| Term | Definition |
| A Jointing | See Joining. |
| a la Duchesse | A type of bed with a canopy suspended from the ceiling rather than supported by posts (also known as an angel bed). |
| A-Frame | A building structure where the main structural members forming the roof and floors are in an A-shape. |
| A/C | An abbreviation for air conditioner or air conditioning. |
| A/C Condenser | The outside fan unit of the Air Conditioning system. It removes the heat from the freon gas and "turns" the gas back into a liquid and pumps the liquid back to the coil in the furnace. |
| A/C Disconnect | The main electrical ON-OFF switch near the A/C Condenser. |
| 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 | Removal of streambank soil as a result of sediment-laden water, ice, or debris rubbing against the bank. Wearing away by friction. |
| Abrasion Resistance | Ability of a surface to resist being worn away by rubbing and friction. |
| Abrasive | A substance used for wearing, grinding, cleaning, or polishing by rubbing or grinding. |
| 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 re |
| Abrasive Paper | Paper with an abrasive surface; sandpaper, emery paper; garnet paper. |
| Abrasive Surface | A surface that has been roughened for safety or for warning. |
| Abrasive Surface Tile | Floor tile that has been roughened to be slip-resistant. |
| ABS | Acrylonitrile Butadiene Styrene; a plastic used for piping; has high resistance to impact, heat, and chemicals. |
| 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. |
| 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 |
| 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 |
| 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 pe |
| 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 perce |
| 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 | 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, |
| Abutment Piece or Member | The bearing plate or piece of a wall system to which the loads are transferred. |
| 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. |
| 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 | 1. Requiring change order work to be done without extension of the contract time. 2. An increase in the rate of speed. |
| 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. |
| 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 th |
| 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 | 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 s |
| 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. |
| 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, |
| Accessory | An object or device aiding or contributing in a secondary way. |
| Accessory, Reinforcing | Items used to facilitate the installation of masonry or concrete reinforcing. |
| 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 | A statement of transactions during a fiscal period and the resulting balance in each category of income and expense. |
| Account balance | The difference between the sum of the debits and credits. |
| Accounting | The recording and auditing of financial accounts. |
| Accounting Period | The time that elapses between the preparation of financial statements. |
| 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. |
| 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 reduc |
| 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. |
| acetate | Many convincing artificial silks are made from acetate. It has almost the same finish and draping qualities as silk but is less prone to fade or rot. |
| 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 | 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, phosp |
| 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-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. |
| Acidity | A general term applying to substances on the acid side of neutral. |
| 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 | 1. Relating to sound or the sense of hearing. 2. The properties of a room or auditorium in transmitting sound. |
| Acoustic Paint | Paint which absorbs or deadens sound. |
| Acoustical | Relating to sound or to the sense of hearing. |
| 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. |
| 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. |
| 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 | 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. 3. Soft, lightweight, man-made fiber, which is warm, strong and crea |
| 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. |
| 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 | A mechanical device for connecting two different parts. |
| 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. |
| 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 | A substance added to another to impart different or special qualities; an admixture. |
| Additive Alternate | An alternate bid that, if accepted, adds to the contract price. |
| Adhered | Attached by adhesion, rather than mechanical anchorage, as adhered veneer. |
| Adhered Veneer | A veneer secured and supported through adhesion to an approved bonding material applied over an approved backing. |
| Adherence | The properties of bodies for sticking together. |
| Adherend | A body that is held to another body by an adhesive. |
| Adherend Failure | Failure of an adhesive joint when the separation is within the adherend. |
| 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 |
| Adhesion Agent | A substance used for the purpose of improving the adhesion between a bituminous binder and the aggregate. The term generally refers to adhesion in the presence of water. |
| 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. |
| 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 fo |
| 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. |
| Adiabatic | 1.Impassable to heat. 2. Occurring without gain or loss of heat. |
| 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. |
| 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 | A shelf that can be adjusted to different heights. |
| Adjustable Shelf Standard | Metal items to support shelves usually in the form of strips attached to vertical surfaces. |
| 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. |
| 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 |
| ADO | Fabric vendor specializing in lace and sheers. (851 Simuel Rd., Spartanburg, SC 29301) |
| Adobe | Unburned or unfired brick, dried in the sun. |
| Adobe Masonry | Construction that utilizes unburned (unfired) clay masonry units. |
| 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 | 1. The round screened screw-on tip of a sink spout. It mixes water and air for a smooth flow. 2. 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. |
| 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 | 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 hydr |
| 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 |
| 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 | 1. An invisible gaseous substance surrounding the earth, a mixture of mainly oxygen and nitrogen; the atmosphere. 2. An air conditioning system. |
| 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 | Coil of wire not having a metal core. |
| Air Core Solenoid | Solenoid which has a hollow core instead of a solid 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 as |
| 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 |
| 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 |
| 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 | The area between insulation facing and interior of exterior wall coverings. Normally a 1" air gap. |
| 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-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 | Dried by exposure to air in a yard or shed without artificial heat. |
| 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-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-Entertainment | The process by which air is introduced into a material while in a liquid or plastic state in the form of small isolated bubbles. |
| Air-Entrained Concrete | Concrete containing an admixture that produces microscopic air bubbles in the concrete; used to improve workability and freeze resistance. |
