perform the test in an environment that does not contribute any significant amount of particulate matter, specimens must be cleaned to the extent that any level of extraneous particles added has a negligible effect on the outcome of the test preferably, the test specimen, glassware, closures, and other required equipment are prepared in an environment protected by high-efficiency particulate air(HEPA) filters, and no shedding garments and powder-free gloves are worm throughout the preparation of samples. Cleanse glassware, closures, and other required equipment, preferably by immersing and scrubbing in warm, nonionic detergent solution. rinse in flowing tap water, and the rinse again in flowing filtered distilled or deionizer water. organic solvents may also be used to facilitate cleaning .(note-these steps describe one way to clean equipment ,alternatively, particulate-free equipment may be obtained from a suitable vendor.)finally, rinse the equipment in filtered distilled or demonized water, using a hand-held pressure nozzle with final filter or other appropriate filtered water source, such as distilled or demonized water passed through a capsule filter having a 1.2UM or finer porosity. To collect blank counts ,use a cleaned vessel of the type and volume representative of that to be used in the test. place a 50ml volume of filtered distilled or deionizer water in the vessel, and agitate the water sample in the cleaned glassware by inversion or swirling.(note--A smaller volume, consistent with the article to be counted, can be used)degas by syndicating(at 80to 120 watts)for about 30 seconds or by allowing to stand. swirl the vessel containing the water sample by hand or agitate by mechanical means to suspend particles, withdraw and obtain the particle counts for three consecutive samples of not less than 5 ml each, disregarding the first count, if more than 10 particles of 10-um or greater size, or more than 2 particles of 25-um or greater size are observed on the combined 10-um sample, the environment is not suitable for particulate analysis: the filtered distilled of deionizer water and glassware have not been properly prepared or the preparatory steps until conditions of analysis are suitable for the test.
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