TLV stands for Threshold Limit Value. It is a term used to describe the level of exposure that an employee can experience without having any adverse side effects. This term is used in a variety of different industries, and in countries around the world. It is mostly used to describe how much exposure to chemicals or other known harmful substances. It can also, however, be used to describe things like noise levels and other potentially harmful things.

There are three main categories or types of TLV to be aware of. These are specifically for exposure to chemical substances:

  • TLV-TWA – This is the threshold limit value-time weighted average and covers the limit for average exposure based on either an eight-hour day or a 40-hour week.
  • TLV-STEL – This is threshold limit value-short-term exposure limit. This is a measurement of the level of exposure an employee can experience in a 15-minute interval.
  • TLV-C – This is threshold limit value-ceiling limit. This is the maximum exposure that an employee should ever experience at any time.

The specific TLV’s for different chemicals, substances, or other things can be set by several different places. In the United States, Workplace Environmental Exposure Levels are set by a committee of volunteers, which is done in association with the Occupational Alliance for Risk Science. There are other groups that may set various TLVs as well. Individual facilities and employers can also set their own TLVs based on the specific environment in which employees are working. Of course, most of these TLVs are not regulatory items, so they are not enforced by the government unless they are adopted by an agency like OSHA.

TLVs are similar in concept to other terms such as acceptable daily intake (ADI), tolerable daily intake (TDI), and others. Being aware of the various limits for exposure that are set forth by experts is very important for ensuring workplace safety.

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