Definition(s)
TWA
Time weighted average.
Source: API RP 49, Recommended Practice for Drilling and Well Servicing Operations Involving Hydrogen Sulfide, Third Edition, May 2001. Global Standards
Source: API RP 98, Personal Protective Equipment Selection for Oil Spill Responders, First Edition, August 2013. Global Standards
TWA
Average airborne exposure in any 8-hour work shift of a 40-hour workweek that shall not be exceeded (see 29 CFR 1910.1000, Table Z2).
Source: API RP 98, Personal Protective Equipment Selection for Oil Spill Responders, First Edition, August 2013. Global Standards