Which tags survive industrial temperatures?
The chip is rarely the limit. The adhesive gives up first, then the substrate softens and lets the antenna move, and only after both does anything electronic come into question. Specify from the adhesive upward rather than from the datasheet down.
What fails first
The adhesive. Bonds soften with heat, and a tag that slides or lifts has failed whatever the chip could have tolerated. This is the limit in most real deployments.
The substrate second. Plastics soften before they melt, and a softened carrier lets the antenna deform. The tag then fails mechanically, which reads as an electronic fault.
The chip last, and usually not at all within the range where the first two have already given way.
Specifying a tag by its chip temperature range therefore answers the wrong question, and it is the number datasheets make easiest to find.
Two different requirements
Continuous service temperature is what the tag lives at. A machine housing that runs warm all day, an engine bay, a heated store.
Process excursion is a short exposure to something much hotter: a paint oven, a sterilisation cycle, a press. The tag must survive it and does not have to work during it.
These are different specifications and they are routinely conflated. A tag rated for a continuous temperature may not survive a short excursion far above it, and a tag built for oven passes may be overkill for a warm cabinet.
Say which one you have, and if you have both, say both.
Materials that go higher
Ordinary paper and PVC give up early, which puts most cheap labels out of the running immediately.
PET film goes considerably further and covers most warm industrial environments.
High performance polymers and ceramic bodied tags exist for genuinely hot processes, at a price that reflects the specialism. These are the tags used where a label passes through an oven with the product.
Adhesives have their own ladder, and a high temperature adhesive is a separate specification from a high temperature substrate. Buying one without the other leaves the weaker of the two in charge.
Specifying for heat
Measure the real temperature at the real spot rather than taking the ambient figure. A surface in direct sun, or next to a motor, runs far above the air around it.
State the continuous range, the excursion peak with its duration, and whether the tag must read while hot.
State the surface, since a metal surface at temperature needs an on metal tag whose ferrite is also rated for it.
Then test in the real cycle, repeatedly. A tag that survives one oven pass and fails on the fifth is a common outcome, and only a repeated test finds it.
Frequently asked questions
Does heat erase the stored data?
Not within any range where the tag physically survives. Data retention limits sit far beyond where the substrate and adhesive have already failed.
Can a tag be read while it is hot?
Often yes, if it is built for the temperature. Reading during an excursion is a separate requirement from surviving one, so state it explicitly.
Is a metal tag better for heat?
An on metal tag is about the surface rather than the temperature, and its ferrite has its own limits. The two requirements have to be specified together.
What about cold?
Cold mainly affects the adhesive, both in service and at application. Applying below an adhesive's minimum temperature produces a bond that fails weeks later.