WSR 08-17-086

PROPOSED RULES

BUILDING CODE COUNCIL


[ Filed August 19, 2008, 3:44 p.m. ]

     Original Notice.

     Preproposal statement of inquiry was filed as WSR 08-14-042.

     Title of Rule and Other Identifying Information: Amending chapter 51-11 WAC, Washington State Energy Code.

     Hearing Location(s): Renton Holiday Inn Select, One South Grady Way, Renton, WA 98055-2500, on October 10, 2008, at 10:00 a.m.

     Date of Intended Adoption: November 14, 2008.

     Submit Written Comments to: John Neff, Council Chair, P.O. Box 42525, Olympia, WA 98504-2525, e-mail sbcc@cted.wa.gov, fax (360) 586-9383, by October 10, 2008.

     Assistance for Persons with Disabilities: Contact Sue Mathers by October 3, 2008, TTY (360) 753-7427 or (360) 725-2966.

     Purpose of the Proposal and Its Anticipated Effects, Including Any Changes in Existing Rules: The state building code council is considering revisions to the energy code to (1) allow for unvented attic assemblies and (2) require residential duct testing or placing the heating systems inside the conditioned space. The requirements for unvented attic assemblies are found in Sections 502.1.6.3, 1007 and 1313.2, and a new definition is added to Section 201. The proposed requirements for residential duct sealing and testing are found in Section 503.10.2.

     Reasons Supporting Proposal: RCW 19.27A.025 and 19.27A.045.

     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.

     Agency Comments or Recommendations, if any, as to Statutory Language, Implementation, Enforcement, and Fiscal Matters: The council is seeking comments on the issue proposed in the rule shown below.

     Name of Proponent: Washington state building code council, governmental.

     Name of Agency Personnel Responsible for Drafting and Implementation: Krista Braaksma, P.O. Box 42525, Olympia, WA 98504-2525, (360) 725-2964; and Enforcement: Local jurisdictions.

     No small business economic impact statement has been prepared under chapter 19.85 RCW. This proposed amendment is intended to reduce the cost of residential cooling systems and was determined to not have a disproportionate cost on small businesses. This rule effectively cancels out the code change previously proposed and reinstates the previous code provision; therefore, there is no difference in cost.

     A cost-benefit analysis is not required under RCW 34.05.328. This rule reinstates a previous rule and poses no change in cost or compliance.

August 19, 2008

John P. Neff

Council Chair

OTS-1759.2


AMENDATORY SECTION(Amending WSR 07-01-089, filed 12/19/06, effective 7/1/07)

WAC 51-11-0201   Scope.   The following definitions shall apply to chapters 1 through 20.


     201.1 Application of Terms: For the purposes of this Code, certain abbreviations, terms, phrases, words and their derivatives, shall be as set forth in this chapter. Where terms are not defined, they shall have their ordinary accepted meanings within the context with which they are used. In the event there is a question about the definition of a term, the definitions for terms in the codes enumerated in RCW 19.27.031 and the edition of Webster's dictionary referenced therein shall be considered as the sources for providing ordinarily accepted meanings.

     Addition: See the Washington State Building Code.

     Advanced framed ceiling: Advanced framing assumes full and even depth of insulation extending to the outside edge of exterior walls. (See Standard Framing and Section 1007.2 of this Code.)

     Advanced framed walls: Studs framed on twenty-four inch centers with double top plate and single bottom plate. Corners use two studs or other means of fully insulating corners, and one stud is used to support each header. Headers consist of double 2X material with R-10 insulation between the header and exterior sheathing. Interior partition wall/exterior wall intersections are fully insulated in the exterior wall. (See Standard Framing and Section 1005.2 of this Code.)

     AFUE. Annual fuel utilization efficiency: Unlike steady state conditions, this rating is based on average usage including on and off cycling as set out in the standardized Department of Energy Test Procedures.

     Air conditioning, comfort: The process of treating air to control simultaneously its temperature, humidity, cleanliness and distribution to meet requirements of the conditioned space.

     Air-impermeable insulation. An insulation having an air permeance equal to or less than 0.02L/s-m2 at 75 Pa pressure differential tested in accordance with ASTM E 2178 or ASTM E 283.

     ARI: Air-Conditioning and Refrigeration Institute.

     ASHRAE: American Society of Heating, Refrigerating and Air Conditioning Engineers, Inc.

     ASTM: American Society for Testing and Materials

     Automatic: Self-acting, operating by its own mechanism when actuated by some impersonal influence, as for example, a change in current strength, pressure, temperature or mechanical configuration. (See Manual.)

     Below grade walls: Walls or the portion of walls which are entirely below the finish grade or which extend two feet or less above the finish grade.

     Boiler capacity: The rate of heat output in Btu/h measured at the boiler outlet, at the design inlet and outlet conditions and rated fuel/energy input.

     Building envelope: For Group R Occupancy, the elements of a building which enclose conditioned spaces through which thermal energy may be transferred to or from the exterior or to or from spaces exempted by the provisions of Section 101.3.1. For other than Group R Occupancy, the elements of a building which enclose conditioned spaces through which thermal energy may be transferred to or from the exterior, or to or from unconditioned spaces, or to or from semi-heated spaces, or to or from spaces exempted by the provisions of Section 1301.

     Building, existing: See the Washington State Building Code.

     Building official: The official authorized to act in behalf of a jurisdiction code enforcement agency or its authorized representative.

     Building project: A building or group of buildings, including on-site energy conversion or electric-generating facilities, which utilize a single submittal for a construction permit or are within the boundary of a contiguous area under one ownership.

     Conditioned floor area: (See Gross conditioned floor area.)

     Conditioned space: A cooled space, heated space (fully heated), heated space (semi-heated) or indirectly conditioned space.

     Cooled space: An enclosed space within a building that is cooled by a cooling system whose sensible capacity

     a. Exceeds 5 Btu/(h•ft2), or

     b. Is capable of maintaining space dry bulb temperature of 90°F or less at design cooling conditions.

     COP - Coefficient of performance: The ratio of the rate of net heat output (heating mode) or heat removal (cooling mode) to the rate of total on-site energy input to the heat pump, expressed in consistent units and under designated rating conditions. (See Net Heat Output, Net Heat Removal, Total On-Site Energy Input.)

     Daylighted zone:

     a. Under overhead glazing: The area under overhead glazing whose horizontal dimension, in each direction, is equal to the overhead glazing dimension in that direction plus either the floor to ceiling height or the dimension to a ceiling height opaque partition, or one-half the distance to adjacent overhead or vertical glazing, whichever is least.

     b. At vertical glazing: The area adjacent to vertical glazing which receives daylighting from the glazing. For purposes of this definition and unless more detailed daylighting analysis is provided, the daylighting zone depth is assumed to extend into the space a distance of 15 feet or to the nearest ceiling height opaque partition, whichever is less. The daylighting zone width is assumed to be the width of the window plus either two feet on each side (the distance to an opaque partition) or one-half the distance to adjacent overhead or vertical glazing, whichever is least.

     Daylight sensing control (DS): A device that automatically regulates the power input to electric lighting near the glazing to maintain the desired workplace illumination, thus taking advantage of direct or indirect sunlight.

     Deadband: The temperature range in which no heating or cooling is used.

     Demand control ventilation (DCV): A ventilation system capability that provides for the automatic reduction of outdoor air intake below design rates when the actual occupancy of spaces served by the system is less than design occupancy.

     Design cooling conditions: The cooling outdoor design temperature from the 0.5% column for summer from the Puget Sound Chapter of ASHRAE publication "Recommended Outdoor Design Temperatures, Washington State, ASHRAE."

     Design heating conditions: The heating outdoor design temperature from the 0.6% column for winter from the Puget Sound Chapter of ASHRAE publication "Recommended Outdoor Design Temperatures, Washington State, ASHRAE."

     Door: All operable opening areas, which are not glazing, in the building envelope including swinging and roll-up doors, fire doors, smoke vents and access hatches.

     Door area: Total area of door measured using the rough opening and including the door and frame.

     Dwelling unit: See the Washington State Building Code.

     Economizer, air: A ducting arrangement and automatic control system that allows a cooling supply fan system to supply outside air to reduce or eliminate the need for mechanical refrigeration during mild or cold weather.

     Economizer, water: A system by which the supply air of a cooling system is cooled directly, indirectly or both, by evaporation of water or by other appropriate fluid in order to reduce or eliminate the need for mechanical refrigeration.

     EER. Energy efficiency ratio: The ratio of net equipment cooling capacity in Btu/h to total rate of electric input in watts under designated operating conditions.

     Efficiency, HVAC system: The ratio of useful energy (at the point of use) to the energy input for a designated time period, expressed in percent.

     Emissivity: The ability to absorb infrared radiation. A low emissivity implies a higher reflectance of infrared radiation.

     Energy: The capacity for doing work; taking a number of forms which may be transformed from one into another, such as thermal (heat), mechanical (work), electrical and chemical; in customary units, measured in kilowatt-hours (kWh) or British thermal units (Btu). (See New energy.)

     Energy, recovered: (See Recovered energy.)

     Exterior envelope: (See Building envelope.)

     F-Factor: The perimeter heat loss factor expressed in Btu/hr•ft•°F.

     F-Value: (See F-Factor.)