| Air-Sensing Thermostat | Thermostat unit in which sensing element is located in refrigerated space. |
| Air-Slack | A condition where soft-body clay, after absorbing moisture and being exposed to the atmosphere, will spall a piece of clay and/or glaze. |
| Air-To-Air Heat Exchanger | A method of heat recovery in which the intake and exhaust ducts are brought together at the heat exchanger; this system transfers only heat. |
| Airborne Sound | Sound originating in a space; airborne sound can be created from the radiation of structure-borne sound into the air. |
| Airfield Marking | Lines, markers, or lines placed on airfield to aid in the takeoff and landing of planes. |
| Airless Spraying | Spraying using hydraulic pressure to atomize the paint. |
| Airway | A space between roof insulation and roof boards for movement of air. |
| AISC | American Institute of Steel Construction, Inc. |
| AISE | Association of Iron and Steel Engineers. |
| AISI | American Iron & Steel Institute. |
| Aisle | A passage space between rows of seats or tables; a passage space between rows of stored goods in a warehouse. |
| AITC | American Institute of Timber Construction. |
| ALA | American Library Association. |
| Alabaster | A compact translucent, usually white, form of gypsum, often carved into lamps, vases, and ornaments. |
| Alarm | A warning sound or device, as in smoke alarm or burglar alarm. |
| Alclad | Tradename for an aluminum alloy coated with pure aluminum to give high corrosion resistance. |
| Alcohol | A colorless volatile inflammable liquid, miscible with water, used as a solvent; in full, ethyl alcohol; the alcohols commonly used in painting are ethyl alcohol as a shellac solvent and methyl alcohol or wood alcohol in paint removers. |
| Alcohol Brine | Water and alcohol solution which remains a liquid below 32°F. (O°C.). |
| Alcohol Resisting | Showing no damage when in contact with alcohol. |
| Alcove | A small recessed section of a room or outdoor area. |
| Alfresco | In the open air. |
| Algae | (plural). A non-flowering stemless water-plant; seaweed, pond scums, and phytoplankton; growing in water in the presence of sunlight and carbon dioxide. |
| Algaecide | Chemical that kills algae. |
| Algebra | `The use of letters and other symbols to represent quantities in mathematical calculations. |
| Algistat | Chemical that inhibits algae growth. |
| Alienation | A conveyance of property to another. |
| Align | To be or come into precise adjustment or correct relative position. |
| Aliphatic | Describes a major class of organic compounds, many of which are useful as solvents. |
| Alizarin Lake | A bright red pigment with blue undertone made from the organic coal tar dyestuff, alizarin; some purple pigments are also marketed under this name. |
| Alkali | A chemical substance which effectively neutralizes acid material so as to form neutral salts; a base, the opposite of acid; examples are ammonia and caustic soda; highly destructive to oil paint films. |
| Alkali-Aggregate Reaction | The chemical reaction in concrete or mortar between alkalis (sodium and potassium oxides) from portland cement or other sources and certain constituents of some aggregates, primarily certain phases of silica, which causes deterioration in the form of stre |
| Alkali-Resistant Grout | A grout that resists the effect of prolonged contact with alkalis. |
| Alkaline | Having the properties of an alkali; having a pH of more than 7. |
| Alkalinity | Amount of bicarbonate, carbonate, or hydroxide compounds in water. |
| Alkyd | A synthetic resin, made usually with phthalic anhydride, glycerol and fatty acids from vegetable oils. |
| All Risk Policy | A property insurance policy that insures against all risks of loss that are not specifically excluded. |
| All Stretcher Bond | A brick bond showing only stretchers on the face of the wall with each stretcher divided evenly over the stretchers under it; staggered vertical joints. |
| All-Inclusive Deed of Trust or Mortgage | A trust deed or mortgage that includes underlying financing; one payment is made to the all-inclusive mortgagee or beneficiary who then makes the payments on the underlying loans; also called a Wraparound Deed of Trust or Mortgage. |
| All-Purpose Compound | In gypsum wallboard installation, a joint treatment material that can be used as a bedding compound for tape, a finishing compound, and as a laminating adhesive or texturing product. |
| Allen Key | An Allen Wrench. |
| Allen Type Screw | Screw with recessed hex-shaped head. |
| Allen Wrench | An L-shaped hexagonal rod designed to fit into a hexagonal hole in a bolt head; also called an Allen Key. |
| Alley | 1. A narrow street or passageway behind buildings. 2. A building for bowling. |
| Alligatoring | . 1. The cracking and crazing that occurs in asphalt roofing due to age and the effect of solar radiation and oxidation. 2. Coarse checking pattern characterized by a slipping of the new paint coating over the old coating to the extent that the old coatin |
| Alligatoring | Coarse checking pattern characterized by a slipping of the new paint coating over the old coating to the extent that the old coating can be seen through the fissures. |
| Allowable Bearing Capacity | The amount of pressure, expressed in pounds per square foot, that any particular soil will support, in the opinion of a soil mechanics engineer, taking into account acceptable settling and a safety factor. |
| Allowance(s) | A sum of money set aside in the construction contract for items which have not been selected and specified in the construction contract. For example, selection of tile as a flooring may require an allowance for an underlayment material, or an electrical a |
| Allowances | The amount of tightness or looseness of male and female parts. |
| Alloy | 1. A substance composed of two or more metals. 2. Or of a metal and a nonmetallic constituent. |
| Alluvium | Any geologically recent deposit of fine soil, silt, sand, and gravel from an ancient river. |
| Alpha Gypsum | A class of specially processed calcined gypsum having properties of low consistency and high strength. |
| Alternate | A stipulated construction item and its cost, in addition to the original base bid, for a specific item to be included or excluded from the project; a mutually agreed upon item that is used in place of the originally specified item. |
| Alternating Current (AC) | Electric current in which direction of flow alternates or reverses in 60-cycle (Hertz) current, direction of flow reverses every 1/120th of a second. |
| Alternating Current Automatic Low Voltage Secondary Network | See Secondary Network. |
| Alternative Dispute Resolution (ADR) | Resolution of a dispute without litigation, includes negotiation, mediation, and arbitration. |
| Alternator | An electric generator for producing alternating current. |
| Alumina | A mineral usually found in the clay used for brickmaking. |
| Alumina Cement | . Used in high early strength concrete. |
| Alumina Porcelain | A vitreous ceramic whiteware for technical application in which Alumina (A12O3) is the essential crystalline phase. |
| Aluminous Cement | A hydraulic cement in which the principal constituents are calcium illuminates, instead of calcium silicates which comprise the major ingredients of portland cement. (See calcium aluminate cement) |
| Aluminum | A bluish silver-white malleable metallic element with good electrical and thermal conductivity, high reflectivity and resistance to oxidation. |
| Aluminum Association (AA) | 900 19th Street, NW, #300, Washington, DC 20006, (202) 862-5100. |
| Aluminum Extrusion | Aluminum sections formed by extrusion. |
| Aluminum Grid Walkway | Walkway fabricated of aluminum grid placed over roof surface to protect roofing surface from damage from traffic. |
| Aluminum Jacket | A watertight outer housing, fashioned from aluminum, placed around a pipe or vessel. |
| Aluminum Leaf | Aluminum hammered into very thin sheets. |
| Aluminum Oxide | 1. Corrosion on surface of an aluminum member caused by oxidation. 2. Hard and sharp abrasive made by fusing mineral Bauxite at high temperature. |
| Aluminum Paint | Mixture of finely divided aluminum particles in flake form combined with vehicle. |
| Aluminum Plate | Flat aluminum sheet material. |
