Abacus - Flat piece at the top of the capital.
Abattoir - A public slaughter house.
Abbey - A convent under an abbot: the church now or formerly attached to it.
Ablution Fitting- A large sanitary fitting in which several people at the same time can wash their hands, arms, or faces. Ablution fittings are made for rough use and have water sprayers, often with touchless controls or foot controls. Trough type can be set in ranges, while washing fountains have a circular pedestal bowl.
Above Ground Level- Higher than ground level, particularly with reference to the superstructure, and to work after a building is out of the ground.
Abrasion Resistance- The ability of a finish to stand up to wear from rubbing,
Abrasives - Rough, hard materials (usually powders, grits or stones) in various forms such as sandpaper, grinding wheels, or grinding discs, used to smooth or clean surfaces or to sharpen and hone edge tools. From hard to soft they include: diamond, garnet, corundum(emery), carborundum, powdered glass, and silica sand. The hardest abrasives cause others to wear the most while lasting the longer themselves. Coarse abrasives remove the most material, fine abrasives give the smoothest surface.
ABS (Acrylonitrile Butadiene Styrene)- A tough co-polymer, used to make plastic pipes for cold water supply or soil and waste drains. Pipes can have solvent welded joints, made with special ABS cement, or push-fit joint rings. Its softening point is higher than that of polypropylene, so that it can handle hot waste water up to 80 degree Cent. However, petrol, oil, and linseed oil can damage it. ABS pipe can be bent at about 125 degree Cent. ; no bending spring is needed. Like all plastics, ABS is combustible.
Absorption Rate - The speed at which water is taken up by a brick when partly immersed for one minute, used to measure initial suction.
Absorption Refrigerator - A refrigerator without a compressor which uses heat to evaporate lithium bromide from water. It is silent and not very efficient but can be run on waste heat.
Absorptivity / Absorptive Power - The relative rate of absorption of heat by a body compared with a similarly shaped black body in the same conditions.
Abstracting - Assembling data so that similar types of work are brought together under one item ready for billing. It is the first part of the working up of bill of quantities.
Abutment - An intersection between a roof slope and a wall that rises above it
Abutment Flashing - A flashing over an abutment. At the head of the slope it is level, at the side of the slope it is raking or stepped.
Abutment Piece - A sill or sole plate.
Accelerated Weathering/ Artificial Ageing - The testing of materials by exposure to cycles of sunlight, heat, frost and wetness or dryness that are more severe than in nature.
Accelerator / Accelerating admixture - An admixture that hastens setting and increases the early strength of concrete, usually causing an increase in temperature. This allows earlier removal of formwork and may give frost protection.
Access - A way in or out, including any circulation area for walking (such as a stair, balcony or ramp), vehicle access to a site (such as a road or a way), or even hand access for inspection.
Access Chamber - A space big enough for a person to get into.
Access Floor - A floor above the structural floor, creating the space between them, for cables going to office work stations, to allow easy wire management for data, telephone, power and lighting.
Access Hole - An opening large enough for a person to get through for work on installations, or for a tool to be passed through for making adjustments. Access holes normally have a cover, such as a panel or a trap.
Accessories - Components used to fix, join, or connect building elements or services, including hardware, fixings and roof flashings.
Accordion Door - A folding door.
Accreditation - An approval of one official body by a higher authority, e.g. for building products certification.
Acetal Resin - Strong, low priced synthetic resin made by polymerizing formaldehyde. Acetal plastics are used in plumbing fittings, particularly for threaded valve components and intricate shapes.
Acoustic - Pertaining to the sense of hearing or to the theory of sounds, acoustic properties of a room determining whether accurate hearing in it is easy or not.
Acoustic Board - Wall and Ceiling acoustic furnishings made with a porous core of insulating board or mineral fibre tiles and a surface that has many round holes, or is fissured or riled. It can be fixed as full boards or made into acoustic tiles. Painting can block the holes and reduce sound absorbency; careful spraying with many thin coats of emulsion paint reduces mainly the high frequency sound absorption.
