TABLE 3.2 Heated Space Criteria
|5||1 and 2|
|15||4 and 5|
|20||6 and 7|
adopting authority: the agency or agent that adopts this standard.
alteration: a replacement or addition to a building or its systems and equipment; routine maintenance, repair, and service, or a change in the building's use classification or category shall not constitute an alteration.
annual fuel utilization efficiency (AFUE): an efficiency descriptor of the ratio of annual output energy to annual input energy as developed in accordance with the requirements of U.S. Department of Energy (DOE) 10 CFR Part 430.
astronomical time switch: a device that turns the lighting on at a time relative to sunset and off at a time relative to sunrise, accounting for geographic location and day of year.
authority having jurisdiction: the agency or agent responsible for enforcing this standard.
automatic: self-acting, operating by its own mechanism when actuated by some nonmanual influence, such as a change in current strength, pressure, temperature, or mechanical configuration.
balancing, air system: adjusting airflow rates through air distribution system devices, such as fans and diffusers, by manually adjusting the position of dampers, splitter vanes, extractors, etc., or by using automatic control devices, such as constant-air-volume or variable-air-volume (VAV) boxes.
balancing, hydronic system: adjusting water flow rates through hydronic distribution system devices, such as pumps and coils, by manually adjusting the position valves or by using automatic control devices, such as automatic flow control valves.
baseline building design: a computer representation of a hypothetical design based on the proposed building project. This representation is used as the basis for calculating the baseline building performance for rating above-standard design.
boiler: a self-contained, low-pressure appliance for supplying steam or hot water.
packaged boiler: a boiler that is shipped complete with heating equipment, mechanical draft equipment, and automatic controls, and that is usually shipped in one or more sections. A packaged boiler includes factory-built boilers manufactured as a unit or system, disassembled for shipment, and reassembled at the site.
bubble point: the refrigerant liquid saturation temperature at a specified pressure.
budget building design: a computer representation of a hypothetical design based on the actual proposed building design. This representation is used as the basis for calculating the energy cost budget.
building entrance: any doorway, set of doors, revolving door, vestibule, or other form of portal that is ordinarily used to gain access to the building or to exit from the building by its users and occupants. This does not include doors solely used to directly enter mechanical, electrical, and other building utility service equipment rooms.
semi-exterior building envelope: the elements of a building that separate conditioned space from unconditioned space or that enclose semiheated spaces through which thermal energy may be transferred to or from the exterior, to or from unconditioned spaces, or to or from conditioned spaces.
circuit breaker: a device designed to open and close a circuit by nonautomatic means and to open the circuit automatically at a predetermined overcurrent without damage to itself when properly applied within its rating.
class of construction: for the building envelope, a subcategory of roof, above-grade wall, below-grade wall, floor, slab-on-grade floor, opaque door, vertical fenestration, or skylight. (See roof, wall, floor, slab-on-grade floor, door, and fenestration.)
coefficient of performance (COP)—cooling: the ratio of the rate of heat removal to the rate of energy input, in consistent units, for a complete refrigerating system or some specific portion of that system under designated operating conditions.
coefficient of performance (COP), heat pump—heating: the ratio of the rate of heat delivered to the rate of energy input, in consistent units, for a complete heat pump system, including the compressor and, if applicable, auxiliary heat, under designated operating conditions.
computer room: a room whose primary function is to house equipment for the processing and storage of electronic data and that has a design electronic data equipment power density exceeding 20 W/ft2 of conditioned floor area.
computer room energy: annual energy use of the data center, including all IT equipment energy, plus energy that supports the IT equipment and computer room space, calculated in accordance with industry-accepted standards defined as Total Annual Energy (see Informative Appendix E).
condensing unit: a factory-made assembly of refrigeration components designed to compress and liquefy a specific refrigerant. It consists of one or more refrigerant compressors, refrigerant condensers (air cooled, evaporatively cooled, and/or water-cooled), condenser fans and motors (where used), and factory-supplied accessories.
continuous air barrier: the combination of interconnected materials, assemblies, and sealed joints and components of the building envelope that minimize air leakage into or out of the building envelope.
continuous daylight dimming: method of automatic lighting control using daylight photosensors, where the lights are dimmed continuously, or using at least four preset levels with at least a five-second fade between levels, where the control turns the lights off when sufficient daylight is available.
continuous insulation (c.i.): insulation that is uncompressed and continuous across all structural members without thermal bridges other than fasteners and service openings. It is installed on the interior or exterior or is integral to any opaque surface of the building envelope.
cooling design temperature: the outdoor dry-bulb temperature equal to the temperature that is exceeded by 1% of the number of hours during a typical weather year.
cooling design wet-bulb temperature: the mean coincident outdoor wet-bulb temperature utilized in conjunction with the cooling design dry-bulb temperature, often used for the sizing of cooling systems.
critical circuit: the hydronic circuit that determines the minimum differential pressure that the pump must produce to satisfy the zone loads (e.g., the circuit with the most-open valve). The critical circuit is the one with the highest pressure drop required to satisfy its load. At part-load conditions, the critical circuit can change based on zone loads.
