Architectural Library
Our mission at Bristolite is to provide our customers with the highest quality products and supreme service at an exceptional value. We also aim to provide the industry with an abundance of accurate and useful information relative to daylighting and energy conservation. We take our corporate responsibility to our employees, associates, industry colleagues and customers very seriously and we see ourselves as stewards for the efficient use of sustainable carbon free energy.
Fenestration Glossary

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

 

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AAMA

American Architectural Manufacturers Association.

Above-Grade Wall

A wall that is not a below-grade wall.

Above-Grade Walls

Those walls (Section 802.2.1) on the exterior of the building and completely above grade or the above-grade portion of a basement or first-story wall that is more than 15 percent above grade.

AC

Alternate current.

ACH

Air changes per hour.

Addition

An extension or increase in the height, conditioned floor area, or conditioned volume of a building. The code applies to additions to existing buildings.

Adopting Authority

The agency or agent that adopts a code or standard.

AFUE

Annual fuel utilization efficiency; combustion heating equipment efficiency is expressed in terms of AFUE. New equipment typically ranges from about 78- to 96-percent AFUE. Higher AFUE ratings indicate more efficient equipment.

AHAM

Association of Home Appliance Manufacturers.

Air Economizer

A duct and damper arrangement and automatic control system that together allow a cooling system to supply outside air to reduce or eliminate the need for mechanical cooling during mild or cold weather.

Air Economizer Systems

Ducting arrangements and automatic control systems that allow a cooling supply fan system to supply outdoor (outside) air to reduce or eliminate the need for mechanical refrigeration during mild or cold weather.

Alteration

Any construction, renovation, or change in a mechanical system that involves an extension, addition, or change to the arrangement, type, or purpose of the original installation.

ANSI

American National Standards Institute.

Application Part-Load Value (APLV)

A single number part-load efficiency figure of merit calculated in accordance with the method described in ARI Standard 550 or 590 referenced with the method rating conditions described in those standards.

AHRI

Air-Conditioning, Heating and Refrigeration Institute.

ASHRAE

American Society of Heating, Refrigerating and Air-Conditioning Engineers.

ASHRAE/IES

The American Society of Heating, Refrigerating and Air-Conditioning Engineers/Illuminating Engineering Society Standard.

ASME

American Society of Mechanical Engineers.

ASTM

American Society for Testing and Materials.

Attic and Other Roofs

All other roofs, including roofs with insulation entirely below (inside of) the roof structure (e.g., 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.

Authority Having Jurisdiction

The agency or agent responsible for enforcing the code or standard.

Auto Operated Control Damper

A damper which automatically opens and closes.

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.

Automatic Control Device

A device capable of automatically turning loads off and on without manual intervention.

Automatic Time-Switch Controls

Controls that automatically switch lights or equipment on and off.

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Balancing, Air

Adjusting air flow 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 boxes.

Balancing, Hydronic

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.

Ballast

A device used in conjunction with an electric-discharge lamp to cause the lamp to start and operate under the proper circuit conditions of voltage, current, wave form, electrode heat, etc.

Basement Wall

Basement walls that enclose heated spaces are part of the building envelope. Basement wall refers to the opaque portion of the wall (excluding windows and doors). To be considered a basement wall, at least 50% of the wall''s total wall area (including openings) must be below grade. Treat walls on each side of the basement individually when determining if they are above-grade or basement walls. For any individual wall less than 50% below grade, include the entire opaque wall area of that individual wall as part of the above-grade walls.

Below-Grade Wall

That portion of a wall in the building envelope that is entirely below the finish grade and in contact with the ground.

Below-Grade Walls

Basement or first-story walls (Section 802.2.8) associated with the exterior of the building that are at least 85 percent below grade.

BOCA

Building Officials and Code Administrators International, Inc.

Boiler

A pressurized system in which water is vaporized to steam by heat transferred from a source of higher temperature, usually the products of combustion from burning fuels. Steam thus generated may be used directly as a heating medium or as the working fluid in a prime mover to convert thermal energy to mechanical work, which in turn may be converted to electrical energy.

Boiler, Packaged

A boiler that is shipped complete with heating equipment, mechanical draft equipment, and automatic controls; 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.

Branch Circuit

The circuit conductors between the final overcurrent device protecting the circuit and the outlet(s); the final wiring run to the load.

BSR

Board of Standards Review.

BTU

British thermal unit, which is the quantity of heat required to raise the temperature of 1 pound (0.454 kg) of water 1°F.

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

A structure wholly or partially enclosed within exterior walls, or within exterior and party walls, and a roof, affording shelter to persons, animals, or property.

Building Entrance

Any doorway, set of doors, turnstiles, or other form of portal that is ordinarily used to gain access to the building by its users and occupants.

Building Envelope

A building envelope includes all components of a building that enclose conditioned space. Building envelope components separate conditioned spaces from unconditioned spaces or from outside air. For example, walls and doors between an unheated garage and a living area are part of the building envelope; walls separating an unheated garage from the outside are not. Although floors of conditioned basements and conditioned crawlspaces are technically part of the building envelope, the code does not specify insulation requirements for these components.

Building Envelope Interior

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, unconditioned spaces, or conditioned spaces.

Building Exit

Any doorway, set of doors, or other form of portal that is ordinarily used only for emergency egress or convenience exit.

Building Grounds Lighting

Lighting provided through building''s electrical service for parking lot, site, roadway, pedestrian pathway, loading dock, and security applications.

Building Information Model (BIM)

A digital representation of the building process. The BIM facilitates exchange and interoperability of information in digital format.

Building Materials

Any element (other than air films and insulation) of the building envelope through which heat flows and that is included in the component U-factor calculations.

Building Official

The officer or other designated representative authorized to act on behalf of the authority having jurisdiction.

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C-Factor

Time rate of steady-state heat flow through the unit area of a material or construction surfaces. Units of C-Factor are Btu/h x ft2 x degrees Fahrenheit. Note that the C-factor does not include soil or air films.

CABO

The Council of American Building Officials.

Cavity Insulation

Insulation installed between structural members such as wood studs, metal framing, and Z-clips.

CC designations

A classification of light transmitting plastics under the Uniform Building Code Standard 26-7. Under this standard, light transmitting plastics are tested to ASTM D625-74 standard and are rated either CC1 or CC2. Plastics rated CC1 have a burning extent of 1 inch (25mm) or less when tested in nominal 0.060 inch (1.5mm) thickness (or in the thickness intended for use) by this test. Plastics rated CC2 have a burning rate of 2.5 inches per minute (64nn/min) or less when tested in nominal 0.060 inch (1.5mm) thickness (or in the thickness intended for use) by this test. Our Trituff Copolyester, Energy Star Fiberlite and Tufflite Polycarbonate glazings all have CC1 ratings.

