TWI Industrial Member Report Summary 871/2007
By G J Carter (TWI) and I Pengelly (HSL)
Emissions data for welding through shop primers are not provided on material safety datasheets (MSDSs), making it impossible to perform a proper risk assessment. If data are to be provided for this purpose, it will be necessary to prescribe appropriate methodology. Welding tests may provide data that are beyond dispute but the tests are expensive to perform and many will be required to cover all situations, if the primer emissions vary with welding process and heat input. A possible alternative would be to generate the data using pyrolysis testing, providing correlation between heating and welding tests could be demonstrated. Pyrolysis testing may be performed in the laboratory, under controlled conditions, and is less expensive to perform than welding, so, if realistic, would be preferred, even if pyrolysis testing at several temperatures was necessary. Work was required to establish the effects of welding process and heat input on emissions. Pyrolysis generated data were also required, to examine the effect of pyrolysis temperature on emissions and to compare the data generated with those from welding, with the overall objective of supplying information that could be used to define the most appropriate methodology. However, overall correlation between pyrolysis and welding results was not the only criterion to be considered in method development. The methodology needed to be conservative in terms of identifying all hygienically significant compounds generated, practical and cost effective.
To generate data to allow prescription of a conservative and cost effective method for generating emissions data for weld-through shop primers.