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Term

Definition

CFC

California Fire Code

CMS

Chemical Management System

Compressed gas

A materials or mixture of materials that 1) is a gas at 68° Fahrenheit (F) or less at 14.7 psia of pressure and 2) has a boiling point of 68°F or less at 14.7 psia, and which is either non-liquefied or in solution, except those gases that have no other health- or physical-hazard properties and that are not considered to be compressed until the pressure in the packaging exceeds 41 psia at 68°F.

Control area

A space within a building where quantities of hazardous materials not exceeding the maximum allowable quantities per control area are stored, dispensed, used, or handled. The space is bounded by not less than a one-hour fire-resistive assembly.

Corrosive gas

A gas that can cause visible destruction of, or irreversible alterations in, living tissue (e.g., skin, eyes, or the respiratory system) by chemical action.

DOT

U.S. Department of Transportation

Exhausted enclosure

An appliance or piece of equipment that consists of a top, a back, and two sides providing a means of containing, capturing, and exhausting gases, fumes, vapors, and mists. Such enclosures include laboratory hoods, exhaust fume hoods, and similar appliances and equipment. Rooms or areas provided with general ventilation are not exhausted enclosures.

EFV

Excess flow valve

Flammable gas

A material that is a gas at 68°F or less and 14.7 pounds per square inch (actual psia of pressure) and which 1) is ignitable at 14.7 psia when in a mixture of 13 percent or less by volume with air or 2) has a flammability range at 14.7 psia with air of at least 12 percent, regardless of the lower limit.

Gas cabinet

A fully enclosed, ventilated, noncombustible enclosure used to provide an isolated environment for compressed gas cylinders that are in storage or use. Doors and access ports for exchanging cylinders and accessing pressure-regulating controls are allowed to be included as part of the cabinet.

Hazardous gas

A gas that is included in one or more of the following hazard categories: corrosive, flammable, health hazard, oxidizer, pyrophoric, reactive, highly toxic, or toxic.

Hazardous-gas detection system

A fixed system used to detect the presence of hazardous gas at potentially unsafe levels.

Health hazard (gas classification)

A classification that indicates statistically significant evidence that acute or chronic health effects are capable of occurring in a person exposed to this chemical. The term "health hazard" includes gases that are toxic, highly toxic, and corrosive. See Work Process D. Health-Hazard Gases.

Immediately Dangerous to Life and Health (IDLH)

The concentration of airborne contaminants that poses a threat of death, immediate or delayed permanent adverse health effects, or effects that could prevent escape from such an environment. This contaminant concentration level is established by the National Institute of Occupational Safety and Health (NIOSH) based on both toxicity and flammability.

Liquefied gas

A liquid contained in a compressed-gas cylinder that has a vapor pressure exceeding 276 kPa at 38°C (40 psi at 100°F)

Lower Flammability Limit (LFL)

The minimum concentration of vapor in air at which propagation of flame will occur in the presence of an ignition source. The LFL is sometimes referred to as the lower explosive limit (LEL).

NFPA

National Fire Protection Association

NTP

Normal Temperature and Pressure

Oxidizing gas

A gas that can support and accelerate combustion of other materials more than air does

Oxygen deficiency

A condition that occurs when a breathable atmosphere contains less than 19.5% oxygen. (Normal air contains 20.9% oxygen.)

Permissible exposure limit (PEL) and threshold limit value (TLV)

Airborne exposure limits established for particular chemicals by the California Occupational Safety and Health Administration (Cal/OSHA) and the American Conference of Governmental Industrial Hygienists (ACGIH), respectively. DOE requires that employee exposures not exceed PELs or TLVs.

Pyrophoric gases

Gases with an auto-ignition temperature in air at or below 54°C (130°F). Specific gases may not ignite in all circumstances or may explosively decompose.

RFO

Restrictive flow orifice

Safety Note

A document that records engineering calculations or tests on specific equipment. A Safety Note may also specify operational requirements addressed in a WPC Activity or in operating instructions. See Pressure System Safety.

STP

Standard temperature and pressure - 1 atm and 0°C (compare with NTP, above)