threshold limit value (TLV)
The concentration in air to which it is believed that most workers can be exposed daily without an @AT06809@ (i.e., effectively, the threshold between safe and dangerous concentrations). The values were established (and are revised annually) by the ACGIH and are time-weighted concentrations (TWA) for a 7- or 8-h workday and 40-h workweek, and thus are related to chronic effects. A short-term @ET06811@ limit (STEL) is defined as a 15-min TWA exposure, which should not be exceeded at any time during a workday even if the 8-h TWA is within the TLV-TWA.
PAC, 2001, 73, 993. (Risk assessment for occupational exposure to chemicals. A review of current methodology (IUPAC Technical Report)) on page 1024 [Terms] [Paper]