HVAC GLOSSARY - O

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Occupational Safety and Health Administration: (OSHA) The regulatory arm of the US Department of Labor, which promulgates safety and health standards, facilitates training programs, and enforces regulations on work sites. OSHA has developed permissible exposure limits for over 600 contaminants present in the industrial workplace.

Ohm: A unit of measure of electrical resistance. One volt can produce a current of one ampere through a resistance of one ohm.

Organic Compounds: Chemicals that contain carbon. Volatile organic compounds vaporize at room temperature and pressure. They are found in many indoor sources, including many common household products, and building materials.

Original Equipment Manufacturer: (OEM) Refers to the manufacturers of complete vehicles or heavy-duty engines, as contrasted with remanufacturers, converters, retrofitters, up-fitters, and repowering or rebuilding contractors who are overhauling engines, adapting, or converting vehicles or engines obtained from the OEMs, or exchanging or rebuilding engines in existing vehicles.

Outdoor Air Supply: Air brought into a building from the outdoors (often through the ventilation system) that has not been previously circulated through the system. Also known as "Make-Up Air."

Outdoor Coil: (See Condenser Coil) Refrigerant containing portion of a fan coil unit similar to a car radiator, typically made of several rows of copper tubing with aluminum fins.

Outside Air: Air taken from outdoors and not previously circulated through the HVAC system.

Ozone: (03) A kind of oxygen that has three atoms per molecule instead of the usual two. The molecule contains three oxygen atoms (O3) a highly reactive form of oxygen. Ozone exposure results in mucous membrane irritation and potential pulmonary damage. Some copier machines and laser printers emit noticeable levels.

Ozone Generator: An air cleaning device that produces highly reactive ozone, which reacts with volatile organic compounds to form nonhazardous products, remove particulates, and reduce the number of bio contaminants.

Ozone Hole: Thin place in the ozone layer located in the stratosphere high above the Earth. Stratospheric ozone thinning has been linked to destruction of stratospheric ozone by CFCs and related chemicals. The 1990 CLEAN AIR ACT has provisions to reduce and eliminate ozone destroying chemicals' production and use. Ozone holes have been found above Antarctica and above Canada and northern parts of the United States, as well as above northern Europe.