ISO 17025-accredited calibration: why it matters

ISO/IEC 17025 is the international standard for the competence of testing and calibration laboratories. A laboratory accredited to it by UKAS has been assessed for each measurement on its schedule, so a certificate it issues inside that scope is traceable to national standards. That is the evidence MHRA inspectors, UKAS assessors and BRCGS auditors look for.

For anyone whose compliance rests on logged temperatures, that matters: the record is only as good as the sensor behind it. We provide calibration for every sensor we supply: traceable to national standards as standard, or UKAS accredited where you need it (temperature in our own UKAS accredited calibration laboratory No. 10723, accredited to ISO/IEC 17025; other parameters through accredited partners). Here is what that means and how to check it.

What ISO 17025 accreditation means

Calibration compares a sensor with a reference of known accuracy and records the difference. Accreditation goes further. It means an accreditation body has assessed the laboratory's whole system: its methods, its references and their traceability, its environment, its staff's competence and how it calculates measurement uncertainty.

Accreditation is granted for a defined scope: named measurements, over stated ranges, with a stated best uncertainty. Outside that scope the laboratory may still calibrate, but the certificate is not an accredited one. Laboratories are accredited, never certified, to ISO/IEC 17025.

The risks of poor or non-accredited calibration

A sensor that is not calibrated, or calibrated without traceability, can read wrong without anyone knowing. The record looks fine while the fridge, store or vehicle runs outside its limits.

• Decisions on wrong data. Stock released, or quarantined, on the strength of a reading that was off.
• False confidence. An alarm-free record that hides real excursions.
• Stock and quality failures. Product spoiled or degraded without the record showing it.
• Findings at inspection. Calibration is one of the first things an inspector or auditor checks, and a certificate with no traceability is hard to defend.
• Weaker evidence in a dispute. Data from an unverified sensor carries less weight when a load or a claim is questioned.

Who needs accredited calibration

The rules below expect monitoring equipment to be calibrated and traceable. Accredited calibration is the most direct way to show that.

See MHRA and GDP, ISO 15189 and BRCGS for what each one expects of monitoring. Outside regulated sectors, customers increasingly ask for proof too, and calibration is a common place where standards slip.

How to check a laboratory's scope

Every UKAS-accredited laboratory has a public schedule of accreditation. Search for it on the UKAS website, then check three things:

1. The measurement. Is the parameter you need (temperature, humidity, pressure) on the schedule?
2. The range. Do the points you need sit inside the accredited range?
3. The uncertainty. Is the best uncertainty small enough for your tolerance and decision rule?

Our own schedule, UKAS accredited calibration laboratory No. 10723, covers temperature only. The two ranges are shown below. Other parameters, such as humidity, are calibrated by accredited partners and come with their own accredited certificates.

UKAS is a signatory to the ILAC Mutual Recognition Arrangement, so accredited certificates are recognised by accreditation bodies in other signatory countries.

What an accredited certificate shows

An accredited certificate carries the UKAS mark and the laboratory's number, and it should give:

• the sensor's serial number, so the certificate belongs to one device;
• the readings at each calibration point, as found and, if adjusted, as left;
• the error at each point and its measurement uncertainty;
• the reference used and its traceability;
• the date of calibration and the method.

The uncertainty is what lets you apply a decision rule, such as guard banding your alarm limits. Our guide to measurement uncertainty in medical laboratories works through that with examples.

How we calibrate

We run a UKAS accredited calibration laboratory No. 10723, accredited to ISO/IEC 17025 for temperature, and work with accredited partners for other parameters. Our calibration is traceable to national standards as standard, or UKAS accredited where you need it.

• Calibration for every sensor we supply: traceable to national standards as standard, or UKAS accredited where you need it (temperature in our own UKAS accredited calibration laboratory No. 10723; other parameters through accredited partners).
• Multi-point temperature checks at the points that matter for how the sensor is used.
• A certificate tied to each sensor's serial number.
• Temperature calibration in our lab or on site, so monitoring keeps running.

Every certificate is uploaded to Sematics against its sensor, where your QA or compliance team can review it, download it for an inspector, approve it in the platform, and get a reminder before it expires. Nobody has to chase paper before an audit.

In the lab or on site

Lab calibration suits sensors that can come off site for a short time. On-site temperature calibration suits fixed probes and sites that cannot lose a sensor even briefly; an engineer brings the reference to the unit and calibrates it in place.

Either way, the certificate is the same accredited certificate, inside the same scope, and it goes into Sematics against the same sensor. Plan calibration around your busiest periods and inspection dates, so certificates are never close to expiry when an inspector arrives.

What accredited calibration gives you

• Evidence that stands up when an inspector or auditor asks for it.
• Confidence that an alarm-free record means the conditions really stayed in limits.
• Measurement uncertainty you can build into alarm limits and decision rules.
• Less time spent finding and checking certificates before an audit.

Find out more about our calibration service and how calibration fits into ISO 17025.