TLV is a proprietary name registered by the American Conference of Governmental Industrial Hygienists (ACGIH) and refers to airborne concentrations of substances or levels of physical agents to which it is believed that nearly all workers may be repeatedly exposed day after day without adverse effect.

the measure of toxicity effect. It is the limit of concentration of a substance in the air that an average person can tolerate without any adverse effect for a period of eight hours of continuous exposure. The TLV is assigned by the American Conference of Governmental Industrial Hygienists (ACGIH).

indicates the concentration of a chemical substance in the atmosphere that is considered non-hazardous in a person's normal working life.

A guideline for the exposure of humans to solvents; it is expressed as a Time Weighted Average (TWA) of the parts per million of vapor in air.

Time-weighted average concentration of an air pollutant at the workplace for a conventional 8-hour workday and a 40-hour workweek, to which nearly all workers may be repeatedly exposed without adverse health effects.

The maximum airborne concentration of a compound to which a person can be exposed to on a daily 8-hour basis. TLV® is the registered trademeak of the American Conference of Governmental Industrial Hygienists.

A number that tells the concentration of a chemical in air that a worker may breathe for a given period of time (a dose) without experiencing adverse effects. The American Conference of Governmental Industrial Hygienists, ACGIH, publishes TLVs for about 500 substances. OSHA uses similar limits called Permissible Exposure Limits, PEL.

published by the American Conference of Governmental Industrial Hygienists (ACGIH) which represents conditions under which it is believed that nearly all workers may be repeatedly exposed to day after day without adverse health effects.

a level of exposure set by the American Conference of Governmental Industrial Hygienists.

The American Conference of Governmental and Industrial Hygienists (ACGIH) has reviewed several hundred existing chemicals in order to provide industrial hygienists with an evaluation of health hazards they may pose in the workplace. The TLV, established by ACGIH, is the limit to which nearly all workers may be repeatedly exposed day after day without adverse effect. The airborne concentration is expressed as TLV/TWA or TLV/STEL (Short-Term Exposure Limit).

Compare? The concentration of an airborne substance that a healthy person can be exposed to for a 40-hour work week without adverse effect; a workplace exposure standard.

Recommended guidelines for occupational exposure to airborne contaminants published by the American Conference of Governmental Industrial Hygienists. Threshold limit values represent the average concentrations in milligrams per cubic meter for an 8-hour workday and a 40-hour workweek to which nearly all workers may be repeatedly exposed, day after day, without adverse effect.

The concentration of an airborne substance to which an average person can be repeatedly exposed without adverse effects. TLVs may be expressed in three ways: TLV-TWA-Time-weighted average, based on an allowable exposure averaged over a normal 8-hour workday or 40-hour workweek. TLV-STEL-Short-term exposure limit, or maximum concentration for a brief specified period of time, depending on a specific chemical (TWA must still be met). TLV-C-Ceiling exposure limit, or maximum exposure concentration not to be exceeded under any circumstances (TWA must still be met).

A list published yearly by the American Conference of Governmental Hygienists as a guide for exposure concentrations that a healthy individual normally can tolerate for 8 hours a day, five days a week, without harmful effects. Airborne particulate concentrations are listed as milligrams per cubic meter of air (mg/m3), and gaseous concentrations are listed as parts per million (ppm,) by volume.

Recommendation provided by the American Conference of Governmental Hygienists (ACGIH) and National Institute of Occupational Safety and Health (NIOSH) as a guideline for the control of potential health hazards in the workplace.

the maximum permissible concentration of a substance typically expressed in ppm that a worker may be exposed to for 8 hours (sometimes 40 hours). TLV is a legally mandated safety limit.

Airborne concentrations of substances devised by the ACGIH, that represents conditions under which it is believed that nearly all workers may be exposed day after day, with no adverse effect. TLVs are advised exposure guidelines, not legal standards, that are based on evidence from industrial experience, animal exposure or human studies when they exist. Three types of TLVs are: Time-weighted Average, Short Term Exposure Limit and Ceiling. See also PERMISSIBLE EXPOSURE LIMIT.

"Concentration in air of a substance to which it is believed that most workers can be exposed daily without adverse effect (the threshold between safe and dangerous concentrations). These values are established (and revised annually) by the American Conference of Governmental Industrial Hygienists and are time-weighted concentrations for a 7 or 8-hour workday and a 40-hour workweek. For most substances the value may be exceeded, to a certain extent, provided there are compensatory periods of exposure below the value during the workday (or in some cases the week). For a few substances (mainly those that produce a rapid response) the limit is given as a ceiling concentration (maximum permissible concentration - designated by "C") that should never be exceeded." [Glossary for Chemists of Terms Used in Toxicology," http://sis.nlm.nih.gov/Glossary/t.html

An airborne concentration of a substance to which indoor workers may be exposed repeatedly without adverse effects.

Recommended guidelines for occupational exposure to airborne contaminants published by the American Conference of Governmental Industrial Hygienists (ACGIH). TLVs represent the average concentration in mg/m3 for an 8-hour workday and a 40-hour work week to which nearly all workers may be repeatedly exposed, day after day, without adverse effect.

Levels of airborne concentrations of chemicals, used to determine safety limits.

an occupational exposure value to which nearly all workers can be exposed day after day for a working lifetime without ill effect.

The Threshold Limit Value (TLV) of a chemical substance defines the reasonable level to which a worker can be exposed without adverse health effects. Strictly speaking, TLV is a reserved term of the American Conference of Governmental Industrial Hygienists (ACGIH). It is however sometimes loosely used to refer to other similar concepts used in occupational health and toxicology.