(a) Flexible pipe couplings of the compression or slip-on type must not be used as expansion joints. To ensure that the maximum axial displacement (approximately 3/8″ maximum) of each coupling is not exceeded, positive restraints must be included in each installation.

(b) Positive means must also be provided to prevent the coupling from “creeping” on the pipe and uncovering the joint. Bite type devices are not generally accepted for this purpose. Machined grooves or centering pins are considered positive means.

(c) The installation must be such as to preclude appreciable difference in the vibration magnitudes of the pipes joined by the couplings. The couplings must not be used as a vibration damper. The vibration magnitude and frequency should not exceed that recommended by the coupling manufacturer.

(d) Flexible couplings made in accordance with the applicable standards listed in table 2 to § 56.60-1 and of materials complying with subpart 56.60 may be used within the material, size, pressure, and temperature limitations of those standards and within any further limitations specified in this subchapter. Flexible couplings fabricated by welding must also comply with part 57 of this subchapter.

(e) Flexible couplings must not be used in cargo holds or in any other space where leakage, undetected flooding, or impingement of liquid on vital equipment may occur, or in tanks where the liquid conveyed in the piping system is not compatible with the liquid in the tank.

(f) Damaged or deteriorated gaskets must not be reinstalled.

(g) Each coupling must be tested in accordance with § 56.97-5.