Pressure testing of pipe-work

Background

There have been several incidents where blank-ends have failed on rolled groove pipe when placed under a pressure test. 

Recently a Plumber received severe facial injuries when he cut the capped end off a 50mm copper line under test.

Previously a worker was killed and his mate seriously injured when a metal cap exploded from a 300mm diameter pipe when it failed whilst under test. 

Failures have occurred when testing with water or air.

Hazards

  • Failure of pipe and/or fittings under excessive pressure.
  • Failure to identify if the installation is under a pressure test.

Risk

Serious injury or death resulting from catastrophic failure when under pressure, or when pressure is released in an uncontrolled manner. For example, a blast of compressed air at 40 psi at 100mm has the potential to rupture an eardrum or cause brain damage.

Control Measures

  • When testing with compressed air, never exceed a maximum pressure above 50kPa. Any testing above this maximum must be under direction of a qualified engineer.
  • Provision for a pressure gauge, stop valve and bleed valve is compulsory.
  • Appropriate training and instruction in procedures for workers involved in the test.
  • Designated test/exclusion zone.
  • Adequate pipe end support.
  • Lock-out/tag system to prevent persons other than those involved in the test from accidentally releasing pressure.
  • Consideration of the effects of hydro-static head pressure on the system in test.

For pipe-work left under pressure after the test;  

  • Adequate signage/information for persons other than those involved in the test.
  • Protection of pipe-work and fittings with the potential to be damaged.
  • See also WSV publication; Safety Alert: "Pressure testing of pipes", www.worksafe.vic.gov.au and the PPTEU Hazard Alert: ‘Hydrostatic testing of fire sprinkler suppression systems’                                                                                                                                
     

Steve Rocco R2 2016

Download

Download a copy of this hazard alert, so you can print it and inform your work mates