The values obtained by this test method are applicable only to conditions that specifically duplicate the procedures used.

After a scaling constant is determined for one diameter, this may be used for calculating the external failure pressures of other diameters as long as the resin and reinforcement (if used), the wall thickness-to-diameter ratio, and the reinforcement pattern (if reinforcement is used) are the same.

Note 3—Based upon tests conducted on one size of pipe, a scaling constant is calculated according to 12.1 or 12.2. The appropriate constant is used to calculate failure pressure for other pipe diameters, but it can only be applied if the same resin and reinforcement are used, the wall thickness to diameter ratios are similar, and the reinforcement pattern is constant.

In the application of the following test requirements and recommendations, care must be exercised to ensure that the specimens tested are truly representative of the group being studied.

FIG. 1 Apparatus Showing Specimen Loading with Both Hoop and Axial Loads

FIG. 2 Apparatus Showing Specimen Loading with Hoop Load Only

1.1 This test method covers determination of the resistance of fiberglass pipe to external pressure. It classifies failures as buckling, compressive, and leaking. Both glass-fiber-reinforced thermosetting-resin pipe (RTRP) and glass-fiber-reinforced plastic mortar pipe (RPMP) are fiberglass pipes.

Note 1—For the purposes of this standard, polymer does not include natural polymers.

1.2 The values stated in inch-pound units are to be regarded as standard. The SI units given in parentheses are for information only.

1.3 This standard does not purport to address all of he safety problems, 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.