ASME B313 Hydrotest gauge tollerance
ASME B313 Hydrotest gauge tollerance
(OP)
When performing hydro static testing of process piping B31.3, is there a tolerance for gauges. For example: The manufacturer is using two gauges; one reads 1000 psi and the other gauge is reading 1020 psi. The gauges are being re calibrated every 6 months however some of the gauges do not read the same while under pressure for the same test. Thank you in advance.





RE: ASME B313 Hydrotest gauge tollerance
RE: ASME B313 Hydrotest gauge tollerance
This reminds me of the saying: the man with one watch always knows what time it is, while the man with two watches never knows what time it is.
RE: ASME B313 Hydrotest gauge tollerance
B31.3 has no requirements for the accuracy of test gauges. Your AI, if you have one, may point you to some and expect you to follow them. Here we have a procedure for checking shop gauges against a master transmitter which is sent out for calibration yearly. That satisfies our AI. The gauges we use are probably closer to +/- 2% within the measured range.
RE: ASME B313 Hydrotest gauge tollerance
RE: ASME B313 Hydrotest gauge tollerance
RE: ASME B313 Hydrotest gauge tollerance
Reminds me of a few years back when I had to change our corporate spec's as a result of a good discussion with a high quality fabricator. I also get frustrated with "digital bias" in issues like reporting a vessel's fabricated weight using 7 significant figures for a roughly 200,000 pound (or kg, your choice) vessel. So the weight changes when a seagull lands on it. Just because we have a readout with a lot of significant figures does not mean the result is precise.
RE: ASME B313 Hydrotest gauge tollerance
"Pressure gauges shall be of the Bourdon tube type, complying with BS 1780. The nominal diameter of each gauge shall be 100mm.dial gauges used for testing shall have a range of a about double, but not less than 1.5 times the test pressure, in no case shall be less than 1.5 nor more than 4 times of intended maximum test pressure."
RE: ASME B313 Hydrotest gauge tollerance
I always recommend two gauges when testing to ASME standards.