     Facade area: Vertical projected area including nonhorizontal roof area, overhangs, cornices, etc. measured in elevation in a vertical plane parallel to the plane of the building face.

     Floor over unconditioned space: A floor which separates a conditioned space from an unconditioned space which is buffered from exterior ambient conditions including vented crawl spaces and unconditioned basements or other similar spaces, or exposed to exterior ambient conditions including open parking garages and enclosed garages which are mechanically ventilated.

     Garden window: A multisided glazing product that projects beyond the plane of the wall.

     Glazed wall system: A category of site assembled fenestration products used in the NFRC 100 and NFRC 200 rating procedures that include curtainwalls.

     Glazing: All areas, including the frames, in the shell of a conditioned space that let in natural light including windows, clerestories, skylights, sliding or swinging glass doors and glass block walls.

     Glazing area: Total area of the glazing measured using the rough opening, and including the glazing, sash, and frame. For doors where the daylight opening area is less than 50% of the door area, the glazing area is the daylight opening area. For all other doors, the glazing area is the door area.

     Gross conditioned floor area: The horizontal projection of that portion of interior space which is contained within exterior walls and which is conditioned directly or indirectly by an energy-using system, and which has an average height of five feet or greater, measured from the exterior faces.

     Gross exterior wall area: The normal projection of the building envelope wall area bounding interior space which is conditioned by an energy-using system and which separates conditioned space from: Unconditioned space, or semi-heated space, or exterior ambient conditions or earth; includes opaque wall, vertical glazing and door areas. The gross area of walls consists of all opaque wall areas, including foundation walls, between floor spandrels, peripheral edges of floors, vertical glazing areas and door areas, where such surfaces are exposed to exterior ambient conditions and enclose a conditioned space including interstitial areas between two such spaces. The area of the wall is measured from the top of the floor insulation to the bottom of the roof insulation. (See Below grade wall.)

     Gross floor area: The sum of the areas of the several floors of the building, including basements, cellars, mezzanine and intermediate floored tiers and penthouses of headroom height, measured from the exterior faces of exterior walls or from the center line of walls separating buildings, but excluding: Covered walkways, open roofed-over areas, porches and similar spaces. Pipe trenches, exterior terraces or steps, chimneys, roof overhangs and similar features.

     Gross roof/ceiling area: A roof/ceiling assembly shall be considered as all components of the roof/ceiling envelope through which heat flows, thus creating a building transmission heat loss or gain, where such assembly is exposed to exterior ambient conditions and encloses a conditioned space. The assembly does not include those components that are separated from a heated and/or cooled space by a vented airspace. The gross area of a roof/ceiling assembly consists of the total interior surface of such assembly, including overhead glazing.

     Guest room: See the Washington State Building Code.

     Heat: The form of energy that is transferred by virtue of a temperature difference.

     Heat storage capacity: The physical property of materials (mass) located inside the building envelope to absorb, store, and release heat.

     Heated space (Fully heated): An enclosed space within a building, including adjacent connected spaces separated by an uninsulated component (e.g., basements, utility rooms, garages, corridors), which is heated by a heating system whose output capacity is

     a. Capable of maintaining a space dry-bulb temperature of 45°F or greater at design heating conditions; or

     b. 8 Btu/(h•ft2) or greater in Climate Zone 1 and 12 Btu/(h•ft2) or greater in Climate Zone 2.

     Heated space (Semi-heated): An enclosed space within a building, including adjacent connected spaces separated by an uninsulated component (e.g., basements, utility rooms, garages, corridors), which is heated by a heating system

     a. Whose output capacity is 3 Btu/(h•ft2) or greater in Climate Zone 1 and 5 Btu/(h•ft2) or greater in Climate Zone 2; and

     b. Is not a Heated Space (Fully Heated).

     High efficacy luminaire: A lighting fixture that does not contain a medium screw base socket (E24/E26) and whose lamps have a minimum efficiency of:

     a. 60 lumens per watt for lamps over 40 watts;

     b. 50 lumens per watt for lamps over 15 watts to 40 watts;

     c. 40 lumens per watt for lamps 15 watts or less.

     HSPF. Heating season performance factor: The total heating output (in Btu) of a heat pump during its normal annual usage period for heating divided by the total (watt hour) electric power input during the same period, as determined by test procedures consistent with the U.S. Department of Energy "Test Procedure for Central Air Conditioners, Including Heat Pumps" published in Standard RS-30. When specified in Btu per watt hour an HSPF of 6.826 is equivalent to a COP of 2.0.

     Humidistat: A regulatory device, actuated by changes in humidity, used for automatic control of relative humidity.

     HVAC: Heating, ventilating and air conditioning.

     HVAC system components: HVAC system components provide, in one or more factory-assembled packages, means for chilling and/or heating water with controlled temperature for delivery to terminal units serving the conditioned spaces of the buildings. Types of HVAC system components include, but are not limited to, water chiller packages, reciprocating condensing units and water source (hydronic) heat pumps. (See HVAC system equipment.)

     HVAC system efficiency: (See Efficiency, HVAC system.)

     HVAC system equipment: HVAC system equipment provides, in one (single package) or more (split system) factory-assembled packages, means for air circulation, air cleaning, air cooling with controlled temperature and dehumidification; and optionally, either alone or in combination with a heating plant, the functions of heating and humidifying. The cooling function may be either electrically or heat operated and the refrigerant condenser may be air, water or evaporatively cooled. Where the equipment is provided in more than one package, the separate packages shall be designed by the manufacturer to be used together. The equipment may provide the heating function as a heat pump or by the use of electric elements. (The word "equipment" used without modifying adjective may, in accordance with common industry usage, apply either to HVAC system equipment or HVAC system components.)

     Indirectly conditioned space: An enclosed space within a building that is not a heated or cooled space, whose area weighted heat transfer coefficient to heated or cooled spaces exceeds that to the outdoors or to unconditioned spaces; or through which air from heated or cooled spaces is transferred at a rate exceeding three air changes per hour. Enclosed corridors between conditioned spaces shall be considered as indirectly conditioned space. (See Heated Space, Cooled Space and Unconditioned Space.)

     Infiltration: The uncontrolled inward air leakage through cracks and interstices in any building element and around windows and doors of a building caused by the pressure effects of wind and/or the effect of differences in the indoor and outdoor air density.

     Insulation baffle: A rigid material, resistant to wind driven moisture, the purpose of which is to allow air to flow freely into the attic or crawl space and to prevent insulation from blocking the ventilation of these spaces, or the loss of insulation. Example materials for this purpose are sheet metal, or wax impregnated cardboard.

     Insulation position:

     a. Exterior Insulation Position: A wall having all or nearly all of its mass exposed to the room air with the insulation on the exterior of the mass.

     b. Integral Insulation Position: A wall having mass exposed to both room and outside air, with substantially equal amounts of mass on the inside and outside of the insulation layer.

     c. Interior Insulation Position: A wall not meeting either of the above definitions; particularly a wall having most of its mass external to the insulation layer.

     International Building Code (IBC): (See Washington State Building Code.)

     International Mechanical Code (IMC): (See Washington State Building Code.)

     IPLV -- Integrated part-load value: A single number figure of merit based on part-load EER or COP expressing part-load efficiency for air conditioning and heat pump equipment on the basis of weighted operation at various load capacities for the equipment as specified in the Air-Conditioning and Refrigeration Institute (ARI) and Cooling Tower Institute (CTI) procedures.

     Luminaire: A complete lighting unit consisting of a lamp or lamps together with the parts designed to distribute the light, to position and protect the lamps and to connect the lamps to the electric power supply.

     Manual: Capable of being operated by personal intervention. (See Automatic.)

     Microcell: A wireless communication facility consisting of an antenna that is either: (a) Four (4) feet in height and with an area of not more than 580 square inches; or (b) if a tubular antenna, no more than four (4) inches in diameter and no more than six (6) feet in length; and the associated equipment cabinet that is six (6) feet or less in height and no more than 48 square feet in floor area.

     NFPA: National Fire Protection Association.

     NFRC: National Fenestration Rating Council.

     Net heat output: The change in the total heat content of the air entering and leaving the equipment (not including supplementary heat and heat from boilers).

     Net heat removal: The total difference in heat content of the air entering and leaving the equipment (without heat) or the difference in total heat content of the water or refrigerant entering and leaving the component.

     New energy: Energy, other than recovered energy, utilized for the purpose of heating or cooling. (See energy.)

     Nominal R-value: The thermal resistance of insulation alone as determined in accordance with the U.S. Federal Trade Commission R-value rule (CFR Title 16, Part 460) in units of h• ft2 • °F/Btu at a mean temperature of 75°F. Nominal R-value refers to the thermal resistance of the added insulation in framing cavities or insulated sheathing only and does not include the thermal resistance of other building materials or air films.

     Nonrenewable energy sources: All energy sources that are not renewable energy sources including natural gas, oil, coal, wood, liquified petroleum gas, steam, and any utility-supplied electricity.

     Nonresidential: All buildings and spaces in the International Building Code (IBC) occupancies other than Group R.

     Occupancy: See the Washington State Building Code.

     Occupancy sensor: A device that detects occupants within an area, causing any combination of lighting, equipment or appliances to be turned on or shut off.

     Opaque envelope areas: All exposed areas of a building envelope which enclose conditioned space, except openings for doors, glazing and building service systems.