CDD

Cooling degree day. See "Cooling Degree Days."

CDD50

Cooling degree days base 50 degrees F. See "Degree Day Base 50F."

CE

Combustion efficiency.

Ceiling

The ceiling requirements apply to portions of the roof and/or ceiling through which heat flows. Ceiling components include the interior surface of flat ceilings below attics, the interior surface of cathedral or vaulted ceilings, skylights, and sloped building assemblies less than 60 degrees from horizontal, but excluding skylight shafts.

CFM

Cubic feet per minute. A standard measurement of airflow.

Check Metering

Measurement instrumentation for the supplementary monitoring of equipment and tenant energy use (electric, gas, oil, etc.) in addition to the revenue metering furnished by the utility.

Circuit Breaker

A device designed to open and close circuit by non-automatic means and to open the circuit automatically at a predetermined overcurrent without damage to itself when properly applied within its rating.

Circulating Water Heater

Hot water continuously circulates through the distribution system.

Circulation Pumps

Pumps that are used to keep hot water circulating through the distribution system.

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.

Clerestory

That part of a building that rises clear of the roofs or other parts and whose walls contain windows for lighting the interior.

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Daylight Glazing

Exterior glazing over 6 feet above the finished floor.

DDC

Direct Digital Control.

Deadband

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

Decorative Lighting

Lighting that is purely ornamental and installed for aesthetic effect. Decorative lighting shall not include general lighting.

Degree Day

See "Heating Degree Days."

Degree Day Base 50F, CDD50

For any one day, when the mean temperature is more than 50 degrees F, there are as many degree days as degrees Fahrenheit temperature difference between the mean temperature for the day and 50 degrees F. Annual cooling degree days (CDDs) are the sum of the degree days over a calendar year.

Demand

The highest amount of power (average kw over an interval) recorded for a building or facility in a selected time frame.

Design A

National Electrical Manufacturers Association (NEMA) design class designations for standard general purpose polyphase squirrel-cage induction motors.

Design B

National Electrical Manufacturers Association (NEMA) design class designations for standard general purpose polyphase squirrel-cage induction motors.

Design Capacity

Output capacity of a system or piece of equipment at design conditions.

Design Conditions

Specified environmental conditions, such as temperature and light intensity, required to be produced and maintained by a system and under which the system must operate.

Design E

National Electrical Manufacturers Association (NEMA) design class designations for standard general purpose polyphase squirrel-cage induction motors.

Design Energy Cost

The annual energy cost calculated for a proposed design.

Design Professional

An architect or engineer licensed to practice in accordance with applicable state licensing laws.

Diffusion

The scattering of direct light from concentrated areas to less concentrated areas by passing the light through a material or by bouncing it off a semi-reflective surface. Highly diffused light creates "softer” more uniform light and does not create shadows.

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 auxilliary equipment as fans, pumps and transformers.

DOE

U.S. Department of Energy.

Domestic Water Heating System

DWH systems may be circulating or non-circulating.

Door

Doors include all openable opaque assemblies (which are not fenestration) located in exterior walls of the building envelope. Doors with glass can be treated as a single door assembly, in which case an aggregate U-factor (a U-factor that includes both the glass and the opaque area) must be used, or the glass area of the door can be included with the other glazing, and an opaque door U-factor can be used to determine compliance of the door.

Door Area

Total area of the door measured using the rough opening and including the door slab and the frame. See "Fenestration Area."

Dry-Type Transformer

A transformer in which the core and coils are in a gaseous or dry compound.

DSM

Demand-side management.

Duct

A tube or conduit used for conveying air. The air passages of self-contained systems should not be construed as air ducts.

Duct Furnace

A furnace normally installed in distribution ducts of air conditioning systems to supply warm air for heating and which depends on a blower not furnished as part of the duct furnace for air circulation.

Duct System

A continuous passageway for the transmission of air that, in addition to ducts, includes duct fittings, dampers, plenums, fans, and accessory air-handling equipment and appliances.

Dwelling Unit

A single housekeeping unit of one or more rooms providing complete, independent living facilities, including permanent provisions for living, sleeping, eating, cooking, and sanitation.

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Economizer

A duct and damper arrangement and automatic control system that allow a cooling supply fan system to supply outdoor air to reduce or eliminate the need for mechanical refrigeration during mild or cold weather.

Efficacy

A metric used to compare light output to energy consumption. Efficacy is measured in lumens per watt. Efficacy is similar to efficiency but is expressed in dissimilar units. For example, if a 100-watt source produces 9000 lumens, then the efficacy is 90 lumens per watt.

Efficiency

Performance at specified rating conditions.

Electric Meter

A mechanical/electrical device that can measure electric power.

Electric Resistance

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.

Electric Supplier

An agency that sells and/or distributes electric power.

Electronic High Frequency Ballasts

Electronic ballasts improve fluorescent system efficacy by converting the standard 60 Hz input frequency to a higher frequency, usually 25,000 to 40,000 Hz. Lights operating on these frequencies produce about the same amount of light while consuming up to 30% less power than a standard magnetic ballast.

Emergency Power System (EPS)

A system that is required by codes or other laws to automatically supply illumination or power or both in the event of failure of the normal supply or in the event of accidents to such systems. Such systems may also include standby loads incidental to system operations but shall not include systems for optional standby loads only.

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.

Enclosed Space

A volume substantially surrounded by solid surfaces such as walls, floors, roofs, and openable devices such as doors and operable windows. Spaces not meeting these criteria for enclosure are considered to be exterior to the building for purposes of determining envelope requirements. For example, most parking garages do not qualify as enclosed space.

Enclosure

The case or housing of an apparatus, or the fence or walls surrounding an installation, designed to prevent personnel from accidentally contacting energized parts and to protect equipment from physical damage.

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. Customary measurement units are British thermal units (Btu).

Energy Cost Budget

The annual energy cost for the budget building.

Energy Efficient Ratio (EER)

The ratio of net equipment cooling capacity in Btu/h to total rate of electric input in watts under designated operating conditions. When consistent units are used, this ratio becomes equal to the coefficient of performance.

Energy Factor (EF)

A measure of water heater overall efficiency.

Energy Performance Rating

The energy use of the proposed building under actual operating conditions. Projected energy use targets can be used for buildings in the design or construction process. Examples include kBtu/sf/yr, $/sf/yr, $/gross sales, Energy Performance Rating Score (US EPA), or like expressions of energy performance.