daylight area under roof monitors: the daylight area under roof monitors is the combined daylight area under each roof monitor within each space. The daylight area under each roof monitor is the product of
- the width of the vertical fenestration above the ceiling level plus, on each side, the smallest of
- 2 ft,
- the distance to any 5 ft or higher vertical obstruction, or
- the distance to the edge of any primary sidelighted area
- the smaller of the following horizontal distances inward from the bottom edge of the vertical fenestration (see Figure 3.2-1):
- The monitor sill height (MSH) (the vertical distance from the floor to the bottom edge of the monitor glazing)
- The distance to the nearest face of any opaque vertical obstruction, where any part of the obstruction is farther away than the difference between the height of the obstruction and the monitor sill height (MSH — OH).
daylight area under skylights: the daylight area under skylights is the combined daylight area under each skylight within a space. The daylight area under each skylight is bounded by the opening beneath the skylight and horizontally in each direction (see Figure 3.2-2), the smaller of
- 70% of the ceiling height (0.7 × CH), or
- the distance to the nearest face of any opaque vertical obstruction, where any part of the obstruction is farther away than 70% of the distance between the top of the obstruction and the ceiling (0.7 × [CH — OH], where CH = the height of the ceiling at the lowest edge of the skylight and OH = the height to the top of the obstruction).
primary sidelighted area: the total primary sidelighted area is the combined primary sidelighted area within each space. Each primary sidelighted area is directly adjacent to vertical fenestration below the ceiling (see Figure 3.2-3).
- The primary sidelighted area width is the width of the vertical fenestration plus, on each side, the smaller of
- The primary sidelighted area depth is the horizontal distance perpendicular to the vertical fenestration which is the smaller of
secondary sidelighted area: the total secondary sidelighted area is the combined secondary sidelighted area within a space. Each secondary sidelighted area is directly adjacent to a primary sidelighted area (see Figure 3.2-4):
- The secondary sidelighted area width is the width of the vertical fenestration plus, on each side, the smaller of
- The secondary sidelighted area depth is the horizontal distance perpendicular to the vertical fenestration, which begins at the edge of the primary sidelighted area depth and ends at the smaller of
dead band: the range of values within which a sensed variable can vary without initiating a change in the controlled process.
degree-day: the difference in temperature between the outdoor mean temperature over a twenty-four-hour period and a given base temperature. For the purposes of determining building envelope requirements, the classifications are defined as follows:
cooling degree-day base 50°F (CDD50): for any one day, when the mean temperature is more than 50°F, there are as many degree-days as degrees Fahrenheit temperature difference between the mean temperature for the day and 50°F. Annual cooling degree-days (CDDs) are the sum of the degree-days over a calendar year.
heating degree-day base 65°F (HDD65): for any one day, when the mean temperature is less than 65°F, there are as many degree-days as degrees Fahrenheit temperature difference between the mean temperature for the day and 65°F. Annual heating degree-days (HDDs) are the sum of the degree-days over a calendar year.
demand: the highest amount of power (average Btu/h over an interval) recorded for a building or facility in a selected time frame.
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 professional: an architect or engineer licensed to practice in accordance with applicable state licensing laws.
direct digital control (DDC): a type of control where controlled and monitored analog or binary data (e.g., temperature, contact closures) are converted to digital format for manipulation and calculations by a digital computer or microprocessor, then converted back to analog or binary form to control physical devices.
disconnect: a device or group of devices or other means by which the conductors of a circuit can be disconnected from their source of supply.
distribution system: conveying means, such as ducts, pipes, and wires, to bring substances or energy from a source to the point of use. The distribution system includes such auxiliary equipment as fans, pumps, and transformers.
door (access hatch): all operable opening areas (that are not fenestration) in the building envelope, including swinging and roll-up doors, fire doors, and access hatches. Doors that are more than one-half glass are considered fenestration (see fenestration). For the purposes of determining building envelope requirements, the classifications are defined as follows:
metal coiling door: an upward-acting, nonswinging door assembly consisting of interlocking horizontal slats or sheets that, upon opening the door, roll up around a horizontal barrel above the door opening.
dwelling unit: a single unit providing complete independent living facilities for one or more persons, including permanent provisions for living, sleeping, eating, cooking, and sanitation.
dynamic glazing: any glazing system/glazing infill that has the fully reversible ability to change its performance properties, including U-factor, solar heat gain coefficient, or visible transmittance. This includes, but is not limited to, shading systems between the glazing layers and chromogenic glazing.
economizer, air: a duct and damper arrangement and automatic control system that together allow a cooling system to supply outdoor air to reduce or eliminate the need for mechanical cooling during mild or cold weather.
economizer, water: a system by which the supply air of a cooling system is cooled indirectly with water that is itself cooled by heat or mass transfer to the environment without the use of mechanical cooling.
efficiency: performance at specified rating conditions.
emittance: the ratio of the radiant heat flux emitted by a specimen to that emitted by a blackbody at the same temperature and under the same conditions.
energy: the capacity for doing work. It takes a number of forms that may be transformed from one into another such as thermal (heat), mechanical (work), electrical, and chemical (Btu).
energy efficiency ratio (EER): the ratio of net cooling capacity (Btu/h) to total rate of electric input in watts under designated operating conditions. (See coefficient of performance [COP]—cooling.)
envelope performance factor: the trade-off value for the building envelope performance compliance option calculated using the procedures specified in Section 5. For the purposes of determining building envelope requirements, the classifications are defined as follows:
equipment: devices for comfort conditioning, electric power, lighting, transportation, or service water heating, including but not limited to furnaces, boilers, air conditioners, heat pumps, chillers, water heaters, lamps, luminaires, ballasts, elevators, escalators, or other devices or installations.
