Could somebody help me to find out which Code or Standard is specifying the valve percent to be hydrotested. Our valve supplier is replied as per below:Type Qty Rating PercentageGate 840 150, 300, 600 20% persize/per ratingGlobe 90 150, 300, 600 20% persize/per ratingCheck 100 150, 300, 600 20% persize/per ratingGate 650 150, 300, 600 10% persize/per ratingFor hydrotesting at 150% of the rated pressure, every code or standard I have ever seen for valves over the last 30 years requires 100%If you are requiring a special test that is in addition to normal valve shell (hydrotest) and seat tests, then some end users allow testing of 10% of the lot but usually state something that if one fails, then the entire lot must be tested.In short, all valves should be hydrtotested to 150% sometime before being put into service. Could be in the valve factory or when the entire piping system is tested. All valves should have a seat test to verify quality. Seat test conditions should be the most challenging for the valve to pass (i.e., don't do a high pressure seat test at 1.1 times the rated pressure on a soft-seated floating ball valve as it will easily pass. Use a low pressure air test).

MORE NEWS