Pressure Test Dial Gage Selection

[Rambo]

During a recent audit, an auditor suggested that our dial gages were insufficient. We are performing pressure tests, which can range from 1,000 to 16,000 psi, depending on the product. We are using fluid-filled dial gages. The dial is graduated in 500 psi increments, and reads up to 30,000 psi.

Our tolerance is +/- 500 psi.; except at the lowest range: 1000 psi, +/-300.

While I understand the concept-- the operator wants to be able to see the needle moving to know the test is active-- I cannot find a standard that indicates what is an acceptable range, given our process.

No, the auditor did not cite a specific standard.

My plan is to go digital, which should address the problem, but with many test stations, it will be difficult to do soon. Is the auditor right?

Thanks.

 

[Mikishots]

During a recent audit, an auditor suggested that our dial gages were insufficient. We are performing pressure tests, which can range from 1,000 to 16,000 psi, depending on the product. We are using fluid-filled dial gages. The dial is graduated in 500 psi increments, and reads up to 30,000 psi.

Our tolerance is +/- 500 psi.; except at the lowest range: 1000 psi, +/-300.

While I understand the concept-- the operator wants to be able to see the needle moving to know the test is active-- I cannot find a standard that indicates what is an acceptable range, given our process.

No, the auditor did not cite a specific standard.

My plan is to go digital, which should address the problem, but with many test stations, it will be difficult to do soon. Is the auditor right?

Thanks.

As you've stated, no citation of a specific standard, and simply a suggestion from the auditor. There are a number of pressure gauges with that range that have much more detailed gradations; I've used a 20,000 psi Winters gauge with 100 psi increments at +/- 0.5% over full scale.

+/- 500 psi gradations is a bit coarse if your tolerance is the same value (or lower). There are many options that can give you more resolution and visibility. Digital is a possibility as well, but if your main concern is time, I can't help you there.