by these requirements unless the occupancy is continuous. Ventilation from adjoining spaces is permissible. When the occupancy is intermittent, infiltration will normally exceed the ventilation requirements.
19. Installed equipment must incorporate positive exhaust and control of undesirable contaminants.
20. Special contamination control systems may be required for processes or functions including laboratory animal occupancy.
21. Special requirements or codes and pressure relationships may determine minimum ventilation rates and filter efficiency. Procedures generating contaminants may require higher rates.
22. Air shall not be recirculated into other spaces.
23. Makeup air for hood exhaust may require more ventilating air.
24. Occupant loading shall be based on the number of bedrooms as follows: first bedroom, two persons; each additional bedroom, one person. Where higher occupant loadings are known, they shall be used.

TABLE 3-5
Prescriptive Integrated Forced Air Supply Duct Sizing


Required

Flow

(CFM) Per

Table 3-2

Minimum

Smooth

Duct

Diameter

Minimum

Flexible

Duct

Diameter

Maximum

Length1

Maximum

Number of

Elbows2

50-80 6" 7" 20' 3
80-125 7" 8" 20' 3
115-175 8" 10" 20' 3
170-240 9" 11" 20' 3

1. For lengths over 20 feet increase duct diameter 1 inch.
2. For elbows numbering more than 3 increase duct diameter 1 inch.

TABLE 3-6
Prescriptive Supply Fan Duct Sizing

Supply Fan Tested CFM At 0.4" WG
Specified

volume

from Table 3-2

Minimum

Smooth

Duct Diameter

Minimum

Flexible

Duct Diameter

50-90 CFM 4 inch 5 inch
90-150 CFM 5 inch 6 inch
150-250 CFM 6 inch 7 inch
250-400 CFM 7 inch 8 inch

[Statutory Authority: RCW 19.27.190, 19.27.020. 01-02-099, 51-13-304, filed 1/3/01, effective 7/1/01. Statutory Authority: RCW 19.27.190. 95-01-128, 51-13-304, filed 12/21/94, effective 6/30/95. Statutory Authority: RCW 19.27.190(2) and 1992 c 132. 93-02-056, 51-13-304, filed 1/6/93, effective 7/1/93. Statutory Authority: RCW 19.27.190. 91-01-102, 51-13-304, filed 12/18/90, effective 7/1/91.]


AMENDATORY SECTION(Amending WSR 98-02-047, filed 1/5/98, effective 7/1/98)

WAC 51-13-402   Solid fuel burning appliances and fireplaces.

  
402.1 General: Solid fuel burning appliances and fireplaces shall satisfy one of the following criteria.


402.2 Solid Fuel Burning Appliances: Solid fuel burning appliances shall be provided with the following:


a) Tight fitting metal or ceramic glass doors.


b) 1. A source from outside the structure of primary combustion air, connected to the appliance as per manufacturer's specification. The air inlet shall originate at a point below the fire box. The duct shall be 4 inches or greater in diameter, not exceed 20 feet in length, and be installed as per manufacturer's instructions;

or


2. The appliance and manufacturer's recommended combustion air supply, as an installed unit, shall be certified by an independent testing laboratory to have passed Test No. 11 - Negative Pressure Test, Section 12.3, of ULC S627-M1984 "Space Heaters for Use with Solid Fuels," modified as follows:


A) Negative pressure of 8 Pascal shall be initially established with the chamber sealed and the air supply, if not directly connected to the appliance, closed off.


B) The air supply, if not directly connected to the appliance, shall then be opened.


C) The maximum allowable air exchange rate from chamber leakage and intentional air supply for the unit (appliance with combustion air supply) in the test chamber is 3.5 air changes per hour, or 28 cfm (cubic feet of air per minute), whichever is less.