Acoustic Clip - A floor clip with a flexible rubber pad to reduce transmission of impact sound through a timber floating floor.
Acoustic Construction - The improvement of sound insulation by using thick walls, heavy materials of low stiffness, or discontinuous construction such as a floating floor, which reduces noise transmission.
Acoustic Finishing - Materials inside which sound energy is lost by absorption. However they usually have high sound transmission.
Acoustic Plaster - Gypsum Plaster with light weight aggregate, used as an acoustic finishing.
Acoustic Tile – A square of acoustic board.
Acoustical Transmission - Sound or noise in buildings is controlled either by reducing transmission between rooms by the methods of construction, or by increasing absorption within the room, with acoustic finishings. In sound measurements the acoustical transmission factor is the amount of sound that passes through a type of construction, while the acoustical reduction factor is its reciprocal, implying the effectiveness of sound insulation.
Acre - Measure of land containing 4840 sq.yds.
Acropolis - Greek citadel sited prominently above the rest of a city.
Acrylic Adhesive - A fast-curing emulsion adhesive, usually white in colour and fairly non-staining. It is used wet but goes tacky quickly, and can hold down curling edges of vinyl floor tiles.
Acrylic Paints - Emulsion paints which hold their colour well, are very durable and resistant to oils, fats and grease, and have sufficient resilience to avoid cracking. They are used as fast-drying floor paints and as organic coatings on metals.
Acrylic Resins - Polymethyl methacrylate, the synthetic resin in acrylic paints, sealants, adhesives, and sheet. It however has poor resistance to alkalis.
Acrylic Sealants - Sealants that set to a tough rubbery material by solvent release. They have good adhesion to most substrates without the need for a primer, but should not be used in wet areas or in contact with cement-based products, which are alkaline.
Acrylic Sheet - Fairly strong, light weight, easily moulded plastics, mainly used for clear or tinted glazing and coloured sanitary fittings, such as baths or basins. Acrylic sheets melt and burn easily, so they are a fire hazard and have low fire resistance. However, they can be broken to allow escape and unlike glass do not splinter into sharp pieces.
Acrylonitrile Butadiene Styrene - A tough co-polymer, used to make plastic pipes for cold water supply or soil and waste drains. Pipes can have solvent welded joints, made with special ABS cement, or push-fit joint rings. Its softening point is higher than that of polypropylene, so that it can handle hot waste water up to 80 degree Cent. However, petrol, oil, and linseed oil can damage it. ABS pipe can be bent at about 125 degree Cent. ; no bending spring is needed. Like all plastics, ABS is combustible.
Active Fire Protection - Mechanical and electrical devices to warn of or extinguish fires, such as sprinklers, alarms, fire detectors, and fans or dampers for a pressurized escape route. They can be very effective but require regular inspection and maintenance, and may need standby power.
Active Leaf - The leaf of double door which is most used, held closed by latching to the inactive leaf.
Active Solar Heating - Heating systems that use solar collectors and mechanical devices such as pumps or fans.
Actuator - A mechanical linkage to create or transmit movements such as pushing, pulling, or slight rotation, which enable automatic controls to control a flow of fluids or the currents in the electric system.
Adaptor - A device which matches different objects, e.g. the connection between pipes or ducts of different sizes or sections, or between British electrical plugs and Continental ones.
Adhesion - The sticking together of components by making a chemical bond, using an adhesive, cement, or bonding compound.
Adhesive, Glue - A liquid that in hardening sticks together by adhesion. It allows joints or fixing to be made without spoiling a surface with nails or screws.
Adjudication - Adding a margin to the net price of builder's estimate to give the tender amount. Adjudication is done by a manager after discussion with the chief estimator.
