(A)		Glossary of Contractor Terminology 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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A Jointing.		See Joining.
AA.		Aluminum Association.
AAA.		American Arbitration Association.
AAC.		1. Autoclaved Aerated Concrete.
AAN.		American Association of Nurserymen.
AASHTO.		American Association of State Highway and Transportation Officials.
Abacus.		The flat slab on top of a column capital, supporting the architrave.
Abandonment.		The failure of both parties to a contract to abide by its terms.
Abattoir.		A slaughterhouse; a place where animals are butchered for food.
Aberration.		A distortion of an image produced by a faulty lens or mirror.
Above Ground Tank.		A large above ground vessel used for the storage of liquids.
Abrade.		Scrape or wear away by friction.
Abrams' Law.		A rule stating that with given concrete materials and conditions of test, the ratio of the amount of water to the amount of the cement in the mixture determines the strength of the concrete, provided the mixture is of a workable consistency.
Abrasion Resistance.		Ability of a surface to resist being worn away by rubbing and friction.
Abrasion.		Wearing away by friction.
Abrasive Coatings.		In closed coating of paper no adhesive is exposed, as surface of paper is completely covered with abrasive; in open coating, surface of backing paper is covered with regulated amount of abrasive, exposing the adhesive; space between the abrasive grains reduces loading and filling when sanding gummy or soft materials.
Abrasive Paper.		Paper with an abrasive surface; sandpaper, emery paper; garnet paper.
Abrasive Surface Tile.		Floor tile that has been roughened to be slip-resistant.
Abrasive Surface.		A surface that has been roughened for safety or for warning.
Abrasive.		A substance used for wearing, grinding, cleaning, or polishing by rubbing or grinding.
ABS Pipe.		A plastic pipe sold in 10 and 20 foot lengths in various diameters for plumbing stacks and drains; used primarily for drain lines.
ABS.		Acrylonitrile Butadiene Styrene; a plastic used for piping; has high resistance to impact, heat, and chemicals.
Absolute Humidity.		The density of water vapor per unit volume of air.
Absolute Pressure.		The pressure measured by a gauge plus a correction for the effect of air pressure on the gauge (l4.7 psi at sea level).
Absolute Temperature.		Temperature measured from absolute zero.
Absolute Viscosity.		A method of measuring viscosity using the poise as the basic measurement unit; this method utilizes a partial vacuum to induce flow in the viscometer.
Absolute Volume.		The volume of an ingredient in its solid state, without voids between individual pieces or particles; in the case of fluids, the cubic content occupied; in concrete, it is the actual volume occupied by the different ingredients determined by dividing the weight of each ingredient in pounds by its specific gravity times the weight of one cubic foot of water in pounds; example. the absolute volume of one sack of cement equals 94 divided by 3.15 times 62.4 equals 0.478 cubic feet.
Absolute Zero.		A theoretical lowest possible temperature, at which all molecular motion ceases, calculated to be exactly minus 273.15°Centigrade or minus 459.67° Fahrenheit.
Absorb.		To swallow up or suck in, like wood absorbing a finishing material.
Absorbed Moisture.		Moisture that has entered a solid material by absorption and has physical properties not substantially different from ordinary water at the same temperature and pressure; in aggregates, that water which is not available to become part of the mixing water.
Absorbent.		Having the ability to suck up liquid, gas, or heat.
Absorber.		The blackened surface in a solar collector that absorbs the solar radiation and converts it to heat energy.
Absorptance.		The ratio of light absorbed by a material to incident light falling on it.
Absorption Chiller.		A system similar to a vapor compression chiller with the exception that it does not use a compressor, but uses thermal energy (low pressure steam, hot water, or other hot liquids) to produce the cooling effect.
Absorption Coefficient.		The absorption coefficient of a material or sound-absorbing device is the ratio of the sound absorbed to the sound incident on the material or device; the sound absorbed by a material or device is usually taken as the sound energy incident on the surface minus the sound energy reflected.