     Open blown: Loose fill insulation pneumatically installed in an unconfined attic space.

     Outdoor air (outside air): Air taken from the outdoors and, therefore, not previously circulated through a building.

     Overhead glazing: A glazing surface that has a slope of less than 60° from the horizontal plane.

     Packaged terminal air conditioner: A factory-selected combination of heating and cooling components, assemblies or sections intended to serve a room or zone. (For the complete technical definition, see Standard RS-5.)

     Permeance (perm): The ability of a material of specified thickness to transmit moisture in terms of amount of moisture transmitted per unit time for a specified area and differential pressure (grains per hour • ft2 • inches of HG). Permeance may be measured using ASTM E-96-00 or other approved dry cup method as specified in RS-1.

     Personal wireless service facility: A Wireless Communication Facility (WCF), including a microcell, which is a facility for the transmission and/or reception of radio frequency signals and which may include antennas, equipment shelter or cabinet, transmission cables, a support structure to achieve the necessary elevation, and reception and/or transmission devices or antennas.

     Pool cover: A vapor-retardant cover which lies on or at the surface of the pool.

     Power: In connection with machines, the time rate of doing work. In connection with the transmission of energy of all types, the rate at which energy is transmitted; in customary units, it is measured in watts (W) or British Thermal Units per hour (Btu/h).

     Process energy: Energy consumed in support of a manufacturing, industrial, or commercial process other than the maintenance of building comfort or amenities for building occupants.

     Radiant slab floor: A slab floor assembly on grade or below, containing heated pipes, ducts, or electric heating cables that constitute a floor or portion thereof for complete or partial heating of the structure.

     Readily accessible: See the Washington State Mechanical Code.

     Recooling: The removal of heat by sensible cooling of the supply air (directly or indirectly) that has been previously heated above the temperature to which the air is to be supplied to the conditioned space for proper control of the temperature of that space.

     Recovered energy: Energy utilized which would otherwise be wasted (i.e. not contribute to a desired end use) from an energy utilization system.

     Reheat: The application of sensible heat to supply air that has been previously cooled below the temperature of the conditioned space by either mechanical refrigeration or the introduction of outdoor air to provide cooling.

     Renewable energy sources: Renewable energy sources of energy (excluding minerals) are derived from: (1) Incoming solar radiation, including but not limited to, natural daylighting and photosynthetic processes; (2) energy sources resulting from wind, waves and tides, lake or pond thermal differences; and (3) energy derived from the internal heat of the earth, including nocturnal thermal exchanges.

     Reset: Adjustment of the set point of a control instrument to a higher or lower value automatically or manually to conserve energy.

     Roof/ceiling assembly: (See Gross roof/ceiling area.)

     SEER - Seasonal Energy Efficiency Ratio: The total cooling output of an air conditioner during its normal annual usage period, in Btu's, divided by the total electric energy input in watt-hours, during the same period, as determined by 10 CFR, Part 430.

     Semi-heated space: Sub-category of Heated Space. (See Heated Space.)

     Sequence: A consecutive series of operations.

     Service systems: All energy-using systems in a building that are operated to provide services for the occupants or processes housed therein, including HVAC, service water heating, illumination, transportation, cooking or food preparation, laundering or similar functions.

     Service water heating: Supply of hot water for domestic or commercial purposes other than comfort heating.

     Shaded: Glazed area which is externally protected from direct solar radiation by use of devices permanently affixed to the structure or by an adjacent building, topographical feature, or vegetation.

     Shading coefficient: The ratio of solar heat gain occurring through nonopaque portions of the glazing, with or without integral shading devices, to the solar heat gain occurring through an equivalent area of unshaded, 1/8 inch thick, clear, double-strength glass.


Note: Heat gains to be compared under the same conditions. See Chapter 30 of Standard RS-1, listed in Chapter 7 of this Code.

     Shall: Denotes a mandatory code requirement.

     Single family: One and two family residential dwelling units with no more than two units in a single building.

     Skylight: (See Overhead glazing.)

     Slab-below-grade: Any portion of a slab floor in contact with the ground which is more than 24 inches below the final elevation of the nearest exterior grade.

     Slab-on-grade, exterior: Any portion of a slab floor in contact with the ground which is less than or equal to twenty-four inches below the final elevation of the nearest exterior grade.

     Small business: Any business entity (including a sole proprietorship, corporation, partnership, or other legal entity) which is owned and operated independently from all other businesses, which has the purpose of making a profit, and which has fifty or fewer employees, or which has a million dollars or less per year in gross sales, of window products.

     Solar energy source: Source of natural daylighting and of thermal, chemical or electrical energy derived directly from conversion of incident solar radiation.

     Solar heat gain coefficient (SHGC): The ratio of the solar heat gain entering the space through the glazing product to the incident solar radiation. Solar heat gain includes directly transmitted solar heat and absorbed solar radiation which is then reradiated, conducted or convected into the space.

     Split system: Any heat pump or air conditioning unit which is provided in more than one assembly requiring refrigeration piping installed in the field.

     Standard framing: All framing practices not defined as "intermediate" or "advanced" shall be considered standard. (See Advanced framed ceiling, Advanced framed walls, Intermediate framed wall and Section 1005.2 of this Code.)

     Substantial contact: A condition where adjacent building materials are placed in a manner that proximal surfaces are contiguous, being installed and supported as to eliminate voids between materials, without compressing or degrading the thermal performance of either product.

     System: A combination of central or terminal equipment or components and/or controls, accessories, interconnecting means, and terminal devices by which energy is transformed so as to perform a specific function, such as HVAC, service water heating or illumination.

     Tapering: Installation of a reduced level of ceiling insulation at the eaves, due to reduced clearance.

     Thermal by-pass: An area where the envelope surrounding the conditioned space is breached, or where an ineffective application compromises the performance of a thermal or infiltration barrier, increasing the structure's energy consumption by exposing finished surfaces to ambient conditions and additional heat transfer.

     Thermal conductance (C): Time rate of heat flow through a body (frequently per unit area) from one of its bounding surfaces to the other for a unit temperature difference between the two surfaces, under steady conditions (Btu/hr • ft2 •°F).

     Thermal resistance (R): The reciprocal of thermal conductance (hr • ft2 •°F/Btu).

     Thermal transmittance (U): The coefficient of heat transmission (air to air). It is the time rate of heat flow per unit area and unit temperature difference between the warm side and cold side air films (Btu/hr • ft2 •°F).

     Thermal transmittance, overall (Uo): The overall (average) heat transmission of a gross area of the exterior building envelope (Btu/hr • ft2 •°F). The Uo-factor applies to the combined effect of the time rate of heat flows through the various parallel paths, such as glazing, doors and opaque construction areas, comprising the gross area of one or more exterior building components, such as walls, floors or roof/ceiling.

     Thermostat: An automatic control device actuated by temperature and designed to be responsive to temperature.

     Total on-site energy input: The combination of all the energy inputs to all elements and accessories as included in the equipment components, including but not limited to, compressor(s), compressor sump heater(s), circulating pump(s), purge devices, fan(s), and the HVAC system component control circuit.

     Transmission coefficient: The ratio of the solar heat gain through a glazing system to that of an unshaded single pane of double strength window glass under the same set of conditions.

     Transverse joint: The primary connection between air distribution system fittings.

     U-factor: (See thermal transmittance.)

     U-Value: (See U-factor.)

     Uniform Plumbing Code (UPC): (See Washington State Plumbing Code.)

     Unitary cooling and heating equipment: One or more factory-made assemblies which include an evaporator or cooling coil, a compressor and condenser combination, and may include a heating function as well. Where such equipment is provided in more than one assembly, the separate assemblies shall be designed to be used together.

     Unitary heat pump: One or more factory-made assemblies which include an indoor conditioning coil, compressor(s) and outdoor coil or refrigerant-to-water heat exchanger, including means to provide both heating and cooling functions. When such equipment is provided in more than one assembly, the separate assemblies shall be designed to be used together.

     Vapor retarder: A layer of low moisture transmissivity material (not more than 1.0 perm dry cup) placed over the warm side (in winter) of insulation, over the exterior of below grade walls, and under floors as ground cover to limit the transport of water and water vapor through exterior walls, ceilings, and floors. Vapor retarding paint, listed for this application, also meets this definition.

     Vaulted ceilings: All ceilings where enclosed joist or rafter space is formed by ceilings applied directly to the underside of roof joists or rafters.

     Ventilation: The process of supplying or removing air by natural or mechanical means to or from any space. Such air may or may not have been conditioned.

     Ventilation air: That portion of supply air which comes from outside (outdoors) plus any recirculated air that has been treated to maintain the desired quality of air within a designated space.

     Vertical glazing: A glazing surface that has a slope of 60° or greater from the horizontal plane.

     Walls (exterior): Any member or group of members which defines the exterior boundaries or courts of a building and which have a slope of sixty degrees or greater with the horizontal plane, and separates conditioned from unconditioned space. Band joists between floors are to be considered a part of exterior walls.

     Washington State Building Code: The Washington State Building Code is comprised of the International Building Code; the International Residential Code; the International Mechanical Code; the International Fire Code; the Uniform Plumbing Code; the state regulations for barrier-free facilities, as designated in RCW 19.27.031; the State Energy Code; and any other codes so designated by the Washington state legislature as adopted and amended by the State Building Code Council.

