At our site in Oman one of the agencies is asking us to condon an area in the periphery of 30 mtr radius around the set-up for hydrotest of one of line. The test pressure is approx. 120 kg/cm2. This shall stop all the work in that area.
Can somebody tell if there is any guide line for cordoning off the area depending on the test pressure, around the set-up for hydrostatic test of piping?

The basic difference between pneumatic and hydrotest is due to the potential hazard as a result of stored energy of the compressed gas in the pneumatic test. This is not the case of Hydrostatic test.The blast wave created by explosion during pneumatic test is comparable to that of TNT explosion.Hence there is a recommendation of isolating the areain case of pneumatic test.

But hydrotest does not have that potential hazard.I have never seen any requirement for isolating the area during hydrotest.Probably it is the requirement( internal standard) of the agency who is doing the job.


Anindya Bhattacharya

Even with a hydrostatic test there is still potential for injury - particularly for example if a failure occurs that results in a missile - possibly a stud bolt, or a flange, or a cap or similar. Hence the 30m rule is most likely precautionary.

There is a British HSE publication entitled "Safety in Pressure Testing" that you may find useful. Guidance Note GS4 (Third Edition). Refer www.hsebooks.com

This note "gives advice to employers, managers and supervisors of pressure testing teams/operators and self-employed persons. It provides guidance on how pressure testing can be safely carried out by means of risk assessment, a safe system of work and suitable precautions. Its technical appendix gives advice on the design of protective barriers if there is a risk of pressure equipment rupture or detachment of a component while under test".