Английский для сварщиков. Гричин С.В. - 140 стр.

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140
after exposure with a thirst, cough, headache, sweat, pain in the limbs and
fever. Complete recovery usually occurs within 1 to 2 days of removal from
the exposure, without any lasting effects.
3. Longer term effects. The continued inhalation of welding fume
over long periods of time can lead to the deposition of iron particles in the
lung, giving rise to a benign condition called siderosis. There is evidence that
welders have a slightly greater risk of developing lung cancer than the
general population. In certain welding situations, there is potential for the
fume to contain certain forms of chromium and/or nickel compounds -
substances which have been associated with lung cancer in processes other
than welding. As yet, no direct link has been clearly established.
Nevertheless, as a sensible precaution and to minimise the risk, special
attention should be paid to controlling fumes which may contain them.
Additional hazards
A number of other specific substances known to be hazardous to health
can be found in welding fume such as barium and fluorides which do not
originate from the metal. If the metal contains a surface coating, there will
also be a potential risk from any toxic substances generated by thermal
degradation of the coating.
Health hazards from gases
The potential hazards from breathing in gases during welding are:
1. Irritation of the respiratory tract. Ozone can cause delayed
irritation of the respiratory tract which may progress to bronchitis and
occasionally pneumonia. Nitrogen oxides can cause a dry irritating cough and
chest tightness. Symptoms usually occur after a delay of 4 to 8 hours. In
severe cases, death can occur from pulmonary oedema (fluid on the lungs)
or pneumonia.
2. Asphyxiation. There may be a risk of asphyxiation due to
replacement of air with gases produced when welding in a workshop or area
with inadequate ventilation. Special precautions are needed when welding in
confined spaces where there is the risk of the build up of inert shielding
gases. Carbon monoxide, formed as a result of incomplete combustion of fuel
gases, can also cause asphyxiation by replacing the oxygen in the blood.
Establishing safe levels of fume in the workplace
The COSHH Regulations* require that exposure is controlled below
specific limits. The limits, known as occupational exposure limits, are
detailed in EH 40 which is revised periodically. The majority of limits listed
are for single substances. Only a few relate to substances which are complex

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