Should the range of the pressure gauge for the withstand voltage test be chosen based on the operating pressure or the test pressure?
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I’ve run into this problem these past few days. How did everyone handle it? One of our products is an isobutane storage tank. The design pressure specified in the drawings is 1.0 MPa, the operating pressure is 0.7 MPa, and the pressure test pressure is 1.25 MPa. Water was chosen as the medium for the tests. Since there were no pressure gauges with a range of over 1.6 MPa that were still within their calibration period, we followed the guidelines outlined in the regulations: the maximum pressure indication on a pressure gauge should be between 1.5 times and 3.0 times the operating pressure. Therefore, we selected two pressure gauges with a range of 1.6 MPa that were still within their calibration period. During the pressure testing, the inspector said that the pressure gauge was not suitable; I told him that the regulations in the standards allowed it, but he cited GB150 as evidence against this. With no other choice, we had to recalibrate the pressure gauges by pressurizing them again, which ultimately led to a delay in delivery.
This post was last edited by In short_myP89 on 2021-6-8 16:47. The inspector is right. In the screenshot, 21 refers to the meter used for device operation, while 150 refers to the meter used for voltage tolerance testing. The current situation is that, for the withstand voltage test, you are using a test pressure of 1.28 times the rated value, which does not fall within the range of 1.5 to 3.0 times. According to the procedural documents, the unit’s inspection personnel and responsible persons failed to fulfill their duties properly. As stated in the procedural documents, upon receiving the equipment manufacturing order, the inspectors and responsible persons should check whether the equipment used for the voltage resistance test meets the requirements; it is only during the test that it is discovered that the pressure gauge has expired and hasn’t been inspected. This is equivalent to discovering that one’s weapons are missing during a war. So, holding the person responsible for the inspection accountable is equivalent to making two mistakes, resulting in delayed delivery; in strict organizations, being fired is a normal punishment for such behavior.
I agree with the view in the second floor post. TSG21 refers to tables for operation, while GB/T150 refers to tables for pressure testing; the pressure used for pressure testing can be considered as the operating pressure specified in the pressure vessel regulations.
That’s how it is; one needs to understand the standards better rather than applying them mechanically
The relationship wasn’t handled well! Things like this are usually not taken seriously!
The inspector is doing the right thing; they are also taking responsibility for the safety of the manufacturing plant.
This post was last edited by Forgetting = Forgetting on 2021-6-9 10:47 with GB150
TSG 21-2016 refers to the gauges used for equipment operation; GB150 refers to the gauges used for pressure testing.
Such minor issues causing delays in delivery seem a bit unjustified to me; it only takes two or three days to recheck the two pressure gauges.