For other substances which have a WEL but are not carcinogens or can cause asthma, adequate control of exposure will involve controlling exposure to below the WEL.Īny revised WEL, which might be implemented, will require improved fume control measures for many welding processes. This means that there is a requirement to reduce exposure to these constituents to a concentration which is as low as is reasonably practicable (ALARP). Hexavalent chromium and nickel in welding fume are both defined occupational carcinogens. Therefore, exposure measurements should be compared to the appropriate limits for the different constituents in the welding fume, such as: iron oxide, hexavalent chromium, nickel and manganese. Occupational Safety and Hazard Administration (OSHA) defines the breathing zone as the area within a ten-inch radius of the workers face. Personal air monitoring results can be compared with the relevant set workplace exposure limits (WELs) which are published in the HSE book EH40/2005: Workplace Exposure Limits In-house limits can also be set and used to compare with results for task-specific exposures. The breathing zone in a workplace is defined as the area closest to an employees mouth and nostrils. This is usually higher than the room average concentration because the worker is typically close to the source of airborne contamination. These things will influence the personal results of the survey for exposure to welding fume. Breathing zone (BZ) samples are collected to determine the concentration in the air inhaled by the worker. The investigation will also need to look at other factors that can influence exposure on the day, such as the production rate setting the amount of welding work needed. The results will then influence the assessment of how well control measures for the welding fume are working. Under the Control of Substances Hazardous to Health (COSHH) system, an initial exploratory exposure monitoring exercise may be needed to reach an accurate judgement about the risk to health. If the pump was operated for 450 minutes under. The weight of the poly vinyl chloride (PVC) filter prior to sampling was 17.30 mg and the post sampling filter weight was 19.75 mg. Monitoring may also be needed to help confirm that the control measures in use are working correctly, as a deterioration or failure of engineering controls could result in welders being exposed to high levels of fume. A particulate air sample was collected with a personal breathing zone pump calibrated at 2.0 liters per minute in a laboratory at 70 degrees F and 29.92 inches of Hg. during the manual metal arc (MMA) welding of stainless steel. Air monitoring and measurement may be needed where there is a serious risk to health from the inhalation of welding fume and the likely exposure level of the welders to the fume is not known, e.g. ture (8, 10) that the breathing zone, defined as a zone of air of one-foot (30.5 cm) radius about the head of the sampled individual, is not a homogeneous.
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