essential facility: those portions of a building serving one of the following functions:
- Hospitals and other health care facilities having surgery or emergency treatment facilities
- Fire, rescue, and police stations and emergency vehicle garages
- Designated earthquake, hurricane, or other emergency shelters
- Designated emergency preparedness, communication, and operation centers and other facilities required for emergency response
- Power-generating stations and other public utility facilities required as emergency backup facilities for other essential facilities
- Structures containing highly toxic materials where the quantity of the material exceeds the maximum allowable quantities
- Aviation control towers, air traffic control centers, and emergency aircraft hangars
- Buildings and other structures having critical national defense functions
evaporation design wet-bulb temperature: the outdoor wet-bulb temperature utilized in conjunction with the mean coincident dry-bulb temperature, often used for the sizing of evaporative systems such as cooling towers.
eye adaptation: the process by which the retina becomes accustomed to more or less light than it was exposed to during an immediately preceding period. It results in a change in the sensitivity to light.
façade area: area of the façade, including overhanging soffits, cornices, and protruding columns, measured in elevation in a vertical plane parallel to the plane of the face of the building. Nonhorizontal roof surfaces shall be included in the calculation of vertical façade area by measuring the area in a plane parallel to the surface.
fan brake horsepower (bhp): the horsepower delivered to the fan's shaft. Brake horsepower does not include the mechanical drive losses (belts, gears, etc.).
fan system brake horsepower (bhp): the sum of the fan brake horsepower of all fans that are required to operate at fan system design conditions to supply air from the heating or cooling source to the conditioned space(s) and return it to the source or exhaust it to the outdoors.
fan system design conditions: operating conditions that can be expected to occur during normal system operation that result in the highest supply airflow rate to conditioned spaces served by the system.
fan system motor nameplate horsepower (hp): the sum of the motor nameplate horsepower of all fans that are required to operate at design conditions to supply air from the heating or cooling source to the conditioned space(s) and return it to the source or exhaust it to the outdoors.
fenestration: all areas (including the frames) in the building envelope that let in light, including windows, plastic panels, clerestories, roof monitors, skylights, doors that are more than one-half glass, and glass block walls. (See building envelope and door.)
field-fabricated fenestration: fenestration whose frame is made at the construction site of materials that were not previously cut, or otherwise formed with the specific intention of being used to fabricate a fenestration product or exterior glazed door. Field-fabricated fenestration does not include site-built fenestration designed to be glazed or assembled in the field using specific factory-cut or otherwise factory-formed framing and glazing units, such as storefront systems, curtain walls, and atrium roof systems.
fenestration area: total area of the fenestration measured using the rough opening and including the glazing, sash, and frame. For doors where the glazed vision area is less than 50% of the door area, the fenestration area is the glazed vision area. For all other doors, the fenestration area is the door area. (See door area.)
fixture: the component of a luminaire that houses the lamp or lamps or positions the lamp, shields it from view, and distributes the light. The fixture also provides for connection to the power supply, which may require the use of a ballast.
floor: that lower portion of the building envelope, including opaque area and fenestration, that has conditioned or semiheated space above and is horizontal or tilted at an angle of less than 60 degrees from horizontal but excluding slab-on-grade floors. For the purposes of determining building envelope requirements, the classifications are defined as follows:
floor area, gross: the sum of the floor areas of the spaces within the building, including basements, mezzanine and intermediate-floored tiers, and penthouses with a headroom height of 7.5 ft or greater. It is measured from the exterior faces of exterior walls or from the centerline 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.
flue damper: a device in the flue outlet or in the inlet of or upstream of the draft control device of an individual, automatically operated, fossil-fuel-fired appliance that is designed to automatically open the flue outlet during appliance operation and to automatically close the flue outlet when the appliance is in a standby condition.
fuel: a material that may be used to produce heat or generate power by combustion.
- is a single-speed induction motor;
- is rated for continuous duty (MG1) operation or for duty type SI (IEC);
- contains a squirrel-cage (MG1) or cage (IEC) rotor;
- has foot-mounting that may include foot-mounting with flanges or detachable feet;
- is built in accordance with NEMA T-frame dimensions or their IEC metric equivalents, including a frame size that is between two consecutive NEMA frame sizes or their IEC metric equivalents;
- has performance in accordance with NEMA Design A (MG1) or B (MG1) characteristics, or equivalent designs, such as IEC Design N (IEC);
- operates on polyphase alternating current 60 Hz sinusoidal power and
- is rated at 230 or 460 V (or both), including motors rated at multiple voltages that include 230 or 460 V (or both) or
- can be operated on 230 or 460 V (or both); and
- includes, but is not limited to, explosion-proof construction.
general purpose electric motor (subtype II): any general purpose electric motor that incorporates the design elements of a general purpose electric motor (subtype I) and that is configured in one or more of the following ways:
- Is built in accordance with NEMA U-frame dimensions, as described in NEMA MG-1-1967, or in accordance with the IEC metric equivalents, including a frame size that is between two consecutive NEMA frame sizes or their IEC metric equivalents
- Has performance in accordance with NEMA Design C characteristics, as described in MG1, or an equivalent IEC design(s) such as IEC Design H
- Is a close-coupled pump motor
- Is a footless motor
- Is a vertical, solid-shaft normal thrust motor (as tested in a horizontal configuration) built and designed in a manner consistent with MG1
- Is an 8-pole motor (900 rpm)
- Is a polyphase motor with voltage rating of not more than 600 V, is not rated at 230 or 460 V (or both), and cannot be operated on 230 or 460 V (or both)
generally accepted engineering standard: a specification, rule, guide, or procedure in the field of engineering, or related thereto, recognized and accepted as authoritative.