| Aluminum Sheet Plate | Flat rolled aluminum plate. |
| Aluminum Silicate | White extender pigment made from China clay or feldspar, which provides very little color or opacity. |
| Aluminum Storefront | A facade of a building or structure which is constructed of a system of aluminum tubing and glass. |
| Aluminum Wire | Electrical conductors and cable manufactured from aluminum. |
| Aluminum, Zinc Coated | Aluminum, zinc plated for corrosion protection by hot dipping into molten zinc or by electrolysis. |
| aluminum-coated lining | Without adding much extra bulk, this type of lining will help to exclude light, cold, or heat. It can be used with curtains or, when bulk is particularly unwelcome, to line shades. The aluminum- coated surface faces inside the curtain or shade, while the |
| Amalgamation | A merger or consolidation of two or more businesses. |
| Ambience | The feeling of the surroundings or atmosphere of a place. |
| Ambient | Surrounding on all sides; encompassing, as the ambient temperature. |
| Ambient Background Samples | Prevalent Level Samples. |
| Ambient Sound | The quiet-state noise level in a room or space, which is a composite of sounds from many external sources, both near and far, over which one individual has no control. |
| Ambient Temperature | 1. Room temperature or the temperature of the surroundings; temperature of fluid (usually air) which surrounds object on all sides. |
| Ambiguous | Having more than one meaning, as in a contract. |
| Ambo | Pulpit in a church. |
| Ambulatory | A sheltered place for walking, as in an aisle or cloister in a church or monastery. |
| Amenity | Pleasant or useful features in real estate that contribute satisfaction and pleasure rather than direct financial benefit. |
| American Arbitration Association (AAA) | 140 West 51st Street, New York, NY 10020- 1203, (212) 484-4000, Fax (212) 765-1203. |
| American Architectural Aluminum Manufacturers Association(AAMA) | 1540 Dundee Road #310, Palatine, Illinois 60067, (708) 202-1350. |
| American Association of Nurserymen (AAN) | 1250 I Street, NW, Washington, DC 20005, (202) 789-2900. |
| American Association of State Highway and Transportation Officials (AASHTO) | 444 North Capitol Street, NW, #225, Washington, DC 20001, (202) 624-5800 - David Hensing. |
| American Bond | In masonry, a form of bond in which every sixth course is a header course and the intervening courses are stretcher courses. |
| American Concrete Institute (ACI) | PO Box 19150, Detroit, Michigan 48219, (313) 532-2600. |
| American Conference of Governmental Industrial Hygienists, Inc (ACGIH) | 1330 Kemper Meadow Drive, #600, Cincinnati, Ohio 45240, (513) 742-3355 |
| American Forest & Paper Association (AFPA) | 111 19th St., NW, #800, Washington, DC 20036, (202) 463-2700. |
| American Gallon | A measure of liquid volume, 231 cubic inches. |
| American Gas Association (AGA) | 1515 Wilson Blvd., Arlington, Virginia 22209, (703) 841-8400. |
| American Hardboard Association (AHA) | 1210 West Northwest Highway, Palatine, Illinois 60067, (708) 934-8800. |
| American Hardware Association (AHA) | 20 North Wacker Drive, Chicago, IL 60606. |
| American Hardware Manufacturer's Association (AHMA) | 801 N Plaza Drive, Schaumburg, Illinois 60173, (708) 605-1025. |
| American Hot Dipped Galvanizers Association (AHDGA) | 1000 Vermont Avenue, NW, Washington, DC 20005, (202) 628-4634. |
| American Institute of Architects (AIA) | 1735 New York Avenue, NW, Washington, DC 20006, (202) 626-7300 |
| American Institute of Steel Construction, Inc (AISC) | One East Wacker Drive, #3100, Chicago, Illinois 60601-2001, (312) 670-2400. |
| American Institute of Timber Construction (AITC) | 7012 South Revere Parkway, #140, Englewood, Colorado 80112, (303) 792-9559. |
| American Insurance Association (AInA) | 1130 Connecticut Avenue, NW, Washington, DC 20036, (202) 828-7100. |
| American Iron & Steel Institute (AISI) | 1101 17th Street, NW #1300, Washington, DC 20036-4700, (202) 452-7100. |
| American Library Association (ALA) | 50 E. Huron Street, Chicago, Illinois 60611, (312) 944-6780. |
| American Lumber Standards | Rules for softwood lumber, dealing with recognized classifications, nomenclature, sizes, descriptions, amounts, shipping provisions, basic grades, grade marking, and inspection. |
| American National Standards Institute, Inc (ANSI) | 11 West 42nd Street, 13th Floor, New York, NY 10036, (212) 642-4900. |
| American Petroleum Institute (API) | 1220 L Street, NW, Washington, DC 20035, (202) 682-8000. |
| American Plywood Association (APA) | 7011 South 19th Street, Tacoma, Washington 98411, (206) 272-2283. |
| American Process Zinc Oxide | Zinc oxide pigment made directly from zinc ores; also called Direct Process. |
| American Public Works Association (APWA), | 1313 E. 60th Street, Chicago, Illinois 60637, (312) 667-2200, Fax. (312) 667-2304. |
| American Society for Testing and Materials (ASTM) | 1916 Race Street, Philadelphia, Pennsylvania 19103, (215) 299-5420. |
| American Society of Architectural Hardware Consultants (ASAHC), | 1815 N. Ft. Myer Drive, Suite 412, Arlington, Virginia 22209, (703) 527-2060. |
| American Society of Civil Engineers (ASCE) | , 345 East 47th St., New York, New York 10017, (212) 705-7551. |
| American Society of Heating, Refrigeration, and Air-Conditioning Engineers, Inc (ASHRAE) | 1791 Tullie Circle, NE, Atlanta, Georgia 30329, (404) 636-8400. |
| American Society of Mechanical Engineers (ASME) | United Engineering Center, 345 East 47th St., New York, New York 10017-2392, (212) 705-8500. |
| American Society of Plumbing Engineers (ASPE) | 3617 Thousand Oaks Boulevard., #210, Westlake, California 91362 - (805) 495-7120. |
| American Society of Sanitary Engineers (ASSE) | P.O. Box 40362, Bay Village, Ohio 44140, (216) 835-3040. |
| American Standard Pipe Thread | Type of screw thread commonly used on pipe and fittings to assure a tight seal. |
| American Standards Association | Now known as American National Standards Institute. |
| American Vermillon | Chrome orange pigment. |
| American Water Works Association (AWWA) | 6666 West Quincy Avenue, Denver, Colorado 80235, (303) 794-7711. |
| American Welding Society (AWS) | 550 NW LeJeune Road, P.O. Box 351040, Miami, Florida 33135, (305) 443-9353. |
| American Wire Gauge | A standard system for designating the diameter of wire. |
| American Wood Preservers Association (AWPA) | P.O. Box 286, Woodstock, Maryland 21163-0286, (410) 465-3169. |
| American Wood Preservers Institute (AWPI) | 1945 Old Gallows Road #150, Vienna, Virginia 22182, (703) 893-4005. |
| Americans with Disabilities Act | National legislation prohibiting discrimination against disabled individuals; the act includes detailed requirements for the planning and design of buildings. |
| Ames Taping Tools | Specially designed tools to mechanically apply taping compound and tape. |
| Amides | Curing agent combined with epoxy resins. |
| Amine Adduct | Amine curing agent combined with a portion of the resin. |
| Amines | Organic substituted ammonia; curing agent combined with epoxy resins. |
| Ammeter | An instrument for measuring electric current in amperes. |
| Ammonia | 1. Chemical combination of nitrogen and hydrogen, NH32. Popular refrigerant for industrial refrigerating systems; also a popular absorption system refrigerant; ammonia refrigerant is identified as R-117. 3. Ammonia combines with free chlorine in pool wate |
| Amortization | The gradual paying off of indebtedness by regular equal payments including interest and principal over a specified period of time. |
| Amortization Schedule | A chart showing the monthly, quarterly, or annual payments necessary to pay off a loan including interest over a particular period of time. |
| Amp | Ampere. |
| Ampacity | Current-carrying capacity expressed in amperes. |
| Amperage | The strength of a current of electricity expressed in amperes; electron or current flow of one coulomb per second past given point in circuit. |
| Ampere | Unit of electric current equivalent to flow of one coulomb per second. |
| Ampere Turns | A measure of magnetic force; represents product of amperes times number of turns in coil of electromagnet. |
| Amplification | An increase in earthquake motion as a result of resonance of the natural period of vibration with that of the forcing vibration. |