EXCEPTION: Combustion air may be supplied to the room in which the solid fuel burning appliance is located in lieu of direct ducting, provided that one of the following conditions is met:
1) The solid fuel burning appliance is part of a central heating plant and installed in an unconditioned space in conformance with the ((Uniform)) International Mechanical Code; or
2) The solid fuel burning appliance is installed in existing construction directly on a concrete floor or surrounded by masonry materials as in a fireplace.
The combustion air terminus shall be located as close to the solid fuel burning appliance as possible and shall be provided with a barometric damper or equivalent. The combustion air source shall be specified by the manufacturer or no less than four (4) inches in diameter or the equivalent in area or as approved.


402.3 Fireplaces: Fireplaces shall be provided with each of the following:


a) Tightly fitting flue dampers, operated by a readily accessible manual or approved automatic control.


EXCEPTION: Fireplaces with gas logs shall be installed in accordance with the ((Uniform)) International Mechanical Code section 901, except that the standards for liquefied petroleum gas installations shall be NFPA 58 (Liquefied Petroleum Gas Code) and NFPA 54 (National Fuel Gas Code).

b) An outside source for combustion air ducted into the firebox. The duct shall be at least six (6) square inches, and shall be provided with an operable outside air duct damper.


EXCEPTION: Washington certified fireplaces shall be installed with the combustion air systems necessary for their safe and efficient combustion and specified by the manufacturer in accordance with the Washington state ((UBC Standard 31-2 (WAC 51-40-31200) and UBC section 3102.5.4 (WAC 51-40-3102))) building code standard 31-2 (WAC 51-50-31200) and International Building Code Section 2114 (WAC 51-50-2114).

c) Site built fireplaces shall have tight fitting glass or metal doors, or a flue draft induction fan, or as approved for minimizing back-drafting. Factory built fireplaces shall use doors listed for the installed appliance.


402.4 Masonry Heaters: Masonry heaters shall be approved by the department of ecology and shall contain both of the following:


a) Primary combustion air ducted from the outside of the structure to the appliance.


b) Tight fitting ceramic glass or metal doors. Flue damper, when provided, shall have an external control and when in the closed position shall have a net free area of not less than five percent of the flue cross sectional area.

[Statutory Authority: RCW 19.27.190 and 19.27.020. 98-02-047, 51-13-402, filed 1/5/98, effective 7/1/98. Statutory Authority: RCW 19.27.190. 95-01-128, 51-13-402, filed 12/21/94, effective 6/30/95. Statutory Authority: RCW 19.27.190(2) and 1992 c 132. 93-02-056, 51-13-402, filed 1/6/93, effective 7/1/93. Statutory Authority: RCW 19.27.190. 91-01-102, 51-13-402, filed 12/18/90, effective 7/1/91.]


AMENDATORY SECTION(Amending WSR 98-02-047, filed 1/5/98, effective 7/1/98)

WAC 51-13-502   Statewide radon requirements.


  
502.1 Crawlspaces:


502.1.1 General: All crawlspaces shall comply with the requirements of this section.


502.1.2 Ventilation: All crawlspaces shall be ventilated as specified in section ((2306.7)) 1203.3 of the ((Washington State Uniform)) International Building Code (chapter ((51-40)) 51-50 WAC).


If the installed ventilation in a crawlspace is less than one square foot for each three hundred square feet of crawlspace area, or if the crawlspace vents are equipped with operable louvers, a radon vent shall be installed to originate from a point between the ground cover and soil. The radon vent shall be installed in accordance with sections 503.2.6 and 503.2.7.


502.1.3 Crawlspace Plenum Systems: In crawlspace plenum systems used for providing supply air for an HVAC system, aggregate, a permanently sealed soil gas retarder membrane and a radon vent pipe shall be installed in accordance with section 503.2. Crawlspaces shall not be used for return air plenums.


In addition, an operable radon vent fan shall be installed. The fan shall be located as specified in section 503.2.7. The fan shall be capable of providing at least one hundred cfm at one inch water column static pressure. The fan shall be controlled by a readily accessible manual switch. The switch shall be labeled "RADON VENT FAN."