growth media: an engineered formulation of inorganic and organic materials including but not limited to heat-expanded clays, slates, shales, aggregate, sand, perlite, vermiculite, and organic material including but not limited to compost worm castings, coir, peat, and other organic material.
heat capacity (HC): the amount of heat necessary to raise the temperature of a given mass 1°F. Numerically, the HC per unit area of surface (Btu/ft2•°F) is the sum of the products of the mass per unit area of each individual material in the roof, wall, or floor surface multiplied by its individual specific heat.
heating design temperature: the outdoor dry-bulb temperature equal to the temperature that is exceeded at least 99.6% of the number of hours during a typical weather year.
heating seasonal performance factor (HSPF): the total heating output of a heat pump during its normal annual usage period for heating (Btu) divided by the total electric energy input during the same period.
historic: a building or space that has been specifically designated as historically significant by the adopting authority, or is listed in The National Register of Historic Places or has been determined to be eligible for such listing by the U.S. Secretary of the Interior.
HVAC system: the equipment, distribution systems, and terminals that provide, either collectively or individually, the processes of heating, ventilating, or air conditioning to a building or portion of a building.
HVAC zone: a space or group of spaces within a building with heating and cooling requirements that are sufficiently similar so that desired conditions (e.g., temperature) can be maintained throughout using a single sensor (e.g., thermostat or temperature sensor).
infiltration: the uncontrolled inward air leakage through cracks and crevices in any building element and around windows and doors of a building caused by pressure differences across these elements due to factors such as wind, inside and outside temperature differences (stack effect), and imbalance between supply and exhaust air systems.
integrated energy efficiency ratio (IEER): a single-number figure of merit expressing cooling part-load EER efficiency for commercial unitary air-conditioning and heat pump equipment on the basis of weighted operation at various load capacities for the equipment.
integrated part-load value (IPLV): a single-number figure of merit based on part-load EER, COP, or kW/kW expressing part-load efficiency for air-conditioning and heat-pump equipment on the basis of weighted operation at various load capacities for the equipment.
interior lighting power allowance: see lighting power allowance.
isolation devices: devices that isolate HVAC zones so that they can be operated independently of one another. Isolation devices include, but are not limited to, separate systems, isolation dampers, and controls providing shutoff at terminal boxes.
IT equipment energy: annual energy used for computer storage and network equipment along with supplemental equipment represented by the uninterruptible power supply (UPS) output calculated in accordance with industry-accepted standards (see Informative Appendix E).
joist, steel: any structural steel member of a building or structure made of hot-rolled or cold-rolled solid or open-web sections.
kilovolt-ampere (kVA): where the term kilovolt-ampere is used in this standard, it is the product of the line current (amperes) times the nominal system voltage (kilovolts) times 1.732 for three-phase currents. For single-phase applications, kVA is the product of the line current (amperes) times the nominal system voltage (kilovolts).
kilowatt (kW): the basic unit of electric power, equal to 1000 W.
lamp: a generic term for a man-made light source often called a bulb or tube.
general service lamp: a class of incandescent lamps that provide light in virtually all directions. General service lamps are typically characterized by bulb shapes such as "A," standard; "S," straight side; "F," flame; "G," globe; and "PS," pear straight.
high-intensity discharge (HID) lamp: an electric discharge lamp in which light is produced when an electric arc is discharged through a vaporized metal such as mercury or sodium. Some HID lamps may also have a phosphor coating that contributes to the light produced or enhances the light color.
reflector lamp: a class of incandescent lamps that have an internal reflector to direct the light. Reflector lamps are typically characterized by reflective characteristics such as "R," reflector; "ER," ellipsoidal reflector; "PAR," parabolic aluminized reflector; "MR," mirrorized reflector; and others.
lighting, general: lighting that provides a substantially uniform level of illumination throughout an area. General lighting shall not include decorative lighting or lighting that provides a dissimilar level of illumination to serve a specialized application or feature within such area.
lighting power allowance, exterior: the maximum lighting power in watts allowed for the exterior of a building.
lighting power allowance, interior: the maximum lighting power in watts allowed for the interior of a building.
liner system (Ls): a continuous vapor barrier liner installed below the purlins and uninterrupted by framing members.
luminaire: a complete lighting unit consisting of a lamp or lamps together with the housing designed to distribute the light, position and protect the lamps, and connect the lamps to the power supply.
makeup air (dedicated replacement air): outdoor air deliberately brought into the building from the outside and supplied to the vicinity of an exhaust hood to replace air, vapor, and contaminants being exhausted. Makeup air is generally filtered and fan-forced, and it may be heated or cooled depending on the requirements of the application. Makeup air may be delivered through outlets integral to the exhaust hood or through outlets in the same room.
manufacturer: the company engaged in the original production and assembly of products or equipment or a company that purchases such products and equipment manufactured in accordance with company specifications.
mean temperature: one-half the sum of the minimum daily temperature and maximum daily temperature.