| Amplifier | An electrical device to obtain amplification of voltage, current or power. |
| Amplitude | Maximum deviation from mean or center line of a wave. |
| Amyl Acetate | Banana oil; solvent for nitrocellulose, formed by esterification of acetic acid with amyl alcohol. |
| Anaerobic | An organism that can live without oxygen, such as the bacteria in a septic tank. |
| Anaglyph | A sculptured, chased, or embossed ornament worked in low relief. |
| Analog | A way of expressing one quantity in terms of another quantity; an analogous or parallel thing; for example, voltage, weight, or length to represent numbers, as watch hands represent time; compare with Digital. |
| Analogous Harmony | Colors which are related by containing one color in common; color harmony. |
| Analogy | Inference from a similar case. |
| Analysis | . 1. Separation into constituent parts. 2. In engineering, the investigative determination of the detailed aspects of a particular phenomenon; may be qualitative, meaning a general evaluation of the nature of the phenomenon, or quantitative, meaning the n |
| Anchor | Irons or metals of special form and shapes used to fasten together and secure timbers or masonry. |
| Anchor Bolt | A bolt embedded in concrete for the purpose of fastening a building frame to a concrete or masonry foundation. |
| Anchor Pattern | Profile surface roughness usually attained by blasting. |
| Anchor Slot | A groove in an object into which a fastener or connector is inserted to attach objects together. |
| Anchor Tenant | The main tenant in a shopping center development; a large stable tenant or tenants that are expected to attract other tenants and customers to the development. |
| Anchor Ties | Any type of fastener used to secure wood framing, steel, or masonry to some stable object, such as a foundation or another wall; usually for tension value. |
| Anchor, Brick | Fasteners that are designed to attach and secure a veneer to a concrete or brick wall. |
| Anchor, Dovetail | A fastener with an interlocking joint that is wider at its end than at its base. |
| Anchor, Rafter | A bolt or fastening device which attaches the rafters to the walls or rafter plate. |
| Anchor, Wood | A bolt or fastening device which attaches wood to wood or wood to other materials. |
| Anchorage | 1. An attachment for resistance to movement; the movement can be a result of overturning, sliding or uplift; the most common anchorage for these movements are tie-downs (hold-downs) for overturning and uplift, and anchor bolts for sliding. 2. In posttensi |
| Anchored Type Ceramic Veneer | Thicker sections of ceramic veneer held in place by grout and wire anchors connected to backing wall. |
| Anchoring Cement | Grout used in sleeves to anchor tubing in place. |
| Andalusite | A polymorph, along with sellimanite and kyanite, of composition Al2O3SiO2; in firing, it dissociates to yield principally mullite. |
| Andiron | A metal stand, usually a pair, for supporting wood fuel in a fireplace. |
| Anechoic Chamber | A room or building that is free from echoes and reverberations. |
| Anemometer | Instrument for measuring the rate of air flow or motion. |
| Aneroid Barometer | An instrument for measuring atmospheric air pressure by its action on the elastic lid of an evacuated box. This is the basis of a surveyor's aneroid barometer which is used to measure altitude; an altimeter. |
| Anesthetizing Location | Areas in hospitals in which flammable anesthetics are or may be administered to patients; such locations include operating rooms, delivery rooms, and anesthesia rooms, and will also include any corridors, utility rooms or other areas which are or may be u |
| Angle | 1. The difference in direction of two lines which meet or tend to meet, usually measured in degrees. 2. An inside corner. 3. A structural section of steel which resembles an L in cross section. 4. In masonry, a portion of a whole brick which is used to cl |
| Angle Bar | A steel structural member in the shape of an L; classified by the thickness of the stock and the length of the legs. |
| Angle Blasting | Blast cleaning at angles less than 90 degrees. |
| Angle Block | A square of tile specially made for changing direction of the trim. |
| Angle Brick | Any brick shaped to an oblique angle to fit a salient corner. |
| Angle Divider | A toolused by tilesetters to determine the degree of an angle to cut; used for fitting trim, moldings, and floors into corners; a corner angle is measured by adjusting the divider to fit the corner. |
| Angle Float | A concrete or plastering finishing tool having a surface bent to form a right angle; used to finish re-entrant angles. |
| Angle Iron | A rolled steel structural member with an L-shaped section; used to support brickwork over doors and windows and is sometimes used as main runners in lieu of channels to support plaster. |
| Angle of Degree | On an airless spray cap, the orifice angle; controls width of spray and pattern angle. |
| Angle of Incidence | The angle that a line or light ray striking a surface makes with the perpendicular at that point, the point of incidence. |
| Angle of Reflection | The angle that a reflected ray makes with the perpendicular to a surface at the point of incidence. |
| Angle of Repose | 1. The natural angle that a pile of a material, such as earth, sand, or gravel will assume. 2. The angle at which a body will slide down an inclined plane impelled only by gravity. |
| Angle Steel | An L-shaped steel member. |
| Angle Stop | A water valve that occurs where there is a 90 degree change in direction of the piping, as under a lavatory or sink. |
| Angle, Shelf | A structural angle which is fastened to the structure of a building to support a wall or other component. |
| Anhydrite | The mineral consisting primarily of anhydrous calcium sulfate, CaSO4 |
| Anhydrous | Dry; free from moisture or water in any form. |
| Anhydrous Calcined Gypsum | Keene's Cement. |
| Anhydrous Calcium Sulphate | A stable form of gypsum from which practically all of the water of crystallization has been removed; also called dead-burned gypsum; dry chemical made of calcium, sulphur and oxygen, CaSO4. |
| Aniline Colors | Coal-tar derivatives precipitated on a colorless base. |
| Anisotropic | Exhibiting different properties when measured along different axes; in general, fibrous materials such as wood are anisotropic; not isotropic. |
| Annealed | Cooled under controlled conditions to minimize internal stresses. |
| Annealed Glass | Glass whose surface has been heated to melting and then cooled to provide a toughened surface; also called heat strengthened glass. |
| Annealing | Process of heat treating metal to get desired properties of softness and ductility. |
| Annex | A wing or an addition to a building. |
| Annual Growth Ring | The layer of wood growth put on a tree during a single growing season, comprised of springwood and summerwood. |
| Annual Percentage Rate (APR) | Annual cost of credit over the life of a loan, including interest, service charges, points, loan fees, mortgage insurance, and other items. |
| Annuity | An investment of money entitling the investor to receive a series of equal monthly or yearly payments. |
| Annular Ring Nail | A nail that has grooves around the shank which prevent easy withdrawal; also called a ring shank nail. |
| Annunciator | A electromagnetic device used to show which of several circuits are activated. |
| Annunciator Panel | A panel mounted on a surface which indicates by lights which circuits have been activated. |
| Anode | 1. The positive electrode in an electrolytic cell. 2. The negative terminal of a primary cell such as a battery. |
| Anodize | Coat a metal, such as aluminum, with a protective oxide layer by electrolysis. |
| Anodized | A metal that has been subjected to electrolytic action in order to coat with a protective or decorative film. |
| Anodized Door | A door which has been given an aluminum oxide coating by electrolytic action. |
| Anodized Tile | Tile which has been given an aluminum oxide coating by electrolytic action. |
| Anodizing | An electrolytic process that forms a permanent, protective coating on aluminum. |
