SKC Limited AirChek 3000 Deluxe Pump Step By Step Guide - Manual (Page 7)

www.skcltd.com 224-G1 Issue D Page 5
Definitions
Exposure Limit Definitions
Maximum
Exposure Limit
(MEL) An MEL is the maximum concentration of airborne substance to which
employees may be exposed by inhalation averaged over a regulatory
required reference period and must not be exceeded.
Occupational
Exposure Limit
(OEL)
As defined by the Occupational Exposure Standards (OES), an OEL is
the concentration of an airborne substance, averaged over a reference
period at which, according to current knowledge, there is no evidence
that it is likely to be injurious to employees if they are exposed by
inhalation day after day to that concentration. These were replaced on
6th April 2005 by WELs (refer to EH40/2005).
Workplace
Exposure Limit
(WEL)
WELs are concentrations of hazardous substances in the air, averaged
over a specified period of time referred to as a time weighted average
(TWA). Two time periods are used: Long term (8 hours) and short term
(15 minutes). Short term exposure limits (STELs) are set to help prevent
effects, such as eye irritation, which may occur following exposure for
a few minutes.