mechanical cooling: reducing the temperature of a gas or liquid by using vapor compression, absorption, desiccant dehumidification combined with evaporative cooling, or another energy-driven thermodynamic cycle. Indirect or direct evaporative cooling alone is not considered mechanical cooling.
metal building: a complete integrated set of mutually dependent components and assemblies that form a building, which consists of a steel-framed superstructure and metal skin.
metering: instruments that measure electric voltage, current, power, etc.
motor power, rated: the rated output power from the motor.
multilevel occupancy sensor: an occupancy sensor having an automatic OFF function that turns off all the lights, and either an automatic or a manually controlled ON function capable of activating between 30% and 70% of the lighting power. After that event occurs, the device shall be capable of all of the following actions when manually called to do so by the occupant:
- Activating alternate sets of lights
- Activating 100% of the lighting power
- Deactivating all lights
multiscene control: a lighting control device or system that allows for two or more predefined lighting settings, in addition to all off, for two or more groups of luminaires to suit multiple activities in the space, and allows the automatic recall of those settings.
nameplate horsepower (hp): the nominal motor horsepower rating stamped on the motor nameplate.
nonstandard part-load value (NPLV): a single-number partload efficiency figure of merit calculated and referenced to conditions other than IPLV conditions, for units that are not designed to operate at AHRI standard rating conditions.
nonweatherized space constrained single-package vertical unit: a single-package vertical air conditioner (SPVAC) or single-package vertical heat pump (SPVHP) that meets all of the following requirements:
- Is for indoor use only
- Has rated cooling capacities no greater than 36,000 Btu/h
- Is a single-package unit requiring opening in an exterior wall with overall exterior dimensions that requires or uses an existing sleeve that meets one of the following criteria:
- Has a width of less than 32 in. and height of less than 45 in.
- Fits inside an existing 1310 in.2 opening
- Is commonly installed in site-built commercial buildings
- Is of a similar cooling capacity and, if a heat pump, similar heating capacity
- Draws outdoor air for heat exchange directly through an existing opening, used for both inlet and outlet, in the exterior wall
- Is restricted to applications where an existing air conditioner, heat pump, or gas/electric unit, installed in an existing exterior wall opening, is to be replaced
- Bears a permanent "Replacement" marking, conspicuously placed, and clearly indicating that its application is limited to installations where an existing air conditioner or heat pump is to be replaced
north-oriented: facing within 45 degrees of true north in the northern hemisphere (however, facing within 45 degrees of true south in the southern hemisphere).
optimum start controls: controls that are designed to automatically adjust the start time of an HVAC system each day with the intention of bringing the space to desired occupied temperature levels immediately before scheduled occupancy.
packaged terminal air conditioner (PTAC): a factory-selected wall sleeve and separate unencased combination of heating and cooling components, assemblies, or sections. It may include heating capability by hot water, steam, or electricity and is intended for mounting through the wall to serve a single room or zone.
performance rating method: a calculation procedure that generates an index of merit for the performance of building designs that substantially exceeds the energy efficiency levels required by this standard.
piping: the pipes or tubes interconnecting the various parts of a fluid distribution system, including all elements that are in series with the fluid flow, such as pumps, valves, strainers, and air separators, but not including elements that are not in series with the fluid flow, such as expansion tanks, fill lines, chemical feeders, and drains.
plenum: a compartment or chamber to which one or more ducts are connected, that forms a part of the air distribution system, and that is not used for occupancy or storage. A plenum often is formed in part or in total by portions of the building.
pool: any structure, basin, or tank containing an artificial body of water for swimming, diving, or recreational bathing. The term includes, but is not limited to, swimming pool, whirlpool, spa, and hot tub.
power roof/wall ventilators (PRV): a fan consisting of a centrifugal or axial impeller with an integral driver in a weather-resistant housing and with a base designed to fit, usually by means of a curb, over a wall or roof opening.
power usage effectiveness—category 0 (PUE0): peak electric demand (kW) for the entire computer room, including IT equipment and supporting infrastructure, divided by peak electric demand (kW) of the IT equipment.
power usage effectiveness—category 1 (PUE1): annual energy consumption (kWh) for the entire computer room, including IT equipment and supporting infrastructure, divided by annual energy consumption (kWh) of the IT equipment.
projection factor (PF): the ratio of the horizontal depth of the external shading projection divided by the sum of the height of the fenestration and the distance from the top of the fenestration to the bottom of the farthest point of the external shading projection, in consistent units.
public facility restroom: a restroom used by the transient public.
pump system power: the sum of the nominal power demand (nameplate horsepower) of motors of all pumps that are required to operate at design conditions to supply fluid from the heating or cooling source to all heat transfer devices (e.g., coils, heat exchanger) and return it to the source.
purchased energy rates: costs for units of energy or power purchased at the building site. These costs may include energy costs as well as costs for power demand as determined by the adopting authority.
rated R-value of insulation: the thermal resistance of the insulation alone as specified by the manufacturer in units of h•ft2•°F/Btu at a mean temperature of 75°F. Rated 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. (See thermal resistance.)
rating authority: the organization or agency that adopts or sanctions use of this rating methodology.
readily accessible: capable of being reached quickly for operation, renewal, or inspection without requiring those to whom ready access is requisite to climb over or remove obstacles or to resort to portable ladders, chairs, etc. In public facilities, accessibility may be limited to certified personnel through locking covers or by placing equipment in locked rooms.