Admixture - A product or agent added in small quantities to the basic constituents ( aggregate, cement or water ) of concrete or mortar to alter a particular combination of properties while it is fresh or after it has hardened.
Adobe, Mud brick - A moulded and sun-dried brick or block of clay (or the clay itself) usually containing chopped straw reinforcement, used for the walls of earth buildings. Adobe construction is common in South and Central America and is occasionally used in semi-arid regions of the USA, Australia, and elsewhere.
Aerated Concrete - Lightweight and highly insulating cellular material made from a mix of fine sand, pulverized fuel ash, and chemical admixtures, cast into moulds and autoclaved to make lightweight concrete blocks. It is easy to saw and drive nails into, although metal fixings do not hold well and may corrode needing the use of resin anchors. Aerated concrete has high moisture movements.
Aesthetics - The principle of taste and of art : the philosophy of fine arts.
A-frame Building - A building with beams straight from the ground to the roof ridge, that form the shape of an A. The lower part of the roof slope usually takes the place of the wall.
African-Mahogany - Timber from West Africa, generally Nigeria or Ghana,
After tack - The defect of a paint film which has been tack-free and then becomes tacky
After-flush - The small quantity of water remaining in the cistern after flushing a water closet. It trickles slowly down and remakes the seal
Ageing - The storing of a material to improve its quality. Varnish that has been aged has improved gloss and reduced pin-holing and crawling. Ageing is done before use, unlike maturing and curing.
Aggregate - Any granular material used as the main constituent of concrete, mortar and plaster. Aggregate is defined by its size, as coarse, fine, or all-in, its source (natural or artificial) and its shape, e.g. rounded or angular.
Agora - Greek forum or market place.
Agreed Levels - A survey of natural ground levels before the commencement of groundworks, marked on a drawing and signed by the site engineer and the clerks of works.
Air Admittance Valve - A device to let air into the sanitary pipe, used in addition to the soil vent, to relieve minor differences in air pressures.
Air Balancing - Adjusting air conditioning dampers so that air is evenly distributed to rooms. It is necessary at commissioning or when partitions are moved.
Air brick - A special brick with perforations through it so that it can be built into wall to ventilate a room or a space under floor. Air bricks can be of normal size, two course high, or made to be laid as a brick-on-edge.
Air brush - A small spray gun.
Air change - A quantity of fresh air equal to the volume of the room being ventilated. The ventilation rate is the number of air changes per hour. Offices need about 30 changes, boiler houses and laundries 10 to 20, classrooms 6, reading rooms 2 and store rooms 1.5. Kitchens often have high air-change rates, although if heat and smoke are withdrawn through hoods, excessive rates can be avoided.
Air Conditioner (Window)- A small to medium capacity packaged air treatment unit or cabinet, usually without ductwork and often mounted in a window.
Air Conditioning - The process of treating air so as to control simultaneously its temperature, humidity, cleanliness and distribution to meet the requirement of conditioned space or,
The supply of cool or warm, dry and filtered air using mechanical services to maintain conditions of temperature and humidity within the comfort zone, with an indirect benefit of a quiet environment, as windows are kept closed to reduce traffic noise. Automatic controls operate the air-treatment plant and determine the setting of air-handling equipment
Air curtain - A strong flow of warm air directed towards a doorway from the outside, to stop cold air entering in winter when the door is left open. Small air curtains are drawn from the sides, but larger units have a high velocity air current from overhead and the return duct in the floor.
Air diffuser - An air terminal unit that controls the direction of supply air for distribution into room or occupied area.
Air distribution - The supply of treated air from a central air-conditioning plant by blowing it through ductwork to air terminal units and into space
Air dried timber - Sawn timber that has had natural seasoning, by stacking cut planks in the open air, usually with stickers between them.
Air Eliminator - A plumbing fitting for the automatic release of gases, as from a cold water supply pipe, to prevent an air lock
Air Gap - The height of water above the rim of sanitary fitting to prevent backflow from contaminating the supply pipe.
