Indoor air quality - commonly used terms

Glossary of commonly used terms found in indoor air quality (IAQ) documents. Last updated 2016.
Term Definition
ACGIH American Conference of Government Industrial Hygienists
AIHA American Industrial Hygiene Association
Anchor Bolt A bolt that is used to attach structures to concrete.
AOEC Association of Occupational and Environmental Clinics
ASHRAE American Society of Heating, Refrigeration and Air-Conditioning Engineers.
Awning Windows A window with hinges at the top of the sash that swings outward.
Blown-in Insulation Insulation that is pumped or injected into walls, roofs, and other areas.
BOCA Building Officials and Code Administrators
Building Envelope The physical separator between the conditioned and unconditioned environment of a building which resists the air, water, heat, light, and noise from the outside from penetrating to the inside.
Cantilever A long projecting beam or girder fixed at only one end, used for balconies.
Carpet Backing Material on the back of a carpet, usually made of  jute, cotton or rayon, sometimes with a latex coating.
Carpet Pile The visible surface of carpet, consisting of yarn tufts in loop and/or cut configuration.
Casement Window A window that is hinged at the side.
Caulking A waterproof filler and sealant, used in building work and repairs.
Ceiling Plenum Space between the structural floor/roof deck and the suspended ceiling.
Cement Block A concrete building unit with hollow space.
CFL Compact fluorescent light bulb.
Chiller A machine that cools the liquid used in cooling coils in an air conditioning system.
Chimney Cap A device fitted to the top of a chimney to improve the draft by presenting an exit aperture to leeward and to prevent rainwater penetration down the chimney.
Clapboard A long, thin, flat piece of wood with edges horizontally overlapping in series, used to cover the outer walls of buildings.
CMR Code of Massachusetts Regulations
CO Carbon monoxide, a product of incomplete combustion.
CO2 Carbon dioxide, a product of metabolism, used as a measure of adequacy of ventilation.
Condensation Water that collects as droplets on a cold surface when humid air is in contact with it.
Condenser An apparatus or container for condensing vapor.
Cooling coil Equipment that performs heat transfer to air when mounted inside an air handling unit or ductwork. It is cooled by circulating liquid.
Cornice Trim A decorative top edge of a building or column.
Coving A strip of molding, typically used for where the wall meets the floor.
Crawlspace An area of limited height under a floor or roof, giving access to wiring and plumbing.
DCAMM Massachusetts Division of Capital Assets Management and Maintenance
DCF Massachusetts Department of Children and Families
DDS Massachusetts Department of Developmental Services
Decay (Radioactive) Spontaneous disintegration of a radionuclide with the emission of energetic particles or radiation, such as alpha or beta particles or gamma rays.
Decibels A unit of measure for sound.
Dew Point The atmospheric temperature (varying according to pressure and humidity) below which water droplets begin to condense and dew can form.
DLS Massachusetts Department of Labor Standards
Door Jamb Each of the two upright parts of a doorframe, on one of which the door is hung.
DOR Massachusetts Department of Revenue
Dormer A window that projects vertically from a sloping roof.
Draeger tube A device/system used to measure airborne chemicals.
Drain Trap A U-, S-, or J-shaped pipe located below or within a
Drainage Plane A surface used in the design and construction of building enclosures to control rain.  Walls and the roof are part of the drainage plane.
Drip Edge A metal flashing or other overhanging component with an outward projecting lower edge, intended to control the direction of rainwater.
Drip Pan A container for catching material that drips from above, such as in an air handling unit to collect condensation.
Dust Spot Efficiency The ability of a filter to remove atmospheric dust from the air.
E.O. Executive Order
Efflorescence A whitish, powdery deposit on the surface of brick and mortar. It is formed as mineral-rich water rises to the surface through capillary action and then evaporates.
EIFS Exterior insulation foam system, a type of exterior building cladding/insulation.
Engineered Wood Wood products which are manufactured by binding or fixing the strands, particles, fibers, or veneers or boards of wood, together with adhesives, or other methods of fixation to form composite materials, also called composite wood, man-made wood, or manufactured board.
EOHHS Executive Office of Health and Human Services
Fascia Board The horizontal board which caps the end of rafters outside a building.
Fenestration Windows and doors of a building.
Fiberglass Fibrous glass used for insulation.
Flash Point The lowest temperature of a volatile substance at which it can vaporize to form an ignitable mixture in air.
Flashing A strip of metal used to stop water from penetrating the junction of a roof, window, or doorframe with another surface.
Floor Plenum Space between the structural floor/roof deck and an elevated floor space, typically found in computer mainframe rooms.
Flue A passage or duct for smoke in a chimney, often where the damper is located.
Foot-candles A unit of illumination equal to that given by a source of one candela at a distance of one foot (equivalent to one lumen per square foot or 10.764 lux).