recirculating system: a domestic or service hot-water distribution system that includes a closed circulation circuit designed to maintain usage temperatures in hot-water pipes near terminal devices (e.g., lavatory faucets, shower heads) in order to reduce the time required to obtain hot water when the terminal device valve is opened. The motive force for circulation is either natural (due to water density variations with temperature) or mechanical (recirculation pump).
reflectance: the ratio of the light reflected by a surface to the light incident upon it.
refrigerant dew point: the refrigerant vapor saturation temperature at a specified pressure.
replacement air: outdoor air that is used to replace air removed from a building through an exhaust system. Replacement air may be derived from one or more of the following: makeup air, supply air, transfer air, and infiltration. However, the ultimate source of all replacement air is outdoor air. When replacement air exceeds exhaust, the result is exfiltration.
residential: spaces in buildings used primarily for living and sleeping. Residential spaces include, but are not limited to, dwelling units, hotel/motel guest rooms, dormitories, nursing homes, patient rooms in hospitals, lodging houses, fraternity/ sorority houses, hostels, prisons, and fire stations.
resistance, electric: the property of an electric circuit or of any object used as part of an electric circuit that determines for a given circuit the rate at which electric energy is converted into heat or radiant energy and that has a value such that the product of the resistance and the square of the current gives the rate of conversion of energy.
roof: the upper portion of the building envelope, including opaque areas and fenestration, that is horizontal or tilted at an angle of less than 60 degrees from horizontal. For the purposes of determining building envelope requirements, the classifications are defined as follows:
attic and other roofs: all other roofs, including roofs with insulation entirely below (inside of) the roof structure (i.e., attics, cathedral ceilings, and single-rafter ceilings), roofs with insulation both above and below the roof structure, and roofs without insulation but excluding metal building roofs.
- is constructed with a metal, structural, weathering surface;
- has no ventilated cavity; and
- has the insulation entirely below deck (i.e., does not include composite concrete and metal deck construction nor a roof framing system that is separated from the superstructure by a wood substrate) and whose structure consists of one or more of the following configurations:
- Metal roofing in direct contact with the steel framing members
- Metal roofing separated from the steel framing members by insulation
- Insulated metal roofing panels installed as described in subitems (a) or (b)
- installed above (outside of) the roof structure and
- continuous (i.e., uninterrupted by framing members).
single-rafter roof: a subcategory of attic roofs where the roof above and the ceiling below are both attached to the same wood rafter and where insulation is located in the space between these wood rafters.
room air conditioner: an encased assembly designed as a unit to be mounted in a window or through a wall or as a console. It is designed primarily to provide direct delivery of conditioned air to an enclosed space, room, or zone. It includes a prime source of refrigeration for cooling and dehumidification and a means for circulating and cleaning air. It may also include a means for ventilating and heating.
saturated condensing temperature: the saturation temperature corresponding to the measured refrigerant pressure at the condenser inlet for single component and azeotropic refrigerants, and the arithmetic average of the dew-point and bubble-point temperatures corresponding to the refrigerant pressure at the condenser entrance for zeotropic refrigerants.
seal class A: a ductwork sealing category that requires sealing all transverse joints, longitudinal seams, and duct wall penetrations. Duct wall penetrations are openings made by pipes, holes, conduit, tie rods, or wires. Longitudinal seams are joints oriented in the direction of airflow. Transverse joints are connections of two duct sections oriented perpendicular to airflow.
seasonal coefficient of performance—cooling (SCOPC): the total cooling output of an air conditioner during its normal annual usage period for cooling divided by the total electric energy input during the same period in consistent units (analogous to SEER but in I-P or other consistent units).
seasonal coefficient of performance—heating (SCOPH): the total heating output of a heat pump during its normal annual usage period for heating divided by the total electric energy input during the same period in consistent units (analogous to HSPF but in I-P or other consistent units).
seasonal energy efficiency ratio (SEER): the total cooling output of an air conditioner during its normal annual usage period for cooling (Btu) divided by the total electric energy input during the same period (Btu).
sensible cooling panel: a panel designed for sensible cooling of an indoor space through heat transfer to the thermally effective panel surfaces from the occupants and/or indoor space by thermal radiation and natural convection.
sensible heating panel: a panel designed for sensible heating of an indoor space through heat transfer from the thermally effective panel surfaces to the occupants and/or indoor space by thermal radiation and natural convection.
sensible recovery effectiveness: change in the dry-bulb temperature of the outdoor air supply divided by the difference between the outdoor air and return air dry-bulb temperatures, expressed as a percentage.
service equipment: the necessary equipment, usually consisting of a circuit breaker or switch and fuses and accessories, located near the point of entrance of supply conductors to a building or other structure (or an otherwise defined area) and intended to constitute the main control and means of cutoff of the supply. Service equipment may consist of circuit breakers or fused switches provided to disconnect all under-grounded conductors in a building or other structure from the service-entrance conductors.
shading coefficient (SC): the ratio of solar heat gain at normal incidence through glazing to that occurring through 1/8 in.-thick clear, double-strength glass. SC does not include interior, exterior, or integral shading devices.
single-line diagram: a simplified schematic drawing that shows the connection between two or more items. Common multiple connections are shown as one line.
