UKAS accredited calibration laboratory No. 10723

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For quality managers who file calibration certificates

What an accredited calibration means, and how to read the certificate

ISO/IEC 17025 is the standard calibration and testing laboratories are accredited against; in the UK, UKAS does the accrediting, and each lab's schedule says exactly what it is accredited to do. An accredited certificate is only as good as its match to that schedule: check the lab's number, that the measurement sits inside its scope, the uncertainty, and that the serial number is the sensor you actually use. 10723 is our UKAS laboratory number; ISO/IEC 17025 is the standard we're accredited to.

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Updated 18 October 2026Reviewed by Jake Farrow, Managing Director

UKAS accredited calibration laboratory No. 10723

Accredited to ISO/IEC 17025 for temperature calibration, in our Tamworth lab and on site. 10723 is our UKAS laboratory number; ISO/IEC 17025 is the standard we're accredited to. Our accreditation is limited to those activities described on our UKAS schedule of accreditation, found here.

Not covered by this accreditation: monitoring, mapping, validation, our traceable (non-accredited) calibrations, and calibration of humidity, CO₂ and other parameters, which go to accredited partner laboratories.

At a glance

What it asks

Our scope, in plain sight

What our UKAS accredited laboratory is accredited for, and how much of our work is UKAS

Our UKAS accreditation (UKAS accredited calibration laboratory No. 10723) covers temperature only. Humidity, CO₂ and other parameters are calibrated through accredited partners, which issue their own certificates under their own UKAS accreditation number.

Our UKAS scope: temperature ranges
Dry block · best uncertainty 0.07 °C−90 to +135 °C
Air chamber · best uncertainty 0.24 °C−35 to +40 °C

In our Tamworth lab or on your site. Anything outside these ranges, and every other parameter, goes to an accredited partner.

3,000+

UKAS accredited calibrations a year

UKAS accredited calibrations a year. We tell you whether you're getting traceable or UKAS accredited calibration before we start.

Up to +660 °C

high-temperature calibration of probes and electronic thermometers through an accredited partner

Above our own range, through an accredited partner working to its own UKAS schedule.

UKAS schedule of accreditation

Accreditation is for a scope, not a company

What it says

A laboratory is accredited to ISO/IEC 17025 for the activities listed on its schedule of accreditation: each parameter, range, method and best measurement capability (the calibration and measurement capability, or CMC). Work outside the schedule can still be done competently, but it isn't accredited, and the certificate shouldn't carry the accreditation mark for it. UKAS publishes every lab's schedule.

What it means on site

'UKAS-calibrated' on a supplier's quote doesn't tell you much. The questions are which lab, which number, and whether your sensor's measurement falls inside that lab's schedule. A humidity calibration from a lab accredited only for temperature isn't an accredited humidity calibration.

How to evidence it

  • The lab's accreditation number on each certificate, and its current UKAS schedule
  • A check that each measurement (parameter and range) sits inside the schedule
  • For work sent to partners, the partner lab's own certificate, under its own accreditation number

ISO/IEC 17025 6.4 and 6.5

Traceability: the chain back to national standards

What it says

The laboratory establishes and maintains metrological traceability of its results through a documented, unbroken chain of calibrations, each contributing to the measurement uncertainty, linking them to an appropriate reference such as the SI through national standards. Its own reference equipment is calibrated and controlled.

What it means on site

Traceability is what makes a reading mean the same thing in your fridge as in the lab. Regulations such as GDP 3.3 and ISO 15189 6.5 ask for it; an accredited certificate is the usual way to show it without having to prove the chain yourself.

How to evidence it

  • The traceability statement on each certificate
  • For non-accredited calibrations, the reference instrument's own certificate

ISO/IEC 17025 7.6

Measurement uncertainty: the number that matters most

What it says

The laboratory identifies the contributions to measurement uncertainty and evaluates it for each calibration. A calibration certificate reports the uncertainty with the result, usually as an expanded uncertainty at a stated coverage factor (k=2, about 95% confidence). The lab's best capability is on its schedule; the uncertainty for your sensor will be that or larger.

What it means on site

A sensor with an uncertainty of ±0.3 °C reading +7.8 °C in a 2 to 8 °C fridge may already be over the limit. That's why alarm limits are set inside the range, by a margin that reflects the uncertainty.

How to evidence it

  • The uncertainty and coverage factor on each certificate
  • Alarm limits for each unit that allow for that uncertainty

ISO/IEC 17025 7.8.2 and 7.8.4

Reading a calibration certificate, line by line

What it says

A certificate identifies the laboratory, the customer and the item calibrated (with its serial number), the date of calibration, the method, the results with their units, the measurement uncertainty, the conditions that affect the results (such as ambient temperature), and a statement of how the measurements are metrologically traceable. Results apply only to the item as calibrated. The certificate doesn't include a recommended recalibration interval unless agreed with the customer.

What it means on site

A common gap is the simplest one: the serial number on the certificate isn't the sensor in the unit, because the sensor was swapped after a fault. Check the serial, the points calibrated (do they cover your working range?), and the error found at each point.