Absorption Rate.		1. The speed at which the real estate market can absorb new offerings of land or buildings during a specified period of time. 2. The amount of water absorbed when a brick is partially immersed for one minute; usually expressed in either grams or ounces per minute per 30 sq. in; also called suction or initial rate of absorption.
Absorption Refrigerator.		Refrigerator which creates low temperatures by using the cooling effect formed when a refrigerant is absorbed by chemical substance.
Absorption, Total.		The amount of water a masonry unit will absorb when immersed in water.Absorption.The relationship of the weight of the water absorbed by a material specimen subjected to prescribed immersion procedure, to the weight of the dry specimen, expressed in percent.
Abstract of Title.		A written summary of all transactions that could affect the ownership of a piece of real property, including deeds, leases, liens, and wills.
Abutment Piece or Member.		The bearing plate or piece of a wall system to which the loads are transferred.
Abutment.		The lateral supporting structure of an arch, bridge or similar pressure; that part of a pier or wall from which an arch springs, specifically the support at either end of an arch, beam or bridge; that part of a structure which takes the thrust of a beam, arch, vault, truss or girder; the part of a bridge that supports the end of the span and prevents the bank from sliding under it; a foundation that carries gravity and also thrust loads.
AC Relay.		An electromagnetic or electromechanical valve or switch using small currents and voltages to control the making or breaking of electrical contacts on a circuit.
AC. 1.		Air Conditioning. 2. Asphaltic Concrete. 3. Alternating Current.
Accelerate.		To quicken or hasten the natural progress of certain actions or events.
Accelerated Depreciation.		The declining balance and sum of the year's digits method which give greater depreciation to the early years of the life of the assets.
Accelerating Admixture.		Substance that increases the rate of hydration, shortens setting time, or increases strength development in concrete, mortar, grout, or plaster.
Acceleration Clause.		A clause in a mortgage or trust deed that would allow the lender to call the whole loan due at any time that certain specified events occur, such as a default in payments or sale of the property.
Acceleration.		1. Requiring change order work to be done without extension of the contract time. 2. An increase in the rate of speed.
Accelerator.		A substance which, when added to concrete, mortar, grout, or plaster, increases the rate of hydration of the hydraulic cement, shortens the time of setting, or increases the rate of hardening of strength development, or both; materials used to speed up the setting of mortar or concrete.
Accelerogram.		The record from an accelerograph showing acceleration as a function of time.
Acceptance.		1. Manifestation that a party assents or agrees to a contract. 2. Approval of the work of a construction contract.
Access Control.		A computerized security system designed to protect against unauthorized entry into buildings or building areas.
Access Door.		A door or panel creating a means of access for the inspection or repair of concealed equipment.
Access Floor.		A raised floor platform with removable panels to provide access to the area below.
Access Panel.		Removable or swinging panel, usually flush with adjoining surface to provide access to concealed equipment or system components for inspection and maintenance purposes.
Access Stair.		A stair system to provide specific access to roofs, mechanical equipment rooms, or as a means of emergency exit.
Access/Secure Control Unit.		The controlling device of a computerized security system designed to protect against unauthorized entry into buildings or building areas.
Accessible Heremetic.		Assembly of motor and compressor inside a single bolted housing unit.
Accessible Location.		A location which can be reached by standing on the floor, platform, runway, or other permanent working area.
Accessible.		1. As applied to equipment, admitting close approach because not guarded by locked doors (unless keys are readily available to those requiring access), elevation or other effective means. 2. As applied to wiring methods, not permanently closed in by the structure or finish of the building; capable of being removed without disturbing the building structure, finish, or fixed appurtenance thereto.
Accessories		1. Tile accessories, ceramic or non-ceramic articles, affixed to or inserted in tile work, as exemplified by towel bars, paper, soap and tumbler holders, grab bars and the like. 2. Concrete accessories, implements or devices used in the formwork, pouring, spreading, and finishing, of concrete surfaces.
Accessory, Reinforcing.		Items used to facilitate the installation of masonry or concrete reinforcing.
Accessory.		An object or device aiding or contributing in a secondary way.
