4.1 Because of the many unique requirements of permit-required confined space rescue operations and the specific construction and composition of some confined spaces, hardline communications systems may be the only type that will meet the requirements for working within these spaces. Some of these requirements are set forth in Federal Regulation and some by safe operating procedures developed for working in confined spaces by industry.

4.2 This guide is not meant to preclude the use of other types of communication systems in confined-space rescue.

1.1 This guide covers recommended criteria for the selection of hardwire communication systems for use in permit-required confined-space rescue operations.

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 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.