Air grille, air grating - A simple type of air terminal unit: a perforated metal plate that allows air to pass, while acting as a sight screen
Air Handling Equipment - Equipment in an air-conditioning system for moving air into and out of rooms, usually by blowing with fans through ducts. The supply air from the air treatment plant goes to air terminal units discharging into the spaces where air is distributed.
Air Handling Luminaire - A luminaire through which extract air is drawn, to reduce the cooling load on the air conditioning system as well to improve light output and improve lamp life
Air Handling Unit (AHU) - A packaged air conditioner either a large individual unit for a special environment, such as a kitchen or computer room, or a simple fan coil unit
Air House (pneumatic structure) - A balloon structure either air-supported or air-inflated. Air houses pay for themselves quickly when used for temporary shelter, because they can span large areas, are inexpensive and easy to transport, and allow fast erection or demounting. In case of fire the burn hole can provide both a means of escape and ventilation
Air lock - A bubble of air, trapped in a high point of a pipe, obstructing the flow of water, OR
Any device for preventing the flow of air, often merely a lobby with two doors far enough apart so that the first closes behind a person before a second is reached. Air lock doors should open in one direction.
Air Receiver, Air Vessel - A pressure vessel connected to a outlet from an air compressor for storage of compressed air until used. One may be connected to the delivery side of a pump to extract air from water.
Air Release Valve, Pet Cock - A small valve for bleeding air from pipework, a pump casing, pressure vessel etc.
Air right - The right of the owner of a low city building with fewer floors than allowed by the plot ratio to sell the space above for another building to be stacked on top. However, this may mean also allowing foundations and columns to be built under and through the property to provide support
Air Seasoned Tmber - Air dried timber
Air Set - Warehouse set.
Air Shaft - A light well.
Air Space - A cavity.
Air Supported Structure - A type of air house with a single membrane carried by low pressure air. The edges need anchorage from concrete beams in the ground or sandbags, and the entrance needs an air lock
Air Terminal Unit - Equipment on the end of air conditioning ductwork to distribute supply air into a space or collect return air
Air Termination Network - The parts of lightning protection system on a roof. Flat roofs have roof conductors. Ridges or high points have a sharp tip to emit ions and neutralize the high static voltages which cause lightning strikes. Both lead any discharge that does occur to the down conductors.
Air test - A drain test using air pressure. The pipe run is blocked at the top and bottom with screw plugs, then air is pumped in until 100 mm of water gauge is shown on glass U-gauge. The test is satisfactory if the pressure does not drop below 75 mm within 5 minutes. Air tests are used for gravity pipes, e.g. the sanitary pipework above ground
Air treatment - Altering the air temperature and humidity, and removing dust and impurities with filters, to make it suitable to be used in an air conditioning system. In winter, air treatment involves normal heating, which may be shared with radiators in a split system and use of humidifiers. In summer or damp weather a chiller runs the cold coils and dehumidifiers are used.
Air valve - A valve for bleeding air from water pipe
Air vessel - An air receiver
Air void - A blowhole
Air Washer, Wet Air Filter - A chamber in which air is mixed with water, removing contaminants such as dust and gases. Suited to industrial exhausts, it is no longer used for air conditioning, supply air owing to costly maintenance and because it is a possible source of bacteria.
Air-blast Cleaning -The flushing of rubbish away from the work surface using a blow gun supplied with compressed air.
Air-entraining Agent - An admixture for concrete.
Airless Spraying - Painting by a spray gun by a miniature high-pressure pump forcing paint through a fine nozzle. With this method there is almost no spray mist and less overspray than with compressed-air spraying
Airtight Inspection Cover - A cast Iron plate over an Inspection chamber. Covers are removable, non ventilating and bolted down to a frame, which has a groove filled with grease. They may be required over a soil drain indoors and are made to resist flooding
Aisle - Subsidiary part of a church or other large building parallel to the main body of the building.