Accord and Satisfaction.		Conduct of a debtor that indicates agreement to an amount of money owed by the debtor to a creditor.
Accordion Folding Door.		A folding, hinged, or creased door with rollers which run along a track.
Accordion Partition.		A folded, creased, or hinged interior dividing wall.
Account balance.		The difference between the sum of the debits and credits.
Account.		A statement of transactions during a fiscal period and the resulting balance in each category of income and expense.
Accounting Period.		The time that elapses between the preparation of financial statements.
Accounting.		The recording and auditing of financial accounts.
Accounts Payable.		Money owed by the firm to vendors for services or materials.
Accounts Receivable.		Money owed to the firm for services rendered or for reimbursements.
Accretion.		An increase of land area by the gradual or imperceptible action of natural forces.
Accrual Accounting.		A method of keeping accounting records in which income is recorded when services are rendered and expenses are recorded when incurred, rather than when cash is received or paid out.
Accruals.		The recognition of income and expenses as they occur even though they are not received or paid for until a later period.
Accrued Expenses.		The entry into the liability accounts of expenses, incurred but not paid, at a given date.
Accrued Income.		The entry into the asset accounts of income earned, but not received, at a given date.
Accrued Interest.		Interest that has been earned but not yet paid.
Accrued Liabilities.		Amounts representing liabilities incurred, but not paid, by a given date.
Accumulator.		Storage tank which receives liquid refrigerant from evaporator and prevents it from flowing into suction line before vaporizing.
Acetic Acid.		A compound, which in the pure state is a colorless, pungent, biting liquid; vinegar contains 4 to 12 percent of acetic acid.
Acetone.		A water-white volatile, highly flammable solvent with ether-like odor; made by destructive distillation of hardwood, fermentation of butyl alcohol, and from petroleum sources; used extensively in making paint removers; dimethyl ketone; see Ketones.
Acetylene.		A colorless hydrocarbon gas, burning with a bright flame, used as a fuel in welding and soldering.
ACGIH.		American Conference of Governmental Industrial Hygienists, Inc.
Achromatic.		1. Having no color, being black, gray, or white. 2. Being neutral in color. 3. Difficult to color. 4. Lenses practically free from light of unwanted color.
ACI.		American Concrete Institute.
Acid Condition In System.		Condition in which refrigerant or oil in system is mixed with fluids that are acid in nature.
Acid Demand.		Amount of acid required to lower pH and total alkalinity of pool water to correct level.
Acid Etch.		1. The use of acid to cut lines into metal or glass. 2. The use of acid to remove the surface of concrete.
Acid Number.		A designation of the amount of free acid in oils, flats, waxes and resins, expressed as the number of milligrams of potassium hydroxide required to neutralize one gram of the material being tested.
Acid Rain.		Sulfur dioxide emissions combining with water in the atmosphere and falling to the earth.
Acid Resisting Brick.		Brick suitable for use in contact with chemicals, usually in conjunction with acid-resistant mortars.
Acid.		A sour substance, one which liberates hydrogen ions in water and is sour and corrosive; will turn litmus red and has a pH of less than 7; acids are generally divided into two classes. (1) strong mineral or inorganic acids such as sulfamic, sulfuric, phosphoric, hydrochloric, or nitric, (2) weak organic or natural acids such as acetic (vinegar), citric (citrus fruit juices), oxalic, and fatty acids (oleic) such as palmitic and stearic.
Acidity.		A general term applying to substances on the acid side of neutral.
Acid-Proof Counter.		A horizontal work surface resistant to acid spills.
Acid-Resistant Grout.		A grout that resists the effect of prolonged contact with acids.
Acid-Test Radio.		A calculation of a firm's liquidity position; that is the ratio of its quick assets (readily convertible to cash) to current liabilities.
ACM.		Asbestos-Containing Material.
ACORD 25-S.		A form of insurance certificate issued by Agency Company Organization for Research and Development which has replaced the AIA standard form.
Acoustic Paint.		Paint which absorbs or deadens sound.