Envelope Components

The building assemblies that provide a barrier between conditioned space and unconditioned space. This includes the floors, walls, and ceiling/roof assemblies of the building.

Envelope 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. It is needed to determine building envelope requirements.

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.

Equipment Efficiency

The measure of equipment efficiency varies with equipment type.

Exfiltration

Uncontrolled outward air leakage from inside a building including leakage through cracks and interstices around windows and doors and through any other exterior partition or penetration.

Existing Building

A building or portion thereof that was previously occupied or approved for occupancy by the authority having jurisdiction.

Existing Equipment

Equipment previously installed in an existing building.

Existing System

A system or systems previously installed in an existing building.

Exterior Lighting Power Allowance

The maximum lighting power in watts allowed for the exterior of a building.

Exterior Wall

An above-grade wall enclosing conditioned space. Includes between-floor spandrels, peripheral edges of floors, roof and basement knee walls, dormer walls, gable end walls, walls enclosing a mansard roof, and basement walls with an average below grade-wall area that is less than 50 percent of the total opaque and non-opaque area of that enclosing side.

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F

Fahrenheit.

F-Factor

The perimeter heat loss factor for slab-on-grade floors, expressed in Btu/h x F.

Facade Area

Area of the facade, including overhanging soffits, cornices, and protruding columns, measured in elevation in a vertical plane parallel to the plane of the face of the building. Non-horizontal roof surfaces shall be included in the calculation of vertical facade area by measuring the area in a plane parallel to the surface.

Fan Coil

A fan-coil terminal is essentially a small air-handling unit which serves a single space without a ducted distribution system. One or more independent terminals are typically located in each room connected to a supply of hot and/or chilled water. At each terminal, a fan in the unit draws room air (sometimes mixed with outside air) through a filter and blows it across a coil of hot water or chilled water and back into the room.

Fan System Energy Demand

The sum of the nominal power demand (nameplate horsepower) of motors 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.

Feeder Conductors

The wires that connect the service equipment to the branch circuit breaker panels.

Fenestration

All areas (including the frames) in the building envelope that let in light, including windows, plastic panels, clerestories, skylights, glass doors that are more than one-half glass, and glass block walls. A skylight is a fenestration surface having a slope of less than 60 degrees from the horizontal plane. Other fenestration, even if mounted on the roof of a building, is considered vertical fenestration.

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.

Fixture

The component of a luminaire that houses the lamp or lamps, 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

A horizontal exterior partition, or a horizontal demising partition, under conditioned space which separates conditioned space from unconditioned space.

Fluorescent Lamps

A light source consisting of a tube filled with argon, along with krypton or other inert gas. When electrical current is applied, the resulting arc emits ultraviolet radiation that excites the phosphors inside the lamp wall, causing them to radiate visible light.

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, and 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.

Fossil Fuel

Fuel derived from a hydrocarbon deposit such as petroleum, coal, or natural gas derived from living matter of a previous geologic time.

Fuel

A material that may be used to produce heat or generate power by combustion.

Fuel Fired Furnace

A self-contained, indirect-fired furnace that supplies heated air through ducts to spaces that require it.

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General Lighting

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 an area.

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.

Generally Accepted Engineering Standard

A specification, rule, guide, or procedure in the field of engineering, or related thereto, recognized and accepted as authoritative.

Glazed Wall System

A category of site-assembled fenestration products, which includes, but is not limited to, curtain walls and solariums.

Glazing

Any translucent or transparent material in exterior openings of buildings, including windows, skylights, sliding doors, the glass area of opaque doors, and glass block.

Glazing Area

The area of a glazing assembly is the interior surface area of the entire assembly, including glazing, sash, curbing, and other framing elements. The nominal area or rough opening is also acceptable for flat windows and doors.

Glazing U-Factor

Based on the interior-surface area of the entire assembly, including glazing, sash, curbing, and other framing elements. Center-of-glass U-factors cannot be used.

Grade

The finished ground level adjoining a building at all exterior walls.

Gross Floor Area

The sum of the floor areas of the spaces within the building including basements, mezzanine and intermediate-floored tiers, and penthouses with 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 it excludes covered walkways, open roofed-over areas, porches and similar spaces, pipe trenches, exterior terraces or steps, chimneys, roof overhangs, and similar features.

Gross Wall Area

The gross wall area includes the opaque area of above-grade walls, the opaque area of any individual wall of a conditioned basement less than 50% below grade (including the below-grade portions), all windows and doors (including windows and doors of conditioned basements), and the peripheral edges of floors.

Gross Window Area

Includes the rough-opening area of the window, not just the transparent-glass area.

Gutter

The space available for wiring inside panel boards and other electric panels; a separate wireway used to supplement wiring spaces in electric panels.

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Harmonics

Voltages and currents at frequencies other than 60 Hz (or 50 Hz where applicable) that cause heating and other detrimental effects in the power system.

Heat Capacity

The amount of heat necessary to raise the temperature of a given mass 1 degree F. Numerically, 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.

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.

Heat Trace

A heating system where the externally applied heat source follows (traces) the object to be heated, e.g., water piping.

Heat Traps

Devices or piping arrangements that effectively restrict the natural tendency of hot water to rise in vertical pipes during standby periods. Examples are the U-shaped arrangement of elbows or a 360-degree loop of tubing.

Heated Slab

Slab-on-grade construction in which the heating elements or hot air distribution system is in contact with or placed within the slab or the subgrade.

Heated Space

Space within a building that is provided with a positive heat supply (see "Positive Heat Supply"). Finished living space within a basement with registers or heating devices designed to supply heat to a basement space shall automatically define that space as heated space.

Heating Degree Days (HDD)

A unit, based upon temperature difference and time, used in estimating fuel consumption and specifying nominal heating load of a building in winter. For any one day, when the mean temperature is less than 65 degrees F (18 degrees C), there exists as many degree days as there are Fahrenheit degrees difference in temperature between the mean temperature for the day and 65 degrees F (18 degrees C).

Heating Degree Day Base 65F (HDD65)

For any one day, when the mean temperature is less than 65 degrees F, there are as many degree days as degrees Fahrenheit temperature difference between the mean temperature for the day and 65 degrees F. Annual heating degree days (HDDS) are the sum of the degree days over a calendar year.

Heating Seasonal Performance Factor (HSPF)

The total heating output of a heat pump during its normal annual usage period for heating, in Btu, divided by the total electric energy input during the same period, in watt hours, as determined by DOE 10 CFR Part 430, Subpart B, Test Procedures, and based on Region 4. Heat pump heating is expressed in terms of HSPF. New equipment ranges from about 6.8 to 10.0 HSPF. Higher HSPF ratings indicate more efficient equipment.

