What Does WEL Measure?

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COSHH, which stands for ‘Control of Substances Hazardous to Health’, is the law that requires employers to control hazardous substances in the workplace, and restrict or prevent the risk these substances pose to employees and workers. One significant part of COSHH is WEL, or the ‘Workplace Exposure Limit’; but what exactly does the Workplace Exposure Limit measure?

What is the WEL?

Workplace Exposure Times are legal limits of exposure, averaged over a specified period of time. For example, within a period of time (often 8 hours, but sometimes as short as 15 minutes), you are only allowed to be exposed to a certain amount of a hazardous substance, before it begins to have an adverse effect on you.

Exposure limits are in place to control the effects of substances, depending on the nature of the substance and the effects of exposure. Some effects require prolonged exposure, while others may be seen after brief exposures.

What does WEL Measure?

Workplace Exposure Limits simply measure the average length of time that it is safe to be exposed to a hazardous substance for. The two main reference periods for these averages are 15 minutes, which is known as the short term exposure limit (STEL); and eight hours, which produces the long term exposure limit (LTEL). Eight hours was chosen for the LTEL as the length of a typical working day in most industries.

As well as this, the Workplace Exposure Limits also measure the amounts of the substance that one can be in contact with, before detriments to your health begin. This is done by using the PPM (parts per million), to measure the concentration of the substance in question. All of these different measurements combined are what the Workplace Exposure Limits use to measure how much of a hazardous substance you can safely be exposed to in the workplace.

When dealing with substances and materials that are measured with the Workplace Exposure Limits, it is vital to make sure that you have the right equipment to deal with and manage these substances, such as using a COSHH Cabinet or COSHH Cupboard to store these substances. These cabinets are especially designed for the safe storage of hazardous substances; for more information, you can view our range of COSHH Cabinets here today. (“:visible

Kirsty Rogers