# 56.97-25 Preparation for testing (modifies 137.2).(a) *Exposure of joints.* All joints including welds must be left uninsulated and exposed for examination during the test.(b) *Addition of temporary supports.* Piping systems designed for vapor or gas may be provided with additional temporary supports, if necessary.(c) *Restraint or isolation of expansion joints.* Expansion joints must be provided with temporary restraint, if required for the additional pressure load under test.(d) *Isolation of equipment not subjected to pressure test.* Equipment that is not to be subjected to the pressure test must be isolated by a blank flange or equivalent means.(e) *Treatment of flanged joints containing blinds.* Flanged joints at which blinds are inserted to blank off other equipment during the test need not be tested.(f) *Precautions against test medium expansion.* If a pressure test is to be maintained for a period of time and the test medium in the system is subject to thermal expansion, precautions must be taken to avoid excessive pressure. A small relief valve set to 1 1/3 times the test pressure is recommended during the pressure test.[CGD 73-254, 40 FR 40167, Sept. 2, 1975]