HID

High-intensity discharge.

High-Intensity Discharge Lamp (HID lamp)

An electric discharge lamp in that 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.

High-Rise Residential Building

Hotels, motels, apartments, condominiums, dormitories, and other residential-type facilities that provide complete housekeeping or transient living quarters and are over three stories in height above grade. Hotels, motels, and other buildings with itinerant occupancies are covered by the "commercial" code regardless of height.

Historic

A building or space that has been specifically designated as historically significant by the adopting authority, is listed in "The National Register of Historic Places," or has been determined to be eligible for listing by the U.S. Secretary of the Interior.

Hot Water Supply Boiler

A boiler used to heat water for purposes other than space heating.

HUD

The U.S. Department of Housing and Urban Development.

Humidistat

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

HVAC

Heating, ventilating, and air conditioning.

HVAC System

The equipment, distribution network, and terminals that provide either collectively or individually the processes of heating, ventilating, or air conditioning to 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).

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ICAA

Insulation Contractors Association of America.

ICBO

The International Conference of Building Officials.

ICC

The International Code Council.

IECC

The International Energy Conservation Code formerly known as the MEC. The IECC was published in 1998, 2000, 2003, 2006, and 2009.

IEEE

Institute of Electrical and Electronics Engineers, inc.

IESNA

Illuminating Engineering Society of North America.

IMC

International Mechanical Code.

Incandescent Lamp

A lamp in which light is produced by a filament heated to incandescence by an electric current.

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. (Also 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 or the effect of differences in the indoor and outdoor air density or both.

Installed Interior Lighting Power

The power in watts of all permanently installed general, task, and furniture lighting systems and luminaires.

Insulated Sheathing

An insulating board having a minimum thermal resistance of R-2 of the core material.

Insulation R-Values

R-values are used to rate insulation and are a measurement of the insulation''s resistance to heat flow. The higher the R-value, the better the insulation.

Integrated-Control Economizers

Allows the cooling load of a building or space to be partially met by supplying outside air while the rest of the load is met by the refrigeration equipment within an HVAC system. Field- and factory-installed economizers supplied by major equipment manufacturers include integrated controls.

Integrated Part Load Value (IPLV)

A single-number figure of merit based on part-load EER, COP, or kW/ton 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 Controls

Offer the ability for systems to be turned on and off either manually or automatically and include switches, time clocks, occupancy sensors, and other devices that regulate a lighting system.

Interior Lighting Power Allowance

The maximum lighting power in watts allowed for the interior of a building.

Interior Walls

Interior walls covered by Section 802.2.9 are those walls not on the exterior of the building and that separate conditioned and unconditioned space.

International Foundation Class (IFC)

An object-oriented file format with a data model developed to facilitate interoperability in the building industry.

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.

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K

Kelvin.

kg

Kilogram.

Kilovolt-Ampere (KVA)

Where the term "kilovolt-ampere" (KVA) is used, 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.

kWh

Kilowatt-hour.

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Labeled

Devices, equipment, appliances, assemblies, or materials to which have been affixed a label, seal, symbol, or other identifying mark of a nationally recognized testing laboratory, inspection agency, or other organization concerned with product evaluation that maintains periodic inspection of the production of the above-labeled items and by whose label the manufacturer attests to compliance with applicable nationally recognized standards.

Lamp

A generic term for a man-made light source often called a bulb or tube.

lb

Pound.

Lighting Power Density (LPD)

The maximum lighting power per unit area of a building classification or space function.

Lighting System

A group of luminaires circuited or controlled to perform a specific function.

Liquid-Immersed Transformer

A transformer in which the core and coils are immersed in an insulating liquid.

Listed

Equipment, appliances, assemblies, or materials included in a list published by a nationally recognized testing laboratory, inspection agency, or other organization concerned with product evaluation that maintains periodic inspection of production of listed equipment, appliances, assemblies, or material, and whose listing states either that the equipment, appliances, assemblies, or material meets nationally recognized standards or has been tested and found suitable for use in a specified manner.

Longitudinal Seam

A duct seam that is parallel to the direction of air flow.

Low Voltage Lighting

Lighting equipment that is powered through a transformer such as a cable conductor, a rail conductor, or track lighting.

Low-Rise Residential

Single-family houses, multi-family structures with three stories or fewer above grade and manufactured houses (modular and mobile homes).

Luminaire

A complete lighting unit consisting of a lamp or lamps, along with the parts designed to distribute the light, hold the lamps, and connect the lamps to a power source. Also called a fixture.

Luminous Light Transmission (LLT)

The measure of how much total light passes through a fenestration. Luminous light transmission (LLT) measures a broader segment of the light spectrum than VLT. This includes portions of the light spectrum that cannot be seen by the human eye. The higher the LLT a skylight has, the greater its light transmission. LLT is expressed as a number from 0 to 1

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Manual (nonautomatic)

Requiring personal intervention for control. Nonautomatic does not necessarily imply a manual controller, only that personal intervention is necessary.

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.

Marked (nameplate) Rating

The design load operating conditions of a device as shown by the manufacturer on the nameplate or otherwise marked on the device.

Mass Wall

A wall with a heat capacity exceeding (1) 7Btu/ft2 or (2) 5 Btu/ft2 x F provided that the wall has a material unit weight not greater than 120 lb/ft3.

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.

Mechanical System

The system and equipment used to provide heating, ventilating, and air conditioning functions as well as additional functions not related to space conditioning, such as, but not limited to, freeze protection in fire protection systems and water heating.

MEEA

Midwest Energy Efficiency Alliance

Metal Building

A complete, integrated set of mutually-dependent components and assemblies that form a building consisting of a steel-framed superstructure and metal skin.

Metal Building Roof

A roof that (a) is constructed with a metal, structural, and weathering surface, (b) has no ventilated cavity, and (c) has the insulation entirely below deck (i.e., includes neither a 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: (1) metal roofing in direct contact with the steel framing members, (2) insulation between the metal roofing and the steel framing members, or (3) insulated metal roofing panels installed as described in 1 or 2.

Metal Building Wall

A wall whose structure consists of metal spanning members supported by steel structural members (i.e., does not include spandrel glass or metal panels in curtain wall systems).

Metal Halide Lamps

A type of high intensity discharge (HID) lamp in which most of the light is produced by radiation of metal halide and mercury vapors in the arc tube. Available in clear and phosphor-coated lamps.

Metering

Instruments that measure electric voltage, current, power, etc.