Acoustic.		1. Relating to sound or the sense of hearing. 2. The properties of a room or auditorium in transmitting sound.
Acoustical and Insulating Materials Association (AIMA).		205 W. Touhy Avenue, Park Ridge, Illinois 60068, (312) 692-5178.
Acoustical Block.		A masonry block used for its sound-absorbing qualities.
Acoustical Materials.		Those capable of absorbing sound waves.
Acoustical Panel.		Ceiling and wall mounted modular units composed of sound absorbing materials.
Accoustical Plaster and Plastic.		Sound absorbing finishing materials mill-formulated for application in areas where a reduction in sound reverberation or noise intensity is desired; these materials usually are applied to a minimum thickness of 1/2 inch and generally provide a noise reduction coefficient of at least .45 decibels.
Acoustical Tile.		Ceiling panels in board form used for its sound absorbing properties, sometimes used on walls.
Acoustical Treatment.		The act or process of applying acoustical materials to walls and ceilings.
Acoustical.		Relating to sound or to the sense of hearing.
Acoustics.		The science of sound including its production, transmission, and effects.
ACR Tubing.		Tubing used in air conditioning and refrigeration; ends are sealed to keep tubing clean and dry.
Acre.		1. A piece of land measuring 43,560 square feet. 2. Unit for measuring land, equal to 43,560 square feet or 4840 square yards or 160 square rods.
Acre-Foot.		A volume unit for measuring large quantities of water as in reservoirs and lakes; the amount of water that would cover one acre one foot deep, equal to 43,560 cubic feet.
Acre-Inch.		One twelfth of an acre-foot.
ACRI.		Air-Conditioning & Refrigeration Institute.
Across.		The application of gypsum board where the long dimension is applied at right angles to the framing.
Acrylic Carpet.		A carpet made from acrylic fiber composed of synthetic polymers.
Acrylic Plastics.		Plastics based on resins made by the polymerization of acrylic monomers, such as ethyl acrylate and methecrylate.
Acrylic Resins.		Family of synthetic resins made by polymerizing esters of acrylic acid; synthetic resins of excellent color and clarity used in both emulsion and solvent-based paints.
Acrylic.		1. A general class of resinous polymers derived from esters, amides or other acrylic aid derivatives. 2. A transparent plastic material used in sheet form for window glass and skylights.
Acrylics.		In carpeting, generic term including acrylic and modified acrylic (modacrylic) fibers; acrylic is a polymer composed of at least 85% by weight of acrylonitrile; modacrylic is a polymer composed of less than 85% but at least 35% by weight of acrylonitrile.
Acrylonitrile Butadiene-Styrene.		Plastic material used in manufacturing drainage pipe and fittings.
Act of God.		An unexpected event, not within the control of either party, that makes the performance of a contract impossible, unreasonable, or illegal.
Activated Carbon.		Specially processed carbon used as a filter-drier; commonly used to clean air; pulverized carbon treated to be especially adsorbent.
Activated Charcoal.		See Activated Carbon.
Activator.		A catalyst, curing agent, or coreactant, as for an epoxy resin.
Active Door.		In a pair of doors, the leaf that opens first and the one to which the lock is applied.
Active Pressure.		The pressure exerted by retained earth; such as the earth retained by a retaining wall.
Active System.		A solar heating or cooling system that requires outside mechanical power to move the collected heat.
Actual Dimension.		The true size of a piece of lumber after it has been milled and dried; see Nominal Dimension.
Actual Notice.		The giving of notice by mailing it or handing it to the recipient.
Actuator.		That portion of a regulating valve which converts mechanical fluid, thermal energy, or electrical energy into mechanical motion to open or close the valve seats.
Acute Angle.		An angle of less than 90 degrees.
AD Plywood.		A designation or gradation of plywood. The A and the D designate quality of surface layers.
Ad Valorem.		A tax imposed at a percentage rate of the value of the property, such as property tax.
ADA.		Americans with Disabilities Act.