Abattoir - A public slaughter house.
Abbey - A convent under an abbot: the church now or formerly attached to it.
Ablution Fitting- A large sanitary fitting in which several people at the same time can wash their hands, arms, or faces. Ablution fittings are made for rough use and have water sprayers, often with touchless controls or foot controls. Trough type can be set in ranges, while washing fountains have a circular pedestal bowl.
Above Ground Level- Higher than ground level, particularly with reference to the superstructure, and to work after a building is out of the ground.
Abrasion Resistance- The ability of a finish to stand up to wear from rubbing,
Abrasives - Rough, hard materials (usually powders, grits or stones) in various forms such as sandpaper, grinding wheels, or grinding discs, used to smooth or clean surfaces or to sharpen and hone edge tools. From hard to soft they include: diamond, garnet, corundum(emery), carborundum, powdered glass, and silica sand. The hardest abrasives cause others to wear the most while lasting the longer themselves. Coarse abrasives remove the most material, fine abrasives give the smoothest surface.
ABS (Acrylonitrile Butadiene Styrene)- A tough co-polymer, used to make plastic pipes for cold water supply or soil and waste drains. Pipes can have solvent welded joints, made with special ABS cement, or push-fit joint rings. Its softening point is higher than that of polypropylene, so that it can handle hot waste water up to 80 degree Cent. However, petrol, oil, and linseed oil can damage it. ABS pipe can be bent at about 125 degree Cent. ; no bending spring is needed. Like all plastics, ABS is combustible.
Absorption Rate - The speed at which water is taken up by a brick when partly immersed for one minute, used to measure initial suction.
Absorption Refrigerator - A refrigerator without a compressor which uses heat to evaporate lithium bromide from water. It is silent and not very efficient but can be run on waste heat.
Absorptivity / Absorptive Power - The relative rate of absorption of heat by a body compared with a similarly shaped black body in the same conditions.
Abstracting - Assembling data so that similar types of work are brought together under one item ready for billing. It is the first part of the working up of bill of quantities.
Abutment - An intersection between a roof slope and a wall that rises above it
Abutment Flashing - A flashing over an abutment. At the head of the slope it is level, at the side of the slope it is raking or stepped.
Abutment Piece - A sill or sole plate.
Accelerated Weathering/ Artificial Ageing - The testing of materials by exposure to cycles of sunlight, heat, frost and wetness or dryness that are more severe than in nature.
Accelerator / Accelerating admixture - An admixture that hastens setting and increases the early strength of concrete, usually causing an increase in temperature. This allows earlier removal of formwork and may give frost protection.
Access - A way in or out, including any circulation area for walking (such as a stair, balcony or ramp), vehicle access to a site (such as a road or a way), or even hand access for inspection.
Access Chamber - A space big enough for a person to get into.
Access Floor - A floor above the structural floor, creating the space between them, for cables going to office work stations, to allow easy wire management for data, telephone, power and lighting.
Access Hole - An opening large enough for a person to get through for work on installations, or for a tool to be passed through for making adjustments. Access holes normally have a cover, such as a panel or a trap.
Accessories - Components used to fix, join, or connect building elements or services, including hardware, fixings and roof flashings.
Accordion Door - A folding door.
Accreditation - An approval of one official body by a higher authority, e.g. for building products certification.
Acetal Resin - Strong, low priced synthetic resin made by polymerizing formaldehyde. Acetal plastics are used in plumbing fittings, particularly for threaded valve components and intricate shapes.
Acoustic - Pertaining to the sense of hearing or to the theory of sounds, acoustic properties of a room determining whether accurate hearing in it is easy or not.
Acoustic Board - Wall and Ceiling acoustic furnishings made with a porous core of insulating board or mineral fibre tiles and a surface that has many round holes, or is fissured or riled. It can be fixed as full boards or made into acoustic tiles. Painting can block the holes and reduce sound absorbency; careful spraying with many thin coats of emulsion paint reduces mainly the high frequency sound absorption.
