AS 3853.2-2006 pdf free download

AS 3853.2-2006 pdf free download.Health and safety in welding and allied processes Sampling of airborne particles and gases in the operator’s breathing zone Part 2: Sampling of gases.
7 Measurement strategy
7.1 General
EN 689 should be referred to for generahsed guidance on measurement strategy. It highlights the need to take an approach which makes the most efficient use of resources by making full use of screening measurements and worst case measurements when it is suspected that exposure levels are well below or above the limit values. The following guidance, specific for measurement of personal exposure to gases and vapours in welding and allied processes, is given to supplement that given in EN 689.
7.2 Personal exposure measurements
The highest concentrations of gases usually occur in the immediate vicinity of the operator and It is therefore essential that personal exposure measurements are performed in the operator’s breathing zone. Welder’s face shields can provide some degree of protection from exposure by physically deflecting the welding plume away from the breathing zone. Personal sampling should therefore take place behind such welding protectors, if used, rather than in the conventional position on the lapel. Measurements of very short duration, e.g. for screening purposes, can be made by directly positioning the sampling line or sampler in the breathing zone and maintaining it in position by hand. However, to obtain time weighted average concentrations of gases and vapours, e.g. for comparison with limit values, it will usually be necessary for the operator to wear special apparatus that enables the sampler to be maintained in position in the breathing zone throughout the sampling period, without impeding normal work activity.
Personal exposure to gases and vapours In welding and allied processes is very variable over a single work period. The pattern of exposure depends on the nature of the job and its location, the use of hygiene controls, the work technique of the operator and the work pattern. Many of these variables are subject to the control of the operator and sampling strategies designed to assess the exposure of one individual as representative of a group carrying out similar work are often not appropriate. Each operator should therefore be the subject of a separate assessment. which does not necessarily imply a separate measurement of exposure.
7.3 Fixed point measurements
Fixed point measurements are required to characterise the background level of gases and vapours in the workplace. They can be useful for assessment of the personal exposure to gases and vapours of workers in adjacent locations or in overhead cranes, and they can give an indication of the efficiency of ventilation.
7.4 Selection of measurement conditions and measurement pattern
7.4.1 General
It is necessary to devise the sampling procedure so as to cause the least possible interference with the operator and the normal performance of his job and to provide samples that are representative of normal working conditions and that are compatible with subsequent methods of analysis. The pattern of measurement should take into consideration practical issues, such as the frequency and duration of welding episodes, and the nature of the measurement task.AS 3853.2-2006 pdf free download.