Glossary

Second.

Second per square centimetre.

The unit of acoustic absorption. One sabin is one square foot of perfect sound-absorbing material.

A formula developed by Wallace Clement Sabine that allows designers to plan reverberation time in a room in advance of construction and occupancy. Defined and improved empirically, the Sabine Formula is T=0.049(V/A) where T=Reverberation time (time required for sound to decay 60 dB after source has stopped) in seconds. V=Volume of room in cubic feet. A=total square footage of absorption in sabins.

A casting, fabricated chair, or member used for the purpose of support.

A manually opened, electrically latched, electrically operated safety shut-off valve designed to automatically shut off fuel when de-energized.

Commercial representative of a company who is appointed to sell its goods and services through his business network in the foreign countries and markets. He can be exclusive or he can represent several companies at the same time. The sales agent is generally not responsible for the goods delivery and the after-sales service of the products. He is remunerated on a commission basis.

The difference between current and previous year's sales divided by the previous year's sales gives an indication of whether the business is meeting goals. Usually expressed as a percentage.

The removal of a portion of a material for examination or analysis.

Air which contains the maximum amount of water vapour that it can hold at its temperature and pressure.

Steam at the temperature and pressure at which evaporation occurs.

Water at its boiling point.

The saturation pressure for a pure substance for any given temperature is that pressure at which vapour and liquid, or vapour and solid, can coexist in stable equilibrium.

The temperature at which no further moisture can be added to the air-water vapour mixture. Equals dew point temperature.

The vapour density at which a dynamic equilibrium exists for exchange of molecules between the gas and an open liquid surface.

A hard coating or layer of materials on surfaces of boiler pressure parts.

Standard cubic feet per minute. A measure of air flow at standard conditions, i.e., dry air at 29.92 in.Hg (760 mm Hg) (gauge), 68°F (20°C).

An air pollution control device for removal of water-soluble vapours and gases, and airborne particulates from gaseous emissions by direct contact with a water or caustic spray or with a dry solid such as lime.

Air for combustion supplied to the furnace to supplement the primary air.

A material that is not a primary product of a chemical process that is generated during the conversion of raw material(s) and sometimes process intermediate(s).

Transferable certificates of ownership of investment products such as notes, bonds, stocks, futures contracts and options.

Asset(s) belonging to the business or to you personally, which are pledged to a lender in support of a loan.

(1) Matter in water which can be removed from suspension by gravity or mechanical means.

(2) A non-combustible solid matter which settles out at bottom of a liquid; a small percentage is present in residual fuel oils.

Traditionally a client who manages a brokerage account with no outside assistance. Self directed accounts have access to all of the traditional brokerage products and services but with less fees.

A steel stack of sufficient strength to require no lateral support.

Difference between the total cooling effect and the dehumidifying effect, usually in watts (Btuh).

Sensible heat modifies the temperature of a matter. Contrary to the latent heat which modifies the physical state of a matter (solid, liquid or gas).

A measure of the minimum change in a variable which can be detected by an instrument.

A device that responds to a stimulus, such as heat, light, or pressure, and generates a signal that can be measured or interpreted.

Overload capacity built into a component, device, engine, motor, etc., as a safety factor. It is expressed usually a number greater than one: a SF of 1.15 means the item can take 15 percent more load than its rated capacity without breakdown. A motor operating continuously at a service factor greater than 1 will have a reduced life expectancy compared to operating at its rated nameplate horsepower.

These two terms are used interchangeably. Certificates representing ownership in a corporation and the appropriate claim on the corporation's earnings and assets.

Housing or outer covering of something.

Document required by the U.S. Department of Commerce for exports of certain controlled items, and/or shipments to certain countries, and/or shipments anywhere that exceed certain dollar amounts. This document is used to monitor shipments of controlled goods.

Note on bill of lading indicating that the contents of a container were loaded and counted by the shipper and not checked or verified by the Steamship Company.

