Page 147 - Quick Guide to Welding and Weld Inspection by S.E. Hughes, Clifford Matthews

Health and Safety

Examples of the effects of hazardous substances include:
. Skin irritation or dermatitis as a result of skin contact.
. Asthma as a result of developing allergy to substances
used at work.
. Losing consciousness as a result of being overcome by
toxic fumes.
. Cancer, which may appear long after the exposure to the
chemical that caused it.
The Health and Safety Commission (HSC) in the UK has
established workplace exposure limits (WEL) for a number
of substances hazardous to health, including fumes or gases
that may be produced through welding. These limits are
intended to prevent excessive exposure to the substances by
keeping exposure below a set limit. A WEL is the maximum
concentration of an airborne substance, averaged over a
reference period, to which employees may be exposed by
inhalation. The WELs are listed in document EH40/2005:
Workplace Exposure Limits. The reference periods used are
eight hours for the long term exposure limit (LTEL) and 15
minutes for the short term exposure limit (STEL). The
toxicity of a substance can be gauged by the value of the
exposure limit, so applying good practice will mean actual
exposures are controlled below the WEL. Advice on applying
the principles can be found in the COSHH Approved Code of
Practice (ACOP). Be aware that the values given in
Guidance Note EH40 can change annually. Table 9.1
contains examples of substances that may be present in
welding under certain conditions.

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