ASTM F1094-87(2020)

5.1 These test methods provide a field technique for the bacteriological analysis of electronic process waters. The sampling of these waters and subsequent bacteriological analysis may be critical to electronic product yields. Bacteria can be the prime source of harmful contamination which can significantly reduce the yield of satisfactory microelectronic device production.

5.2 The test methods described here may be used both to monitor the bacteriological quality of water used in microelectronic product processing, and to locate the source of bacterial contamination in a water purification system.

5.3 These test methods are simple field methods, combining sampling and bacteriological analysis techniques that do not require bacteriological laboratory facilities.

5.4 The test methods described employ culture techniques for bacteriological analysis. The user should be aware that such techniques cannot provide a complete count of the total viable bacteria present, since clumps and clusters of bacteria will appear as one single colony when cultured, and since some viable bacteria will not grow under the test conditions used. However, a meaningful comparative bacteria count will be achieved by this method if the culturing of the sample is always done at the same temperature, and for the same period of time. The temperature of incubation should always be at 28 ± 2°C, and the period of incubation should be 48 h (or 72 h if time permits). The period of incubation and temperature should be the same for all comparative studies.

1.1 These test methods cover sampling and analysis of high purity water from water purification systems and water transmission systems by the direct sampling tap and filtration of the sample collected in the bag. These test methods cover both the sampling of water lines and the subsequent microbiological analysis of the sample by the culture technique. The microorganisms recovered from the water samples and counted on the filters include both aerobes and facultative anaerobes.

1.2 Three methods are described as follows:

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.