[Statutory Authority: RCW 19.27.190 and 19.27.020. 98-02-047, 51-13-502, filed 1/5/98, effective 7/1/98. Statutory Authority: RCW 19.27.190. 95-01-128, 51-13-502, filed 12/21/94, effective 6/30/95. Statutory Authority: RCW 19.27.190(2) and 1992 c 132. 93-02-056, 51-13-502, filed 1/6/93, effective 7/1/93. Statutory Authority: RCW 19.27.190. 91-12-045, 51-13-502, filed 6/5/91, effective 7/1/91; 91-01-102, 51-13-502, filed 12/18/90, effective 7/1/91.]


AMENDATORY SECTION(Amending WSR 01-02-099, filed 1/3/01, effective 7/1/01)

WAC 51-13-503   Radon prescriptive requirements.  


503.1 Scope: This section applies to those counties specified in section 501.2.2. This section establishes prescriptive construction requirements for reducing the potential for radon entry into all Group R Occupancies, and for preparing the building for future mitigation if desired.


In all crawlspaces, except crawlspace plenums used for providing supply air for an HVAC system, a continuous air barrier shall be installed between the crawlspace area and the occupied area to limit air transport between the areas. If a wood sheet subfloor or other material is utilized as an air barrier, in addition to the requirements of section 502.1.6.2 of the Washington state energy code, all joints between sheets shall be sealed.


503.2 Floors in Contact with the Earth


503.2.1 General: Concrete slabs that are in direct contact with the building envelope shall comply with the requirements of this section.


EXCEPTION: Concrete slabs located under garages or other than Group R Occupancies need not comply with this chapter.

503.2.2 Aggregate: A layer of aggregate of four inch minimum thickness shall be placed beneath concrete slabs. The aggregate shall be continuous to the extent practical.


503.2.3 Gradation: Aggregate shall:


a) Comply with ASTM Standard C-33 Standard Specification for Concrete Aggregate and shall be size No. 8 or larger size aggregate as listed in Table 2, Grading Requirements for Coarse Aggregate; or


b) Meet the 1988 Washington State Department of Transportation specification 9-03.1 (3) "Coarse Aggregate for Portland Cement Concrete," or any equivalent successor standards. Aggregate size shall be of Grade 8 or larger as listed in section 9-03.1 (3) C, "Grading"; or


c) Be screened, washed pea gravel free of deleterious substances in a manner consistent with ASTM Standard C-33 with one hundred percent (100%) passing a one-half (1/2) inch sieve and less than five percent (5%) passing a No. 16 sieve. Sieve characteristics shall conform to those acceptable under ASTM Standard C-33.


EXCEPTION: Aggregate shall not be required if a substitute material or system, with sufficient load bearing characteristics, and having approved capability to provide equal or superior air flow, is installed.

503.2.4 Soil-Gas Retarder Membrane: A soil-gas retarder membrane, consisting of at least one layer of virgin polyethylene with a thickness of at least six mil, or equivalent flexible sheet material, shall be either placed directly under all concrete slabs so that the slab is in direct contact with the membrane, or on top of the aggregate with two inches (2") minimum of fine sand or pea gravel installed between the concrete slab and membrane. The flexible sheet shall extend to the foundation wall or to the outside edge of the monolithic slab. Seams shall overlap at least twelve inches. The membrane shall also be fitted tightly to all pipes, wires, and other penetrations of the membrane and sealed with an approved sealant or tape. All punctures or tears shall be repaired with the same or approved material and similarly lapped and sealed.


503.2.5 Sealing of Penetrations and Joints: All penetrations and joints in concrete slabs or other floor systems and walls below grade shall be sealed by an approved sealant to create an air barrier to limit the movement of soil-gas into the indoor air.


Sealants shall be approved by the manufacturer for the intended purpose. Sealant joints shall conform to manufacturer's specifications. The sealant shall be placed and tooled in accordance with manufacturer's specifications. There shall be no gaps or voids after the sealant has cured.