How to evidence it

  • A certificate for each sensor whose serial matches the installed sensor
  • Calibration points that cover the range the unit operates in
  • The error at each point, and whether you've applied a correction
  • The calibration date and your own recalibration interval, set by risk

ISO/IEC 17025 7.8.6 and 7.8.4.1 d)

Pass, fail and who decides

What it says

When a certificate states that an item conforms to a specification (a 'pass'), the laboratory documents the decision rule it used, taking account of the risk of a false accept or reject, and reports which specification and rule apply. When a customer asks for a pass or fail statement, the specification and decision rule are defined first and, unless the specification already sets one, agreed with the customer (7.1.3). UKAS LAB 48 explains how decision rules and guard bands work.

What it means on site

We report results as found and, where we adjust a sensor, as left, with the error and measurement uncertainty at each point; the standard itself asks for this, since a certificate gives the results before and after any adjustment or repair, where available (7.8.4.1 d)). You decide whether the sensor is suitable for use. We don't state pass or fail; you judge each sensor against your own acceptance criteria, because only you know what the storage needs. A sensor within ±1 °C may be fine for an ambient store and not for a 2 to 6 °C blood fridge. If a certificate from any laboratory does say 'pass', ask which specification and decision rule it used. The HPRA puts it plainly: "All calibration certificates should be reviewed and approved by the wholesaler to ensure that the calibration results for the probes are acceptable" (IA-G0011, section 7). In Sematics, your nominated user views each certificate and approves the sensor as suitable for use, so that decision is recorded against the sensor.

How to evidence it

  • Your own acceptance criteria for each sensor, written down, including how you allow for measurement uncertainty
  • A record of each certificate reviewed against those criteria, with the outcome and who decided
  • The specification and decision rule behind any pass or fail a laboratory has stated

In the inspector's words

Questions to be ready for

The kind of questions an inspector, assessor or auditor puts. If you can answer each with a record, you're ready.

  1. “Is this the sensor on this certificate?”
  2. “Which lab calibrated it, and is that measurement inside their UKAS schedule?”
  3. “What is the uncertainty, and how have you taken it into account in your alarm limits?”
  4. “Does the calibration cover the range this unit runs at?”
  5. “Who decided the recalibration interval, and on what basis?”
  6. “Who reviewed this certificate against your acceptance criteria, and what did they decide?”

Where JTF fits

Where JTF fits

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). Our UKAS scope covers temperature indicators and recorders with their sensors, from −90 to +135 °C in a dry block and −35 to +40 °C in an air chamber, in our lab or on your site. Above that range we offer high-temperature calibration through accredited partners, Up to +660 °C, and CO₂ in incubators through an accredited partner on site, each working to its own UKAS schedule. We say before we start whether a calibration will be traceable, UKAS accredited in our laboratory No. 10723, or by an accredited partner laboratory under its own accreditation, and each certificate sits against its sensor in Sematics, with its due date, so the serial on file is the sensor in the unit.

Related

Keep reading

Questions

Common questions

Is ISO/IEC 17025 a certification?

No. Laboratories are accredited to ISO/IEC 17025 by a national accreditation body, in the UK UKAS, for a defined scope. Certification is a different process that applies to standards such as ISO 9001.

Is a traceable calibration the same as an accredited one?

Not quite. Both should be traceable to national standards. An accredited calibration has had the lab's competence, method and uncertainty checked by UKAS for that measurement; with a traceable-only certificate you may need to show the chain yourself.

Do you calibrate humidity or CO₂ in your own lab?

No. Our own UKAS accreditation covers temperature only. We arrange humidity, CO₂ and other parameters through accredited partner laboratories, which issue their own certificates under their own UKAS accreditation number. Our CO₂ partners cover 0 to 20% CO₂: incubators on site, and gas detectors in the partner's own laboratory.

How often should sensors be recalibrated?

ISO/IEC 17025 leaves the interval to you. Set it by risk: how critical the store is, how stable the sensor has been, and what your regulator expects. Many sites recalibrate yearly; the Green Book asks for annual calibration of vaccine fridge thermometers.

Are accredited certificates accepted outside the UK?

UKAS is a signatory to the international ILAC arrangement, under which signatories recognise each other's accredited calibration certificates.

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Sources

  1. ISO/IEC 17025:2017 General requirements for the competence of testing and calibration laboratories
  2. UKAS schedule of accreditation 10723 (JTF Wireless Ltd, calibration)
  3. UKAS: Calibration laboratory accreditation (ISO/IEC 17025)
  4. UKAS: Search accredited organisations and their schedules
  5. UKAS LAB 48: Decision rules and statements of conformity
  6. ILAC: Mutual Recognition Arrangement and signatories

This summary isn't official guidance. The source documents are what an inspector works from.

Next step

Calibration due soon?

Tell us how many sensors, probes or loggers, where they are and when they're due. We'll quote in writing and say which work is on our UKAS scope and which goes to an accredited partner.

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or call 0121 794 8092

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