Zener finds sterile isolator sensor issue during routine maintenance

25-Mar-2022

Zener Engineering Services has found a worrying oversight during a maintenance review of a company's equipment

As part of a maintenance review, a Zener Engineering Services (ZES) consultant realised that a sterile isolator's independent environmental particle counter sensor's "As Received" calibration tolerance limits, set by the supplier, were actually outside those as stated by ISO-21501.

ZES is an engineering consultancy and service provider who was performing checks on the equipment.

After speaking with the supplier, it turned out that the supplier had decided to allocate a ±10% tolerance (100% extra) for "As Received" (supplier terminology) calibration values and then would adjust back to within the ISO standard of ±5%, without issuing an Out of Calibration Certificate or even formally notifying the Life Science Organisation.

Only on the "As Left" Calibration Certificate did the supplier's Calibration Certificate clearly state "This calibration complies with the requirements of ISO-21501".

The Calibration Certificates were reviewed and accepted by a non-technical representative

In the experience of the ZES consultant, other cleanroom environmental monitoring system suppliers comply with the ISO tolerances for their "As Found" or "As Received" calibration tolerance criteria.

ZES finds it astonishing that a life science supplier should just decide to apply their own criteria, which differed from the ISO standard, for "As Found" or "As Received" calibrations.

The Calibration Certificates were reviewed and accepted by a non-technical representative of the Life Science Organisation, who had very little understanding of calibration.

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For the benefit of the reader: "As Found" and "As Received" calibration checks are the same (calibration check before adjustment). Different organisations use different terminology.

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