Foundation Vent Vent openings in a foundation wall that allow for
Four-way Louver A fresh air supply vent that directs air in four different directions.
Friable Easily crumbled or reduced to powder.
Frieze Board A decorative band located on an outside wall or at the top of an interior wall.
Fume hood A ventilated enclosure in a chemistry laboratory or vocational shop, in which harmful chemicals can be used.
Gable The part of a wall that encloses the end of a pitched roof.
Gable Vent A vent located in the gable of a building.
Gambrel Roof A gable roof, each side of which has a shallower slope above a steeper one.
Ghosting Black streaking on walls and ceiling, typically from airflow patterns.
Glass Block Windows A hollow, translucent, high-strength glass block used as a building material, chiefly for exterior and interior walls.
Gravity Ventilation The process of supplying air to and removing air from an indoor space without using mechanical systems (also called natural ventilation).
Gypsum Wallboard Wallboard with a gypsum plaster core bonded to layers of paper or fiberboard; used instead of plaster or wallboard to make interior walls.
Heat Index A measure expressing the discomfort felt as a result of the combined effects of the temperature and humidity of the air.
HEPA High efficiency particle arrestance (or air), used to describe filters that must remove (from the air that passes through) 99.97% of particles that have a size of 0.3 µm.
Hip Roof A type of roof where all sides slope downwards to the walls, usually with a fairly gentle slope.
Homasote® A brand name associated with the product generically known as cellulose based fiber wall board, which is similar in composition to papier-mâché.
Hopper Windows A window with hinges at the bottom of the sash that swings outward.
HUD U.S. Housing and Urban Development
I-beam A steel beam with an I- or H-shaped cross-section.
IICRC Institute of Inspection, Cleaning and Restoration Certification
IPM Integrated Pest Management
Isocyanate A chemical compound used in spray foam insulation.  It is also a known chemical sensitizer in exposed individuals.
Jalousie Windows A window composed of parallel glass, acrylic, or wooden louvers set in a frame. The louvers are joined onto a track so that they may be tilted open and shut in unison to control airflow, usually by turning a crank.
Joist A length of timber or steel supporting part of the structure of a building, typically arranged in parallel series to support a floor or ceiling.
Kerf A cut or incision made in a piece of wood.
Kiln A furnace or oven for burning, baking, or drying, especially one for firing pottery.
Laminated Wood Flooring A multi-layer synthetic flooring product fused together with a lamination process. Laminate flooring simulates wood (or sometimes stone) with a photographic applique layer under a clear protective layer.
Lath A thin flat strip of wood, especially one of a series forming a foundation for the plaster of a wall or the tiles of a roof.
LBOH Local Board of Health
Louvers Horizontal slats that are angled to admit light and air, but to keep out rain, direct sunshine, and noise; the angle of the slats may be adjustable.
Lumens A unit of illumination (visible light) emitted by a source.
Mansard Roof A roof that has four sloping sides, each of which becomes steeper halfway down.
Mastic A paste-like filler and sealant used in buildings.
MBI Modular Building Institute
MDI Methylene diphenyl diisocyanate
MERV rating Minimum efficiency reporting value, commonly known as MERV rating, is a measurement scale designed in 1987 by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) to rate the effectiveness of air filters.
MGL Massachusetts General Laws
Micromanometer A device used to measure air pressure differentials.
Micron A unit of measure of length (diameter) of a particle.
Modular building A prefabricated building that comes in sections.
Mortar A mixture of lime with cement, sand, and water, used in building to bond bricks or stones.
Mortise A hole or recess cut into a part, designed to receive a corresponding projection (a tenon) on another part so as to join or lock the parts together.
MSBA Massachusetts School Building Authority
ng/m3 Nanograms per cubic meter; a nanogram is 10-9 grams.
NIH National Institute of Health
NO2 Nitrogen dioxide, a product of combustion associated with propane and a significant respiratory irritant.
Ozone A form of oxygen that consists of 3 oxygen atoms in one molecule.  It can be produced by arcing electricity, arc welding and other industrial and natural processes.  Ozone is a significant respiratory irritant.
Particle board An engineered wood product manufactured from wood chips, sawmill shavings, or even sawdust, and a synthetic resin or other suitable binder, which is pressed and extruded.
Passive Air Vent A grate, window, or undercut in a door or wall to allow natural airflow between rooms or between the inside and the outside.
PCBs Polychlorinated biphenyls, a hazardous material use as an insulating compound frequently found in caulking, light ballast and transformers.
pCi/L Picocurie per liter, a unit of measure of radiation associated with radon levels in buildings.
Perc (or PCE) Perchloroethylene
Pilaster An architectural structure used to give the appearance of a supporting column that is ornamental.
Plywood An engineered wood product that is type of strong thin wooden board consisting of two or more layers glued and pressed together with the direction of the grain alternating, and usually sold in sheets of four by eight feet.