     Zone: A space or group of spaces within a building with heating and/or cooling requirements sufficiently similar so that comfort conditions can be maintained throughout by a single controlling device. Each dwelling unit in residential buildings shall be considered a single zone.

[Statutory Authority: RCW 19.27A.022, 19.27A.025, 19.27A.045, and chapters 19.27 and 34.05 RCW. 07-01-089, § 51-11-0201, filed 12/19/06, effective 7/1/07. Statutory Authority: RCW 19.27A.020, 19.27A.045. 04-01-106, § 51-11-0201, filed 12/17/03, effective 7/1/04; 02-24-076, § 51-11-0201, filed 12/4/02, effective 5/1/03. Statutory Authority: RCW 19.27A.025, 19.27A.045. 01-03-010, § 51-11-0201, filed 1/5/01, effective 7/1/01; 98-03-003, § 51-11-0201, filed 1/8/98, effective 7/1/98. Statutory Authority: Chapters 19.27, 19.27A and 34.05 RCW. 94-05-059, § 51-11-0201, filed 2/10/94, effective 4/1/94. Statutory Authority: RCW 19.27A.025. 93-21-052, § 51-11-0201, filed 10/18/93, effective 4/1/94. Statutory Authority: RCW 19.27A.020 and 1990 c 2. 91-01-112, § 51-11-0201, filed 12/19/90, effective 7/1/91.]


AMENDATORY SECTION(Amending WSR 07-01-089, filed 12/19/06, effective 7/1/07)

WAC 51-11-0502   Building envelope requirements.  


     502.1 General:


     502.1.1: The stated U- or F-factor of any component assembly, listed in Table 5-1 ((or 5-2)), such as roof/ceiling, opaque wall or opaque floor may be increased and the U-factor for other components decreased, provided that the total heat gain or loss for the entire building envelope does not exceed the total resulting from compliance to the U-factors specified in this section.


     The U-factors for typical construction assemblies are included in Chapter 10. These values shall be used for all calculations. Where proposed construction assemblies are not represented in Chapter 10, values shall be calculated in accordance with Chapters 23-30 in Standard RS-1 listed in Chapter 7, using the framing factors listed in Chapter 10 where applicable.


     For envelope assemblies containing metal framing, the U-factor shall be determined by one of the following methods:


     1. Results of laboratory or field measurements.


     2. Standard RS-1, listed in Chapter 7, where the metal framing is bonded on one or both sides to a metal skin or covering.


     3. The zone method as provided in Chapter 25 of Standard RS-1, listed in Chapter 7.


     4. Results of parallel path correction factors effective framing/cavity R-values as provided in Table 10-5A - EFFECTIVE R-VALUES FOR METAL FRAMING AND CAVITY ONLY for metal stud walls and roof/ceilings.


     502.1.2: For consideration of thermal mass effects, see section 402.4.


     502.1.3: When return air ceiling plenums are employed, the roof/ceiling assembly shall:


     a. For thermal transmittance purposes, not include the ceiling proper nor the plenum space as part of the assembly; and


     b. For gross area purposes, be based upon the interior face of the upper plenum surface.


     502.1.4 Insulation:


     502.1.4.1 General: All insulating materials shall comply with sections 2603 and/or 719 of the International Building Code. Substantial contact of the insulation with the surface being insulated is required. All insulation materials shall be installed according to the manufacturer's instructions to achieve proper densities and maintain uniform R-values and shall be installed in a manner which will permit inspection of the manufacturer's R-value identification mark. To the maximum extent possible, insulation shall extend over the full component area to the intended R-value.


     Alternatively, the thickness of roof/ceiling and wall insulation that is either blown in or spray-applied shall be identified by inches of thickness, density and R-value markers installed at least one for every 300 square feet (28 m2) through the attic, ceiling and/or wall space. In attics, the markers shall be affixed to the trusses or joists and marked with the minimum initial installed thickness and minimum settled thickness with numbers a minimum 1.0 inch (25 mm) in height. Each marker shall face the attic access. The thickness of installed attic insulation shall meet or exceed the minimum initial installed thickness shown by the marker. In cathedral ceilings and walls, the markers shall be affixed to the rafter and wall frame at alternating high and low intervals and marked with the minimum installed density and R-value with numbers a minimum 1.0 inch (25 mm) in height. Each marker shall face the conditioned room area.


     502.1.4.2 Insulation Materials: All insulation materials including facings such as vapor barriers or breather papers installed within floor/ceiling assemblies, roof/ceiling assemblies, walls, crawl spaces, or attics shall have a flame spread rating of less than 25 and a smoke density not to exceed 450 when tested in accordance with ASTM E84-01.


EXCEPTIONS: 1. Foam plastic insulation shall comply with section 2603 of the International Building Code.
2. When such materials are installed in concealed spaces of Types III, IV and V construction, the flame spread and smoke developed limitations do not apply to facing, provided that the facing is installed in substantial contact with the unexposed surface of the ceiling, floor or wall finish.
3. Cellulose insulation shall comply with section 719 of the International Building Code.

     502.1.4.3 Clearances: Where required, insulation shall be installed with clearances according to manufacturer's specifications. Insulation shall be installed so that required ventilation is unobstructed. For blown or poured loose fill insulation, clearances shall be maintained through installation of a permanent retainer.


     502.1.4.4 Access Hatches and Doors: Access doors from conditioned spaces to unconditioned spaces (e.g., attics and crawl spaces) shall be weatherstripped and insulated to a level equivalent to the insulation on the surrounding surfaces. Access shall be provided to all equipment which prevents damaging or compressing the insulation. A wood framed or equivalent baffle or retainer must be provided when loose fill insulation is installed, the purpose of which is to prevent the loose fill insulation from spilling into the living space when the attic access is opened, and to provide a permanent means of maintaining the installed R-value of the loose fill insulation.


     502.1.4.5 Roof/Ceiling Insulation: Open-blown or poured loose fill insulation may be used in attic spaces where the slope of the ceiling is not more than 3 feet in 12 and there is at least 30 inches of clear distance from the top of the bottom chord of the truss or ceiling joist to the underside of the sheathing at the roof ridge. When eave vents are installed, baffling of the vent openings shall be provided so as to deflect the incoming air above the surface of the insulation. Baffles shall be, rigid material, resistant to wind driven moisture. Requirements for baffles for ceiling insulation shall meet the International Building Code section 1203.2 for minimum ventilation requirements. When feasible, the baffles shall be installed from the top of the outside of the exterior wall, extending inward, to a point 6 inches vertically above the height of noncompressed insulation, and 12 inches vertically above loose fill insulation.


     502.1.4.6 Wall Insulation: Insulation installed in exterior walls shall comply with the provisions of this section. All wall insulation shall fill the entire framed cavity. Exterior wall cavities isolated during framing shall be fully insulated to the levels of the surrounding walls. All faced insulation shall be face stapled to avoid compression.


EXCEPTION: Framed cavity can be empty or partially filled provided:
1. The wall assembly calculations are performed along with a completed performance calculation for the whole building; and
2. Insulation installed in partially filled cavities is not included in the performance calculation.

     502.1.4.7 Floor Insulation: Floor insulation shall be installed in a permanent manner in substantial contact with the surface being insulated. Insulation supports shall be installed so spacing is no more than 24 inches on center. Foundation vents shall be placed so that the top of the vent is below the lower surface of the floor insulation.


EXCEPTION: Insulation may be omitted from floor areas over heated basements, heated garages or underfloor areas used as HVAC supply plenums. When foundation walls are insulated, the insulation shall be attached in a permanent manner. The insulation shall not block the airflow through foundation vents when installed. When foundation vents are not placed so that the top of the vent is below the lower surface of the floor insulation, a permanently attached baffle shall be installed at an angle of 30° from horizontal, to divert air flow below the lower surface of the floor insulation.

     502.1.4.8 Slab-On-Grade: Slab-on-grade insulation, installed inside the foundation wall, shall extend downward from the top of the slab for a minimum distance of 24 inches or downward and then horizontally beneath the slab for a minimum combined distance of 24 inches. Insulation installed outside the foundation shall extend downward to a minimum of 24 inches or to the frostline. Above grade insulation shall be protected.

EXCEPTION: For monolithic slabs, the insulation shall extend downward from the top of the slab to the bottom of the footing.

     502.1.4.9 Radiant Slabs: The entire area of a radiant slab shall be thermally isolated from the soil, with a minimum of R-10 insulation. The insulation shall be an approved product for its intended use. If a soil gas control system is present below the radiant slab, which results in increased convective flow below the radiant slab, the radiant slab shall be thermally isolated from the sub-slab gravel layer.


     502.1.4.10 Below Grade Walls: Below grade exterior wall insulation used on the exterior (cold) side of the wall shall extend from the top of the below grade wall to the top of the footing and shall be approved for below grade use. Above grade insulation shall be protected.


     Insulation used on the interior (warm) side of the wall shall extend from the top of the below grade wall to the below grade floor level.


     502.1.5 Glazing and Door U-factors: Glazing and door U-factors shall be determined in accordance with sections 502.1.5.1 and 502.1.5.2. All products shall be labeled with the NFRC certified or default U-factor. The labeled U-factor shall be used in all calculations to determine compliance with this Code. Sealed insulating glass shall conform to, or be in test for, ASTM E-774-81 class A.