| Anomaly | An irregularity, abnormality, peculiarity, or deviation from the norm. |
| ANSI | American National Standards Institute, Inc. |
| Antenna | A metallic device used for radiating or receiving radio waves. |
| Anterior | Situated before or toward the front. |
| Anteroom | A small room leading to a main room; a waiting room. |
| Anti Stripping Agent | See Adhesion Agent |
| Anti-Corrosive Paint | Metal paint designed to inhibit corrosion; applied directly to the metal. |
| Anti-Flooding Agent | A synthetic organic product used to reduce floating and flooding of iron blues, carbon blacks, and chrome greens. |
| Anti-Fouling Paint | A special coating for ship bottoms, containing poison like copper or mercury, formulated to effect the release of the poison at a controlled rate, to prevent attachment and growth of marine organisms such as barnacles and algae. |
| Anti-Friction Bearing | Any bearing having the capacity of effectively reducing friction. |
| Anti-Friction Latch Bolt | A latch bolt designed to reduce friction when the bolt starts to engage the lock strike. |
| Anti-Scour Protection Apron | An apron in front of a revetment to help protect the revetment against underscour. |
| Anti-Siphon Trap | A trap which is designed to prevent the siphonage of its water seal by increasing the diameter of the outlet leg of the trap so that it contains a sufficient volume of water to prevent a siphoning action. |
| Anti-Skinning Agent | A synthetic organic product, used to prevent forming of surface skin in packaged varnishes and paints. |
| Anticipatory Breach | A positive statement by a party to a contract that the party will not perform the terms of the contract. |
| Anticlastic | Saddle-shaped, or having curvature in two opposing directions. |
| Antihammer Device | An air chamber such as a closed length of pipe or a coil which is designed to absorb the shock caused by closing a valve rapidly. |
| Antimicrobial | Agent that kills microbial growth. |
| Antimony Oxide | Pure white pigment which provides about same hiding power as lithopone. |
| Antioxidant | . Protective compound used on ends of aluminum wiring at connections to prevent corrosion that would interfere with a solid safe connection. |
| Antiquing | Furniture finishing technique intended to give appearance of age or wear. |
| APA | American Plywood Association. |
| Apartment | A suite of rooms, usually let as a dwelling; a dwelling unit. |
| Apartment Hotel | A hotel containing apartments as well as transient rooms. |
| Apartment House | A building containing three or more separate residential apartments; also called an Apartment Building. |
| Aperture | 1. Any opening. 2. An opening that varies the amount of light entering a camera. |
| Apex | The highest point; vertex. |
| API | American Petroleum Institute. |
| Apices | Plural of apex. |
| Appliance | An appliance is current-consuming utilization equipment, generally other than industrial, normally built in standardized sizes or types, which is installed or connected as a unit to perform one or more functions such as clothes washing, air conditioning, |
| Appliance, Fixed | An appliance which is fastened or otherwise secured at a specific location. |
| Appliance, Portable | An appliance which is movable or can easily be moved from one place to another in normal use. |
| Appliance, Stationary | An appliance which is not easily moved from one place to another in normal use. |
| Application for Payment | A written document forwarded by the contractor requesting payment for work completed. |
| Application Rate | The quantity (mass, volume or thickness) of material applied per unit area. |
| Applicator | 1. One who applies. 2. Tool for applying. |
| Applied Preservative Treated | Applied treatment of wood or plywood to make it resistant to deterioration from moisture and insects. |
| appliquÈ | A form of decoration produced by superimposing one material on another. It may consist of figured patterns cut out and applied, or embroidered bands of patterns. |
| Appraisal | A valuation of property by a qualified person, usually in the form of a written report. |
| Appraise | To give an expert judgment of the value or merit of. |
| Appreciation | The increase in value of a property from any cause. |
| Apprentice | A person who is learning a trade, art or calling by being employed in it for an agreed period for low wages. |
| Approved | Acceptable to that enforcing agency having the responsibility and authority to grant the approval for the specified condition or application. |
| APR | Annual Percentage Rate. |
| Apron | 1. The lower trim member under the sill of the interior casing of a window. 2. An upward or downward vertical extension of a sink or lavatory. 3. A paved area immediately adjacent to a building, structure or facility. 4. The flat member of the inside trim |
| Apron Wall | That part of a panel wall between the window sill and the support of the panel wall. |
| Apse | A projecting part of a building, such as in a church, usually semicircular and vaulted. |
| APWA | American Public Works Association. |
| Aqueduct | 1. An artificial channel or conduit for conveying large quantities of water, usually supported by a bridge-like structure. 2. A structure for conveying a canal over a river or a valley. |
| Aqueous | Containing water. |
| Aquifer | A strata of porous permeable rock or soil that is capable of holding a large quantity of water. |
| AR | Acid Resisting. |
| Arabesque | 1. An ornament, style or design of intertwined leaves, flowers, or fruit to produce an intricate pattern of interlaced lines. 2. Decoration characterized by symmetrical intertwining branches, leaves and other plant forms together with abstract curvilinear |
| Arabic Numeral | One of the number symbols, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9. |
| Arbitration | 1. A proceeding for resolution of disputes in which a neutral person or panel, after hearing evidence presented by both sides, makes a final and binding decision that resolves the dispute. 2. A hearing used to resolve disputes. |
| Arbitration Award | The arbitrator's judgment or decision in an arbitration. |
| Arbitration Demand | A written notice by one party to a contract served on the other to avail of the arbitration provisions of the contract. |
| Arbor | 1. A light open-work structure of wood or metal, covered or intended to be covered with vines, as in a park or garden. 2. An Axle or spindle on which something revolves. 3. A device holding a tool in a lathe. |
| Arc | 1. Arched or curved. 2. A portion of an ellipse or circle. |
| Arc Blow | The deflection of an electric arc from its normal path because of magnetic forces. |
| Arc Voltage | The voltage (electrical potential) across the welding arc. |
| Arc Welding | A process of joining two pieces of metal by melting them together at their interface with a continuous electric spark and adding a controlled additional amount of molten metal from a metallic electrode. |
| Arcade | 1. An arched covered passageway. 2. An amusement center with coin-operated games. |
| Arch | A curved structural member used to span an opening or recess; also built flat. Structurally, an arch is a piece or assemblage of pieces so arranged over an opening that the supported load is resolved into pressures on the side supports, and practically no |
| Arch Brick | Wedge-shaped brick for special use in an arch. |
| Arch Corner Bead | A job-shaped length of corner bead used to define the curved portion of arched openings. |
| Arch Culvert | A curved shaped drain under a roadway, canal or embankment. |
| Archeology | The study of human history and prehistory through the excavation of sites and the analysis of human remains. |
| Archetype | An original model; a Prototype. |
| Archimedes' Principle | A law of physics that states that a floating body displaces a weight of liquid equal to its own weight. |
| Archimedes' Screw | A primitive device for raising water, consisting of a pipe spirally wound around an axis. |
| Archipelago | A group of islands in the sea. |
| Architect | One who has completed a course of study in building and design, and is licensed by the state as an architect. One who draws up plans. One who designs buildings and advises on their construction. |