PM2.5 Particulate matter of a diameter of 2.5 microns of less.
Porous Materials that can readily absorb water. Examples included gypsum wall board, carpeting, ceiling tiles, cardboard, paper upholstered furniture.
ppb (parts per billion) Used to report the mass of a chemical per unit volume of air.
ppm (parts per million) Used to report the mass of a chemical per unit volume of air.
Prestressed concrete Concrete in which reinforcing steel bars are stretched and anchored to compress it and thus increase its resistance to stress.
P-trap A drain trap in the shape of the letter “P” designed to have water remain in the pipe to provide a seal against sewer gas penetration.
R Value A measurement of thermal resistance, the capacity of an insulating material to resist heat flow. The higher the R-value, the greater the insulating power.
Radon The chemical element of atomic number 86, a rare radioactive gas belonging to the noble gas series.
Rafter An internal beam extending from the eaves to the peak of a roof and constituting its framework.
Rebar A steel reinforcing rod in concrete.
Register An adjustable plate for widening or narrowing an opening and regulating a draft.
Ridge Vent A type of vent installed at the peak of a sloped roof which allows warm, humid air to escape a building's attic.
RMV Massachusetts Registry of Motor Vehicles
Sash Windows Windows made of one or more movable panels that form a frame to hold panes of glass; the term is used almost exclusively to refer to windows where the glazed panels are opened by sliding (vertically or horizontally).
Scouring Occurs when soil is removed by force of water.
Scupper An intentionally constructed hole in a parapet/edge of a building with a flat roof to allow water to exit the roof.
Sensitizer (chemical) A chemical that can cause allergic reactions after repeated exposure.
SIPS Structural Insulated Panels System
SMACNA Sheet Metal & Air Conditioning Contractors’ National  Association
Soffit Vent A screened vent that allows air to flow into the attic or the space below the roof sheathing. Installed in concert with a ridge vent.
Soil Stack The pipe that takes all the wastewater from the plumbing system of a building.
Solar Gain The increase in temperature in a space, object or structure that results from direct sunlight.
Spackle A compound used to fill cracks in plaster and produce a smooth surface.
Spalling When stone or masonry breaks into smaller pieces as a result of weathering, corrosion or pressure.
Spandrel The area between the sill of a window and the head of the window below it. In steel or reinforced concrete structures there will sometimes be a spandrel beam extending horizontally from one column to another and supporting a section of wall.
Sphygmomanometer Blood pressure measure device that can contain mercury.
Spline Ceiling A strip of metal or fiber inserted in the kerfs of adjacent acoustical tile to form a concealed mechanical joint seal.
Spray booth An enclosure containing a flammable or combustible spraying operation and confining and limiting the escape of paint, vapor and residue by means of a powered exhaust system.
Spray Foam Insulation Spray foam insulation is a polyurethane foam used to insulate homes.  It is a two-component mixture composed of isocyanate and polyol resin.
S-trap A drain trap in the shape of the letter “S” designed to have water remain in the pipe to provide a seal against sewer gas penetration.
Stringers The structural members of a stairway that support the treads and risers.
TDI Toluene diisocyanate
Tenon A projecting piece of wood made for insertion into a mortise in another piece.
Thermohygrometer A device the measures temperature and humidity.
Tongue-in-groove Flooring A joint between two boards in which a raised area on the edge of one board fits into a corresponding groove in the edge of the other to produce a flush surface
Transfer Air Air transferred from one indoor area to another indoor area, usually via a passive air vent.
Transfer Air Vent Passive air vent between one indoor area and another.
Truss A framework of rafters, posts, and struts used to support a roof or floor.
Turbine Vent A ventilator, usually mounted on the roof of a building, having
Tyvek® A brand of material made of non-woven high-density polyethylene fibers; the name is a registered trademark of DuPont. It is often seen used as house wrap, a synthetic material used to protect buildings during construction and provide a drainage plane after buildings are completed.  It is pervious to water vapor but repels liquid water.
UFFI Urea formaldehyde foam insulation.
Univent A unit ventilator consists of a heating coil, fan assembly, dampers, filter and controls contained in a metal cabinet, usually located on the outside wall of a building.
Veneer A thin decorative covering of fine wood applied to a coarser wood or other material.
VOC Volatile organic compound, any volatile compound of carbon.
Waferboard An engineered wood product that is a structural material made from rectangular wood flakes of controlled length and thickness bonded together with waterproof phenolic resin under extreme heat and pressure.
Wall Stud A wall stud is a vertical framing member in a building's wall that is smaller in cross section than a post.
Weep Hole A small opening in an exterior wall that allows water to drain from within the wall assembly. Weep holes are located at the bottom of the object to allow for drainage.
μg/m3 Micrograms per cubic meter, a measure of concentration of a chemical in air.  A microgram is 10-6 grams.

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