7 replies to this topic

[sienna]

Hello everyone,
I have a question regarding section 6.4 of the BRC-calibration.
It states that any measuring equipment must be calibrated to a national or international standard. The only standard I know is UKAS. My metal detectors have been calibrated but I have no idea to what standard. What is a national standard?

Regards
Michaela

[beautiophile]

Hi,

I'm working with BRC/IoP but sometimes take a look on BRC food.

To be clear, the statement is that devices shall be checked and where necessary adjusted:

- ...

- to a defined method traceable to a recognised national or national standard where possible.

The key idea here is the traceability to a(n) (inter)national standard. You don't have to use such standard directly. You only ensure that your calibration records can link to UKAS.

For an instance, a company has got 10 scales with accuracy of 1g and 1 scale with accuracy of 0.5g. They send the 0.5g-scale to a lab, accredited by government, to calibrate. They compare the reliability of 10 scales against the 1st one as internal calibration standards. And only the 10 1g-scales are used in production.

For record, a calibration of a 1g-scale is based on the 0.5g-scale which is calibrated by an authorised organisation, which means a link to a national standard. 

That's good enough.

[sienna]

_{Thank you.}

_{But to calibrate a metal detector what UKAS equipment can be used?}

_{I would have thought that a UKAS accredited company would need to calibrate CCP equipment.}

 

_{Really do appreciate your feedback :)}

[Anki]

There is no such thing as “Traceable to UKAS” or “UKAS Traceable” calibration, these terms are common misnomers. Unfortunately some calibration companies continue to use these misleading terms (either out of ignorance or intentional deception) to advertise calibration services that are traceable to National Standards. (Their calibration is normally traceable to Nation Standards via a calibration certificate for their calibration equipment that has been issued by a UKAS accredited company). They may also state that their equipment is UKAS calibrated, which can easily be misinterpreted as being able to offer UKAS calibration, but this is not the same as the laboratory being UKAS (ISO/IEC 17025) accredited for calibration. (source: TMS Europe)

 

In simple words, do not look for standards traceable to UKAS. Technically, you don't need to calibrate your metal detector, all you have to do is validate it. The validation normally is done on each product size and type. Each food type has different moisture content/properties and you may have to have different settings on electro magnetic field. The validation is done by simply running your product say 50 times (more than 30 should be statistically valid), with each type of metal piece (Stainless steel, Ferrous & Non-Ferrous) inside the product you are validating and your goal is to catch the metal every time. If you fail, change the setting and repeat the process and document it.

 

Now, as far as traceability to national or international standard, you can ask the metal pieces supplier to give you calibration certificate for test pieces. They should be traceable to a lab which is ISO 17025 accredited or in US, traceable to NIST standards.

 

If this answers your question, please feel free to comment or hit "thanks".

[Charles.C]

Hi Michaela,

 

There are many opportunities for confusion in calibration topics. And particularly in BRC driven ones.

 

The clause 6.4.3 is, perhaps critically, being misquoted in OP.

 

Reference measuring equipment shall be calibrated and traceable to a recognised national or international standard and records maintained. The uncertainty of calibration shall be considered when equipment is used to assess critical limits.

 

 

The first sentence only of above appeared verbatim in BRC6 as clause 6.3.3, and afaik was there interpreted as -

 

This clause refers only to reference equipment. This could be a master thermometer from which you calibrate other probes, or it could be a master set of standard weights, for example. Any item like this must be calibrated to a national or international standard.

If the external (calibration) company used is accredited, for example in the United Kingdom by UKAS, then this will confirm traceability. (but note that Post 4 suggests that some claims of accreditation are "optimistic").

 

On the other hand, "equipment" as used in the second sentence of BRC7 clause appears to be being used for "everything". In this case, from a BRC POV, a detailed  analysis of the "calibration" situation for a metal detector was attempted in the Post linked below (and surrounding thread) -

 

http://www.ifsqn.com...rs/#entry105910

[Madam A. D-tor]

Wow!

 

I always have interpreted "traceable to international or national standards" as  with reference to (inter)national measuring units. E.g. gram, meter, volt, degree Celsius, etc. The SI units.

I never heard of traceability to UKAS certification, but then again, I am not in UKAS area.

 

I use to check if the calibration company, makes reference to the equipment used and the calibration status of the equipment used.

I check if the results are to internationally agreed standards. E.g. meter instead of thumbs.

 

Back to the original post:

metal detector calibration is mostly done by the supplier during maintenance to the metal detector. Standards used are normally the test pieces of the customer themselves or test pieces from the supplier. Reference to the test pieces and (if applicable) the certificate of the test pieces should be somewhere on the calibration report.

[Charles.C]

Hi Madam A.D-tor,

 

But do note my BRC quote in above referenced sub- link that metal detectors cannot technically be "calibrated".

 

This topic is a confusional hotch-potch of arbitrary terminologies.

[Madam A. D-tor]

Dear Charles,

 

I agree with you that metal detectors can not be calibrated.

I am always wondering why this is done.

The test that the supplier performs is actually the same test as the verification test, which the user of the metal detector is doing on risk based frequency. Just checking if test piece of known size gives the needed reaction .

In the beginning I never checked these "calibration"-reports for metal detectors, because I did not see the use of it. Now-a-days everyone seems to have these "certificates".

Somehow we like to have certificates for everything.