Thermometer verification
With every piece of equipment that is required in your laboratory, there’s always regulations! Today, we’ll discuss thermometers and what the EPA and Standard Methods says about their use. Most of it involves “verification.”
Thermometer verification (or calibration) is the process of verifying a thermometer’s accuracy. This is done by a comparison of the thermometer’s temperature readings against a reference thermometer, which is traceable to national standards (NIST, usually).
Both EPA and Standard Methods require that thermometers are verified at least annually. Most states go with annual verification, although Standard Methods recommends semiannual. If your thermometer does not read exactly what the NIST certified thermometer reads, you must record a “correction factor” to align both readings. Standard Methods also recommends that general purpose thermometers should be graduated in increments of 0.5℃ or less. But for a 44.5℃ water bath, use a submersible thermometer graduated to 0.2℃ or less.
How does LabtronX make this process easier for you? Our techs carry NIST Traceable thermometers, and we keep our certificates up to date. Which means, if we verify your thermometers and they pass, yours are also traceable! And the EPA is happy. We sticker the thermometer, noting that it passed. If the reading passed but wasn’t exact, the correction factor will be right on the sticker.
So… what passes and what doesn’t? That’s based on the thermometer’s readability – where the graduations/divisions are marked. Our criteria for passing a thermometer is ± 2 of the least significant divisions, or 1 division where readability ≥ 1°. So what exactly does that mean? Here’s a few examples for you:
So, what if you have a thermometer that only has 5° graduation marks? If it is off by more than one graduation mark, it fails our standards. (But if you think about it, you probably need a more specific thermometer anyway!)
Here’s some more helpful information when it comes to thermometers.
- When we come to visit, just leave the thermometers in their places, that way we can verify them at their operating temperature.
- If you have extra thermometers laying around, for example refrigerator thermometers, store them in the refrigerator or near where they would be used (operating temperature again).
- Also, store them in the position they will be used. If they are used in a vertical position, store them vertically, not laying down horizontally.
If you ever have questions regarding thermometers and which ones you should be using for whatever application, give us a call or talk to the Service Tech when he comes to your plant!
