3 replies to this topic

[Fara Dieba]

Hi,

 

I hope someone can assist me with this topic. I would like to know can we just send calibration weight for external calibration or we need to send our weighing scale too? can auditor accept if we only do external calibration for calibration weight once a year? but we will do internal calibration every week.

 

For incubator, can we just send mercury thermometer to external calibration as master yearly and we will do internal calibration every month with that thermometer because our lab is not frequently use. do we still need external calibration for incubator?

 

thanks in advance!

 

 

[Evans X.]

Greetings Fara,

 

Short answer is yes you can. Calibrating either the weight or the scale works and then you can do the internal check of the other with the calibrated one. The calibration interval is also acceptable and from my experience in ISO 17025 accredited labs the weights can even be sent for calibration bi-annually (they are not likely to be off when preserved in their package, get hit/scratched or get mishandled without cloth gloves etc) while the scales should be done annually if you choose to go with them. Also, in the case of calibrated weights, you can increase the weekly interval of in-house calibration if there is no trend arising from the data you have by now. Meaning that if your scale doesn't go off balance from week to week, then you can do it bi-weekly or monthly.

 

For the incubator, the calbration of the thermometer works just fine.

 

Regards!

[cookinmaple]

I only have my standard check weights certified, and the auditor was ok with it. I did go overboard and provided all relevant regulatory information and the auditor was happy with it. Info below was very helpful in justifying this decsion. 

 

https://laws-lois.justice.gc.ca/eng/Regulations/C.R.C.,_c._1605/index.html

https://www.nist.gov...current-edition

NIST Handbook 44 Specifications, Tolerances, And Other Technical Requirements for Weighing and Measuring Devices

3.3.  Accuracy of Standards. - Prior to the official use of testing apparatus, its accuracy should invariably be verified.  Standards should be re-verified as often as circumstances require.  By their nature, metal volumetric standards are more susceptible to damage in handling than are standards of some other types.  A standard should be re-calibrated whenever damage is known or suspected to have occurred or significant repairs have been made.  In addition, standards, particularly volumetric standards, should be re-calibrated with sufficient frequency to affirm their continued accuracy, so that the official may always be in an unassailable position with respect to the accuracy of his testing apparatus.  Secondary standards, such as special fabric testing tapes, should be verified much more frequently than such basic standards as steel tapes or volumetric provers to demonstrate their constancy of value or performance. Accurate and dependable results cannot be obtained with faulty or inadequate standards.  If either the service person or official is poorly equipped, their results cannot be expected to check consistently.  Disagreements can be avoided, and the servicing of commercial equipment can be expedited and improved if service persons and officials give equal attention to the adequacy and maintenance of their testing apparatus.

NIST Handbook 105-1- Specification and Tolerance, for Reference Standards and Field Standard Weights and Measures.

[jfrey123]

I'm trying to remember back to when I last was in charge of scale calibrations.  I think we had a company come in and officially certify our scales once per year, and they'd bring their own certified scale to check all of our test weights at the same time.  They'd give us a certificate showing our registered test weights were in-spec.  We then did our own internal checks every shift to make sure scales were accurate and place them on hold if they showed deviations (and then get that company to come back out and recalibrate as needed).  This was acceptable to our SQF auditors.