Adapter Terminal.		Electrical fitting attached to the end of a conductor or to a piece of equipment, for taking power from an outlet in a way for which it was not designed.
Adapter, Cubicle.		See Cubical Adapter.
Adapter.		A mechanical device for connecting two different parts.
Adaptive reuse.		Adapting an old or historical building for a new purpose.
Addenda.		A revision in the contract document made prior to the execution of the owner-contractor contract.
Additive Alternate.		An alternate bid that, if accepted, adds to the contract price.
Additive.		A substance added to another to impart different or special qualities; an admixture.
Adhered Veneer.		A veneer secured and supported through adhesion to an approved bonding material applied over an approved backing.
Adhered.		Attached by adhesion, rather than mechanical anchorage, as adhered veneer.
Adherence.		The properties of bodies for sticking together.
Adherend Failure.		Failure of an adhesive joint when the separation is within the adherend.
Adherend.		A body that is held to another body by an adhesive.
Adhesion Type Ceramic Veneer.		Thinner sections of ceramic veneer, held in place by adhesion of mortar to unit and to backing; no metal anchors are required.
Adhesion, Mechanical.		Adhesion between surfaces in which the adhesive holds the parts together by interlocking action.
Adhesion.		1. The state in which two surfaces are held together by interfacial forces which may consist of valence forces or interlocking action, or both; bonding strength; the attraction of a coating to the substrate, or of one coat of paint to another. 2. The soil quality of sticking to buckets, blades, and other parts of excavators.
Adhesive Application.		A means of applying gypsum board utilizing adhesives and supplemental mechanical fasteners.
Adhesive Bond.		A relationship between two materials in contact with each other causing them to stick or adhere together by means other than cohesion.
Adhesive Failure.		Failure of an adhesive joint when the plane of separation is at the adhesive-adherend interface.
Adhesive Spreader.		A notched trowel used in the application of laminating adhesives.
Adhesive Wall Cups.		Special clips or nails with large perforated bases for mastic application to most firm surfaces.
Adhesive, Ceramic.		Used for bonding tile to a surface; rubber solvents; rubber- and resin-based emulsions used as adhesives.
Adhesive, Pressure-Sensitive.		An adhesive that will adhere to a surface at room temperature by briefly applied pressure alone.
Adhesive, Roof.		A bonding agent used to cement roof materials.
Adhesive, Solvent.		An adhesive having a volatile organic liquid as a vehicle, not including water-based adhesives.
Adhesive, Tile.		Organic adhesive used for bonding tile to a surface; rubber solvents and resin-based and rubber emulsions can be used as adhesives.
Adhesive.		1. A material capable of holding other materials together by surface attachment; glues, cements, pastes, epoxy, and mucilage are some of the common adhesives. 2. A compound, glue, or mastic used in the application of gypsum board products to framing or for laminating one or more layers of gypsum boards.
Adiabatic Compression.		Compressing refrigerant gas without removing or adding heat.
Adiabatic Curing.		The maintenance of ambient conditions during the setting and hardening of concrete so that heat is neither lost nor gained.
Adiabatic.		1.Impassable to heat. 2. Occurring without gain or loss of heat.
Adjacent.		Nearby or adjoining.
Adjustable Bar Hanger.		A metal hanger that can be made to fit the varying distances between floor and ceiling joists or rafters to securely hold electrical outlet boxes and devices.
Adjustable Shelf Standard.		Metal items to support shelves usually in the form of strips attached to vertical surfaces.
Adjustable Shelf.		A shelf that can be adjusted to different heights.
Adjustable Speed Motor.		One in which the speed can be varied gradually over a considerable range, but when once adjusted remains practically unaffected by the load, such as shunt motors designed for a variation of field strength.
Adjustable Triangle.		A transparent plastic drafting tool that can be adjusted and set for any angle.
Administrative Staff Organization		Payroll Admininstration Organization which independently represents services as a third party carrier such as; workers' compensation, health benefits, etc.  Services are not offered directly under the umbrella corporation as they are with a PEO Professional Staff Organization.
