Calibration T
emperature is one of the most frequently measured quantities in industry, it is said second only to time; and one of the most frequently misunderstood. Whether it is pharmaceutical production,
blister packaging, aerospace, manufacturing, or healthcare, small errors in temperature measurement can lead to major problems. Correct calibration is vital, and it needs careful consideration, not just being able to say that it has been calibrated and that there is a certificate. This article reflects on temperature calibration, what can go wrong, and making informed choices around equipment, certificates, and calibration methods.
WHY TEMPERATURE CALIBRATION MATTERS
Temperature influences emissions, legal trade, efficiency, and safety. Even small errors can be the difference between an acceptable product or process and a failed one. In critical sectors, that same deviation might mean failed audits, customer complaints, or worse
Despite that, temperature measurement is often assumed to be “close enough”. Calibration, if it is done at all, may be treated as an annual formality. But calibration is not simply about compliance. It is about knowing what you can rely on—how accurate your measurements really are, and if they stand up to scrutiny.
WHEN IT GOES WRONG We have encountered a number of real- world cases where inaccurate temperature measurement caused unexpected and sometimes costly problems.
In one example, issues with blister packaging were eventually traced to poor surface temperature measurements and inadequate calibration methods. The sensors did not represent the true sealing surface temperature, and the calibration method did not replicate actual conditions. The result was both inconsistent seals and product failure.
In another case, colour variation in photographic film processing was affecting quality across sites. The solution? Each location implemented on-site calibration using gallium fixed-point cells, offering a stable reference at 29.7646°C. By tying calibration back to a known physical standard, an ITS-90 cell, consistency was restored.
Temperature also played a critical role in NASA’s STS-51F shuttle mission (Challenger, July 1985). A premature engine shutdown occurred during ascent when both temperature sensors monitoring the centre engine’s high-pressure fuel turbopump failed. The system shut down the engine not due to actual overheating, but because the logic required valid sensor input
16
GETTING TEMPERATURE RIGHT
CALIBRATION INSIGHTS FROM THE LABORATORY TO ON-SITE CALIBRATION By David Southworth, temperature calibration specialist and technical trainer, Isotech
to continue operation. The crew executed an “Abort to Orbit” the only such in-flight abort of the Shuttle era, reaching a lower-than-planned orbit. The measurement didn’t reflect the reality of the situation but had very real consequences. For all these examples, from blister packaging machines to spaceflight, the message is the same: poor temperature measurement, even when subtle, can lead to very real problems.
NOT ALL CALIBRATION IS EQUAL When a measurement is questioned either by an auditor, a regulator, or in a contractual dispute, the type of calibration behind it matters. A certificate marked “traceable” may indicate that reference standards were used, but that does not guarantee how well the work was carried out. Was the uncertainty calculated? Were the
September 2025 Instrumentation Monthly
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72
