How data logger validation works, how it differs from calibration, what records auditors expect, and how often to repeat it. A practical guide for Australian sites.
Data logger validation confirms that a logger is fit for the job you have given it: it reads accurately, it is placed where it represents the real conditions, and you hold records that prove both. For most Australian sites that means a traceable calibration certificate, a documented check of the logger in its working position, and a defined interval for repeating both. We explain each step below, with the tests, records and decisions that hold up when an auditor asks to see them.
A data logger is only useful if people trust what it recorded. Validation is the work that earns that trust. It answers three questions:
The word is used loosely across industries. In pharmaceutical and laboratory settings, validation or qualification often covers the whole monitoring system: the logger, its software, its sensor positions and its alarm settings. In a cold store or a food business, it usually means proving that the loggers behind your temperature records are accurate and suitably placed. We use it here in the broader sense, and flag where a step belongs to calibration alone.
The two terms are often swapped, and that causes audit findings.
| Calibration | Validation | |
|---|---|---|
| Question answered | Does the sensor read correctly against a reference? | Is the logger fit for its intended use and location? |
| Done by | An accredited calibration laboratory, or a competent in-house team with traceable standards | Your quality team, often with a calibration provider’s help |
| Typical evidence | Calibration certificate with measured values, uncertainty and traceability statement | Check records, mapping or placement records, acceptance criteria, decision to release or reject |
| Trigger | Scheduled interval, repair, suspected drift | Commissioning, relocation, change of process, failed check, scheduled interval |
A freshly calibrated logger can still be placed in the wrong spot, such as next to a door or a cooling coil, and give you a misleading record. Equally, a logger in a well-chosen location can have drifted out of tolerance. Neither on its own gives you a defensible record.
Some of the most common situations we see are these:
If your site sits in any of these groups, the logger is part of your quality system, not just an accessory.
The sequence below suits a typical temperature logger. Adapt the points and tolerances to your process and to the logger’s published specification.
Write down what the logger monitors, the temperature range that matters, the accuracy you need and the decision the data supports (release product, quarantine stock, trigger an alarm). The tolerance you need is set by the process, not by whatever the logger happens to offer. A logger with ±0.5 °C accuracy suits a +2 °C to +8 °C fridge. A heat-treatment cycle needs different performance at different points.
Confirm it has a current certificate from a laboratory whose traceability you can demonstrate. NATA’s criteria say that where metrological traceability is required, equipment must be calibrated by a calibration service subject to peer review, or by a service not subject to peer review, in which case the facility must perform extra measures. In practice, most quality teams choose a NATA-accredited laboratory because it removes those extra measures. Our guide to NIST versus NATA certificates covers what to look for on the document.
A point check between calibrations is the quickest way to confirm a logger still reads true. NIST describes an ice melting point validation method for data loggers:
The method checks one point, so it does not replace a multi-point calibration. It does give you a cheap, repeatable test that you can run in your own facility and that generates a record every time.
This is the step that separates validation from calibration. Place the logger where it will operate and confirm that it represents the space. Consider:
Record the positions, with a sketch or photos, so the setup can be reproduced after maintenance.
Decide before testing what passes. Acceptance criteria come from the process requirement, the logger’s specification and any regulator or customer requirement. WHO’s PQS specification for vaccine loggers offers a useful benchmark: its temperature sensor requirement of ±0.5 °C or better within -30 °C to +20 °C. Your own criteria might be tighter or looser, but they must be written down and justified.
Sign and date the result, state whether the logger is released for use, and file it with the certificate and placement record. Our article on what to check on cold chain logger calibration covers the paperwork in more depth.
An auditor does not just ask whether you validated. They ask to see it. A good file contains:
If the difference between traceable and accredited calibration is unclear, our six-document checklist explains what each one proves.
NIST states that regular validation, such as an annual measurement at the ice point, is necessary. Annual is a common starting point for calibration as well. NATA’s general accreditation guidance covers establishing calibration and checking intervals for equipment and points to the equipment assurance and traceability policies alongside it. Base your interval on:
Shorten the interval if the history shows drift, and extend it only when the records support that. For a practical view on balancing frequent checks with annual calibration, see this guide to monthly checks and annual calibration for temperature measuring devices.
Re-validate immediately after a drop, a repair, a battery or probe replacement, a firmware update, or any move to a new location.
NIST’s guidance is clear. If the measured error exceeds the stated tolerance, such as ±0.5 °C in its example, the device is not acceptable for vaccine temperature monitoring in its current condition. Readings outside the manufacturer’s stated accuracy at the ice point mean the device should be removed from service and either recalibrated or adjusted, or replaced. Before the new or recalibrated logger goes back into use, repeat the ice point check.
In practice, add two actions of your own:
Many sites run ice point checks themselves and send loggers out for full calibration. That split works well, provided the in-house part is controlled. NATA’s policy on in-house calibration says facilities performing it must demonstrate technical competence, hold evidence of metrological traceability and achieve the required measurement uncertainty. For a quality manager, that means trained staff, a documented procedure, a reference thermometer with a current traceable certificate and a record each time.
For full multi-point calibration, an accredited laboratory gives you a certificate with stated uncertainty and an unbroken traceability chain. NATA also notes that for calibration by a National Measurement Institute, the BIPM KCDB is the authoritative source for verifying which services are covered by the CIPM MRA.
Some loggers make validation simpler. Look for:
We compare options in our guide to the best temperature data loggers for Australian businesses, and explain why NATA traceable loggers make audits easier. If you use Testo loggers, our piece on annual Testo data logger checks covers what auditors can verify.
We see the same pattern across manufacturing, food, pharmaceutical and laboratory sites. The logger is calibrated, the certificate is filed, and nobody has asked whether the logger is in the right place or whether it has been checked since.
Our view is that validation should be a routine, not an event. A short interim check, recorded on a control chart, costs very little and turns an annual surprise into a trend you can see. When that sits on top of NATA-accredited calibration, your records are traceable and your decisions are defensible.
We calibrate on-site or in our workshop, and we service multiple equipment brands regardless of where the equipment was bought. That matters for logger fleets, which are rarely a single brand. A single provider that can handle the whole fleet keeps your intervals aligned and your paperwork in one format.
Kaz
PCS Precision is NATA accredited and ISO 9001 certified, with more than 40 years of industry experience. We calibrate temperature data loggers and other measuring instruments on-site or in our workshop, and we can supply loggers and measuring equipment as well. Our NATA calibration service produces certificates that carry the traceability statement your auditor looks for. See the full list of calibration, maintenance and repair services, browse our measuring equipment, or contact us through our site for a tailored quote. We also offer 24/7 emergency support.
No. Calibration compares the logger’s sensor with a traceable reference and reports the error. Validation confirms the logger is fit for its intended use, including its location, acceptance criteria and records. Most quality systems need both.
NIST describes regular validation, such as an annual ice point check, as necessary. Many sites pair an annual accredited calibration with shorter interim checks. Use drift history and the criticality of the measurement to shorten or extend the interval, and re-check after any drop, repair or relocation.
Take it out of service and have it recalibrated, adjusted or replaced. Repeat the ice point check before it returns to use. Review the data it recorded since the last good check, and document the investigation and corrective action.
NATA’s criteria call for calibration by a service subject to peer review, or extra measures by the facility if it is not. A NATA-accredited laboratory’s certificate gives you a stated traceability reference and uncertainty. Check your regulator’s or customer’s requirements for your sector.
Yes, for interim checks such as the ice point method, provided you have trained staff, a documented procedure, a traceable reference thermometer and a record each time. Full multi-point calibration is best left to an accredited laboratory.