Adjustable Wrench.		An open faced wrench which can be adjusted to different sizes.
Admixture.		1. A material other than water, aggregates, and hydraulic cement used as an ingredient of concrete or mortar, and added immediately before or during its mixing. 2. A chemical additive used to alter the normal properties of concrete. 3. Any substance added to a plaster component or to plaster mortar for the purpose of altering its properties.
Adobe Masonry.		Construction that utilizes unburned (unfired) clay masonry units.
Adobe.		Unburned or unfired brick, dried in the sun.
ADR.		Alternative Dispute Resolution; includes mainly negotiation, mediation, and arbitration.
Adsorbed Water.		Water held on surfaces in a material by either physical and/or chemical forces.
Adsorbent.		Usually of a solid, having the ability to attract molecules of liquids, solutions, or gasses that adhere to its surface.
Adsorption.		The process of attraction to a surface; the attachment of foreign molecules on the surface of a substance.
Adulteration.		The addition of unwanted materials.
Advancing Colors.		Colors that give an illusion of being closer to the observer; warm colors in which red-orange predominates.
Adverse Possession.		The overt occupation of real property under some claim of right that is opposed to the claim of some other claimant.
Advertisement for Bids.		Published notice for receiving of bids for a construction project.
Advisor CM.		A construction manager who is an advisor to the owner and who does not guarantee the construction cost.
Adze.		A tool for cutting away the surface of wood, like an axe with an arched blade at right angles to the handle.
Aerate.		To introduce air into a substance, such as into water at the kitchen sink.
Aeration.		Act of combining substance with air.
Aerator.		Device which adds air to water; fills flowing water with bubbles.
Aerembolism.		Caisson Desease.
Aerial		. 1. Relating to the air or atmosphere. 2. An antenna.
Aerobic.		Activities or processes that can take place only in the presence of air or oxygen.
Aerosol.		1. A colloidal suspension of fine solid or liquid particles in gas, like smoke, fog, and mist. 2. A substance dispensed from a pressurized can in aerosol form.
Aesthetic Effect.		Relating to the beautiful rather than to the merely pleasing, useful, or utilitarian; artistic and in accordance with the principles of good taste.
Aesthetics.		Concerned with beauty, refinement, and good taste.
AEV.		Automatic Expansion Valve.
Affidavit.		A written statement that is made under oath.
AFPA (Formerly NFoPA).		American Forest & Paper Association.
A-Frame.		A building structure where the main structural members forming the roof and floors are in an A-shape.
Aftershock.		An earthquake occurring subsequent to a large earthquake, the main shock; the magnitude of an aftershock is usually smaller than the main shock.
AGA.		American Gas Association.
AGC.		Associated General Contractors of America.
Agent.		One who acts with delegated authority for a principal.
Agglomeration.		Formation of masses or aggregates of pigments; not dispersed.
Aggregate Coated Panel.		Sheet material, usually plywood, with decorative face of aggregate bonded with epoxy applied to one face.
Aggregate Storage Bins.		In a concrete batching plant, the bins that store the necessary aggregate sizes and feed them to the dryer in substantially the same proportions as are required in the finished mix.
Aggregate, Coarse.		One of the four ingredients of concrete, usually gravel, which is retained on a #4 sieve.
Aggregate, Fine.		One of the four ingredients of concrete, usually sand, which will pass the #4 sieve and will be retained on the #200 sieve.
Aggregate, Heavyweight.		Aggregate of high specific gravity such as barite, magnetite, limonite, limenite, iron, or steel used to produce heavy concrete.
Aggregate, Lightweight.		Aggregate of low specific gravity, such as expanded or sintered clay, shale, slate, diatomaceous shale, perlite, vermiculite, or slag; natural pumice, scoria, volcanic cinders, tuff, and diatomite, sintered fly ash, or industrial cinders; used to produce lightweight concrete; aggregate with a dry, loose weight of 70 pounds per cubic foot or less.
