Title of Rule and Other Identifying Information: Chapter 51-51 WAC, Washington state amendment of the 2009 International Residential Code.

     Purpose of the Proposal and Its Anticipated Effects, Including Any Changes in Existing Rules: WAC 51-51-1508, this section contained several editorial errors that were carried over from the previous whole house ventilation method in the Ventilation and Indoor Air Quality Code. Various instances of the term "intermediate" were removed where they were not appropriate in the methodology adopted for the 2009 code. In addition, a new section was added as Section 1508.1.1 that consolidated requirements found scattered throughout the section to increase clarity. The other sections on controls and system operation were deleted. (OTS 4113.1)

     Reasons Supporting Proposal: Some editorial errors were identified in the rules filed under WSR 10-03-098. This rule corrects those errors and makes other editorial reorganizations to make the section easier to use.

     Statutory Authority for Adoption: RCW 19.27A.025, 19.27A.045.

     Statute Being Implemented: Chapters 19.27, 19.27A, and 34.05 RCW.

     Rule is not necessitated by federal law, federal or state court decision.

     Name of Proponent: State building code council, governmental.

     Name of Agency Personnel Responsible for Drafting and Implementation: Krista Braaksma, P.O. Box 41449, Olympia, WA 98504-1449, (360) 407-9278; and Enforcement: Local jurisdictions.

September 6, 2011

Kristyn Clayton

Council Chair

OTS-4113.1

AMENDATORY SECTION(Amending WSR 10-03-098, filed 1/20/10, effective 7/1/10)

WAC 51-51-1508   Section M1508 -- Whole house ventilation.  

M1508.1 General. This section establishes minimum prescriptive design requirements for whole house ventilation systems. Each dwelling unit or guest room shall be equipped with a ventilation system complying with Section M1508.4, M1508.5, M1508.6 or M1508.7. Compliance is also permitted to be demonstrated through compliance with the International Mechanical Code.

M1508.1.1 ((Operating Instructions. Installers shall provide the manufacturer's installation, operating instructions, and a whole house ventilation system operation description.)) Control and Operation.

     1. Location of controls. Controls for all ventilation systems shall be readily accessible by the occupant.

     2. Instructions. Operating instructions for whole house ventilation systems shall be provided to the occupant by the installer of the system.

     3. Source specific ventilation systems. Source specific ventilation systems shall be controlled by manual switches, dehumidistats, timers, or other approved means.

     4. Continuous whole house ventilation systems. Continuous whole house ventilation systems shall operate continuously. Exhaust fans, forced-air system fans, or supply fans shall be equipped with "fan on" as override controls. Controls shall be capable of operating the ventilation system without energizing other energy-consuming appliances. A label shall be affixed to the controls that reads "Whole House Ventilation (see operating instructions)."

     5. Intermittent whole house ventilation systems. Intermittent whole house ventilation systems shall comply with the following:

     5.1 They shall be capable of operating intermittently and continuously.

     5.2 They shall have controls capable of operating the exhaust fans, forced-air system fans, or supply fans without energizing other energy-consuming appliances.

     5.3 The ventilation rate shall be adjusted in accordance with Section M1508.3.

     5.4 The system shall be designed so that it can operate automatically based on the type of control timer installed.

     5.5 The intermittent mechanical ventilation system shall operate at least one hour out of every twelve.

     5.6 The system shall have a manual control and automatic control, such as a 24-hour clock timer.

     5.7 At the time of final inspection, the automatic control shall be set to operate the whole house fan according to the schedule used to calculate the whole house fan sizing.

     5.8 A label shall be affixed to the control that reads "Whole House Ventilation (see operating instructions)."

M1508.2 Continuously Operating Exhaust Ventilation Systems. Continuously operating exhaust ventilation systems shall provide the minimum flow rates specified in Table M1508.2.

