Importance of Workplace Exposure Limits

Gas detection is a valuable tool for occupations needing to handle and use hazardous gas. There are three categories of hazardous gases industries can identify: flammable, toxic, and asphyxiant. 

Combustion is a basic chemical reaction between a substance and oxygen, resulting in released energy in the form of heat. Flammable gases such as methane and propane do not have a personal exposure limit but are fire and explosion risks. For combustible gases, exposure limits are measured as flammable limits. Gases that are risks for fires and explosions have a limited range of concentration for the reaction to occur, classified as upper and lower explosive levels (UEL or LEL). 

Toxic gas presents the risk of poisoning, with some displays major health risks at very low concentrations. Gases such as hydrogen sulfide and carbon monoxide are examples of toxic gas. Exposure limits are measured in parts per million (ppm) and parts per billion (ppb) and can be inhaled, ingested, or absorbed through the skin. Short and long-term exposures have a variety of risks, but gas detection instruments can keep employees from danger. 

Asphyxiant hazard involves the alternation of oxygen in the air. The standard concentration of oxygen we breathe is 20.9% and when it falls below 19.5% or rises above 24%, can create a hazardous environment. Oxygen depletion can be caused by several factors and occurs when oxygen levels start falling. This occurs when an inert atmosphere is created, or when oxygen is displaced by another gas. Oxygen enrichment is when oxygen levels start to increase, leading to spontaneous combustion due to oxygen creating a more flammable environment. 

Workplace exposure limits are used to define the area of health monitoring, aiming to ensure levels of the workplace are below statutory limits of the hazardous gas. To preserve the safety of workers, gas detection instruments are worn or implemented in the area with those limits programmed into the device. Short-term exposure limits (STEL) indicate when the concentration of the gas is in the atmosphere with no immediate effects. Long-term exposure limits (LTEL) indicate when the gas is reaching a determined higher concentration. Gases with long-term exposure limits can be present for long periods of time without any immediate effects. 

The Occupational Safety and Health Administration (OSHA) assists companies with exposure limits by providing gas charts and other useful information about the gases they use. Other agencies and programs aid in the process as well, and some assist with regulations to make sure the gases used don’t create other risks. Otis Instruments offers a vast selection of Wired and WireFree easy-to-use, robust, and configurable gas detectors and monitors capable of detecting both toxic and non-toxic gases for diverse applications. More information regarding gases used in your industry and their exposure limits can be provided by a team member. To ask a question, learn about other solutions for your industry, contact Otis Instruments today!

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