Acoustic Clip - A floor clip with a flexible rubber pad to reduce transmission of impact sound through a timber floating floor.
Acoustic Construction - The improvement of sound insulation by using thick walls, heavy materials of low stiffness, or discontinuous construction such as a floating floor, which reduces noise transmission.
Acoustic Finishing - Materials inside which sound energy is lost by absorption. However they usually have high sound transmission.
Acoustic Plaster - Gypsum Plaster with light weight aggregate, used as an acoustic finishing.
Acoustic Tile – A square of acoustic board.
Acoustical Transmission - Sound or noise in buildings is controlled either by reducing transmission between rooms by the methods of construction, or by increasing absorption within the room, with acoustic finishings. In sound measurements the acoustical transmission factor is the amount of sound that passes through a type of construction, while the acoustical reduction factor is its reciprocal, implying the effectiveness of sound insulation.
Acre - Measure of land containing 4840 sq.yds.
Acropolis - Greek citadel sited prominently above the rest of a city.
Acrylic Adhesive - A fast-curing emulsion adhesive, usually white in colour and fairly non-staining. It is used wet but goes tacky quickly, and can hold down curling edges of vinyl floor tiles.
Acrylic Paints - Emulsion paints which hold their colour well, are very durable and resistant to oils, fats and grease, and have sufficient resilience to avoid cracking. They are used as fast-drying floor paints and as organic coatings on metals.
Acrylic Resins - Polymethyl methacrylate, the synthetic resin in acrylic paints, sealants, adhesives, and sheet. It however has poor resistance to alkalis.
Acrylic Sealants - Sealants that set to a tough rubbery material by solvent release. They have good adhesion to most substrates without the need for a primer, but should not be used in wet areas or in contact with cement-based products, which are alkaline.
Acrylic Sheet - Fairly strong, light weight, easily moulded plastics, mainly used for clear or tinted glazing and coloured sanitary fittings, such as baths or basins. Acrylic sheets melt and burn easily, so they are a fire hazard and have low fire resistance. However, they can be broken to allow escape and unlike glass do not splinter into sharp pieces.
Acrylonitrile Butadiene Styrene - A tough co-polymer, used to make plastic pipes for cold water supply or soil and waste drains. Pipes can have solvent welded joints, made with special ABS cement, or push-fit joint rings. Its softening point is higher than that of polypropylene, so that it can handle hot waste water up to 80 degree Cent. However, petrol, oil, and linseed oil can damage it. ABS pipe can be bent at about 125 degree Cent. ; no bending spring is needed. Like all plastics, ABS is combustible.
Active Fire Protection - Mechanical and electrical devices to warn of or extinguish fires, such as sprinklers, alarms, fire detectors, and fans or dampers for a pressurized escape route. They can be very effective but require regular inspection and maintenance, and may need standby power.
Active Leaf - The leaf of double door which is most used, held closed by latching to the inactive leaf.
Active Solar Heating - Heating systems that use solar collectors and mechanical devices such as pumps or fans.
Actuator - A mechanical linkage to create or transmit movements such as pushing, pulling, or slight rotation, which enable automatic controls to control a flow of fluids or the currents in the electric system.
Adaptor - A device which matches different objects, e.g. the connection between pipes or ducts of different sizes or sections, or between British electrical plugs and Continental ones.
Adhesion - The sticking together of components by making a chemical bond, using an adhesive, cement, or bonding compound.
Adhesive, Glue - A liquid that in hardening sticks together by adhesion. It allows joints or fixing to be made without spoiling a surface with nails or screws.
Adjudication - Adding a margin to the net price of builder's estimate to give the tender amount. Adjudication is done by a manager after discussion with the chief estimator.
Admixture - A product or agent added in small quantities to the basic constituents ( aggregate, cement or water ) of concrete or mortar to alter a particular combination of properties while it is fresh or after it has hardened.
