The ACGIH - American Conference of Governmental Industrial Hygienists - has established a Threshold Limit Value (TLV) for several commonly used compounds. These values are “concentrations of substances in the air”, representing conditions under which it is believed that almost all workers are exposed daily, without any adverse effect. The TLV refers to the concentration measured over time, for a work period of 7-8 hours and a week of 40 hours. Based on experiments and experience, TLV provides a quantitative assessment of
relative toxicity of the compounds. Normally, TLV is expressed in parts per million of the volume and is abbreviated as “ppm”.
Exposure to chemicals should be minimal and should not exceed TLV.
As this value is a concentration measured over time, occasional exposure periods above TLV are expected.
