Calibration frequency

My favourite subject calibration . We have a large number approx 100 anti static guns and snakes on site , which are monitored through our calibration system .

The frequency is set at 3 months and I was reviewing if this is overkill and should be changed to 6 or 12 months .

Was looking for some insight / advice into setting frequency or thinking being moving the frequency out , breakdown risk ect.

 

I agree with Miner that these are (probably) not instruments which require calibration, but instead should be on a PM schedule.

But lets look at the original question - how do you set calibration frequency?

Over the last 30+ years I have seen too many companies that use the generic 'annual calibration' as their guideline.....they calibrate EVERYTHING every year. That is ok if you only have a few dozen gauges, but if you have a large number (my last company we had over 800 gauges) the task becomes unmanageable.

Calibration frequency can be modified based on RISK ASSESSMENT and history. One of the first things I did at my current company was to change the frequency of calibration of digital calipers and micrometers from annual to 18 months. My experience has shown that these type of instruments either work, or don't work at all.....they are subject to damage which results in the instrument not working at all (rather than giving a false measurement).

I documented this decision in our Calibration Guidelines (an appendum to our Lab Scope) and was questioned about it once by an external auditor. I gave the same explanation that I showed above, and this was accepted without question.

And yes, the calibration frequency for ANALOGUE calipers and micrometers is still at 12 months - there is a MUCH higher potential for instrument wear/damage which can result in an incorrect reading.

 

Sorry guys it is more of a basic check not calibration where we check using device that we are getting anti static not just air blast . I agree though about there is very little risk in reducing frequency of checking on certain gauges .

 

If my 3 certificates are within 80% of the standard error limit, I extend it for a quarter of my current frequency and renew it every 3 certificates.