Adobe, Mud brick - A moulded and sun-dried brick or block of clay (or the clay itself) usually containing chopped straw reinforcement, used for the walls of earth buildings. Adobe construction is common in South and Central America and is occasionally used in semi-arid regions of the USA, Australia, and elsewhere.
Aerated Concrete - Lightweight and highly insulating cellular material made from a mix of fine sand, pulverized fuel ash, and chemical admixtures, cast into moulds and autoclaved to make lightweight concrete blocks. It is easy to saw and drive nails into, although metal fixings do not hold well and may corrode needing the use of resin anchors. Aerated concrete has high moisture movements.
Aesthetics - The principle of taste and of art : the philosophy of fine arts.
A-frame Building - A building with beams straight from the ground to the roof ridge, that form the shape of an A. The lower part of the roof slope usually takes the place of the wall.
African-Mahogany - Timber from West Africa, generally Nigeria or Ghana,
After tack - The defect of a paint film which has been tack-free and then becomes tacky
After-flush - The small quantity of water remaining in the cistern after flushing a water closet. It trickles slowly down and remakes the seal
Ageing - The storing of a material to improve its quality. Varnish that has been aged has improved gloss and reduced pin-holing and crawling. Ageing is done before use, unlike maturing and curing.
Aggregate - Any granular material used as the main constituent of concrete, mortar and plaster. Aggregate is defined by its size, as coarse, fine, or all-in, its source (natural or artificial) and its shape, e.g. rounded or angular.
Agora - Greek forum or market place.
Agreed Levels - A survey of natural ground levels before the commencement of groundworks, marked on a drawing and signed by the site engineer and the clerks of works.
Air Admittance Valve - A device to let air into the sanitary pipe, used in addition to the soil vent, to relieve minor differences in air pressures.
Air Balancing - Adjusting air conditioning dampers so that air is evenly distributed to rooms. It is necessary at commissioning or when partitions are moved.
Air brick - A special brick with perforations through it so that it can be built into wall to ventilate a room or a space under floor. Air bricks can be of normal size, two course high, or made to be laid as a brick-on-edge.
Air brush - A small spray gun.
Air change - A quantity of fresh air equal to the volume of the room being ventilated. The ventilation rate is the number of air changes per hour. Offices need about 30 changes, boiler houses and laundries 10 to 20, classrooms 6, reading rooms 2 and store rooms 1.5. Kitchens often have high air-change rates, although if heat and smoke are withdrawn through hoods, excessive rates can be avoided.
Air Conditioner (Window)- A small to medium capacity packaged air treatment unit or cabinet, usually without ductwork and often mounted in a window.
Air Conditioning - The process of treating air so as to control simultaneously its temperature, humidity, cleanliness and distribution to meet the requirement of conditioned space or,
The supply of cool or warm, dry and filtered air using mechanical services to maintain conditions of temperature and humidity within the comfort zone, with an indirect benefit of a quiet environment, as windows are kept closed to reduce traffic noise. Automatic controls operate the air-treatment plant and determine the setting of air-handling equipment
Air curtain - A strong flow of warm air directed towards a doorway from the outside, to stop cold air entering in winter when the door is left open. Small air curtains are drawn from the sides, but larger units have a high velocity air current from overhead and the return duct in the floor.
Air diffuser - An air terminal unit that controls the direction of supply air for distribution into room or occupied area.
Air distribution - The supply of treated air from a central air-conditioning plant by blowing it through ductwork to air terminal units and into space
Air dried timber - Sawn timber that has had natural seasoning, by stacking cut planks in the open air, usually with stickers between them.
Air Eliminator - A plumbing fitting for the automatic release of gases, as from a cold water supply pipe, to prevent an air lock
Air Gap - The height of water above the rim of sanitary fitting to prevent backflow from contaminating the supply pipe.