| Architect's Project Representative | A more or less continuous architect's representative on the jobsite; reports to the architect; formerly called Clerk of the Works. |
| Architectonic | 1. Architectural. 2. Having an organized and unified structure or concept that suggests an architectural design. |
| Architectonics | The science of architecture. |
| Architectural | 1.Of or relating to or conforming to the rules of architecture. 2. Having a single, unified overall design, form, or structure. |
| Architectural Equipment | The implements, apparatus, or equipment used in the construction and initial outfitting of a building. |
| Architectural Fee | The amount of money charged by an architect for professional services such as programming, design, preparation of contract documents, and administration of the construction of a building or facility. |
| Architectural Terra Cota | Hard-burned, glazed or unglazed clay building units, plain or ornamental, machine-extruded or hand-molded, and generally larger in size than brick or facing tile; also see Ceramic Veneer. |
| Architectural Woodwork | Finish work using wood or composites for ornamental designs or casework. |
| Architectural Woodwork Institute (AWI) | 13924 Braddlock Road #100, Centerville, Virginia 22020, (703) 222-1100. |
| Architrave | 1. The lowest division of an entablature. 2. The molding around a rectangular opening, such as a door or window. |
| Are | A metric unit of measure equal to 100 square meters. 100 ares equal 1 hectare. |
| Area | 1. The extent or measure of a surface, expressed in square units. 2. The space allocated to a particular function. |
| Area Divider | In roof construction, a raised double wood member attached to a properly flashed wood base plate that is anchored to the roof deck; used to relieve the stresses of thermal expansion and contraction in a roof system where no expansion joints have been prov |
| Area Drain | Any drain installed for the purpose of collecting rain water from an open area and channeling it to the storm drain. |
| Area Wall | 1. The masonry surrounding or partly surrounding an area. 2. The retaining wall around basement windows below grade. |
| Area wells | Corrugated metal or concrete barrier walls installed around a basement window to hold back the earth |
| Areaway | An open subsurface space adjacent to a building used to admit light or air or as a means of access to a basement. A sunken space providing access, air, and light to a subterranean building area. |
| Ark | A repository in a synagogue for the scrolls of the Torah. |
| Armature | Part of an electric motor, generator, or other device moved by magnetism. |
| Armor | To protect, protective covering, shield. |
| Armor Plate | A kick-plate made of metal installed on the bottom of a door to protect it from denting and scratching. |
| Armored Cable | Metal sheathed flexible electrical cable; BX cable. |
| Armored Faceplate | A metal plate which is fastened into the strike at the door jamb to provide a protection for the lock and keeper mechanisms. |
| Aromatic | Derived from or belonging to a major class of organic compounds, many of which are useful as solvents. |
| Aromatic Hydrocarbons | Strong solvents such as benzene, toluene, xylene. |
| Arrester, Lightning | A device connected to an electrical system to protect from lightning and/or voltage surges. |
| Arris | The sharp edge or salient angle formed by the meeting of two surfaces, as in a molding. |
| Art | Work exhibiting human creative skill or its application; creative activity; human skill or workmanship; an occupation requiring knowledge or skill. |
| Arterial Streets | Primary surface roads connecting to expressways with on and off ramps, also connecting sectors of cities, with surface crossings (controlled by traffic lights), normally over continuous long stretches of the cityscape, restricted for parking and to direct |
| Artesian Well | 1.A bored well from which water flows from internal pressure. 2. A deep- bored well. |
| Artificer | 1. A skilled or artistic craft worker. 2. An inventor. |
| Artificial Intelligence | The ability of a computer to think and work like a human being; at present no computer has full artificial intelligence. |
| Artificial or Accelerated Drying | The process of drying block or brick with relatively warm, dry air, or other means. |
| Artificial Pozzolan | Fly ash and other similar substances such as rice hull ash and microsilica. |
| Artisan | A skilled worker in a trade such as carpentry, plumbing, or painting. |
| As 1160 | Australian Standard for Bitumen Emulsions for Construction and Maintenance of Pavements |
| AS 2008 | Australian Standard for Residual Bitumen for Pavements. |
| AS 2150 | Australian Standard for Hot Mixed Asphalt. |
| AS 2758 | Australian Standard for Aggregate and Rock for Engineering Purposes. |
| As-Built Drawings | See Record Drawings. |
| As-Builts | See Record Drawings. |
| ASAHC | American Society of Architectural Hardware Consultants. |
| Asbestine | Natural fibrous magnesium silica, which is pure white in color; used as an extender pigment in paints. |
| Asbestos | A group of natural, fibrous, impure silicate materials, formerly used for its noncombustible, non-conducting, or chemically resistant properties; no longer used as it causes Asbestosis |
| Asbestos Abatement | Procedures to control fiber release from asbestos-containing materials in a building or to remove it entirely; may involve removal, encapsulation, repair, enclosure, encasement, and operations and maintenance programs. |
| Asbestos Cement | Cement asbestos. |
| Asbestos Program Manager | A building owner or designated representative who supervises all aspects of the facility asbestos management and control program. |
| Asbestos Removal | A special trade or occupation for the removal and disposal of hazardous asbestos. |
| Asbestos Vacuum | A filtered device using air suction to collect wetted down asbestos for easy removal into specially made bags. |
| Asbestos-Containing Material (ACM) | Any material containing more than one percent asbestos. |
| Asbestos-Free Compound | Joint treatment products that have no asbestos fiber. |
| Asbestosis | A lung disease caused by inhaling asbestos particles. |
| ASCE | American Society of Civil Engineers. |
| Ascrete | Open Graded Asphalt with the addition of cement slurry to provide strong surface resistance to deformation and oil spillage. |
| Aseismic Region | A region that is relatively free of earthquakes. |
| Ash Dump | A metal access door in the floor of a fireplace firebox to dump the ashes into the ash pit below. |
| Ash Pit | The compartment below a fireplace in which ashes may be dumped from the firebox and stored for later removal. |
| Ashlar | A pattern of masonry consisting of squared stones. |
| Ashlar Veneer | An ornamental or protective facing of masonry composed of squared stones. |
| ASHRAE | American Society of Heating, Refrigeration, and Air-Conditioning Engineers, Inc. |
| Askarael | A synthetic nonflammable insulating liquid which, when decomposed by the electric arc, evolves only nonflammable gaseous mixtures. |
| ASLA | American Society of Landscape Architects. |
| ASME | American Society of Mechanical Engineers. |
| ASME Boiler Code | Standard specifications issued by the American Society of Mechanical Engineers for the construction of boilers. |
| ASPE | American Society of Plumbing Engineers. |
| Aspect Ratio | Ratio of length to width of a rectangular air grille or duct. |
| Asphalt | A brown to black bituminous pitch occurring naturally or made from a residue of petroleum refining; also called asphaltum; used for pavements, roofing, and as a waterproofing cement; asphalt comes in a wide range of viscosities and softening points, from |
| Asphalt | Most native asphalt is a residue from evaporated petroleum. It is insoluble in water but soluble in gave. line when heated. Used widely in building for waterproofing roof coverings of many types, exterior wall coverings, flooring tile, and the like. |
| Asphalt (BC or AC) | A mixture of bitumen and aggregates (coarse and fine including sand). Produced as Hot Mix or Cold Mix. Referred to as BC (Bituminous Concrete) or AC (Asphaltic Concrete). See also Types N, H, L, R, T and V. |