A fault or defect in a winding causing part of the normal electrical circuit to be bypassed, frequently resulting in overheating of the winding and burnout.

ACGIH-recommended exposure limit.

Maximum concentration to which workers can be exposed for a short period of time (15 minutes) for only four times throughout the day with at least one hour between exposures.

A skirt of material sealed to a pipe and to the floor or ceiling providing a watertight or airtight joint . It may be of neoprene, polythene, metal, etc.

A conductor joining two points in an electrical circuit to form a parallel path. All or some portion of the current may pass through the shunt.

If more than 20 percent of the building occupants complain of such problems as headache, eye irritation, fatigue and dizziness for more than two weeks; if the symptoms are relieved when the complainant leaves the building; and, if no specific cause of the problem can be identified.

The sound level of a speaker above background noise, at the listener’s ear level. The inverse square law impacts the S/N ratio.

A regenerative absorbent consisting of the amorphous silica manufactured by the action of HCl on sodium silicate. Hard, glossy, quartz like in appearance. Used in dehydrating and in drying and as a catalyst carrier.

Any motor energized by a single alternation voltage.

An HVAC system where one thermostat controls the temperature of the entire building.

Solid non-combustible residue that has melted and fused into glassy aggregates at high temperature during combustion.

An inclined manometer for measuring differential pressures.

A piece of tube, usually of wrought iron or mild steel placed in walls and floors, and sited to allow passage of some service pipe through them.

Common in home appliance motors. Normally used in blower applications where low noise levels are important.

(1) A solid residue separated from wastewater during treatment.
(2) A solid chemical process residue which may be further processed for material recovery or discarded as a waste for treatment.

Carbon or soot particles less than 1μ in size result from incomplete combustion of carbonaceous materials such as coal or oil. Smoke generally contains droplets as well as dry particles. Tobacco, for instance, produces a wet smoke composed of minute tarry droplets.

Visible cloud of airborne particles derived from combustion or from chemical reaction.

Water which contains little or no calcium or magnesium salts, or water from which scale forming impurities have been removed or reduced.

A form of business organization in which one person is the sole owner. In effect, there is no distinction between the owner's and the business' responsibility regarding the commitments made on behalf of the business.

(1) Usually interpreted to encompass all waste that is not liquid or gaseous.
(2) In a narrow sense, non-hazardous waste such as municipal refuse.

Particulate elemental carbon formed as a product of incomplete combustion.

Unburned particles of carbon derived from hydrocarbons.

(n) A substance which absorbs or adsorbs or both.
(adj.) The quality of absorbency and/or adsorbency possessed by a material.

(1) A material that removes toxic gases and vapours from air inhaled through a canister or cartridge.
(2) Material used to collect gases and vapours during air-sampling.

A device that converts sound pressure variations in air into corresponding electronic signals. The signals are filtered to exclude sound.

The ratio of the mass of a unit volume of a substance to the mass of the same volume of a standard substance at a standard temperature. Water at 4°C (39.2°F) is the standard usually referred to for liquids; for gases, dry air (at the same temperature and pressure as the gas) is often taken as the standard substance.

The quantity of heat, expressed in Btu, required to raise the temperature of 1 lb of a substance 1°F.

A dimensionless parameter based on fan rotational speed, flow rating and pressure rating. It's a tool used to select the type of fan for a specific application. Each different fan type achieves peak efficiency at a unique specific speed range.

The reciprocal of density and is used to determine the cubic feet of volume, if the pounds of weight are known. Both density and specific volume are affected by temperature and pressure. The specific volume of air under standard conditions is 13.33 cubic feet per pound and the specific volume of water at standard conditions is 0.016 cubic feet per pound.

Motor has moderate starting torque, high breakdown torque. Used on easy-starting equipment, such as belt-driven fans and blowers, grinders, centrifugal pumps, gear motors, etc.

Square feet.

A single chimney/flue or a cluster of chimneys or flues.

The point of continuous release from combustion devices of gaseous emissions that have been treated in air pollution control devices.