Air grille, air grating - A simple type of air terminal unit: a perforated metal plate that allows air to pass, while acting as a sight screen
Air Handling Equipment - Equipment in an air-conditioning system for moving air into and out of rooms, usually by blowing with fans through ducts. The supply air from the air treatment plant goes to air terminal units discharging into the spaces where air is distributed.
Air Handling Luminaire - A luminaire through which extract air is drawn, to reduce the cooling load on the air conditioning system as well to improve light output and improve lamp life
Air Handling Unit (AHU) - A packaged air conditioner either a large individual unit for a special environment, such as a kitchen or computer room, or a simple fan coil unit
Air House (pneumatic structure) - A balloon structure either air-supported or air-inflated. Air houses pay for themselves quickly when used for temporary shelter, because they can span large areas, are inexpensive and easy to transport, and allow fast erection or demounting. In case of fire the burn hole can provide both a means of escape and ventilation
Air lock - A bubble of air, trapped in a high point of a pipe, obstructing the flow of water, OR
Any device for preventing the flow of air, often merely a lobby with two doors far enough apart so that the first closes behind a person before a second is reached. Air lock doors should open in one direction.
Air Receiver, Air Vessel - A pressure vessel connected to a outlet from an air compressor for storage of compressed air until used. One may be connected to the delivery side of a pump to extract air from water.
Air Release Valve, Pet Cock - A small valve for bleeding air from pipework, a pump casing, pressure vessel etc.
Air right - The right of the owner of a low city building with fewer floors than allowed by the plot ratio to sell the space above for another building to be stacked on top. However, this may mean also allowing foundations and columns to be built under and through the property to provide support
Air Seasoned Tmber - Air dried timber
Air Set - Warehouse set.
Air Shaft - A light well.
Air Space - A cavity.
Air Supported Structure - A type of air house with a single membrane carried by low pressure air. The edges need anchorage from concrete beams in the ground or sandbags, and the entrance needs an air lock
Air Terminal Unit - Equipment on the end of air conditioning ductwork to distribute supply air into a space or collect return air
Air Termination Network - The parts of lightning protection system on a roof. Flat roofs have roof conductors. Ridges or high points have a sharp tip to emit ions and neutralize the high static voltages which cause lightning strikes. Both lead any discharge that does occur to the down conductors.
Air test - A drain test using air pressure. The pipe run is blocked at the top and bottom with screw plugs, then air is pumped in until 100 mm of water gauge is shown on glass U-gauge. The test is satisfactory if the pressure does not drop below 75 mm within 5 minutes. Air tests are used for gravity pipes, e.g. the sanitary pipework above ground
Air treatment - Altering the air temperature and humidity, and removing dust and impurities with filters, to make it suitable to be used in an air conditioning system. In winter, air treatment involves normal heating, which may be shared with radiators in a split system and use of humidifiers. In summer or damp weather a chiller runs the cold coils and dehumidifiers are used.
Air valve - A valve for bleeding air from water pipe
Air vessel - An air receiver
Air void - A blowhole
Air Washer, Wet Air Filter - A chamber in which air is mixed with water, removing contaminants such as dust and gases. Suited to industrial exhausts, it is no longer used for air conditioning, supply air owing to costly maintenance and because it is a possible source of bacteria.
Air-blast Cleaning -The flushing of rubbish away from the work surface using a blow gun supplied with compressed air.
Air-entraining Agent - An admixture for concrete.
Airless Spraying - Painting by a spray gun by a miniature high-pressure pump forcing paint through a fine nozzle. With this method there is almost no spray mist and less overspray than with compressed-air spraying
Airtight Inspection Cover - A cast Iron plate over an Inspection chamber. Covers are removable, non ventilating and bolted down to a frame, which has a groove filled with grease. They may be required over a soil drain indoors and are made to resist flooding
Aisle - Subsidiary part of a church or other large building parallel to the main body of the building.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
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