| Asphalt Cement | A fluxed or unfluxed asphalt specially prepared as to quality and consistency for direct use in the manufacture of asphalt pavements. |
| Asphalt Curb | An extruded berm made from asphaltic concrete. |
| Asphalt Cut Back | Asphalt plus thinner; asphalt solution; asphalt coating formed by dissolving asphalt. |
| Asphalt Dampproofing | The application of asphalt to act as a water-resisting treatment to the surface of a concrete or masonry wall. |
| Asphalt Demolition | The destruction of roadways constructed of asphalt using large wheeled machinery that tears up the old asphalt into manageable pieces for easy removal. |
| Asphalt Emulsion | Asphalt dispersion; not a solution; a water emulsion of asphalt. |
| Asphalt Expansion Joint | Felt or fiberboard premolded and impregnated with asphalt and used as an expansion joint for cast-in-place concrete. |
| Asphalt Felt | An asphalt-saturated felt or an asphalt-coated felt. |
| Asphalt Institute (AI) | 6917 Arlington Road #210, Bethesda, Maryland 20814, (301) 656-5824. |
| Asphalt Leveling Course | A course asphalt aggregate mixture of variable thickness used to eliminate irregularities in the contour of an existing surface prior to a superimposed treatment or construction. |
| Asphalt Mastic | A mixture of asphaltic material, mineral aggregates, and fine mineral aggregates that can be poured when heated but needs mechanical manipulation to apply when cool. |
| Asphalt Membrane | A layer of asphalt used on a flat roof. |
| Asphalt Prime Coat | A low viscosity liquid asphalt applied to prepare an untreated surface to penetrate into the voids, harden the top and help bind it to the overlying asphalt surface. |
| Asphalt Repair | The act or process of patching worn road surfaces or leaking roofs. |
| Asphalt Rock | Porous rock such as sandstone or limestone that has become impregnated with natural asphalt through geologic process; also called Rock Asphalt. |
| Asphalt Roof | A roof system which uses asphalt materials as a covering. |
| Asphalt Saturated Felt | A building and roofing felt sheet impregnated with a bituminous waterproofing material. |
| Asphalt Shingle | Saturated roofing felt either in large rolls or cut into composition shingles, impregnated with aggregate particles applied to a roof surfaces. |
| Asphalt Subgrade, Improved | Subgrade, improved as a working platform (1) by the incorporation of granular materials or stabilizers such as asphalt, lime, or portland cement, prepared to support a structure or a pavement system, or (2) any course or courses of select or improved mate |
| Asphalt Surface | A flat layer of asphalt. |
| Asphalt-Saturated Felt | A moisture-resistant sheet material, available in several different thicknesses, usually consisting of a heavy paper that has been impregnated with asphalt. |
| Asphaltenes | The high molecular weight hydrocarbon fraction precipitated from asphalt by a designated paraffinic naphtha solvent at a specified solvent-asphalt ratio. |
| Asphaltic Concrete | Refer Asphalt. |
| Asphaltic Paint | 1.A liquid form of asphalt which can contain other materials such as aluminum flakes and mineral pigments, generally used for creating a water-resistant coating. 2. A liquid product used for weatherproofing. |
| Asphlatic Concrete | High quality, thoroughly controlled hot mixture of asphalt cement and well-graded, high quality aggregate, thoroughly compacted into a uniform dense mass. |
| Aspirating Psychrometer | Device which draws sample of air through it to measure humidity. |
| ASSE | American Society of Sanitary Engineers. |
| Assemblage | 1. Something put together from parts. 2. A random, unordered assemblage is called a gathering. 3. An ordered assemblage is a system. |
| Assembly Area | An outdoor place for the gathering of a group of people exiting from a building or for an educational, sporting, or entertainment event. |
| Assembly Room | A room for the gathering of a group of people, such as an auditorium, gymnasium, restaurant, or meeting room. |
| Assessed Value | The value of a parcel of real property, usually a fraction of the market value, used for the purpose of determining the amount of property tax. |
| Assessment | A tax levied on a property, or a value placed on the worth of a property. |
| Asset | A possession or resource having value. |
| Assignment | Transfer of the rights and duties under a contract from one party to another. |
| Associated General Contractors of America (AGC) | 1957 E Street, NW, Washington, DC 20006, (202) 393-2040. |
| Association of Iron and Steel Engineers (AISE) | Three Gateway Center, #2350, Pittsburgh, Pennsylvania 15222, (412) 281-6323. |
| Assumption | Allows a buyer to assume responsibility for an existing loan instead of getting a new loan. |
| ASTM | American Society for Testing and Materials. |
| ASTM Standards | Materials specifications issued by the American Society of Testing Materials. |
| Astragal | An interior molding attached to one of a pair of doors or window sash in order to prevent swinging through; also used with sliding doors to insure tighter fitting where doors meet. |
| Astragal Weatherstripping | Fabric, rubber or plastic strips attached to the molding that is attached to one of a pair of doors or casement windows to cover the joint between the two stiles. |
| Asymmetrical | Not symmetrical; asymmetry. |
| Athletic Equipment | Various devices used for exercising or the playing of sporting events. |
| Atlantis miniblinds | 1" commercial aluminum blind made by Hunter Douglas. |
| Atmospheric Corrosion | Galvanic corrosion that occurs between two adjoining dissimilar metals in a humid atmospheric condition. |
| Atmospheric Pressure | The pressure that atmospheric gases in air exert upon the earth; measured in pounds per square inch or grams per square centimeter;one standard atmosphere equals 14.69 psi of pressure and measures 760 mm (29.92 inches) in a barometer of mercury. |
| Atmospheric Vacuum Breaker | A simple mechanical device consisting essentially of a check valve in the supply line and a valve member (on the discharge side of the check valve) opening to the atmosphere when the pressure in the line drops to atmospheric; also called a siphon breaker. |
| Atom | The smallest particle of a chemical element; considered as a source of vast potential energy. |
| Atomic-Hydrogen Welding | An arc-welding process wherein coalescence is produced by heating with an electric arc maintained between two metal electrodes in an atmosphere of hydrogen; shielding is obtained from the hydrogen; pressure may or may not be used and filler metal may or m |
| Atomize | Process of changing a liquid to minute particles or a fine spray; break steam into small particles. |
| Atomizer | Device by which air is introduced into material at the nozzle to regulate the texture of machine-applied plaster. |
| Atrium | A central courtyard with surrounding rooms opening off it. |
| Attachment Bug | A device which, by insertion in a receptacle, establishes connection between the conductors of the attached flexible cord and the conductors connected permanently to the receptacle. |
| Attenuation | The reduction of the energy or intensity of sound. |
| Attenuation Blanket | Material utilized to help in the reduction of the energy or intensity of sound. |
| Attic | A room or space immediately below the roof of a building. |
| Attic access | An opening that is placed in the drywalled ceiling of a home providing access to the attic. |
| Attic Draft Stop | A partition in an attic, from roof to ceiling level, dividing the attic into discrete areas to prevent the spread of smoke and drafts. |
| Attic Insulation | Treated shreds of cellulose material that are blown into attic spaces or fiberglass rolls that are rolled out between ceiling joists to aid in weatherproofing a building or facility. |
| Attic Ventilators | 1. Openings in the roof or in gables for the purpose of allowing air to circulate. 2. Mechanical devices with power-driven fans to force the circulation of air. 3. In houses, screened openings provided to ventilate an attic space. They are located in the |
| Attorney | A qualified lawyer licensed to practice. |
| Attorney-in-Fact | A person acting for another under the authority of a power of attorney. |
