Term
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Definition
| Any gas, or mixture of gases, which will burn when exposed to an ignition source. |
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Term
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Definition
| Any gas, or mixture of gases, which will burn when exposed to an ignition source. |
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Term
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Definition
| Any gas, or mixture of gases, which will burn when exposed to an ignition source. |
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Term
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Definition
| Any liquid having a flash point lower than 100 degrees F. |
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Term
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Definition
| Any liquid having a flash point greater than 100 degrees F. |
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Term
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Definition
| A substance that caused a sudden, almost instantaneous release of pressure, gas, and heat, when subjected to sudden shock, pressure, or high temperature. |
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Term
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Definition
| The minimum temperature at which a liquid gives off a vapor in sufficient concentration to ignite when exposed to an ignition source. (It may or may not continue to burn.) |
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Term
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Definition
| An action level of a harmful substance is an exposure level at which an employer is required to implement corrective action to start reducing exposure to the substance to which employees are being exposed. Action levels are most commonly required where a substance is considered to be harmful in extremely small quantities. Action Levels are always lower than Permissible Exposure Limits (PELs). |
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Term
| Permissible Exposure Limit (PEL) |
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Definition
| A Permissible Exposure Limit (PEL) is the maximum concentration of a harmful substance that employees may be exposed to eight (8) hours per day and forty (40) hours per week without the expectation of adverse physical effects. |
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Term
| Short Term Exposure Limit (STEL) |
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Definition
| A Short Term Exposure Limit (STEL) is the maximum concentration of a harmful substance that employees may be exposed to for a limited period of time. The standard time period is 15 minutes. |
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Term
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Definition
| A Ceiling Limit is the maximum concentration of a harmful substance that employees may be exposed to at any one time. When any harmful substance reaches its Ceiling Limit in a work environment, all employees must be removed immediately. |
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Term
| Immediately Dangerous to Life and Health (IDLH) |
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Definition
| Immediately Dangerous to Life and Health (IDLH) is an Exposure Limit primarily used in confined space work. When a workspace is determined to be IDLH, specific respirator regulations are enforced. There is a margin of safety provided by allowing a 30 minute escape time, but this is for escape only, and is not to be confused with the 15 minute work time in STEL. |
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Term
| Permissible Equipment and Systems |
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Definition
Tested and certified by MSHA or USBM to be so constructed that when a spark is produced, the housing surrounding the spark source is designed so that the heat cannot be propagated to the surrounding or "outside" atmosphere.
The equipment must be operated and maintained in the same condition in which it was certified. |
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Term
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Definition
Permissible Explosives are explosives that are manufactured so they are less likely to ignite combustible dusts and flammable gases than "standard" Fume Class 1 explosives.
Additional ventilation is required when using Permissible Explosives because they produce a greater volume of poisonous gases than Fume Class 1 explosives. |
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Term
| Intrinsically Safe Equipment and Systems |
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Definition
Devices or systems which are incapable of releasing enough electrical or thermal energy --under normal OR abnormal conditions-- to cause ignition of a hazardous mixture of flammable gas and air.
Examples include wooden tamping rods, most gas meters, some instruments, etc. |
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Term
| Molecular Weight of a gas |
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Definition
| The molecular weight of a gas, when compared to air, will tell you if it is heavier or lighter than air. |
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Term
| Specific Gravity of a gas |
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Definition
| The specific gravity of a gas is the result of dividing the molecular weight of a gas by the molecular weight of air. Specific gravities above 1.0 are heavier than air. Those below 1.0 are lighter than air. |
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