Instrument Calibration 1

[Inchtain]

Hello,

With regards to the calibration of the UT thickness Gauges, Coating Gauges, Pressure Gauges, etc. I have two queries:

- Is calibration needed every year? and which Standard states this interval?

- When reading a calibration certificate for a device or a temperature or pressure gauge, there are what is called error indications or uncertainties from a certain standard values. During real use of the equipment or gauge, shall we consider those indications and record the values after corrections?

Thanks and best regards,

 

[EdStainless]

Your internal procedures will dictate calibration intervals.
For devices like UT or coating thickness I would presume that you have internal standards that are checked every time the device is used.
For something like a pressure gage a lot depends on how critical it is.
For our test gages we used 6mo or less depending on how frequently they were cycled.
Gages at steady conditions we would use 1 yr.
Just remember if a device comes back and it was out of your acceptable range and needed adjustment then you need to evaluate everything that it has been used for since the previous calibration and document the possible implications of these errors.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[hacksaw]

Calibration tests are simple, make your own and check it with a micrometer.
If you need traceable calculations and certification, based on national lab tests you'll have to spend the money.

 

[Taicho567]

Normally you would refer to your internal procedures. The place I worked at - I believe the practice was generally applicable to all - do a yearly calibration on non-critical equipment. The critical equipment, on the other hand, would have a shorter interval, say bi-yearly calibration.

With regard to the uncertainties values, these are indicatives and shall give you a picture of how accurate the devices are. I would normally read and accept the indications as they are. However, you may want to accept the indications with caution if the uncertainties are too high.