MICA

Midwest Insulation Contractors Association.

Model Energy Code (MEC)

The Model Energy Code. The MEC was first published in 1983, with subsequent full editions published in 1986, 1989, 1992, 1993, and 1995. The MEC became the IECC, first published in 1998.

Motor Power Rated

The rated output power from the motor.

Multifamily

A multifamily building is a residential building three stories or fewer in height that contains three or more attached dwelling units. Multifamily buildings include apartments, condominiums, townhouses, and rowhouses. Hotels and motels are considered commercial rather than residential buildings.

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NAECA

The National Appliance Energy Conservation Act of 1987, 42 USC 6291 et seq., as amended, Public Law 100-12.

NAGDM

National Association of Garage Door Manufacturers.

NCSBCS

The National Conference of States on Building Codes and Standards.

Net Wall Area

The net wall area includes the opaque wall area of all above-grade walls enclosing conditioned spaces, the opaque area of conditioned basement walls less than 50% below grade (including the below-grade portions), and peripheral edges of floors. The net wall area does not include windows, doors, or other such openings, as they are treated separately.

NEEA

Northwest Energy Efficiency Alliance.

NEEP

Northeast Energy Efficiency Partnerships.

NFPA

National Fire Protection Association.

NFRC

National Fenestration Rating Council.

Non-Standard Part Load Value (NPLV)

A single-number, part-load efficiency figure of merit calculated and referenced to conditions other than IPLV conditions, for units that are not designed to operate at ARI Standard Rating Conditions.

Non-Recirculating System

A domestic or service hot water distribution system that is not a recirculating system.

Non-Renewable Energy

Energy derived from a fossil fuel source.

Non-Residential

All occupancies other than residential.

North-Oriented

Facing within 45 degrees of true north (northern hemisphere).

NPLV

Non-standard part load value.

NWWDA

National Wood Window and Door Association.

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Occupancy Type

The type of activity occurring within a building.

Occupant Sensing Device

A device that detects the presence or absence of people within an area and causes any combination of lighting, equipment, or appliances to be adjusted accordingly.

Occupant Sensor

A device that detects the presence or absence of people within an area and causes lighting, equipment, or appliances to be regulated accordingly.

Opaque

All areas in the building envelope, except fenestration and building service openings such as vents and grilles.

Opaque Areas

Opaque areas include all areas of the building envelope except openings for windows, skylights, doors, and building service systems. For example, although solid wood and metal doors are opaque, they should not be included as part of the opaque wall area (also referred to as the net wall area).

Operational Performance Requirements

A written document that details the functional requirements of a project and the expectations of how it will be used and operated. This includes project and design goals, measurable performance criteria, budgets, schedules, success criteria, and supporting information.

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.

Orientation

The direction an envelope element faces, i.e., the direction of a vector perpendicular to and pointing away from the surface outside of the element.

Outdoor Air

Air taken from the outdoors and, therefore, not previously circulated through the system.

Overcurrent

Any current in excess of the rated current of equipment or the ampacity of a conductor. It may result from overload, short circuit, or ground fault.

Overhead Glazing Area

The area whose horizontal dimension, in each direction, is equal to the overhead glazing dimension plus either the floor to ceiling height or the dimension to the nearest 66" or higher opaque partition, or one-half the distance to the adjacent overhead or vertical glazing.

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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.

Packaged Terminal Heat Pump (PTHP)

A PTAC capable of using the refrigerating system in a reverse cycle or heat pump mode to provide heat.

Party Wall

A fire wall on an interior lot line used or adapted for joint service between two buildings.

Performance Approach

A performance approach (also known as a systems performance approach) compares a proposed design with a baseline or reference design and demonstrates that the proposed design is at least as efficient as the baseline in terms of annual energy use. This approach allows the greatest flexibility but may require considerably more effort. A performance approach is often necessary to obtain credit for special features such as a passive solar design, photovoltaic cells, thermal energy storage, fuel cells, and other nontraditional building components. This approach requires an annual energy use value. There are several commercially available software tools that perform this analysis.

Perm Rating

The amount of water vapor that passes through an area in a certain period of time.

Permanantly Wired Luminaires

Light fixtures physically attached to a surface (e.g. ceiling or wall) using a permanent mounting system and wired directly to a power source. Examples include fluorescent fixtures located in a ceiling grid and wall sconces.

Permanently Installed

Equipment that is fixed in place and is not portable or movable.

Photo Cell

A light-sensing device used to control luminaires and dimmers in response to detected light levels.

Plenum

An enclosure that is part of the air-handling system and is distinguished by having a very low air velocity. 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.

Positive Cooling Supply

Mechanical cooling deliberately supplied to a space, such as through a supply register. Also, mechanical cooling indirectly supplied to a space through uninsulated surfaces of space-cooling components, such as evaporator coil cases and cooling distribution systems that continually maintain air temperatures within the space of 85 degrees F (29 degrees C) or lower during normal operation.

Positive Heat Supply

Heat deliberately supplied to a space by design, such as a supply register, radiator, or heating element. Also, heat indirectly supplied to a space through uninsulated surfaces of service water heaters and space-heating components, such as furnaces, boilers, and heating and cooling distribution systems that continually maintain air temperature within the space of 50 degrees F (10 degrees C) or higher during normal operation.

Power Factor

The ratio of total real power in watts to the apparent power (root-mean-square volt amperes).

Prescriptive Approach

A prescriptive approach lists the minimum R-value or maximum U-factor requirements for each building component such as windows, walls, and roofs. For lighting systems in commercial buildings, a prescriptive approach would simply list the allowable watts per square foot for various building types. For mechanical systems and equipment, a prescriptive approach would list the minimum required equipment efficiencies.

Primary Air System

The central, air-moving, heating, and cooling equipment that serves multiple zones through mixing boxes, VAV boxes, or reheat coils.

Process Energy

Energy consumed in support of a manufacturing, industrial, or commercial process other than conditioning spaces and maintaining comfort and amenities for the occupants of a building.

Process Load

The load on a building resulting from the consumption or release of process energy.

Projection Factor (PF)

The ratio of the distance the overhang projects from the window surface to its height above the sill of the window it shades.

Proposed Design

A computer representation of the actual proposed building design or portion thereof used as the basis for calculating the design energy cost.

psi (g)

Pounds per square inch gauge.

Pump System Energy Demand (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.

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R-Value

A measure (h ft2 °F/Btu) of thermal resistance, or how well a material or series of materials resists the flow of heat. The R-value is the reciprocal of the U-factor. An expression of insulating value. R Value is the reciprocal of U Factor a measure of the rate of heat loss of a fenestration. The higher the R Value the greater the skylight’s resistance to heat flow and the greater its insulating value.

