4 replies to this topic

[Fundive]

I have to establish a process to calibrate scales.
Is there a guideline from BRC how to calibrate scales? Particularly I'm interested to know if I have to log the difference of the weight before and after the calibration process.

Any suggestions are appreciated.

Many thanks
Fundive

[BVRC]

Hi there

In terms of measuring and monitoring equipment, I suggest you look at the requirements of ISO 9001:2000 as well as ISO 17025(Good Laboratory Practices). The jist of it is that you develop a business wide calibration procedure, where you determine based on the critical steps in your process which instruments you require to be calibrated. These are then added to your master calibration list. You can either calibrate the instruments internally or externally. I.e. you can do it yourself or outsource it, either way the standard, in this case mass piece must be traceable to a national standard.

The best way to do it and then you know you have handled it once and for all is to use an outsourced metrology service provider that is ISO 17025 accredited. You have a yearly schedule where they come in and calibrate your balances/scales. All you do is buy a mass piece (size relevant to your testing levels), have that calibrated and you just periodically validate the calibration, normally at the beginning of the day, or more often if your scales is exposed to robust treatment or your sample numbers are high.

Regards
Bennii

[salmonboy]

We calibrate our scales daily with a 100g test piece which is calibrated annualy by an external body.
In a recent Efsis/BRC audit however we recieved a minor n/c because we did not have calibrated test pieces over the ful range of products that we produce (ie:50g to 400g) so this is something you may wish to consider when setting up the system.
Gary

[Simon]

I have to establish a process to calibrate scales.
Is there a guideline from BRC how to calibrate scales? Particularly I'm interested to know if I have to log the difference of the weight before and after the calibration process.

Any suggestions are appreciated.

Many thanks
Fundive

Just to add to the good advice already provided; I think you will find the discussion here: Calibration of Scales very useful. If you still have further questions feel free to ask.

Regards,
Simon

[okido]

Hi Fundive,

As Benni already stated get some mass pieces (size and accuracy relevant)
Calibration frequency depends on usage conditions. With conditions I mean, who is using the pieces, what environment are they used in, what quality are they and what accuracy are they, how oft are they used and so on.
For example I have standard length that is only calibrated once every 5 years, it is only used if we buy a new type of ruler.
One auditor had a problem with this term of 5 years.
But what can happen with a bar stainless steel that is stored in a box in a climatized room and that is calibrated on 0.01mm and were the accuracy needed is only +/- 0.5mm. You have to be persistent against auditors every now and then.
Calibrate your scales preferable at 3 to 5 points over the whole scale.
Frequency of calibration/validation of scales depends on usage conditions, roughly the same conditions as mentioned above. But also take into account food safety risks of deviations, legality and cost’s of miss measurement.
And above all use scales that are fit for the job, do not use a 30kg scale to measure 100 gr products.

Have a nice day, Okido