EXCEPTIONS: 1. For glazed wall systems, assemblies with all of the following features are deemed to satisfy the vertical glazing U-factor requirement in Table 6-1 or 6-2 options with vertical glazing U-0.40 and greater:
a. Double glazing with a minimum 1/2 inch gap width, having a low-emissivity coating with e = 0.10 maximum, with 90% minimum argon gas fill, and a non-aluminum spacer (as defined in footnote 1 to Table 10-6B), and
b. Frame that is thermal break aluminum (as defined in footnote 9 to Table 10-6B), wood, aluminum clad wood, vinyl, aluminum clad vinyl, or reinforced vinyl.
The only labeling requirement for products using this exception shall be a description of the product and a label stating: "This product is deemed to satisfy the Table 6-1 or 6-2 vertical glazing U-factor requirement using the exception to Section 502.1.5 in the Washington State Energy Code."
2. For overhead glazing, assemblies with all of the following features are deemed to satisfy the overhead glazing U-factor requirement in Table 6-1 or 6-2 options except the unlimited glazing area options (Options IV and V in Table 6-1 and Options V, VI and VII in Table 6-2):
a. Either, double glazing with a minimum 1/2 inch gap width, having a low-emissivity coating with e =0.20 maximum, with 90% minimum argon gas fill, or, triple glazed plastic domes, and
b. Frame that is thermal break aluminum (as defined in footnote 9 to Table 10-6B), wood, aluminum clad wood, vinyl, aluminum clad vinyl, or reinforced vinyl.
The only labeling requirement for products using this exception shall be a description of the product and a label stating: "This product is deemed to satisfy the Table 6-1 or 6-2 overhead glazing U-factor requirement using the exception to Section 502.1.5 in the Washington State Energy Code."
3. For solariums with a floor area which does not exceed 300 square feet, assemblies which comply with the features listed in exception 2 are deemed to satisfy the vertical glazing and overhead glazing U-factor requirement in Table 6-1 or 6-2 options with vertical glazing U-0.40 and greater.
The only labeling requirement for products using this exception shall be a description of the product and a label stating: "This product is deemed to satisfy the Table 6-1 or 6-2 vertical glazing and overhead glazing U-factor requirements using the exception to Section 502.1.5 in the Washington State Energy Code."

     502.1.5.1 Standard Procedure for Determination of Glazing U-factors: U-factors for glazing shall be determined, certified and labeled in accordance with the National Fenestration Rating Council (NFRC) Product Certification Program (PCP), as authorized by an independent certification and inspection agency licensed by the NFRC. Compliance shall be based on the Residential Model Size. Product samples used for U-factor determinations shall be production line units or representative of units as purchased by the consumer or contractor. Products that are listed in the NFRC Certified Products Directory or certified to the NFRC standard shall not use default values.

EXCEPTIONS: 1. Glazing products without NFRC ratings may be assigned default U-factors from Table 10-6A for vertical glazing and from Table 10-6E for overhead glazing.
2. Units without NFRC ratings produced by a small business may be assigned default U-factors from Table 10-6A for garden windows, from Table 10-6B for other vertical glazing, and from Table 10-6E for overhead glazing.

     502.1.5.2 Standard Procedure for Determination of Door U-factors: All doors, including fire doors, shall be assigned default U-factors from Table 10-6C.


EXCEPTIONS: 1. U-factors determined, certified and labeled in accordance with the National Fenestration Rating Council (NFRC) Product Certification Program (PCP), as authorized by an independent certification and inspection agency licensed by the NFRC.
2. The default values for the opaque portions of doors shall be those listed in Table 10-6C, provided that the U-factor listed for a door with a thermal break shall only be allowed if both the door and the frame have a thermal break.
3. One unlabeled or untested exterior swinging door with the maximum area of 24 square feet may be installed for ornamental, security or architectural purposes. Products using this exception shall not be included in the U-factor calculation requirements, however glazing area shall be included in glazing area calculations.

     502.1.6 Moisture Control:


     502.1.6.1 Vapor Retarders: Vapor retarders shall be installed on the warm side (in winter) of insulation as specified in the following cases.

EXCEPTION: Vapor retarder installed with not more than 1/3 of the nominal R-value between it and the conditioned space.

     502.1.6.2 Floors: Floors separating conditioned space from unconditioned space shall have a vapor retarder installed. The vapor retarder shall have a one perm dry cup rating or less (i.e., four mil [0.004 inch thick] polyethylene or kraft faced material).


     502.1.6.3 Roof/Ceilings: Roof/ceiling assemblies where the ventilation space above the insulation is less than an average of 12 inches shall be provided with a vapor retarder. Faced batt insulation where used as a vapor retarder shall be face stapled. Single rafter joist vaulted ceiling cavities shall be of sufficient depth to allow a minimum one inch vented air space above the insulation.


EXCEPTION: Unvented attic assemblies (spaces between the ceiling joists of the top story and the roof rafters) shall be permitted if all the following conditions are met:
1. The unvented attic space is completely contained within the building thermal envelope.
2. No interior vapor retarders are installed on the ceiling side (attic floor) of the unvented attic assembly.
3. Where wood shingles or shakes are used, a minimum 1/4 inch (6 mm) vented air space separates the shingles or shakes and the roofing underlayment above the structural sheathing.
4. Any air-impermeable insulation shall be a vapor retarder, or shall have a vapor retarder coating or covering in direct contact with the underside of the insulation.
5. Either Items a, b or c shall be met, depending on the air permeability of the insulation directly under the structural roof sheathing.
a. Air-impermeable insulation only. Insulation shall be applied in direct contact to the underside of the structural roof sheathing.
b. Air-permeable insulation only. In addition to the air-permeable insulation installed directly below the structural sheathing, rigid board or sheet insulation shall be installed directly above the structural roof sheathing as specified per WA Climate Zone for condensation control.
i. Climate Zone #1 - R-10 minimum rigid board or air-impermeable insulation R-value.
ii. Climate Zone #2 - R-25 minimum rigid board or air-impermeable insulation R-value.
c. Air-impermeable and air-permeable insulation. The air-impermeable insulation shall be applied in direct contact to the underside of the structural roof sheathing as specified per WA Climate Zone for condensation control. The air-permeable insulation shall be installed directly under the air-impermeable insulation.
i. Climate Zone #1 - R-10 minimum rigid board or air-impermeable insulation R-value.
ii. Climate Zone #2 - R-25 minimum rigid board or air-impermeable insulation R-value.

     502.1.6.4: Vapor retarders shall not be required in roof/ceiling assemblies where the ventilation space above the insulation averages 12 inches or greater.


     502.1.6.5: Vapor retarders shall not be required where all of the insulation is installed between the roof membrane and the structural roof deck.


     502.1.6.6 Walls: Walls separating conditioned space from unconditioned space shall have a vapor retarder installed. Faced batt insulation shall be face stapled.

EXCEPTION: For climate zone 1, wood framed walls with a minimum of nominal R-5 continuous insulated sheathing installed outside of the framing and structural sheathing. For climate zone 2, wood framed walls with a minimum of nominal R-7.5 continuous insulated sheathing installed outside of the framing and structural sheathing. The interior cavity insulation for this exception shall be a maximum of nominal R-21.

     502.1.6.7 Ground Cover: A ground cover of six mil (0.006 inch thick) black polyethylene or approved equal shall be laid over the ground within crawl spaces. The ground cover shall be overlapped 12 inches minimum at the joints and shall extend to the foundation wall.

EXCEPTION: The ground cover may be omitted in crawl spaces if the crawl space has a concrete slab floor with a minimum thickness of 3-1/2 inches.

     502.2 Thermal Criteria for Group R Occupancy:


     502.2.1 UA Calculations: The proposed UA as calculated using Equations 2 and 3 shall not exceed the target UA as calculated using Equation 1. For the purpose of determining equivalent thermal performance, the glazing area for the target UA shall be calculated using values in Table 5-1. The opaque door area shall be the same in the target UA and the proposed UA.

EXCEPTION: Log and solid timber walls that have a minimum average thickness of 3.5" and with space heat type other than electric resistance, are exempt from wall target UA and proposed UA calculations.

     502.2.2 Space Heat Type: The following two categories comprise all space heating types:


     1. Electric Resistance: Space heating systems which include baseboard units, radiant units and forced air units as either the primary or secondary heating system.

EXCEPTION: Electric resistance systems for which the total electric heat capacity in each individual dwelling unit does not exceed the greater of: 1) One thousand watts (1000 w) per dwelling unit, or; 2) One watt per square foot (1 w/ft2) of the gross floor area.

     2. Other: All gas, wood, oil and propane space heating systems, unless electric resistance is used as a secondary heating system, and all heat pump space heating systems. (See EXCEPTIONS, Electric Resistance, section 502.2.2 above.)


     502.3 Reserved.


     502.4 Air Leakage:


     502.4.1 General: The requirements of this section shall apply to all buildings and structures, or portions thereof, and only to those locations separating outdoor ambient conditions from interior spaces that are heated or mechanically cooled.


     502.4.2 Doors and Windows, General: Exterior doors and windows shall be designed to limit air leakage into or from the building envelope. Site-constructed doors and windows shall be sealed in accordance with Section 502.4.3.