Radiant Heating System

A heating system that transfers heat to objects and surfaces within the heated space primarily (greater than 50%) by infrared radiation.

Raised Truss

Raised truss refers to any roof/ceiling construction that allows the insulation to achieve its full thickness over the plate line of exterior walls. Several constructions allow for this, including elevating the heel (sometimes referred to as an energy truss, raised-heel truss, or Arkansas truss), use of cantilevered or oversized trusses, lowering the ceiling joists, or framing with a raised rafter plate.

Rated Lamp Wattage

The power consumption of a lamp as published in manufacturers'' literature.

Readily Accessible

Capable of being reached quickly for operation, renewal, or inspections without requiring those to whom ready access is requisite to climb over or remove obstacles or 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.

RECD

The Rural Economic and Community Development, formerly the Farmer''s Home Administration.

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).

Recooling

Lowering the temperature of air that has been previously heated by a mechanical heating system.

Record Drawings

Drawings that record the conditions of the project as constructed. These include any refinements of the construction or bid documents.

Reflectance

The ratio of the light reflected by a surface to the light incident upon it.

Reflector Lamp

A class of incandescent lamps that have an internal reflector to direct the light. Reflector lamps are typically characterized by reflector shapes such as R (reflector), ER (elipsodial reflector), PAR (parabolic aluminized reflector), MR (multi-faceted reflector), and others.

Reheating

Raising the temperature of air that has been previously cooled either by mechanical refrigeration or an economizer system.

Reset

Automatic adjustment of the controller set point to a higher or lower value.

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, hotels, prisons, and fire stations.

Residential Building, Group R-2

Residential occupancies containing more than two dwelling units where the occupants are primarily permanent in nature such as apartment houses, boarding houses (not transient), convents, monasteries, rectories, fraternities and sororities, dormitories and rooming houses. For the purpose of this code, reference to Group R-2 occupancies shall refer to buildings that are three stories or less in height above grade.

Residential Building, Group R-4

Residential occupancies shall include buildings arranged for occupancies as Residential Care/Assisted Living Facilities including more than five but not more than 16 occupants, excluding staff. For the purpose of this code, reference to Group R-4 occupancies shall refer to buildings which are three stories or less in height above grade.

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.

Roof Assembly

A roof assembly shall be considered to be all roof/ceiling components of the building envelope through which heat flows, thus creating a building transmission heat loss or gain, where such assembly is exposed to outdoor air and encloses conditioned space. The gross area of a roof assembly consists of the total interior surface of all roof/ceiling components, including opaque surfaces, dormer and bay window roofs, treyed ceilings, overhead portions of an interior stairway to an unconditioned attic, doors and hatches, glazing, and skylights exposed to conditioned space that are horizontal or sloped at an angle less than 60° from the horizontal.

Roofing With Insulation Entirely Above Deck

A roof with all insulation (1) installed above (outside of) the roof structure and (2) continuous (i.e., uninterrupted by framing members).

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 meant 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.

Room Cavity Ratio

A factor that characterizes room configuration as a ratio between the walls and veiling and is based upon room dimensions.

rpm

Revolutions per minute.

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SBCCI

The Southern Building Code Congress International, Inc.

Screw Lamp Holders

A lamp base that requires a screw-in-type light such as an incandescent or tungsten-halogen bulb.

Seasonal Coefficient of Performance (cooling)

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 the HSPF but for IP or other consistent units).

Seasonal Coefficient of Performance (heating)

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 the HSPF but for IP 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, in Btu/h (W), divided by the total electric energy input during the same period, in watt-hours, as determined by DOE 10 CFR Part 430, Subpart B, Test Procedures. New equipment ranges from about 10 to 16 SEER. Higher SEER ratings indicate more efficient equipment.

Semiheated Space

An enclosed space within a building that is heated by a heating system whose output capacity is greater than or equal to 3.4 Btu/Ft2 of floor area but is not a conditioned space.

Service Agency

An agency capable of providing calibration, testing, or manufacture of equipment, instrumentation, metering, or control apparatus, such as a contractor, laboratory or manufacturer.

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 underground conductors in a building or other structure from the service-entrance conductors.

Service Water Heating

Heating water for domestic or commercial purposes other than space heating and process requirements.

Set Point

Point at which the desired temperature (degrees Fahrenheit) of the heated or cooled space is set.

Setback

Reduction of heating (by reducing the set point) or cooling (by increasing the set point) during hours when a building is unoccupied or during periods when lesser demand is acceptable.

Shading Coefficient (SC)

The ratio of solar heat gain through fenestration, with or without integral shading devices, to that occurring through unshaded 1/8-in.-thick double-strength glass. A measure of the solar heat transmission of a fenestration in comparison to the solar heat transmission of 1/8” clear glass. Shading coefficient is being phased out in favor of the newer solar heat gain coefficient (SHGC) measurement, and is approximately equal to the SHGC multiplied by 1.15. The shading coefficient is expressed as a number from 0 to 1. The lower a skylight’s shading coefficient, the less solar heat it transmits, and the greater its shading ability. A low shading coefficient in combination with a high LT% and high diffusion is the key to optimal skylight performance.

Simulation Program

A computer program that is capable of simulating the energy performance of building systems.

Single Family

A detached residential building, irrespective of height, including duplexes.

Single Zone Units

Unitary HVAC systems that serve a single zone. Single zone systems can provide either heating or cooling, but they provide supply air at the same volume and temperature to the entire zone which they serve.

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.

Single-Zone System

An HVAC system serving a single HVAC zone.

Site-Recovered Energy

Waste energy recovered at the building site that is used to offset consumption of purchased fuel or electrical energy supplies.

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

A fenestration surface having a slope of less than 60 degrees from the horizontal plane. Other fenestration, even if mounted on the roof of a building, is considered vertical fenestration.

Skylight Well

The shaft from the skylight to the ceiling.

Solar Heat Gain Coefficient (SHGC)

A measure of the solar heat transmission of a fenestration in comparison to the solar heat transmission of 1/8” clear glass. Solar Heat Gain Coefficient is now favored over Shading Coefficient. SHGC measurements include both the radiant solar heat as well as a calculation of the conductive heat from the fenestration. SHGC is expressed as a number between 0 and 0.87. The relationship between SHGC and SC is SHGC = SC x 0.87. The lower the SHGC the less solar heat the skylight transmits, and the greater it’s shading ability. A low solar heat gain coefficient in combination with a high LT% and high diffusion is the key to optimal skylight performance.

