ASTM G 93/G 93M:2025

1.1 This guide provides information regarding selection and implementation of cleanliness levels, cleaning methods, and associated practices for materials, components, and equipment used in oxygen-enriched environments. The main topics include cleaning methods, cleanliness inspection methods, and cleanliness preservation techniques. 1.2 The information provided is applicable to many industries and applications that use oxygen-enriched environments and rely on cleaning to help mitigate the risk of fire and/or equipment damage or performance. 1.3 The cleaning methods and associated practices described for oxygen-enriched service are also applicable to other oxidizers, systems that interface oxygen or oxidizer systems, and high- pressure compressed air systems. 1.4 There are no specific applicable limits (for example, oxygen pressure, temperature) to the presented concepts and approaches regarding cleaning, cleanliness inspection, and preservation of cleanliness for oxygen service equipment. Rather, basic principles, best practices, and common methods are described which may be used across a broad range of applications, though some may be better suited to certain materials, types of equipment, or applications. 1.5 Codes that designate levels of cleanliness are provided in this document to facilitate specifications of required cleanliness. 1.6 Cleanliness levels acceptable for specific applications are not given, however, examples of cleanliness levels used by various applications or industries at the time of this publication are provided for reference. It is noteworthy that conditions specific to an application (for example, pressure, temperature, materials of construction) may dictate the use of more or less stringent cleanliness. 1.7 This guide provides relevant information on parameters related to the acceptability of cleanliness levels (for example, ignitability of contaminants) which may be useful to define a cleanliness level specification for an application. 1.8 A variety of cleaning methods, equipment, and cleaning agents are described with information regarding applicability to different materials, components, and systems. 1.9 This guide describes mechanical and chemical cleaning processes, including solvent-based and aqueous-based processes. 1.10 Cleaning examples for some specific materials, components, and equipment, and the cleaning methods for particular applications, are given in the appendices. 1.11 Information is provided regarding cleanliness evaluation of cleaned materials, components, and/or systems by inspection and analysis. 1.12 Values stated in SI units are to be regarded as the standard unit. The values given in parentheses are for information only. 1.13 With regard to expressing cleanliness levels, as the mass of contaminants per unit surface area (m/A), this document designates a nominal surface area of 0.1 m², considered, for this purpose, to be equivalent to the historically prevalent 1 ft². The difference between 0.1 m² and 1 ft² was considered insignificant based on the general uncertainty of area and mass measurement techniques when used in practice. 1.14 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. Federal, state and local safety and disposal regulations concerning the particular hazardous materials, reagents, operations, and equipment being used should be reviewed by the user. The user is encouraged to obtain the Safety Data Sheet (SDS) from the manufacturer for any material incorporated into a cleaning process. Specific cautions are noted for some cleaning methods and fluids. 1.15 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.

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