ASTM G93/G93M-19

5.1 The purpose of this guide is to furnish qualified technical personnel with pertinent information for the selection of cleaning methods for cleaning materials and equipment to be used in oxygen-enriched environments. This guide furnishes qualified technical personnel with guidance in the specification of oxygen system cleanliness needs. It does not actually specify cleanliness levels.

5.2 Insufficient cleanliness of components used in oxygen systems can result in the ignition of contaminants or components by a variety of mechanisms such as particle, mechanical, or pneumatic impact. These mechanisms are explained in detail in Guide G88.

5.3 Adequate contamination control in oxygen systems is imperative to minimize hazards and component failures that can result from contamination. Contamination must also be minimized to ensure an acceptable product purity.

5.4 Removal of contaminants from materials and components depends on system configuration, materials of construction, and type and quantity of contaminant.

5.5 Examples of cleaning procedures contained herein may be followed or specified for those materials, components, and equipment indicated. The general cleaning text can be used to establish cleaning procedures for materials, components, equipment, and applications not addressed in detail. See Guide G127 for discussion of cleaning agent and procedure selection.

1.1 This guide covers the selection of methods and apparatus for cleaning materials and equipment intended for service in oxygen-enriched environments. Contamination problems encountered in the use of enriched air, mixtures of oxygen with other gases, or any other oxidizing gas may be solved by the same cleaning procedures applicable to most metallic and nonmetallic materials and equipment. Cleaning examples for some specific materials, components, and equipment, and the cleaning methods for particular applications, are given in the appendixes.

1.2 This guide includes levels of cleanliness used for various applications and the methods used to obtain and verify these levels.

1.3 This guide applies to chemical-, solvent-, and aqueous-based processes.

1.4 This guide describes nonmandatory material for choosing the required levels of cleanliness for systems exposed to oxygen or oxygen-enriched atmospheres.

1.5 This guide proposes a practical range of cleanliness levels that will satisfy most system needs, but it does not deal in quantitative detail with the many conditions that might demand greater cleanliness or that might allow greater contamination levels to exist. Furthermore, it does not propose specific ways to measure or monitor these levels from among the available methods.

1.6 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.

1.7 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. 1.8 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.