single-package vertical air conditioner (SPVAC): a type of air-cooled small or large commercial package air-conditioning and heating equipment; factory assembled as a single package having its major components arranged vertically, which is an encased combination of cooling and optional heating components; is intended for exterior mounting on, adjacent interior to, or through an outside wall and is powered by single or three-phase current. It may contain separate indoor grille(s), outdoor louvers, various ventilation options, or indoor free air discharge, ductwork, wall plenum, or sleeve. Heating components may include electrical resistance, steam, hot water, gas, or no heat, but may not include reverse-cycle refrigeration as a heating means.
single-package vertical heat pump (SPVHP): an SPVAC that utilizes reverse-cycle refrigeration as its primary heat source, with secondary supplemental heating by means of electrical resistance, steam, hot water, or gas.
site-solar energy: thermal, chemical, or electrical energy derived from direct conversion of incident solar radiation at the building site and used to offset consumption of purchased fuel or electrical energy supplies. For the purposes of applying this standard, site-solar energy shall not include passive heat gain through fenestration systems.
|skylight area||=||total fenestration area of skylights|
|skylight VT||=||area weighted average visible transmittance of skylights as determined in accordance with Section 126.96.36.199.|
|WF||=||area weighted average well factor, where well factor is 0.9 if light well depth is less than 2 ft, or 0.7 if light well depth is 2 ft or greater. Light well depth is measured vertically from the underside of the lowest point on the skylight glazing to the ceiling plane under the skylight.|
slab-on-grade floor: that portion of a slab floor of the building envelope that is in contact with the ground and that is either above grade or is less than or equal to 24 in. below the final elevation of the nearest exterior grade.
small electric motor: a NEMA general purpose, alternating current, single-speed induction motor, built in a two-digit frame number series in accordance with NEMA Standards Publication MG1-1987, including IEC metric equivalent motors; constructed in the NEMA 42, 48, and 56 frame sizes or IEC metric equivalent.
solar heat gain coefficient (SHGC): the ratio of the solar heat gain entering the space through the fenestration area 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. (See fenestration area.)
- cooled space: an enclosed space within a building that is cooled by a cooling system whose sensible output capacity exceeds 5 Btu/h•ft2 of floor area.
- heated space: an enclosed space within a building that is heated by a heating system whose output capacity relative to the floor area is greater than or equal to the criteria in Table 3.2.
- indirectly conditioned space: an enclosed space within a building that is not a heated space or a cooled space, which is heated or cooled indirectly by being connected to adjacent space(s) provided:
- the product of the U-factor(s) and surface area(s) of the space adjacent to connected space(s) exceeds the combined sum of the product of the U-factor(s) and surface area(s) of the space adjoining the outdoors, unconditioned spaces, and to or from semiheated spaces (e.g., corridors) or
- that air from heated or cooled spaces is intentionally transferred (naturally or mechanically) into the space at a rate exceeding 3 ach (e.g., atria).
unconditioned space: an enclosed space within a building that is not a conditioned space or a semiheated space. Crawlspaces, attics, and parking garages with natural or mechanical ventilation are not considered enclosed spaces.
- nonresidential conditioned space (See nonresidential.)
- residential conditioned space (See residential.)
- nonresidential and residential semiheated space (See space.)
story: portion of a building that is between one finished floor level and the next higher finished floor level or the roof, provided, however, that a basement or cellar shall not be considered a story.
substantial contact: a condition where adjacent building materials are placed so that proximal surfaces are contiguous, being installed and supported so they eliminate voids between materials without compressing or degrading the thermal performance of either product.
system(s): a combination of equipment and auxiliary devices (e.g., controls, accessories, interconnecting means, and terminal elements) by which energy is transformed so it performs a specific function, such as HVAC, service water heating, or lighting.
task lighting: lighting directed to a specific surface or area that provides illumination for visual tasks.
temperature control throttling range: the number of degrees that room temperature must change in order to go from full heating to no heating or from full cooling to no cooling.
thermal conductance (C-factor): time rate of steady-state heat flow through unit area of a material or construction, induced by a unit temperature difference between the body surfaces (Btu/h•ft2•°F). Note that the C-factor does not include soil or air films.
thermal resistance (R-value): the reciprocal of the time rate of heat flow through a unit area induced by a unit temperature difference between two defined surfaces of material or construction under steady-state conditions (h•ft2•°F/Btu).
thermal transmittance (U-factor): heat transmission in unit time through unit area of a material or construction and the boundary air films, induced by unit temperature difference between the environments on each side (Btu/h•ft2•°F).
tinted: (as applied to fenestration) bronze, green, blue, or gray coloring that is integral with the glazing material. Tinting does not include surface-applied films such as reflective coatings, applied either in the field or during the manufacturing process.
transfer air: air transferred from one room to another through openings in the room envelope, whether it is transferred intentionally or not. The driving force for transfer air is generally a small pressure differential between the rooms, although one or more fans may be used.
unitary cooling equipment: one or more factory-made assemblies that normally include an evaporator or cooling coil and a compressor and condenser combination. Units that perform a heating function are also included.
unitary heat pump: one or more factory-made assemblies that normally include an indoor conditioning coil, compressor(s), and an outdoor refrigerant-to-air coil or refrigerant-to-water heat exchanger. These units provide both heating and cooling functions.
