- Project plans
- Project activities
- Legislation and standards
- Industry context
Last edited 05 Aug 2018
Workplace exposure limits
Some workplace processes involve the use of substances that could cause harm. The Control of Substances Hazardous to Health Regulations 2002 (COSHH) require that employers prevent or reduce workers' exposure to such substances.
Workers might be exposed by:
- Contact with the skin.
- Contact with the eyes.
- Skin puncture.
COSHH stipulates that the control of hazardous substance exposure will only be regarded as being adequate if it falls below the necessary workplace exposure limit (WEL). The regulations place a duty on employers to prevent or control exposure to within the particular WEL.
WEL values are approved by the Health and Safety Commission (HSC), which acts on the advice of the Advisory Committee on Toxic Substances (ACTS). They are expressed as a time weighted average (TWA). There are two variations of WEL:
- Long-term exposure limit (LTEL): The maximum exposure over an 8-hour period. This is intended to protect the workforce from contaminants which, over a long period of time, may cause ill health.
- Short-term exposure limit (STEL): The maximum exposure over a 15-minute reference period. This is intended to protect the workforce from peak exposure incidents which might result in immediate and acute ill health.
Since there are a large number of chemical compounds used in construction, there will be some that are not included on this list of WELs, perhaps due to a lack of information about them. However, this does not mean that they are therefore safe. They should be controlled to a level at which the workforce could be exposed for a long period of time without experiencing any adverse health effects.
 Find out more
 Related articles on Designing Buildings Wiki
Featured articles and news
What are the benefits of smart homes for Millennial end-users?
How dynamic briefing can result in an efficient project.
Achieving sustainable roads funding in England.
Your chance to comment on the draft BS 851188 - flood resistance products and flood protection products.
Rebuilding could take 20 to 40 years.
RSHP’s high-rise residential towers win a tall buildings award for excellence.
BSRIA study reveals strong growth in 2018.
Dame Judith Hackitt confirmed as keynote speaker – one year on from the Hackitt Report.
Save £100 on tickets.
Modern slavery in the construction sector.
What to bear in mind when claiming damages in construction.
How do we achieve sustainable clean-water infrastructure for all?