A vertical conduit, which due to the difference in density between internal and external gases, creates a draft at its base.

A device on the end of a ventilation system that disperses exhaust contaminants for dilution by the atmosphere.

The magnitude of the draft measured at the inlet to the stack.

Gas and solid products discharged from stacks.

(1) The opening (which may be controlled) through which gases passing up a flue/stack/chimney are discharged to the atmosphere.

(2) The vent for a heating system in the form of a vertical flue or stack. (preferred term: flue or stack)

An area within a space where the air velocity is less than 25 fpm.

Or Standard Temperature and Pressure (STP).
Defined temperature and pressure to which all values are referenced for comparison. Generally 760 mm Hg (1 atm), 25°C.

Force produced by a motor as it begins to turn from standstill and accelerate (sometimes called locked rotor torque).

Refers to the form of a fluid, either liquid, gas or solid. Liquids used in environmental systems are water, thermal fluids such as ethylene glycol solutions, and refrigerants in the liquid state. Gases are steam, evaporated refrigerants and the air-water vapour mixture found in the atmosphere. Some substances, including commonly used refrigerants, may exist in any of three states. A simple example is water, which may be solid (ice), liquid (water), or gas (steam or water vapour).

Difference between the total fluid pressure and the dynamic pressure if any.

The pressure due to the weight of a fluid above the point of measurement.

The pressure developed in a duct by a fan; SP exerts influence in all directions.

The force in inches of water measured perpendicular to flow at the wall of the duct.

The difference in pressure between atmospheric pressure and the absolute pressure inside a duct, cleaner, or other equipment.

The measure of potential energy of a fluid.

The difference in air pressure between the suction side and pressure side of the blower. Unit of measure is inches of water column (in. wc) or Pascals (Pa).

The difference, in consistent units, between absolute pressure at a point and the absolute pressure of the ambient atmosphere.

A method of duct sizing wherein the duct velocities are systematically reduced, allowing a portion of the velocity pressure to convert to static pressure offsetting the duct friction losses.

The actual temperature of a moving gas stream. It is the temperature indicated by a thermometer moving in the stream and at the same velocity.

The fixed part of an AC motor, consisting of copper windings within steel laminations.

The part of the fan's motor that is stationary.

The final state of a system after any disturbance.

Water vapour produced by heating water to its boiling point and adding more heat; generally considered to be at or above 212°F (100°C).

The vapour phase of water, unmixed with other gases.

A pressure vessel containing water and/or steam, which is used to store the heat of steam for use at a late period and at some lower pressure.

A unit to which water, fuel, and air are supplied and in which steam is generated. It consists of a boiler furnace, and fuel burning equipment, and may include as component parts water walls, superheater, reheater, economizer, air heater, or any combination thereof.

The percent by weight of vapour in a steam and water mixture.

A device used to keep the steam out of the condensate line, while allowing the condensate to go through the trap to the condensate line.

Unmixed air in a duct that is in thermal layers that have temperature variations of more than five degrees.

Passages, ducts or geometric forms designed to avoid discontinuities and thus, flow separation, thereby reducing turbulence.

An archaic term that refers to static pressure on the upstream side of the fan.

A common gaseous (acid) pollutant arising mainly from the combustion of fossil fuels.

A chemical grouping of sulphur dioxide (SO2) and sulphur trioxide (SO3).

Cooling of a liquid to a temperature below its condensing temperature.

That air delivered to the conditioned space and used for ventilation, heating, cooling, humidification, or dehumidification.

(1) The local value of pressure experienced at a surface.
(2) The local value of sea-level atmospheric pressure.

A very small particle maintained in the air by bombardment with air molecules.

Undissolved solids in boiler water.

A term in the HWC MACT (Hazardous Waste Combustor Maximum Achievable Control Technology) rule referring to a group of metals that include lead and cadmium.

A graphic presentation of the pressure vs. volume flow rate characteristics of a particular system.