unmet load hour: an hour in which one or more zones is outside of the thermostat setpoint plus or minus one half of the temperature control throttling range. Any hour with one or more zones with an unmet cooling load or unmet heating load is defined as an unmet load hour.
variable-refrigerant-flow (VRF) system: an engineered direct expansion (DX) multisplit system incorporating at least one variable capacity compressor distributing refrigerant through a piping network to multiple indoor fan-coil units, each capable of individual zone temperature control, through integral zone temperature control devices and common communications network. Variable refrigerant flow utilizes three or more steps of control on common, interconnecting piping.
vent damper: a device intended for installation in the venting system of an individual, automatically operated, fossil-fuel-fired appliance in the outlet or downstream of the appliance draft control device, which is designed to automatically open the venting system when the appliance is in operation and to automatically close off the venting system when the appliance is in a standby or shutdown condition.
ventilation system motor nameplate horsepower (hp): the sum of the motor nameplate horsepower of all fans that are required to operate as part of the system.
vertical fenestration: all fenestration other than skylights. Trombe wall assemblies, where glazing is installed within 12 in. of a mass wall, are considered walls, not fenestration. For the purposes of determining building envelope requirements, the vertical fenestration classifications are defined as follows:
metal framing, entrance door: any doorway, set of doors, turnstile, vestibule, or other form of portal that is ordinarily used to gain access by its users and occupants to the building or to individual tenant spaces accessed from the exterior. (See building entrance and door.)
metal framing, fixed: all types of vertical fenestration, other than entrance door and operable, including, but not limited to, curtain walls, window walls, fixed windows, picture windows, glass block walls, nonopenable clerestory windows, and nonopenable sidelights and transoms.
metal framing, operable: all vertical fenestration that opens, except entrance doors, including, but not limited to, casement windows, projecting windows, pivoting windows, horizontal sliding windows, vertical sliding windows, openable clerestory windows, openable sidelights and transoms, sliding glass doors, and doors that are not entrance doors.
nonmetal framing: all products with framing materials other than metal with or without metal reinforcing or cladding.
visible transmittance (VT): the ratio of visible radiation entering the space through the fenestration product to the incident visible radiation, determined as the spectral transmittance of the total fenestration system, weighted by the photopic response of the eye and integrated into a single dimensionless value.
voltage drop: a decrease in voltage caused by losses in the lines connecting the power source to the load.
wall: that portion of the building envelope, including opaque area and fenestration, that is vertical or tilted at an angle of 60 degrees from horizontal or greater. This includes above- and below-grade walls, between floor spandrels, peripheral edges of floors, and foundation walls. For the purposes of determining building envelope requirements, the classifications are defined as follows:
|ach||air changes per hour|
|AFUE||annual fuel utilization efficiency|
|AHAM||Association of Home Appliance Manufacturers|
|ANSI||American National Standards Institute|
|AHRI||Air-Conditioning, Heating and Refrigeration Institute|
|ASHRAE||American Society of Heating, Refrigerating and Air-Conditioning Engineers|
|BSR||Board of Standards Review|
|Btu||British thermal unit|
|Btu/h||British thermal unit per hour|
|Btu/ft2•°F||British thermal unit per square foot per degree Fahrenheit|
|Btu/h•ft2||British thermal unit per hour per square foot|
|Btu/h•ft•°F||British thermal unit per hour per linear foot per degree Fahrenheit|
|Btu/h•ft2 °F||British thermal unit per hour per square foot per degree Fahrenheit|
|CDD50||cooling degree-days base 50°F|
|cfm||cubic feet per minute|
|COP||coefficient of performance|
|CTI||Cooling Technology Institute|
|DCV||demand control ventilation|
|DDC||direct digital control|
|DOE||U.S. Department of Energy|
|EER||energy efficiency ratio|
|gr||grains of moisture per pound of dry air|
|HDD65||heating degree-days base 65°F|
|h ft2 °F/Btu||hour per square foot per degree Fahrenheit per British thermal unit|
|HSPF||heating seasonal performance factor|
|HVAC||heating, ventilating, and air conditioning|
|HVACR||heating, ventilating, air conditioning, and refrigeration|
|IEC||International Electrotechnical Commission|
|IES||Illuminating Engineering Society of North America|
|IPLV||integrated part-load value|
|lin ft||linear foot|
|LPD||lighting power density|
|m2•K/W||square metre per kelvin per watt|
|MICA||Midwest Insulation Contractors Association|
|MSH||monitor seal height|
|NAECA||U.S. National Appliance Energy Conservation Act|
|NFPA||National Fire Protection Association|
|NFRC||National Fenestration Rating Council|
|NPLV||nonstandard part-load value|
|PTAC||packaged terminal air conditioner|
|PTHP||packaged terminal heat pump|
|R||R-value (thermal resistance)|
|Rc||thermal resistance of a material or construction from surface to surface|
|RCR||room cavity ratio|
|Ru||total thermal resistance of a material or construction including air film resistances|
|rpm||revolutions per minute|
|SEER||seasonal energy efficiency ratio|
|SHGC||solar heat gain coefficient|
|SMACNA||Sheet Metal and Air Conditioning Contractors' National Association|
|UL||Underwriters Laboratories Inc.|
|VT||visible transmittance (also known as visible light transmittance [VLT])|
|W/ft2||watts per square foot|
1. Schedules and internal loads, by building area type, are located at http://sspc901.ashraepcs.org/documents.php.