Level of Accuracy for Pressure Gauges

That is in the middle declared range, so where is the problem?

As said above, the manuf. accuracy is the worst case range. The calibration report is the actual calibration accuracy that they have tested it for. These are only for the gauge when it is new and unused. Once the gauge is installed the accuracy very often changes due to the conditions it is used in and what other equipment may be used with it. If there are vibrations, especially high intensity ones, it can and usually will change. If a snubber, internal liquid or other pressure pulse reducer is used prior to the gauge it will usually lengthen the time length of the actual accuracy. Vibrations and pulses are usually, but not always, the cause of the accuracy range widening.

If you want to check the accuracy of a gauge, the proper way is to purchase a calibration grade gauge with a similar range as the tested gauge. The calibration gauge has an even better accuracy range. Tee them to a suitable pressure source and compare the pressures on each gauge. That will be the current deviation of the tested gauge. If the tested gauge is adjustable, you probably can bring it back to the manufactures worst case range.

If you want even better accuracy, you can buy a test gauge, for a lot of money, whose accuracy is traceable to a NIST standard gauge. For most purposes this is not necessary.

Good Luck, Old Salt

Probably better to use a dead weight tester rather than an abitory pressure souce and check gauge on both rising and falling pressures (elastic hysteresis).

or you can send your gauges to a commercial standards lab, where exactly that procedure will be followed. This poster has been in a real calibration lab, that's clear. GA