| Audio | Acoustical, mechanical or electrical frequencies used in the transmission, reception or reproduction of sound. |
| Audio Cable | A cable over which the transmission, reception, or reproduction of sound is carried. |
| Audio Sensor | A device that responds to the physical stimulus of sound and transmits a resulting impulse. |
| Audio Visual | Involving both sight and sound. |
| Audit | A formal examination and report of a person's or entity's financial condition, usually by a qualified certified public accountant. |
| Auditorium | A building or room where an audience sits. |
| Auger | An instrument or device used for boring or forcing through materials or soil. |
| Auger, Fence | A rotating drill with a screw thread used to drill deep, straight, and narrow holes for the installation of fence posts. |
| Austrian shade | A soft fabric shade that pulls up on vertical cords into swags and appears gently ruched at the base when let down. |
| Authorized Person | One who is properly authorized to perform specific duties under the conditions existing, usually in relation to a contract. |
| Auto Lift | 1. An apparatus for lifting automobiles in order to have access to the carriage underneath. 2. An apparatus used to move automobiles up and down in a parking structure. |
| Auto Transfer Switch | An electrical transfer switch that operates automatically. |
| Autoclave | A pressure vessel in which an environment of superheated steam at high pressure may be produced; used for sterilizing, assisting a chemical reaction, in the curing of concrete products, and in the testing of hydraulic cement. |
| Autoclave Curing | Steam curing of concrete products, sand-lime brick, asbestos-cement products, hydrous calcium silicate insulation products, or cement in an autoclave at maximum ambient temperatures generally between 340 and 420° F (170-215° C); also called High Pressure |
| Autoclaved Aerated Concrete | A factory-produced building stone; precast, lightweight concrete, in the form of large building blocks, panels, or planks; made of closed cell concrete steam cured in a pressurized autoclave. |
| Automatic | 1. A device that works by itself without human intervention, usually actuated by some impersonal influence, as for example, a change in current strength, pressure, temperature, or mechanical configuration. 2. Done spontaneously without conscious intention |
| Automatic Control | Valve action reached through self-operated or self-actuated means, not requiring manual adjustment. |
| Automatic Cyclic Control | A control system in which the opening and closing of the weigh hopper discharge gate, the bituminous discharge valve, and the pugmill discharge gate are actuated by means of self-acting mechanical or electrical machinery without any intermediate manual co |
| Automatic Defrost | System of removing ice and frost from evaporators automatically. |
| Automatic Door | A door equipped with a power-operated mechanism and controls that open and close the door automatically upon receipt of a momentary actuating signal; the switch that begins the automatic cycle may be a photoelectric device, floor mat, or manual switch. |
| Automatic Dryer Control | In a concrete batching plant, a system that automatically maintains the temperature of aggregates discharged from the dryer within a preset range. |
| Automatic Expansion Valve (AEV) | Pressure-controlled valve which reduces high-pressure liquid refrigerant to low-pressure liquid refrigerant. |
| Automatic Frost Control | Control which automatically cycles refrigerating system to remove frost formation on evaporator. |
| Automatic Ice Cube Maker | Refrigerating mechanism designed to automatically produce ice cubes in quantity. |
| Automatic Proportioning Control | In an asphaltic concrete plant, a system in which proportions of the aggregate and asphalt fractions are controlled by means of gates or valves which are opened and closed by means of self- acting mechanical or electronic machinery without any intermediat |
| Automatic Skimmer | See Surface Skimmer. |
| Automation | 1. The use of automatic equipment to save mental and manual labor. 2. A piece of mechanism with concealed motive power; a Robot. |
| Automotive Equipment | Implements or apparatus that pertain to the repair and care of the automobile. |
| Automotive Hoist | 1. An apparatus for hoisting automobiles in order to have access to the carriage underneath. 2. An elevator used to move automobiles up and down in a parking structure. |
| Autopsy Table | Surface upon which a body is placed for examination after death; a specified item installed in hospitals, laboratories, and police crime labs. |
| Autotransformer | Transformer in which both primary and secondary coils have turns in common; step-up or step-down of voltage is accomplished by taps on common winding. |
| Auxiliary Heat | The extra heat provided by a conventional heating system for periods of cloudiness or intense cold, when a solar heating system is insufficient. |
| Auxiliary Members | In a concrete shell structure, ribs or edge beams which serve to strengthen, stiffen or support the shell; usually, auxiliary members act jointly with the shell. |
| Auxiliary Switch | A standby device for switching. |
| Available Chlorine | Free or combined chlorine used to disinfect pool water. |
| Avenue | An access road or street. |
| Average | 1. An arithmetic mean. 2. An amount obtained by adding the elements of a set and dividing by the number in the set. 3. The ordinary standard. |
| Average Least Dimension (ALD) | The average height of the aggregate particles when they are spread as a single layer with their least dimensions vertical |
| Aviary | An enclosure or building for keeping birds confined. |
| Avoirdupois | 1. Weight. 2. Avoirdupois Weight. |
| Avoirdupois Weight | The weight system based on the pound of 16 ounces and the ounce of 16 drams. |
| Award | 1. Arbitration award. 2. Contract award. |
| Awarding Authority | The owner or the agent of the owner who awards an original building or construction contract, also known as the prime contract; this term is generally used with public works. |
| AWG | American Wire Gauge. |
| AWI | Architectural Woodwork Institute; A small sharp pointed hand tool for marking lines or piercing small holes in wood surfaces |
| Awning | A sheet of canvas, plastic, or metal stretched on a frame to give shelter over a window, doorway, or other area. |
| Awning Window | A window hinged at the top. |
| AWPA | American Wood Preservers Association. |
| AWPI | American Wood Preservers Institute. |
| AWS | American Welding Society. |
| AWWA | American Water Works Association. |
| Axial | In a direction parallel to the long axis of a structural member; in line with the axis; an axial force causes tension or compression stress over the cross section of a member. |
| Axial Load | Force directly coincident with the primary axis of a structural member such as a beam. |
| Axial Stresses | Compressive or tensile stresses that are coincidental with the central axis of a structural member. |
| Axis | A straight line of reference; in three dimensions, the three axes are referred to as x, y, and z. |
| Axis of a Weld | An imaginary line through the length of a weld perpendicular to the cross section at its center of gravity. |
| Axis of Symmetry | A line dividing an area into two similar but opposite handed figures. |
| Axis, Neutral | Centroidal axis, transverse to longitudinal axis of a structural member, which is neither stretched nor shortened by bending of the member. |
| Axle | A fixed or rotating rod or spindle on which a wheel or group of wheels rotate. |
| Axminster Carpet | One of the four basic weaves used in making carpets; woven on an Axminster loom, the pile tufts in this weave are mechanically inserted and bound to the back in a manner similar to the hand knotting of Oriental rugs, making possible almost unlimited combi |
| Axonometric Projection | A drafting projection in which objects on the drawing appear inclined with three sides showing and with horizontal and vertical distances drawn to scale but diagonal and curved lines distorted. |
| Azeotrope | Having constant maximum and minimum boiling points. |
| Azimuth | The horizontal angle or direction of a compass bearing. |