This method describes a laboratory device and procedure for obtaining representative fume samples and determining fume generation rates of welding and allied processes. A separate collection procedure for determining fume constituents is described. A standard set of fume generation test conditions is specified to calibrate the sampling equipment. Methods for obtaining breathing zone and general area welding fume samples are not within the scope of this standard. Sampling of gases is not within the scope of this standard. This standard will be revised as required in accordance with acknowledged technical advancements in the field. This standard makes sole use of U.S. Customary Units except for measures of mass@ fume generation rate@ and filter pore size. Approximate mathematical equivalents in the International System of Units (SI) are provided for comparison in parentheses or in appropriate columns in tables and figures. Purpose Welding and allied processes produce fumes and gases. The amount or rate generated by a particular process and material depends upon the conditions of use. The laboratory sampling procedure described herein is designed to evaluate the effects of variations in materials@ processes@ and operating conditions on fume generation rate. Fume generation rates can be useful in prescribing adequate ventilation@ making process selections@ influencing process variables@ and calculating air filtering requirements. In order to provide a safe working environment@ it may be necessary to compare the fume generation rate and identify the constituents present in the fumes of various processes. The samples obtained using the techniques described herein are representative of the fumes present and@ if collected on appropriate filters@ may be used for fume constituent analyses. This procedure is designed for a short testing time@ normally two minutes or less@ which yields useful results that are reproducible within an acceptable range. The method described in this procedure is suitable for use with the majority of welding and allied processes and allows for variation of selected conditions. Fume generation rate data@ if collected in accordance with this procedure@ can be correlated to and compared with data from different sources.