Aggregate.		1. Inert particles such as sand, gravel, crushed stone, or expanded materials, in a concrete, plaster, or terrazzo mixture. 2. Granular material, such as sand, gravel, crushed stone, and iron blast-furnace slag, used with a cementing medium to form a hydraulic-cement, concrete or mortar. 3. Crushed stone, crushed slag, or water-worn gravel used for surfacing a built-up roof. 4. Any granular mineral material.
Agitator.		Device used to cause motion in confined fluid.
Agreement.		A mutual understanding; a meeting of the minds; a contract duly executed and legally binding.
Agricultural Varnishes.		Varnishes designed to protect and beautify farm implements and machinery.
AHA.		1. American Hardware Association. 2. American Hardboard Association.
AHC.		Architectural Hardware Consultant, a member of the Door and Hardware Institute.
AHDGA.		American Hot Dipped Galvanizers Association.
AHMA.		American Hardware Manufacturer's Association.
AHU.		Air Handling Unit.
AI.		Asphalt Institute.
AIA.		American Institute of Architects.
AIMA.		Acoustical and Insulating Materials Association.
AInA.		American Insurance Association.
Air Adjusting Valve.		Spray gun valve controlling input air.
Air Break.		In a plumbing system, a physical separation between a drain outlet from a fixture and an indirect waste receptor from the fixture.
Air Bubble.		Bubble in paint film caused by entrapped air.
Air Cap.		Perforated housing for atomizing air at head of spray gun; also called air nozzle.
Air Carbon-Arc Cutting.		An arc-cutting process in which the severing of metals is effected by melting with the heat of an arc between an electrode and the base metal and an air stream is used to facilitate cutting.
Air Chamber.		A short piece of pipe about 10 long, installed above the hot and cold valves of fixtures such as sinks, lavatories, and clothes washers which traps a column of air intended to cushion the rush of water as the valve is closed and prevents water hammer.
Air Change Method.		A method of calculating the quantity of infiltration air into a building.
Air Changes per Hour.		The number of times the air volume of a room or building can be replaced in an hour by an air-handling, circulating, or exhaust system.
Air Cleaner.		Device used for removal of airborne impurities.
Air Cleaning.		A control strategy to remove various airborne particulates and/or gases from the air; the three types of air cleaning most commonly used are particulate filtration, electrostatic precipitation, and gas absorption.
Air Coil.		Coil on some types of heat pumps used either as an evaporator or a condenser.
Air Compressor.		A mechanism which forces air at a high pressure into a storage tank where it is released through a regulator and a hose to power small tools.
Air Conditioner.		Device used to control temperature, humidity, cleanliness, and movement of air in conditioned space.
Air Content.		The amount of entrained or entrapped air in concrete or mortar, exclusive of pore space in aggregate particles, usually expressed as a percentage of total volume of concrete or mortar.
Air Cooled Compressor.		The condenser component of a refrigeration system placed out of the refrigerant area in a series of copper tubes; a fan blows outdoor air across the tubes which contain the refrigerant.
Air Cooler.		Mechanism designed to lower temperature of air passing through it.
Air Core Solenoid.		Solenoid which has a hollow core instead of a solid core.
Air Core.		Coil of wire not having a metal core.
Air Diffuser.		Air distribution outlet or grille designed to direct airflow into desired patterns.
Air Distribution.		To force air to desired locations in a building or facility.
Air Drying.		Drying by oxidation or evaporating by simple exposure to air; used for drying block, brick, wood, or paint without any special equipment, simply by exposure to ambient air.
Air Eliminator.		A mechanical device that expels excess air.
Air Embolism.		Caisson Disease.
Air Entraining Agent.		A substance added to concrete, mortar or cement that produces air bubbles during mixing, making it easier to work with and increasing its resistance to frost and freezing.
Air Entraining Cement.		A portland cement with an admixture that causes a controlled quantity of stable, microscopic air bubbles to form in the concrete during mixing.
Air Entrainment.		Introduction of air into a process such as in concrete mixing or in a whirlpool bath.
Air Entrapment.		Inclusion of air bubbles in paint film.