     502.4.3 Seals and Weatherstripping:


     a. Exterior joints around windows and door frames, openings between walls and foundation, between walls and roof and wall panels; openings at penetrations of utility services through walls, floors and roofs; and all other openings in the building envelope for all occupancies and all other openings in between units in R-1 and R-2 Occupancy shall be sealed, caulked, gasketed or weatherstripped to limit air leakage. Other exterior joints and seams shall be similarly treated, or taped, or covered with moisture vapor permeable housewrap.


     b. All exterior doors or doors serving as access to an enclosed unheated area shall be weatherstripped to limit leakage around their perimeter when in a closed position.


     c. Site built windows are exempt from testing but shall be made tight fitting. Fixed lights shall have glass retained by stops with sealant or caulking all around. Operating sash shall have weatherstripping working against overlapping trim and a closer/latch which will hold the sash closed. The window frame to framing crack shall be made tight with caulking, overlapping membrane or other approved technique.


     d. Openings that are required to be fire resistive are exempt from this section.


     502.4.4 Recessed Lighting Fixtures: When installed in the building envelope, recessed lighting fixtures shall be Type IC rated and certified under ASTM E283 to have no more than 2.0 cfm air movement from the conditioned space to the ceiling cavity. The lighting fixture shall be tested at 75 Pascals or 1.57 lbs/ft2 pressure difference and have a label attached, showing compliance with this test method. Recessed lighting fixtures shall be installed with a gasket or caulk between the fixture and ceiling to prevent air leakage.

[Statutory Authority: RCW 19.27A.022, 19.27A.025, 19.27A.045, and chapters 19.27 and 34.05 RCW. 07-01-089, § 51-11-0502, filed 12/19/06, effective 7/1/07. Statutory Authority: RCW 19.27A.025, 19.27A.045 and chapters 19.27, 19.27A, and 34.05 RCW. 05-01-013, § 51-11-0502, filed 12/2/04, effective 7/1/05. Statutory Authority: RCW 19.27A.020, 19.27A.045. 04-01-106, § 51-11-0502, filed 12/17/03, effective 7/1/04. Statutory Authority: RCW 19.27A.025, 19.27A.045. 02-01-112, § 51-11-0502, filed 12/18/01, effective 7/1/02; 01-03-010, § 51-11-0502, filed 1/5/01, effective 7/1/01; 98-03-003, § 51-11-0502, filed 1/8/98, effective 7/1/98. Statutory Authority: Chapters 19.27 and 19.27A RCW and 1994 c 226. 95-01-126, § 51-11-0502, filed 12/21/94, effective 6/30/95. Statutory Authority: Chapters 19.27, 19.27A and 34.05 RCW. 94-05-059, § 51-11-0502, filed 2/10/94, effective 4/1/94. Statutory Authority: Chapter 19.27A RCW. 92-01-140, § 51-11-0502, filed 12/19/91, effective 7/1/92. Statutory Authority: RCW 19.27A.020 and 1990 c 2. 91-01-112, § 51-11-0502, filed 12/19/90, effective 7/1/91.]

     Reviser's note: The brackets and enclosed material in the text of the above section occurred in the copy filed by the agency and appear in the Register pursuant to the requirements of RCW 34.08.040.
AMENDATORY SECTION(Amending WSR 07-01-089, filed 12/19/06, effective 7/1/07)

WAC 51-11-0503   Building mechanical systems.  

     503.1 General: This section covers the determination of design requirements, system and component performance, control requirements, insulating systems and duct sealing. For all other duct construction requirements, refer to the State Mechanical Code (chapter 51-42 WAC).


     503.2 Calculations of Heating and Cooling Loads, and System Sizing Limits: The design parameters specified in Chapter 3 shall apply for all computations.


     503.2.1 Calculation Procedures: Heating and cooling design loads for the purpose of sizing HVAC systems are required and shall be calculated in accordance with accepted engineering practice, including infiltration and ventilation.


     503.2.2 Space Heating and Space Cooling System Sizing Limits: Building mechanical systems for all buildings which provide space heating and/or space cooling shall be sized no greater than one hundred fifty percent (150%) of the heating and cooling design loads as calculated above.


EXCEPTIONS: The following limited exemptions from the sizing limit shall be allowed; however, in all cases heating and/or cooling design load calculations shall be submitted.
1. For equipment which provides both heating and cooling in one package unit, including heat pumps with electric heating and cooling and gas-pack units with gas heating and electric cooling, compliance need only be demonstrated for either the space heating or space cooling system size.
2. Natural gas- or oil-fired space heating equipment whose total rated space heating output in any one dwelling unit is
a. 40,000 Btu/h or less is exempt from the sizing limit,
b. Larger than 40,000 Btu/h may exceed the one hundred fifty (150%) percent sizing limit but not exceed 250 percent provided that the installed equipment has an annual fuel utilization efficiency (AFUE) of ninety (90%) percent or greater.
3. Stand-by equipment may be installed if controls and other devices are provided which allow redundant equipment to operate only when the primary equipment is not operating.

     503.3 Simultaneous Heating and Cooling: Systems and equipment that provide simultaneous heating and cooling shall comply with the requirements in, as appropriate, Section 1422 or Section 1435.


     503.4 HVAC Equipment Performance Requirements: All heating equipment shall meet the requirements of the National Appliance Energy Conservation Act (NAECA) and be so labeled. Equipment shall also comply with Section 1411.


     503.5 Reserved.


     503.6 Balancing: The HVAC system design shall provide a means for balancing air and water systems. Balancing the system shall include, but not be limited to, dampers, temperature and pressure test connections and balancing valves.


     503.7 Cooling with Outdoor Air (Economizer Cycle): Systems and equipment that provide mechanical cooling shall comply with Section 1413 and, as appropriate, Section 1423 or 1433.


     503.8 Controls:


     503.8.1 Temperature Control: Each system shall be provided with at least one adjustable thermostat for the regulation of temperature. Each thermostat shall be capable of being set by adjustment or selection of sensors as follows:


     503.8.1.1: When used to control heating only: Fifty-five degrees to seventy-five degrees F.


     503.8.1.2: When used to control cooling only: Seventy degrees to eighty-five degrees F.


     503.8.1.3: When used to control both heating and cooling, it shall be capable of being set from fifty-five degrees to eighty-five degrees F and shall be capable of operating the system heating and cooling in sequence. The thermostat and/or control system shall have an adjustable deadband of not less than ten degrees F.


     503.8.2 Humidity Control: If a system is equipped with a means for adding moisture to maintain specific selected relative humidities in space or zones, a humidistat shall be provided. Humidistats shall be capable of being set to prevent new energy from being used to produce space-relative humidity above thirty percent.


EXCEPTION: Special uses requiring different relative humidities may be permitted when approved by the building official.

     503.8.3 Zoning for Temperature Control:


     503.8.3.1 One- and Two-Family Dwellings: At least one thermostat for regulation of space temperature shall be provided for each separate system. In addition, a readily accessible manual or automatic means shall be provided to partially restrict or shut off the heating and/or cooling input to each zone or floor.


     503.8.3.2 Multifamily Dwellings: For multifamily dwellings, each individual dwelling unit shall have at least one thermostat for regulation of space temperature. A readily accessible manual or automatic means shall be provided to partially restrict or shut off the heating and/or cooling input to each room. Spaces other than living units shall meet the requirements of 503.8.3.3.


     503.8.3.3 Control Setback and Shutoff:


     One- and Two-Family and Individual Multifamily dwelling units -- The thermostat required in section 503.8.3.1 or section 503.8.3.2, or an alternate means such as a switch or clock, shall provide a readily accessible, manual or automatic means for reducing the energy required for heating and cooling during the periods of nonuse or reduced need, such as, but not limited to unoccupied periods and sleeping hours. Lowering thermostat set points to reduce energy consumption of heating systems shall not cause energy to be expended to reach the reduced setting.


     503.8.3.4 Systems Serving Multiple Dwelling Units, Guest Rooms, and Common Areas: Systems that serve more than two dwelling units, guest rooms, and common areas shall comply with the control requirements in Sections 1412 and 1432, with the exceptions of Sections 1412.4.2 and 1432.1.


     503.8.3.5 Heat Pump Controls: Programmable thermostats are required for all heat pump systems. The cut-on temperature for the compression heating shall be higher than the cut-on temperature for the supplementary heat, and the cut-off temperature for the compression heating shall be higher than the cut-off temperature for the supplementary heat. Heat pump thermostats will be capable of providing at least two programmable setback periods per day. The automatic setback thermostat shall have the capability of limiting the use of supplemental heat during the warm-up period.


     503.9 Air Handling Duct System Insulation: Ducts, plenums and enclosures installed in or on buildings shall be thermally insulated per Table 5-11.


EXCEPTIONS: Duct insulation (except where required to prevent condensation) is not required in any of the following cases:
1. When the heat gain or loss of the ducts, without      insulation, will not increase the energy requirements of the building.
2. Within the HVAC equipment.
3. Exhaust air ducts.
4. Supply or return air ducts installed in unvented crawl spaces with insulated walls, basements, or cellars in one- and two-family dwellings.

