4.1 Purpose of Guide G88—The purpose of this guide is to furnish qualified technical personnel with pertinent information for use in designing oxygen systems or assessing the safety of oxygen systems. It emphasizes factors that cause ignition and enhance propagation throughout a system's service life so that the occurrence of these conditions may be avoided or minimized. It is not intended as a specification for the design of oxygen systems.

4.2 Role of Guide G88—ASTM Committee G04’s abstract standard is Guide G128, and it introduces the overall subject of oxygen compatibility and the body of related work and related resources including standards, research reports and a DVD3 G04 has developed and adopted for use in coping with oxygen hazards. The interrelationships among the standards are shown in Table 1. Guide G88 deals with oxygen system and hardware design principles, and it is supported by a regulator ignition test (see G175). Other standards cover: (1) the selection of materials (both metals and nonmetals) which are supported by a series of standards for testing materials of interest and for preparing materials for test; (2) the cleaning of oxygen hardware which is supported by a series of standards on cleaning procedures, cleanliness testing methods, and cleaning agent selection and evaluation; (3) the study of fire incidents in oxygen systems; and (4) related terminology.

4.3 Use of Guide G88—Guide G88 can be used as an initial design guideline for oxygen systems and components, but can also be used as a tool to perform safety audits of existing oxygen systems and components. When used as an auditing tool for existing systems, Guide G88 can be applied in two stages: first examining system schematics/drawings, then by visually inspecting the system (that is, “walking the pipeline”). Guide G88 can be used in conjunction with the materials selection/hazards analysis approach outlined in Guides G63 and G94 to provide a comprehensive review of the fire hazards in an oxygen or oxygen-enriched system (1).7

1.1 This guide applies to the design of systems for oxygen or oxygen-enriched service but is not a comprehensive document. Specifically, this guide addresses system factors that affect the avoidance of ignition and fire. It does not thoroughly address the selection of materials of construction for which Guides G63 and G94 are available, nor does it cover mechanical, economic or other design considerations for which well-known practices are available. This guide also does not address issues concerning the toxicity of nonmetals in breathing gas or medical gas systems.

Note 1: The American Society for Testing and Materials takes no position respecting the validity of any evaluation methods asserted in connection with any item mentioned in this guide. Users of this guide are expressly advised that determination of the validity of any such evaluation methods and data and the risk of use of such evaluation methods and data are entirely their own responsibility.

1.2 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.

1.3 This standard guide is organized as follows:

Section Title

Section

Referenced Documents

2

 ASTM Standards

2.1

 ASTM Adjuncts

2.2

 ASTM Manuals

2.3

 NFPA Documents

2.4

 CGA Documents

2.5

 EIGA Documents

2.6

Terminology

3

Significance and Use

4

 Purpose of G88

4.1

 Role of G88

4.2

 Use of G88

4.3

Factors Affecting the Design for an Oxygen or Oxygen-
 Enriched System

5

 General

5.1

 Factors Recognized as Causing Fires

5.2

  Temperature

5.2.1

  Spontaneous Ignition

5.2.2

  Pressure

5.2.3

  Concentration

5.2.4

  Contamination

5.2.5

  Particle Impact

5.2.6

  Heat of Compression

5.2.7

  Friction and Galling

5.2.8

  Resonance

5.2.9

  Static Electric Discharge

5.2.10

  Electrical Arc

5.2.11

  Flow Friction

5.2.12

  Mechanical Impact

5.2.13

  Kindling Chain

5.2.14

  Other Ignition Mechanisms

5.2.15

Test Methods

6

System Design Method

7

 Overview

7.1

 Final Design

7.2

 Avoid Unnecessarily Elevated Temperatures

7.3

 Avoid Unnecessarily Elevated Pressures

7.4

 Design for System Cleanness

7.5

 Avoid Particle Impacts

7.6

 Minimize Heat of Compression

7.7

 Avoid Friction and Galling

7.8

 Avoid Corrosion

7.9

 Avoid Resonance

7.10

 Use Proven Hardware

7.11

 Design to Manage Fires

7.12

 Anticipate Indirect Oxygen Exposure

7.13

 Minimize Available Fuel/Oxygen

7.14

 Avoid Potentially Exothermic Material Combinations

7.15

 Anticipate Common Failure Mechanism Consequences

7.16

 Avoid High Surface-Area-to-Volume (S/V) Conditions
  where Practical

7.17

 Avoid Unnecessarily-Elevated Oxygen Concentrations

7.18

 Anticipate Permutations from Intended System Design

7.19

 Avoid Designs and Failure Scenarios that can Introduce
  Potential Flow Friction Ignition Hazards

7.20

 Use Only the Most Compatible of Practical Materials
  and Designs

7.21

 Provide Thorough Safety Training for All Personnel
  Working with Oxygen or Oxygen-Enriched
  Components or Systems, including Design,
  Cleaning, Assembly, Operations, and
  Maintenance as Applicable to Personnel

7.22

 Miscellaneous

7.23

Examples

8

Key Words

9

References

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.