The American Society for Testing and Materials (ASTM) standard, "ASTM G93/G93M Standard Guide for Cleanliness Levels and Cleaning Methods for Materials and Equipment Used in Oxygen-Enriched Environments," covers the selection of methods and devices for cleaning materials and equipment designed for service in oxygen-enriched environments. Contamination problems encountered in the use of enriched air, oxygen-with-other-gas mixtures, or other oxidizing gases can be addressed with the same cleaning procedures applicable to most metallic and nonmetallic materials and equipment. Examples of cleaning for specific materials, components, and equipment, as well as cleaning methods for specific applications, are provided in the appendices.
This guide covers the cleanliness levels used for various applications and the methods used to achieve and verify those levels. This guide applies to chemical, solvent, and water-based processes. This guide describes non-essential materials for selecting the required cleanliness levels for systems exposed to oxygen or oxygen-enriched atmospheres.
This guide suggests a practical range of cleanliness levels that will meet most system needs, but it does not quantitatively address the many conditions that may require increased cleaning or allow higher contamination levels to occur. Furthermore, it does not recommend a specific way to measure or monitor these levels from among the available methods.
The purpose of this guide is to provide qualified technical personnel with the necessary information regarding the selection of cleaning methods for cleaning materials and equipment used in oxygen-enriched environments. This guide provides guidance to qualified technical personnel in determining oxygen system cleaning requirements. However, it does not specify cleaning levels.
Inadequate cleaning of components used in oxygen systems can lead to ignition of contaminants or components by various mechanisms, including particulate, mechanical, or pneumatic impact. These mechanisms are described in detail in the ASTM G88 guide.
Adequate contamination control in oxygen systems is essential to minimize contamination-related hazards and component failures. Contamination must also be minimized to ensure acceptable product purity.
Removal of contaminants from materials and components depends on system configuration, materials of construction, and the type and quantity of contaminant.
Examples of cleaning procedures included herein can be followed or specified for the materials, components, and equipment specified. The general cleaning text can be used to identify cleaning procedures for materials, components, equipment, and applications not covered in detail. ASTM G127 guidance is available for guidance on selecting cleaning agents and procedures.
The risk of fire and explosion is ever-present in industries where oxygen plays a critical role, such as aviation, medical gas supply, pharmaceuticals, and industrial manufacturing. While essential for life and many processes, oxygen can significantly accelerate combustion when contaminants are present. To mitigate these hazards, rigorous standards for cleaning materials and equipment are essential. ASTM G93 provides a framework for selecting appropriate cleaning techniques, ensuring components are free of residues that could ignite in oxygen-rich atmospheres.
The ASTM G93 standard addresses the unique challenges of oxygen service. It emphasizes that even trace amounts of hydrocarbons, particulates, or moisture can promote combustion, underscoring the need for precise cleaning. As oxygen systems become increasingly prevalent in new technologies such as space exploration and clean energy, this standard remains an increasingly vital tool.
Oxygen-enriched environments are defined as environments with an oxygen concentration greater than 23,5 percent by volume, including pure oxygen systems. In such environments, contaminants act as fuel sources. For example, a thin film of oil on a valve can ignite under high pressure, leading to catastrophic failure. Past incidents, such as oxygen fires in spacecraft or hospital oxygen lines, highlight the risks: a single oversight can lead to loss of life, equipment failure, and costly downtime.
The importance of the ASTM G93 standard lies in its proactive approach. It provides technical personnel with data-driven methods to assess risks and implement controls. By specifying cleanliness levels, the standard helps prevent oxygen fires, which are rapid-burning fires that differ from typical fires because they lack an ignition source threshold in pure oxygen. Compliance with this standard not only protects operations but also complies with regulatory requirements from organizations such as NASA, OSHA, and the FDA.
The ASTM G93 standard adopts a flexible, risk-based methodology that can be adapted to specific applications, from low-pressure medical devices to high-speed rocket engines.
This guide covers various techniques classified according to their effectiveness and application areas:
The selection depends on the material type (e.g., metals, plastics) and system pressure. ASTM G93 emphasizes post-cleaning drying, typically using heated air or vacuum ovens, to prevent moisture retention.
Unlike more stringent standards, the ASTM G93 standard defines four levels of cleanliness based on risk:
These levels guide selection, with Level A for extreme hazards and Level D for harmless uses. Particle counts (e.g., via laser scanning) and NVR measurements (gravimetric analysis) determine compliance.
Post-cleaning verification is non-negotiable. The methods are:
Ultimately, the ASTM G93 standard is more than just a technical standard; it's a safeguard against invisible threats in oxygen systems. By providing actionable guidance on cleaning and validation, it enables industries to operate safely and efficiently. From medical device design to rocket design, adhering to this standard ensures oxygen remains an ally.
Our organization, which has been operating for many years and meticulously follows global developments in science and technology, employs a team of experienced professionals and a broad infrastructure to conduct testing, measurement, and analysis in a wide range of areas for businesses across all sectors. In this context, we also provide testing services in accordance with the ASTM G93/G93M Standard Guide for Cleanliness Levels and Cleaning Methods for Materials and Equipment Used in Oxygen-Enriched Environments.
To get an appointment, to get more detailed information or to request an evaluation, you can ask us to fill in our form and reach you.
EUROLAB reporting and certification activities, United Accreditation Foundation (UAF), Turkish Accreditation Agency (TÜRKAK), Enterprise Accreditation Foundation (EAF) based on the accreditation provided by its institution. The Enterprise Accreditation Foundation (EAF) is also a signatory to the United Nations (UN GLOBAL COMPACT).