     503.10 Ducts.


     503.10.1 Leakage Testing: High-pressure and medium-pressure ducts shall be leak tested in accordance with the 1985 Edition of the SMACNA HVAC Air Duct Leakage Test Manual with the rate of air leakage not to exceed the maximum rate specified in that standard.


     503.10.2 ((Seams and Joints)) Sealing: All ((low-pressure supply and return duct transverse joints, and enclosed stud bays or joist cavities/space used to transport air, shall be securely fastened and sealed with welds, gaskets, mastics (adhesives), or mastic-plus-embedded-fabric systems installed in accordance with the manufacturer's installation instructions)) ducts, air handlers, filter boxes, and building cavities used as ducts shall be sealed. Joints and seams shall comply with Section M1601.3 of the International Residential Code or Section 603.9 of the International Mechanical Code. Duct tightness testing shall be conducted to verify that the ducts are sealed. A signed affidavit documenting the test results shall be provided to the jurisdiction having authority by the testing agent. When required by the building official, the test shall be conducted in the presence of department staff. Duct tightness shall be verified by either of the following:


     1. Postconstruction test: Leakage to outdoors shall be less than or equal to 6 cfm per 100 ft2 of conditioned floor area or a total leakage less than or equal to 8 cfm per 100 ft2 of conditioned floor area when tested at a pressure differential of 0.1 inches w.g. (25 Pa) across the entire system, including the manufacturer's air handler enclosure. All register boots shall be taped or otherwise sealed during the test.


     2. Rough-in test: Total leakage shall be less than or equal to 6 cfm per 100 ft2 of conditioned floor area when tested at a pressure differential of 0.1 inches w.g. (25 Pa) across the roughed-in system, including the manufacturer's air handler enclosure. All register boots shall be taped or otherwise sealed during the test. If the air handler is not installed at the time of the test, total leakage shall be less than or equal to 4 cfm per 100 ft2 of conditioned floor area
.


EXCEPTIONS: 1. ((Ducts or building cavities used for air distribution that are located entirely within the conditioned space of the building are exempt from this section.)) Duct tightness test is not required if the air handler and all ducts are located within conditioned space.
2. ((UL 181A listed tapes used with listed rigid fibrous glass ducts may be used as the primary sealant, when installed in accordance with the listing.)) Duct tightness test is not required if the furnace is a nondirect vent type combustion appliance installed in an unconditioned space. A maximum of six feet of connected ductwork in the unconditioned space is allowed. All additional supply and return ducts shall be within the conditioned space. Ducts outside the conditioned space shall be sealed with a mastic type duct sealant and insulated on the exterior with R-8 insulation for above grade ducts and R-5 water resistant insulation when within a slab or earth.
((3. UL 181B listed tapes used with listed flexible air ducts may be used as the primary sealant, when installed in accordance with the listing.
4. Where enclosed stud bays or joist cavities/spaces are used to transport air sealing may be accomplished using drywall, drywall tape plus joint compound.
5. Tapes installed in accordance with the manufacturer's installation instructions, providing detailed information specific to application on ducts, including approved duct materials and required duct surface cleaning.))

     503.10.3 Dampers: Requirements for Automatic or manual dampers are found in the Washington State Ventilation and Indoor Air Quality Code.


     503.11 Pipe Insulation: All piping shall be thermally insulated in accordance with Table 5-12.


EXCEPTION: Piping installed within unitary HVAC equipment.

Cold water pipes outside the conditioned space shall be insulated in accordance with the Washington State Plumbing Code (chapter 51-56 WAC).

[Statutory Authority: RCW 19.27A.022, 19.27A.025, 19.27A.045, and chapters 19.27 and 34.05 RCW. 07-01-089, § 51-11-0503, filed 12/19/06, effective 7/1/07. Statutory Authority: RCW 19.27A.020, 19.27A.045. 04-01-106, § 51-11-0503, filed 12/17/03, effective 7/1/04; 02-24-076, § 51-11-0503, filed 12/4/02, effective 5/1/03. Statutory Authority: RCW 19.27A.025, 19.27A.045. 02-01-112, § 51-11-0503, filed 12/18/01, effective 7/1/02; 01-03-010, § 51-11-0503, filed 1/5/01, effective 7/1/01. Statutory Authority: RCW 19.27A.020, 19.27A.045, and 19.27.020. 98-24-075, § 51-11-0503, filed 12/1/98, effective 7/1/99. Statutory Authority: RCW 19.27A.025 and 19.27A.045. 98-03-003, § 51-11-0503, filed 1/8/98, effective 7/1/98. Statutory Authority: RCW 19.27A.025. 93-21-052, § 51-11-0503, filed 10/18/93, effective 4/1/94. Statutory Authority: Chapter 19.27A RCW. 92-01-140, § 51-11-0503, filed 12/19/91, effective 7/1/92. Statutory Authority: RCW 19.27A.020 and 1990 c 2. 91-01-112, § 51-11-0503, filed 12/19/90, effective 7/1/91.]


AMENDATORY SECTION(Amending WSR 04-01-106, filed 12/17/03, effective 7/1/04)

WAC 51-11-1007   Section 1007 Ceilings.  

     1007.1 General: Table 10-7 lists heat-loss coefficients for the opaque portion of exterior ceilings below vented attics, vaulted ceilings, and roof decks in units of Btu/h•ft2•°F of ceiling.

     They are derived from procedures listed in Standard RS-1, listed in Chapter 7. Ceiling U-factors are modified for the buffering effect of the attic, assuming an indoor temperature of 65° F and an outdoor temperature of 45°F.

     Metal Framed Ceilings: The nominal R-values in Table 10-5A - EFFECTIVE R-VALUES FOR METAL FRAMING AND CAVITY ONLY may be used for purposes of calculating metal framed ceiling section U-factors in lieu of the ASHRAE zone calculation method as provided in Chapter 25 of Standard RS-1.

     1007.2 Component Description: The four types of ceilings are characterized as follows:

     Ceilings Below a Vented Attic: Attic insulation is assumed to be blown-in, loose-fill fiberglass with a K-value of 2.6 hr • ft2 • °F/Btu per inch. Full bag count for specified R-value is assumed in all cases. Ceiling dimensions for flat ceiling calculations are forty-five by thirty feet, with a gabled roof having a 4/12 pitch. The attic is assumed to vent naturally at the rate of three air changes per hour through soffit and ridge vents. A void fraction of 0.002 is assumed for all attics with insulation baffles. Standard-framed, unbaffled attics assume a void fraction of 0.008.

     Attic framing is either standard or advanced. Standard framing assumes tapering of insulation depth around the perimeter with resultant decrease in thermal resistance. An increased R-value is assumed in the center of the ceiling due to the effect of piling leftover insulation. Advanced framing assumes full and even depth of insulation extending to the outside edge of exterior walls. Advanced framing does not change from the default value.

     U-factors for flat ceilings below vented attics with standard framing may be modified with the following table:


U-Factor for

Standard Framing

Roof Pitch R-30 R-38
4/12 .036 .031
5/12 .035 .030
6/12 .034 .029
7/12 .034 .029
8/12 .034 .028
9/12 .034 .028
10/12 .033 .028
11/12 .033 .027
12/12 .033 .027

     Vented scissors truss attics assume a ceiling pitch of 2/12 with a roof pitch of either 4/12 or 5/12. Unbaffled standard framed scissors truss attics are assumed to have a void fraction of 0.016.

     Vaulted Ceilings: Insulation is assumed to be fiberglass batts installed in roof joist cavities. In the vented case, at least 1.5-inches between the top of the batts and the underside of the roof sheathing is left open for ventilation in each cavity. A ventilation rate of 3.0 air changes per hour is assumed. In the unvented or dense pack case, the ceiling cavity is assumed to be fully packed with insulation, leaving no space for ventilation.


EXCEPTION: Where spray polyurethane foam meets the requirements of Section 502.1.6.3 or Section 1313.2, the cavity shall be filled to the depth to achieve R-value requirements.

     Roof Decks: Rigid insulation is applied to the top of roof decking with no space left for ventilation. Roofing materials are attached directly on top of the insulation. Framing members are often left exposed on the interior side.

     Metal Truss Framing: Overall system tested values for the roof/ceiling Uo for metal framed truss assemblies from approved laboratories shall be used, when such data is acceptable to the building official.

     Alternatively, the Uo for roof/ceiling assemblies using metal truss framing may be obtained from Tables 10-7A, 10-7B, 10-7C, 10-7D and 10-7E.


