Should the hydrostatic test value be rounded?
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The value obtained from the hydrostatic test is usually expressed with four decimal places; for example, it might be 5.4321. On our drawings, we generally round to two decimal places, so it would be 5.44. I would like to ask whether this value should be rounded down to 5.43 or rounded up to 5.44? Rounded, the pressure value does not reach the calculated value – are there any legal issues? Since the carry is also higher than the value calculated according to the standard, is it necessary to conduct a verification?
Writing 5.5 directly is too precise and unrealistic; it’s simply not possible to control a pressure gauge with such accuracy. Anyway, software calculations are subject to verification
It should be rounded up. As for the number of decimal places to retain, if one wants to be precise, it’s necessary to determine the accuracy of the corresponding pressure gauge; a slightly higher precision will ensure successful verification, but if the precision is too low, errors will occur
This post was last edited by SDHZZXM on 2015-8-28 at 17:13. The ending method is generally used, with precision to 0.1 MPa...
Thank you all, let’s move forward. The software only checks the heads and cylinders, and it has many defects as well; for example, the test pressure generated automatically is sometimes calculated based on the small bolts, and it takes into account any component that is under pressure, regardless of whether it is a primary pressure-bearing element or not. The main stressed components also include large pipes, flanges, large bolts, etc.; you’ll need to pay attention to checking these on your own as well. {:1_90:}
You mean that since it’s not clear, one should adopt methods that can avoid risks.
It should be rounded up, and the test pressure specified in the calculation sheet must be no less than the test pressure indicated on the drawings.
It should be rounded up; generally, two decimal places are retained. If one wants to be precise, the accuracy of the corresponding pressure gauge must be taken into account. A slightly higher accuracy ensures that the checks pass without issues, but if the accuracy is too low, errors will occur if one insists on precision
Should it be one decimal place or two?
The pressure value should be on the high side rather than the low side; if it is too high, it is called excess margin, while if it is too low, it is considered illegal.