Sun. Nov 29th, 2020


Health, Safety, Security and Environment

Threshold Limit Value (TLV)

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Definition – What does the Threshold Limit Value (TLV) mean?

Threshold Limit Value (TLV) is a registered and reserved term of the American Conference of Governmental Industrial Hygienists (ACGIH). It is an occupational exposure value recommended by ACGIH to which it is believed nearly all workers can be exposed for a lifetime without affecting health. It is the maximum average concentration of a hazardous material floating in the workplace to which workers can be exposed during an eight-hour workday and 40-hour workweek, over a working lifetime, without experiencing significant adverse health concerns.

HSSE WORLD explains Threshold Limit Value (TLV)

Three types of TLVs for chemical substances are defined: Threshold Limit Value – Time Weighted

  • Average (TLV-TWA) is the average exposure on the basis of a 8h/day, 40h/week work schedule.
  • Threshold Limit Value – Short-Term Exposure Limit (TLV-STEL) is the spot exposure for duration of 15 minutes that cannot be repeated more than 4 times per day.
  • Threshold Limit Value – Ceiling Limit (TLV-C) is the absolute exposure limit that should not be exceeded at any time

TLV is a guideline and not a legal standard. It is determined on the basis of the available data and is revised annually. Only the specialists can interpret these valuesThere are other types of “Acceptable Exposure” Limits, such as:

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