Page 145 - Quick Guide to Welding and Weld Inspection by S.E. Hughes, Clifford Matthews

Health and Safety

. Goggles/face mask for eye protection when grinding or
chipping.
. Gaiters and spats can give protection from burning metal
or spatter falling into boots and burning feet. Otherwise,
ensure overalls are outside boots.
. A leather apron may be required depending on the process
used.
. A welder’s hat is especially useful when performing
overhead welding.
Gases and fumes
Exposure to the dangerous fumes and gases produced by
welding can lead to many health problems, ranging from
minor respiratory problems to major respiratory problems
(such as no longer breathing at all). Metallic fumes (fumes
containing metal particles) and/or gases can come from
electrodes, plating or base metals used during the welding
cycle. Metallic fumes produced from welding cadmium and
zinc are extremely toxic and can result in death, so the
importance of removing coatings or plating before welding
cannot be overemphasised. The use of the correct extraction
or breathing system is essential to maintain a safe welding
environment.
Dangerous gases that may be produced during the welding
process include ozone, nitrous oxides and phosgene (a form
of mustard gas caused by the breakdown of some degreasing
agents in arc light). These gases are all extremely poisonous
and overexposure can result in death. Other gases used in
welding cause problems by displacing air or reducing the
oxygen content and so cause death by asphyxiation or
suffocation. An example is the use of inert argon gas in a
confined space; the argon is heavier than air and will sink to
the bottom of the space and reduce the oxygen content as it
slowly displaces the air and fills the space from the bottom
up. Helium, on the other hand, will fill a space from the top
down.
Gases such as oxygen or acetylene can build up in a space

129

Woodhead Publishing Ltd – A Quick Guide to Welding and Weld Inspection
Data Standards Ltd, Frome, Somerset – 17/9/200909QG Welding chap9.3d Page 129 of 134