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Tandem Wiring

A wiring option in which a ballast is shared by two or more luminaires. This reduces labor, materials, and energy costs.

TE

Thermal efficiency.

Temperature Reset Controllers

Controls that automatically reset supply water temperatures by representative building loads (including return water temperature) or by outside air temperature.

Thermal Block

A collection of one or more HVAC zones grouped together for simulation purposes. Spaces need not be contiguous to be combined within a single thermal block.

Thermal Bridge

A component, or assembly of components, in a building envelope through which heat is transferred at a substantially higher rate than through the surrounding envelope area.

Thermal Conductance

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/h x ft² x °F) [W/(m² x K)].

Thermal Resistance (R)

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.

Thermal Transmittance

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/h x ft² x °F) [W/(m² x K)]. The U-factor applies to combinations of different materials used in series along the heat flowpath, single materials that comprise a building section, cavity airspaces and surface air films on both sides of a building element.

Thermostat

An automatic control device responsive to temperature.

Thermostat Set Back

Usually done at night to reduce the amount of conditioning provided at night by allowing the interior temperature to drift naturally to a marginal temperature during the night and then to recondition it to normal conditions in the morning.

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.

Trade-Off Approach

A trade-off approach involves trading enhanced energy efficiency in one component against decreased energy efficiency in another component. These trade-offs typically occur within major building systems (e.g. envelope, mechanical) or in commercial lighting.

Transformer

A piece of electrical equipment used to convert electric power from one voltage to another voltage.

Transverse Seam

All duct seams other than the longitudinal seam (which runs parallel to the direction of air flow).

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U-Factor

A measure (Btu/h ft2 °F) of how well a material or series of materials conducts heat. U-factors for window and door assemblies are the reciprocal of the assembly R-value. The smaller the number, the less the heat flow. A measure of the rate of heat loss of a fenestration. U Factor ratings are expressed as a number between .20 and 1.20. In the US this number represents Btu/h ft² F. The metric equivalent is W/m²K. Insulating value is indicated by the R Value, which is the inverse of the U Factor. The lower a skylight’s U Factor the greater its resistance to heat flow and the greater its insulating value.

UA

U-factor X area; REScheck performs a simple UA calculation for each building assembly to determine the overall UA of your building. The UA that would result from a building conforming to the code requirements is compared against the UA for your building. If the total heat loss (represented as a UA) through the envelope of your building does not exceed the total heat loss from the same building conforming to the code, then the software declares that you pass. A high-efficiency equipment trade-off can also be performed under certain codes.

UL

Underwriters Laboratories Inc.

UL 181A/B

A test procedure for tapes and mastics used to seal ductwork.

Unconditioned Space

An enclosed space within a building that is not a conditioned space.

Unenclosed Space

A space that is not an enclosed space.

Unit Energy Costs

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.

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 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 heat pump equipment is provided in more than one assembly, the separate assemblies shall be designed to be used together.

Unitary Heating and Cooling

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

Unitary Packaged

Each package is a standalone system which provides all of the heating and cooling requirements for the area of the building that it serves.

UV

Ultraviolet.

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Vapor Retarder

A component that retards water vapor diffusion but does not totally prevent its transmission. Vapor retarder material is usually a thin sheet or coating. However, a construction of several materials, some perhaps of substantial thickness, could also constitute a vapor retarder system.

Variable Air Volume (VAV)

HVAC system that controls the dry-bulb temperature within a space by varying the volumetric flow of heated or cooled supply air to the space.

Variable Frequency Drive

Changes the speed of the motor by changing the voltage and frequency of the electricity supplied to the motor based upon system requirements.

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.

Ventilated Mechanically

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

Ventilated Naturally

The process of supplying or removing air by natural means to or from any space.

Ventilation

The process of supplying or removing air by natural or mechanical means to or from any space. Such air shall be permitted to be conditioned or unconditioned.

Ventilation Air

That portion of supply air that comes from outside (outdoors) plus any recirculated air that has been treated to maintain the desired quality of air within a designated space. See ASHRAE 62 and definition of "Outdoor Air."

Vertical Fenestration

All fenestration other than skylights.

Visible Light Transmittance (VLT)

The fraction of solar radiation in the visible light spectrum that passes through the fenestration. The measure of how much visible light passes through a fenestration. Visible light transmission or simply visible transmission (VT) measures the segment of the light spectrum from 380 to 740 nanometers. This is the portion of the light spectrum that can be seen by the human eye. The higher the VLT or VT a skylight has, the greater its light transmission. VLT is expressed as a number from 0 to 1.

Voltage Drop

A decrease in voltage caused by losses in the lines connecting the power source to the load.

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W

Watt.

Wall

Opaque portion of the building envelope.

Warm-Up

Increase in space temperature to occupied set point after a period of shutdown or setback.

Water Economizer

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.

Water Heater

Vessel in which water is heated and is withdrawn for use external to the system.

Water Heating

The process or system used to heat service water.

WH

Watt-hour.

Window

The terms "fenestration", "window", and "glazing" are often used interchangeably. However, window actually describes a system of several components. Window is the term given to an entire assembly comprised of the sash, glazing, and frame.

Window Projection Factor

A measure of the portion of glazing that is shaded by an eave or overhang.

Window-Wall Ratio

The window-wall ratio is the percentage that results from dividing the total glazed area of the building by the total wall area.

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Zone

A space or group of spaces within a building with any combination of heating, cooling, or lighting requirements sufficiently similar so that desired conditions can be maintained throughout by a single controlling device.

    Leed Credits Estimate

    Please complete the information requested below including the Bristolite model number you plan to specify and/or purchase.

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  • You will receive by return email a LEED Credits Worksheet providing an estimate for the following.

    Post Industrial / Pre-Consumer Recycled Content ______%
    Material used in manufacturing of the product.

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    Recyclable material after product life.

    Local Regional Materials _____% (Our materials do not routinely qualify)
    Material Inbound/Outbound sourced within 500 miles of destination.

Trituff Copolyester Passes 267 lb/
36" ASTM Drop Test

A new, pending ASTM skylight fall protection drop test requires dropping a 267 lb sand filled canvas bag with a 5.5" bull nose from a height of 36" on the skylight glazing. As evidenced by this video Trituff Coployester passes the test. The total impact force and pressure developed in this test is 2,278.6 foot pounds and 95.9 lb per square inch.