503.2.6 Radon Vent: One continuous sealed pipe shall run from a point within the aggregate under each concrete slab to a point outside the building. Joints and connections shall be permanently gas tight. The continuous sealed pipe shall interface with the aggregate in the following manner, or by other approved equal method: The pipe shall be permanently connected to a "T" within the aggregate area so that the two end openings of the "T" lie within the aggregate area. A minimum of five feet of perforated drain pipe of three inches minimum diameter shall join to and extend from the "T."

The perforated pipe shall remain in the aggregate area and shall not be capped at the ends. The "T" and ((it's)) its perforated pipe extensions shall be located at least five feet horizontally from the exterior perimeter of the aggregate area.


The continuous sealed pipe shall terminate no less than twelve inches above the eave, and more than ten horizontal feet from a woodstove or fireplace chimney, or operable window. The continuous sealed pipe shall be labeled "radon vent." The label shall be placed so as to remain visible to an occupant.


The minimum pipe diameter shall be three inches unless otherwise approved. Acceptable sealed plastic pipe shall be smooth walled, and may include either PVC schedule 40 or ABS schedule of equivalent wall thickness.


The entire sealed pipe system shall be sloped to drain to the sub-slab aggregate.


The sealed pipe system may pass through an unconditioned attic before exiting the building; but to the extent practicable, the sealed pipe shall be located inside the thermal envelope of the building in order to enhance passive stack venting.


EXCEPTION: A fan forced sub-slab depressurization system includes:

1) Soil-gas retarder membrane as specified in section 503.2.4;
2) Sealing of penetrations and joints as specified in section 503.2.5;
3) A three-inch continuous sealed radon pipe shall run from a point within the aggregate under each concrete slab to a point outside the building;
4) Joints and connections ((may)) shall be gas tight, and may be of either PVC schedule 40 or ABS schedule of equivalent in wall thickness;
5) A label of "radon vent" shall be placed on the pipe so as to remain visible to the occupant;
6) Fan circuit and wiring as specified in section 503.2.7 and a fan.
If the sub-slab depressurization system is exhausted through the concrete foundation wall or rim joist, the exhaust terminus shall be a minimum of six feet from operable windows or outdoor air intake vents and shall be directed away from operable windows and outdoor air intake vents to prevent radon re-entrainment.


503.2.7 Fan Circuit and Wiring and Location: An area for location of an in-line fan shall be provided. The location shall be as close as practicable to the radon vent pipe's point of exit from the building, or shall be outside the building shell; and shall be located so that the fan and all downstream piping is isolated from the indoor air.


Provisions shall be made to allow future activation of an in-line fan on the radon vent pipe without the need to place new wiring. A one hundred ten volt power supply shall be provided at a junction box near the fan location.


503.2.8 Separate Aggregate Areas: If the four-inch aggregate area underneath the concrete slab is not continuous, but is separated into distinct isolated aggregate areas by a footing or other barrier, a minimum of one radon vent pipe shall be installed into each separate aggregate area.


EXCEPTION: Separate aggregate areas may be considered a single area if a minimum three-inch diameter connection joining the separate areas is provided for every thirty feet of barrier separating those areas.

503.2.9 Concrete Block Walls: Concrete block walls connected to below grade areas shall be considered unsealed surfaces. All openings in concrete block walls that will not remain accessible upon completion of the building shall be sealed at both vertical and horizontal surfaces, in order to create a continuous air barrier to limit the transport of soil-gas into the indoor air.

[Statutory Authority: RCW 19.27.190, 19.27.020. 01-02-099, 51-13-503, filed 1/3/01, effective 7/1/01. Statutory Authority: RCW 19.27.190(2) and 1992 c 132. 93-02-056, 51-13-503, filed 1/6/93, effective 7/1/93. Statutory Authority: RCW 19.27.190. 91-01-102, 51-13-503, filed 12/18/90, effective 7/1/91.]

Washington State Code Reviser's Office