Glossary

A system that uses the maximum outside air for ventilation and free cooling, as long as dehumidification is not necessary.

Electrical discharge machining.

Electronic data processing.

The ratio of output to input.

That which flows out, specifically gas flowing out of a chimney outlet.

Velocity of gases issuing from a chimney outlet.

A boiler in which electric energy is used as the source of heat.

Also called Electronic Air Cleaner (EAC).
Uses a high voltage between two conductors to remove particles (dust, etc.) from the air flowing through it.

A quick opening, counter-balanced safety device to allow release of rapidly expanding gases (explosion) and pressure relief thereby preventing harm to employees or serious equipment damage.

Electromagnetic interference.

The gaseous output from a combustion unit after treatment by air pollution control devices.

Electromagnetic pulse.

Term used to describe the motor housing.

Document intended to supplement or modify the contract.

The total quantity of heat energy contained in a substance, also called total heat.

The thermodynamic property of a substance defined as the sum of its internal energy plus the quantity Pv/J, where P = pressure of the substance, v = its volume, and J = the mechanical equivalent of heat.

The conveying of particles of water or solids from the boiler water by the steam.

The gas flow velocity, which tends to keep particles suspended and cause deposited particles to become airborne.

The ratio of the heat added to a substance to the absolute temperature at which it is added.

The exterior surface of a building including all external additions e.g. chimneys, bay windows, etc.

Explosion proof or Emergency Power.

The Federal agency responsible for promulgating environmental regulations as dictated by Congress under CAA, CWA, RCRA, SARA and TSCA. (Clean Air Act, Clean Water Act, Resource Conservation and Recovery Act, Superfund Amendment and Reauthorization Act and Toxic Substances Control Act).

A sudden increase in frequency of a disease, above the normal expectancy, in a population of human beings.

The field of science that concerns itself with the determinants of disease and with the factors that influence its distribution.

Earnings per Share = Portion of a company's profit allocated to each outstanding share of common stock.

Curves represented in graph form as a function of sound level and frequency which listeners perceive as being equally loud. High frequency sounds above 2000 Hz are more annoying. Human hearing is less sensitive to low frequency sound.

The amount expressed as a mass or volume of a particular constituent in equilibrium in a given enclosure.

The cash that the owner or investor has invested in the business in return for a share of ownership.

Electrostatic Discharge.

An air pollution control device for removing very fine solids from gaseous emissions by attracting them to electrically charged surfaces. The units may be wet or dry.

The change of state from a liquid to a vapour.

The movement of air out of a building, through cracks and other openings, such as around windows and doors.

The uncontrolled leakage of air out of a building.

Air removed from a space and not reused therein.

A reaction in which heat is given off as in a fire, or in the combination of water and lithium bromide.

The joint to permit movement due to expansion without undue stress.

A door in a furnace or boiler setting that is designed to be opened by a pre-determined gas pressure.

A totally enclosed motor that will withstand an explosion of a specific vapour or gas within its housing, or will prevent sparks or flashes generated within its housing from igniting surrounding vapour or gas.

The position of a building, or a room within a building relative to its environment as it affects the properties of the building such as thermal conductivity, air infiltration, noise levels, solar gain etc.

Leakage taking place between spaces inside a building and the outside of the building.

Exhaust air that is discharged to atmosphere.

Duct through which bad air is rejected to the outside of the building. This term is usually confined to cases involving forced extraction, e.g. kitchens, workplaces, laboratories, fume cupboards etc.

A fan withdrawing air from a conditioned space which may be partially or wholly exhausted to atmosphere.

Mechanical ventilation removing air from an enclosed space, directly or through ducting.