Tufflite Heavy Weather / High Security Polycarbonate Takes a Tromping

Rick Beets, Bristolite President, demonstrates the resilience of Tufflite for customers. This Tufflite model HWHS (Heavy Weather High Security) skylight is Miami Dade County Hurricane Zone Approved NOA # 10-0216.02 and Florida Building Code Approved # FL14006.

Tufflite Heavy Weather / High Security Polycarbonate Takes a Beating

Rick Beets, Bristolite President, demonstrates the impact resistance of Tufflite for customers. This Tufflite model HWHS (Heavy Weather High Security) skylight is Miami Dade County Hurricane Zone Approved NOA# 10-0216.02 and Florida Building Code Approved # FL14006.

Energy Star Fiberlite CC1 Fire Resistance

Energy Star Fiberlite, Trituff Copolyester and Tufflite Polycarbonate are all CC1 Fire Rated.

Custom Glass Skylight Positive Load Cycling after Large Missile Impact Test

Positive load cycling from 10.30 psf to 51.38 psf after large missile impact test. This model 1000 custom glass skylight series is Miami Dade County Hurricane Zone Approved NOA # 07-0524.05.

Custom Glass Skylight Positive and Negative Load Cycling

Positive load cycling from 10.30 psf to 51.38 psf and negative load cycling from 20.6 psf to 34.3 psf. This model 1000 custom glass skylight series is Miami Dade County Hurricane Zone Approved NOA # 07-0524.05.

Custom Glass Skylight Negative Load Cycling

Negative load cycling from 20.6 psf to 34.3 psf after multiple large missile impact tests. This model 1000 custom glass skylight series is Miami Dade County Hurricane Zone Approved NOA # 07-0524.05.

Custom Glass Skylight Large Missile Impact Test

Large missile impact test requires firing a 9 lb missile at a velocity of 49 fps to 50 fps at a distance of 17 ft from the skylight. This model 1000 custom glass skylight series is Miami Dade County Hurricane Zone Approved NOA # 07-0524.05.

Custom Glass Skylight Large Missile Impact Test

Large missile impact test requires firing a 9 lb missile at a velocity of 49 fps to 50 fps at a distance of 17 ft from the skylight. This model 1000 custom glass skylight series is Miami Dade County Hurricane Zone Approved NOA # 07-0524.05.

20 Year Old Energy Star Fiberlite
Supports 5,000 lb

20 year old Energy Star Fiberlite supports 5,000 lb in a concentrated (1 sq ft) load test by an independent 3rd party testing laboratory.

Trituff Copolyester Supports 1,950 lb

Trituff Copolyester supports 1,950 lb in a concentrated (1 sq ft) load test by an independent 3rd party testing laboratory.

Tufflite Heavy Weather / High Security Polycarbonate Negative Load Cycling

Negative 19.5 psf to 32.5 psf load cycling. This Tufflite model HWHS (Heavy Weather High Security) skylight is Miami Dade County Hurricane Zone Approved NOA # 10-0216.02 and Florida Building Code Approved # FL14006.

Tufflite Heavy Weather / High Security Polycarbonate Positive Load Cycling

Positive 11.0 psf to 55.0 psf load cycling. This Tufflite model HWHS (Heavy Weather High Security) skylight is Miami Dade County Hurricane Zone Approved NOA # 10-0216.02 and Florida Building Code Approved # FL14006.

Tufflite Heavy Weather / High Security Polycarbonate Negative Load Cycling

Negative 19.5 psf to 32.5 psf load cycling. This Tufflite model HWHS (Heavy Weather High Security) skylight is Miami Dade County Hurricane Zone Approved NOA # 10-0216.02 and Florida Building Code Approved # FL14006.

Tufflite Heavy Weather / High Security
Positive and Negative Load Cycling

Positive 11.0 psf to 55.0 psf and negative 19.5 psf to 32.5 psf load cycling. This Tufflite model HWHS (Heavy Weather High Security) skylight is Miami Dade County Hurricane Zone Approved NOA # 10-0216.02 and Florida Building Code Approved # FL14006.

Tufflite Heavy Weather / High Security Polycarbonate Negative Load Cycling

Negative 19.5 psf to 32.5 psf load cycling. This Tufflite model HWHS (Heavy Weather High Security) skylight is Miami Dade County Hurricane Zone Approved NOA # 10-0216.02 and Florida Building Code Approved # FL14006.

Tufflite Heavy Weather / High Security Polycarbonate
Positive and Negative Load Cycling

Positive 11.0 psf to 55.0 psf and negative 19.5 psf to 32.5 psf load cycling. This Tufflite model HWHS (Heavy Weather High Security) skylight is Miami Dade County Hurricane Zone Approved NOA # 10-0216.02 and Florida Building Code Approved # FL14006.

Gladiator Safety Screen
Supports 600 lb Static Load

Gladiator Safety Screen installed on a wood curb supports two 300 lb loads in opposing corners.

Gladiator Safety Screen
Supports 867 lb Static Load

Gladiator Safety Screen installed on a wood curb supports two 300 lb loads in opposing corners and a 267 lb load in the center for a total static load of 867 lb

Gladiator Safety Screen
Passes 267 lb / 36" ASTM Drop Test

A new, pending ASTM skylight fall protection drop test requires dropping a 267 lb sand filled canvas bag with a 5.5" bull nose from a height of 36" on the skylight glazing. As evidenced by this video our Gladiator Safety Screen passes the test. The total impact force and pressure developed in this test is 2,278.6 foot pounds and 95.9 lb per square inch.

Gladiator Safety Screen
Passes 267 lb / 36" ASTM Drop Test

A new, pending ASTM skylight fall protection drop test requires dropping a 267 lb sand filled canvas bag with a 5.5" bull nose from a height of 36" on the skylight glazing. As evidenced by this video our Gladiator Safety Screen passes the test. The total impact force and pressure developed in this test is 2,278.6 foot pounds and 95.9 lb per square inch.

Tufflite Heavy Weather / High Security Polycarbonate Large Missile Impact Test

Large missile impact test requires firing a 9 lb missile at a velocity of 49 fps to 50 fps at a distance of 17 ft from the skylight. This Tufflite model HWHS (Heavy Weather High Security) skylight is Miami Dade County Hurricane Zone Approved NOA # 10-0216.02 and Florida Building Code Approved # FL14006.

Tufflite Heavy Weather / High Security Polycarbonate Large Missile Impact Test

Large missile impact test requires firing a 9 lb missile at a velocity of 49 fps to 50 fps at a distance of 17 ft from the skylight. This Tufflite model HWHS (Heavy Weather High Security) skylight is Miami Dade County Hurricane Zone Approved NOA # 10-0216.02 and Florida Building Code Approved # FL14006.