Adale, the method for welding fume sampling is very similar to 14/3, the only difference may be the choice of filter paper (depending on which method you choose for metal analysis) and sampling head - there has been some interesting developments on the best choice to use here especially if you are sampling in the breathing zone 'under' the visor
Further guideance on sampling methods and materials (in addition to MDHS) can be found from reputable supliers such as:
https://www.skcinc.comor
http://www.salltd.co.uk/I know from personal experience the latter will always be happy to discuss with you the best approach to take ^ (no connection)
But you raise an interesting question in your original question, "a strategy for exposure monitoring", this will depend on what it is you are trying to show.
Compliance with exposure limits for example applies to every worker, but it is usually not possible or practical to measure each, enough times (this is also of significance - did you know it has been recommended to have over 30 samples! per SEG to have statistical confidently in the results) to determine compliance. But where different workers are carrying out the same task in the same way, it is usual to limit the number of workers sampled by grouping them into Similarly Exposed Groups (SEGs), and to make measurements on only some of the members of each group.
Assigning workers to a SEG usually requires discussion and observation of the work activities to ensure the materials handled, the processes involved, and the ways of working are the same. People can do the same task, but very differently (position of the head in the fume plume, or use or position of LEV for example). You may even want to do a initial observation or pilot study if there are several methods of working to determine which is most likely to be the best (lowest exposures) and then train / advise other workers accordingly, sometimes video can be a real help here!
Perhaps I am not adding anything specifically to the original post, but I thought it was a good oportunity to raise an all to common issue with exposure monitoring, I often see results of monitoring but if the choice of person monitored, number or type of sample has not been thought through (the "strategy") then the results are often meaningless wihtout this context.
If anyone is interested in this subject further information can be found in:
AIHA Publication: A Strategy for Assessing and Managing Occupational Exposures, 4th edition
BOHS Publication: Testing Compliance with Occupational Exposure Limits for Airborne Substances (free)
Or the massive amount of free! approved hygiene training information, notes and manuals available at:
http://www.ohlearning.com