TABLE M1508.2
MINIMUM VENTILATION RATES
(Continuously operating systems)

Qf = Qr/(&egr;f)

Where:

Qf	=	Fan flow rate
Qr	=	Ventilation air requirement (from Table M1508.2)
&egr;	=	Ventilation effectiveness (from Table M1508.3)
f	=	Fractional operation time

TABLE M1508.3
VENTILATION EFFECTIVENESS FOR INTERMITTENT FANS

M1508.4.1 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 ((M1503.2 [M1508.2])) M1508.2 or M1508.3, as applicable. Manufacturers' fan flow ratings shall be determined according to HVI 916 (April 1995) or AMCA 210.

M1508.4.2 Fan Noise. Whole house fans located 4 feet or less from the interior grille shall have a sone rating of 1.0 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.

M1508.4.3 ((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 8 hours a day. A label shall be affixed to the control that reads "Whole House Ventilation (see operating instructions)."

M1508.4.4)) 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.

((M1508.4.5)) M1508.4.4 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. Doors shall be undercut to a minimum of 1/2 inch above the surface of the finish floor covering.

     Individual room outdoor air inlets shall:

     1. Have controllable and secure openings;

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

     3. Provide not less than 4 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 4 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:

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

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

     3. A hazardous or unsanitary location.

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

     5. 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.

     6. Attic, crawl spaces, or garages.

M1508.5 ((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.

M1508.5.1 Integrated Whole House Ventilation Systems. Integrated whole house ventilation systems shall provide outdoor air at the rate calculated using Section M1508.2 or M1508.3, as applicable. 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 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 system will be equipped with a motorized damper connected to the automatic ventilation control as specified in Section M1508.5.2. The required flow rate shall be verified by field testing with a flow hood or a flow measuring station.

M1508.5.2 ((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 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 8 hours a day. A label shall be affixed to the control that reads "Whole House Ventilation (see operating instructions)."

M1508.5.3)) Ventilation Duct Insulation. All supply ducts in the conditioned space shall be insulated to a minimum of R-4.

((M1508.5.4)) M1508.5.3 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:

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

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

     3. A hazardous or unsanitary location.

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

     5. 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.

     6. Attic, crawl spaces, or garages.

M1508.6 ((. 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.

    
M1508.6.1 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 M1508.2 or M1508.3, as applicable, at 0.40 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, in line with the fan, or, in the case of a connection to the return plenum of the air handler, using the furnace filter. An outdoor air inlet shall be connected to either the supply or return air stream.

M1508.6.2 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 4 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 M1508.6.2. The terminal element on the outside of the building shall be sized 2 inches in diameter larger than the outdoor air inlet duct.

TABLE M1508.6.2
     PRESCRIPTIVE SUPPLY FAN DUCT SIZING

     1. A calibrated manual volume damper installed and set to meet the measured flow rates specified in Table ((M1508.2)) M1508.3 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 ((M1508.2)) M1508.3 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 M1508.2 which provides constant flow over a pressure range of 0.20 to 0.60 inches water gauge.

M1508.6.4 ((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 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 8 hours a day. A label shall be affixed to the control that reads "Whole House Ventilation (see operating instructions)."

M1508.6.5)) Ventilation Duct Insulation. All supply ducts in the conditioned space shall be insulated to a minimum of R-4.

((M1508.6.6)) M1508.6.5 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:

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

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

     3. A hazardous or unsanitary location.

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

     5. 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.

     6. Attic, crawl spaces, or garages.

M1508.7 ((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.

M1508.7.1 Heat Recovery Ventilation Systems. All duct work in heat recovery systems shall be sized and installed per the manufacturer's instructions. System minimum flow rating shall be not less than that specified in Table M1508.2 or M1508.3, as applicable. Heat recovery ventilation systems shall have a filter on the upstream side of the heat exchanger in both the intake and exhaust airstreams with a minimum efficiency ratings value (MERV) of 6.

M1508.7.2 ((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 8 hours a day. A label shall be affixed to the control that reads "Whole House Ventilation (see operating instructions)."

M1508.7.3)) 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.

((M1508.7.4)) M1508.7.3 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:

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

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

     3. A hazardous or unsanitary location.

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

     5. 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.

     6. Attic, crawl spaces, or garages.

[Statutory Authority: RCW 19.27.031 and 19.27.074. 10-03-098, § 51-51-1508, filed 1/20/10, effective 7/1/10.]

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