TABLE 10-7
DEFAULT U-FACTORS FOR CEILINGS

Ceilings Below Vented Attics

Standard Frame Advanced Frame
Flat Ceiling Baffled
R-19 0.049 0.047
R-30 0.036 0.032
R-38 0.031 0.026
R-49 0.027 0.020
R-60 0.025 0.017
Scissors Truss
R-30 (4/12 roof pitch) 0.043 0.031
R-38 (4/12 roof pitch) 0.040 0.025
R-49 (4/12 roof pitch) 0.038 0.020
R-30 (5/12 roof pitch) 0.039 0.032
R-38 (5/12 roof pitch) 0.035 0.026
R-49 (5/12 roof pitch) 0.032 0.020
Vaulted Ceilings
16" O.C. 24" O.C.
Vented
R-19 2x10 joist 0.049 0.048
R-30 2x12 joist 0.034 0.033
R-38 2x14 joist 0.027 0.027
Unvented
R-30 2x10 joist 0.034 0.033
R-38 2x12 joist 0.029 0.027
R-21 + R-21 2x12 joist 0.026 0.025
Roof Deck
4x Beams, 48" O.C.
R-12.5 2" Rigid insulation 0.064
R-21.9 3.5" Rigid insulation 0.040
R-37.5 6" Rigid insulation 0.025
R-50 8" Rigid insulation 0.019

Table 10-7A

Steel Truss1 Framed Ceiling UO

Cavity Truss Span (ft)
R-value 12 14 16 18 20 22 24 26 28 30 32 34 36
19 0.1075 0.0991 0.0928 0.0878 0.0839 0.0807 0.0780 0.0757 0.0737 0.0720 0.0706 0.0693 0.0681
30 0.0907 0.0823 0.0760 0.0710 0.0671 0.0638 0.0612 0.0589 0.0569 0.0552 0.0538 0.0525 0.0513
38 0.0844 0.0759 0.0696 0.0647 0.0607 0.0575 0.0548 0.0525 0.0506 0.0489 0.0474 0.0461 0.0449
49 0.0789 0.0704 0.0641 0.0592 0.0552 0.0520 0.0493 0.0470 0.0451 0.0434 0.0419 0.0406 0.0395

Table 10-7B

Steel Truss1 Framed Ceiling UO with R-3 Sheathing2

Cavity Truss Span (ft)
R-value 12 14 16 18 20 22 24 26 28 30 32 34 36
19 0.0809 0.0763 0.0728 0.0701 0.0679 0.0661 0.0647 0.0634 0.0623 0.0614 0.0606 0.0599 0.0592
30 0.0641 0.0595 0.0560 0.0533 0.0511 0.0493 0.0478 0.0466 0.0455 0.0446 0.0438 0.0431 0.0424
38 0.0577 0.0531 0.0496 0.0469 0.0447 0.0430 0.0415 0.0402 0.0392 0.0382 0.0374 0.0367 0.0361
49 0.0523 0.0476 0.0441 0.0414 0.0393 0.0375 0.0360 0.0348 0.0337 0.0328 0.0319 0.0312 0.0306

Table 10-7C

Steel Truss1 Framed Ceiling UO with R-5 Sheathing2

Cavity Truss Span (ft)
R-value 12 14 16 18 20 22 24 26 28 30 32 34 36
19 0.0732 0.0697 0.0670 0.0649 0.0633 0.0619 0.0608 0.0598 0.0590 0.0583 0.0577 0.0571 0.0567
30 0.0564 0.0529 0.0502 0.0481 0.0465 0.0451 0.0440 0.0430 0.0422 0.0415 0.0409 0.0403 0.0399
38 0.0501 0.0465 0.0438 0.0418 0.0401 0.0388 0.0376 0.0367 0.0359 0.0351 0.0345 0.0340 0.0335
49 0.0446 0.0410 0.0384 0.0363 0.0346 0.0333 0.0322 0.0312 0.0304 0.0297 0.0291 0.0285 0.0280

Table 10-7D

Steel Truss1 Framed Ceiling UO with R-10 Sheathing2

Cavity Truss Span (ft)
R-value 12 14 16 18 20 22 24 26 28 30 32 34 36
19 0.0626 0.0606 0.0590 0.0578 0.0569 0.0561 0.0555 0.0549 0.0545 0.0541 0.0537 0.0534 0.0531
30 0.0458 0.0437 0.0422 0.0410 0.0401 0.0393 0.0387 0.0381 0.0377 0.0373 0.0369 0.0366 0.0363
38 0.0394 0.0374 0.0359 0.0347 0.0337 0.0330 0.0323 0.0318 0.0313 0.0309 0.0305 0.0302 0.0299
49 0.0339 0.0319 0.0304 0.0292 0.0283 0.0275 0.0268 0.0263 0.0258 0.0254 0.0251 0.0247 0.0245


Table 10-7E

Steel Truss1 Framed Ceiling UO with R-15 Sheathing2

Cavity Truss Span (ft)
R-value 12 14 16 18 20 22 24 26 28 30 32 34 36
19 0.0561 0.0550 0.0541 0.0535 0.0530 0.0526 0.0522 0.0519 0.0517 0.0515 0.0513 0.0511 0.0509
30 0.0393 0.0382 0.0373 0.0367 0.0362 0.0358 0.0354 0.0351 0.0349 0.0347 0.0345 0.0343 0.0341
38 0.0329 0.0318 0.0310 0.0303 0.0298 0.0294 0.0291 0.0288 0.0285 0.0283 0.0281 0.0279 0.0278
49 0.0274 0.0263 0.0255 0.0249 0.0244 0.0239 0.0236 0.0233 0.0230 0.0228 0.0226 0.0225 0.0223

1 - Assembly values based on 24 inch on center truss spacing; 11 Truss member connections penetrating insulation (4 at the eaves, 7 in the interior space); 1/2 inch drywall ceiling; all truss members are 2x4 "C" channels with a solid web.
2 - Ceiling sheathing installed between bottom chord and drywall.

[Statutory Authority: RCW 19.27A.020, 19.27A.045. 04-01-106, § 51-11-1007, filed 12/17/03, effective 7/1/04. Statutory Authority: RCW 19.27A.025, 19.27A.045. 01-03-010, § 51-11-1007, filed 1/5/01, effective 7/1/01; 98-03-003, § 51-11-1007, filed 1/8/98, effective 7/1/98. Statutory Authority: RCW 19.27A.020 and 1990 c 2. 91-01-112, § 51-11-1007, filed 12/19/90, effective 7/1/91.]


AMENDATORY SECTION(Amending WSR 04-01-106, filed 12/17/03, effective 7/1/04)

WAC 51-11-1313   Moisture control.  


1313.1 Vapor Retarders: Vapor retarders shall be installed on the warm side (in winter) of insulation as required by this section.


EXCEPTION: Vapor retarder installed with not more than 1/3 of the nominal R-value between it and the conditioned space.

1313.2 Roof/Ceiling Assemblies: Roof/ceiling assemblies where the ventilation space above the insulation is less than an average of twelve inches shall be provided with a vapor retarder. (For enclosed attics and enclosed rafter spaces see Section 1203.2 of the International Building Code.) Roof/ceiling assemblies without a vented airspace, allowed only where neither the roof deck nor the roof structure are made of wood, shall provide a continuous vapor retarder with taped seams.


EXCEPTIONS: 1. Vapor retarders need not be provided where all of the insulation is installed between the roof membrane and the structural roof deck.
2. Unvented attic assemblies (spaces between the ceiling joists of the top story and the roof rafters) shall be permitted if all the following conditions are met:
2.1 The unvented attic space is completely contained within the building thermal envelope.
2.2 No interior vapor retarders are installed on the ceiling side (attic floor) of the unvented attic assembly.
2.3 Where wood shingles or shakes are used, a minimum 1/4 inch (6 mm) vented air space separates the shingles or shakes and the roofing underlayment above the structural sheathing.
2.4 Any air-impermeable insulation shall be a vapor retarder, or shall have a vapor retarder coating or covering in direct contact with the underside of the insulation.
2.5 Either Items a, b or c shall be met, depending on the air permeability of the insulation directly under the structural roof sheathing.
a. Air-impermeable insulation only. Insulation shall be applied in direct contact to the underside of the structural roof sheathing.
b. Air-permeable insulation only. In addition to the air-permeable insulation installed directly below the structural sheathing, rigid board or sheet insulation shall be installed directly above the structural roof sheathing as specified per WA Climate Zone for condensation control.
i. Climate Zone #1 - R-10 minimum rigid board or air-impermeable insulation R-value.
ii. Climate Zone #2 - R-25 minimum rigid board or air-impermeable insulation R-value.
c. Air-impermeable and air-permeable insulation. The air-impermeable insulation shall be applied in direct contact to the underside of the structural roof sheathing as specified per WA Climate Zone for condensation control. The air-permeable insulation shall be installed directly under the air-impermeable insulation.
i. Climate Zone #1 - R-10 minimum rigid board or air-impermeable insulation R-value.
ii. Climate Zone #2 - R-25 minimum rigid board or air-impermeable insulation R-value.

1313.3 Walls: Walls separating conditioned space from unconditioned space shall be provided with a vapor retarder.


1313.4 Floors: Floors separating conditioned space from unconditioned space shall be provided with a vapor retarder.


1313.5 Crawl Spaces: A ground cover of six mil (0.006 inch thick) black polyethylene or approved equal shall be laid over the ground within crawl spaces. The ground cover shall be overlapped twelve inches minimum at the joints and shall extend to the foundation wall.


EXCEPTION: The ground cover may be omitted in crawl spaces if the crawl space has a concrete slab floor with a minimum thickness of three and one-half inches.

[Statutory Authority: RCW 19.27A.020, 19.27A.045. 04-01-106, § 51-11-1313, filed 12/17/03, effective 7/1/04. Statutory Authority: RCW 19.27A.025, 19.27A.045. 01-03-010, § 51-11-1313, filed 1/5/01, effective 7/1/01. Statutory Authority: RCW 19.27A.025. 93-21-052, § 51-11-1313, filed 10/18/93, effective 4/1/94.]

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