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.
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 Section101.3.1
. 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.