1.1 This test method determines the minimum internal air pressure at which rapid crack propagation (RCP) can be sustained along a section of plastic pipe. This is termed the critical pressure.

1.2 This technique achieves steady state RCP in a small specimen by restraining the decompression which normally accompanies fracture, and therefore indicates a lower critical pressure than that measured on the same pipe using full-scale tests. This test method has been called "Small Scale Steady State" or S4.

1.3 This test method was developed for polyethylene pipe, and has been shown to correlate with the full-scale RCP test method. The user should determine if it is applicable to other plastic piping methods.

1.4 The values stated in inch-pound units are to be regarded as the standard.

1.5 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 and health practices and determine the applicability of regulatory limitations prior to use.