Testing Ammonia Hoses (Non-Refrigeration)

Hoses are commonly used to transfer chemicals from one container to another. Anhydrous ammonia is no exception. In non-refrigeration applications, it is important that facility owners familiarize with the requirements for pressure testing hoses.

In California, OSHA requires that hoses be tested annually to twice the tank working pressure, but not less than 500 psi. Since most ammonia storage tanks have a 265 psig maximum allowable working pressure, a hose used in this application would require pressure testing to 530 psig (see Title 8 CCR §510(c)[1]).

Additionally, CGA G2.1-2014 §5.7.10, which is widely considered RAGAGEP for non-refrigeration applications, requires in part that:

Hoses shall be pressure tested at least annually…Pressure testing shall be completed in accordance with section 8.2 of CGA P-42. Recommended Hose Management Practice for Compressed Gas Transfer Hoses. First Edition [44].

CGA P42 §8.2 outlines best practices when conducting a hydrostatic or pneumatic pressure test, both of which are acceptable methods for testing hoses. Hydrostatic tests can be performed using water in conjunction with a pressure-washer, or other means to increase the hose internal pressure. Pneumatic pressure tests should be conducted with dry nitrogen or dry, oil-free compressed air. To pass a pressure test, hoses must hold pressure without decay for at least one minute.

More could be said on the steps required to perform a pressure test, but the information in this blog and the corresponding RAGAGEP references will help a facility to determine if their mechanical integrity program includes these important tests.

[1] All anhydrous ammonia hoses and hose connections subjected to tank pressure shall be tested at least once each year to twice the tank working pressure but not less than 500 psi. While in transit all hoses and hose connections shall be protected from wear or injury.