Air Exchange Rate.		1. The number of times that the outdoor air replaces the volume of air in a building per unit time, typically expressed as air changes per hour. 2. The number of times that the ventilation system replaces the air within a room or area within the building.
Air Gap.		1. In a water supply system, the vertical distance from the top of the flood rim to the faucet or spout which supplies fresh water to the fixture; designed to prevent backsiphonage. 2. The space between magnetic poles or between rotating and stationary assemblies in a motor or generator.
Air Handler.		Fan-blower, heat transfer coil, filter, and housing parts of a system.
Air Handling System.		A system to heat, cool, humidify, dehumidify, filter, and transport air, consisting of an air handling unit, fresh air and exhaust air damper at the building exterior, ductwork, supply air, diffusers or registers, and return air grills in the conditioned space.
Air Handling Unit (AHU).		Equipment that is designed to move conditioned air, containing fan(s), filter(s), heating coil(s), and/or cooling coil(s); units can be classified as either a central system or unitary; unitary equipment can be classified as rooftop unit, unitary package unit, unitary split system, or compound room unit.
Air Hose.		Hose of air supply quality, usually red.
Air Infiltration.		Leakage of air into rooms through cracks, windows, doors, and other openings.
Air Jet.		In blast cleaning, type of blast cleaning gun in which the abrasive is conveyed to the gun by partial vacuum.
Air Lock.		Air trapped within a pipe which restricts or blocks the flow of liquid through the pipe.
Air Manifold.		Common air supply chamber for several lines.
Air Monitoring Test.		A procedure used to determine the contents in a volume of air over a measurable period of time.
Air Nozzle.		See Air Cap.
Air Plenum.		Any space used to convey return air in a building or structure.
Air Powered Hoist.		A hoist that is operated by compressed air.
Air Purger.		A mechanical device that removes unwanted air.
Air Rights.		The right to use the space above a piece of real property.
Air Space.		An open space or cavity in a wall or between building materials.
Air Structure.		A canvas structure supported by air produced by fans.
Air Tool.		Attachments using compressed air to saw, spray-paint, sand, drill, or nail.
Air Transformer.		Device for controlled reduction in air pressure.
Air Valve.		Control valve in air line system.
Air Vent.		1. An opening in a building or structure for the passage of air. 2. Valve, either manual or automatic, to remove air from the highest point of a coil or piping assembly.
Air Voids.		The small hollow spaces in cement paste caused by unwanted entrapped air bubbles and the smaller voids caused by air-entraining admixtures.
Air Volume.		Quantity of air in cubic feet, usually per minute, at atmospheric pressure.
Air Washer.		Device used to clean air while increasing or lowering its humidity.
Air, Standard.		See Standard Atmosphere.
Air.		1. An invisible gaseous substance surrounding the earth, a mixture of mainly oxygen and nitrogen; the atmosphere. 2. An air conditioning system.
Airborne Sound.		Sound originating in a space; airborne sound can be created from the radiation of structure-borne sound into the air.
Air-Conditioning & Refrigeration Institute (ACRI)		, 4301 North Fairfax Drive, #425, Arlington, Virginia 22203, (703) 524-8800.
Air-Cooled Condenser.		Heat of compression is dissipated from condensing coils to surrounding air, by convection or by a fan or blower.
Air-Dried Lumber.		Lumber that has dried by being stored in yards or sheds for any length of time; for North America as a whole, the minimum moisture content of thoroughly air-dried lumber is 12 to 15%, and the average is higher.
Air-Dried.		Dried by exposure to air in a yard or shed without artificial heat.
Air-Dry Weight.		The unit weight of a light weight concrete specimen cured for seven days with neither loss nor gain of moisture at 60° F. to 80° F. and dried for 21 days in 50 plus or minus 7% relative humidity at 73.4° F. plus or minus 2° F.
Air-Entrained Concrete.		Concrete containing an admixture that produces microscopic air bubbles in the concrete; used to improve workability and freeze resistance.
Air-Entertainment.		The process by which air is introduced into a material while in a liquid or pl