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ASTM G93/G93M-25
Standard Guide for Cleanliness Levels and Cleaning Methods for Materials and Equipment Used in Oxygen-Enriched Environments
Standard Guide for Cleanliness Levels and Cleaning Methods for Materials and Equipment Used in Oxygen-Enriched Environments
G0093_G0093M-25
ASTM|G0093_G0093M-25|en-US
Standard Guide for Cleanliness Levels and Cleaning Methods for Materials and Equipment Used in Oxygen-Enriched Environments
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G93/G93M Standard Guide for Cleanliness Levels and Cleaning Methods for Materials and Equipment Used in Oxygen-Enriched Environments>
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BOS Vol. 14.04 Committee G04
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ASTM International
Significance and Use
4.1 The rationale for cleaning materials, components, and systems for oxygen service is predominantly related to the risk of ignition and fire, but other performance aspects also benefit from cleaning. Thorough cleaning is considered a fundamental fire safety measure applied to oxygen systems. Contaminants may not only result in malfunction or process anomalies, but are also potential fuels. Materials become more flammable and more readily ignitable as oxygen concentration, pressure, and temperature increase. Contaminants, particularly in the form of hydrocarbon oil or grease surface films, have been shown to be more readily ignitable than the bulk materials of a component or system by ignition mechanisms such as compression heating (Guide G88). If present in sufficient quantity, ignition and subsequent combustion of contaminants has the potential to ignite other materials, possibly developing into a kindling chain involving the bulk materials of the component or system. Likewise, solid contaminants, particularly metal debris, may be ignitable either directly by ignition mechanisms such as particle impact (Guide G88), or become a secondary element in a kindling chain initiated by ignition of oil or grease contaminants. Therefore, avoiding contaminants is paramount in developing, operating, and maintaining a safe oxygen system.
4.2 Cleaning for oxygen service is recommended for any system or component that is exposed to oxygen-enrichment (oxygen or other oxidizers) or those that interface oxygen systems that could either inadvertently be oxygen-enriched or supply potential contaminants into the oxygen system. The definition of an oxygen-enriched atmosphere (OEA) can vary by industry, but is defined in Terminology G126 to be concentrations above 25 mol percent oxygen. Furthermore, high-pressure or high-temperature air systems, or both, (~21 percent oxygen) may also benefit from cleaning in accordance with the guidance of this document. Historical fires have been observed in high pressure air systems where contaminants were ignited.
4.3 This guide furnishes qualified technical personnel with guidance in the specification of oxygen system cleanliness needs. However, it does not specify cleanliness levels for industries or specific applications. While examples of cleanliness levels used by various industries or applications are provided for reference, specific applications may require more or less stringent cleanliness.
4.4 Another primary purpose of this guide is to furnish qualified technical personnel with information regarding selection of cleaning methods and associated practices for materials and equipment to be used in oxygen-enriched environments.
4.4.1 General methods, apparatus, and reagents for cleaning materials and equipment used in oxygen-enriched environments are described in this guide. Exact procedures are not given because they depend on the contaminant type and material to be cleaned, cleaning agent used, and degree of cleanliness required. Methods may be used individually, or may be combined or repeated to achieve the desired results. Examples of cleaning procedures that have been successfully used for specific materials, components, and equipment in selected applications are described in the appendices. An index of the specific materials, components, equipment, and applications covered in these examples is given in Table X1.1.
4.5 Methods to qualitatively or quantitatively evaluate the cleanliness of materials or components cleaned for oxygen service are provided. These techniques may be used to validate new or revised cleaning processes to demonstrate that target cleanliness levels are being achieved, routinely inspect cleaned parts as part of a quality control sampling, or to evaluate in-service cleanliness of components or systems.
4.6 The cleanliness achieved from the cleaning process should be preserved until the material or component is put into oxygen service. Principles and best practices regarding the cleaning environment, packaging and labeling of cleaned items, and assembly practices to maintain cleanliness are discussed.
Scope
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.