Temperature/humidity requirements in internal metrology laboratory




I know it is a norm that specifies temperature/humidity requirement in a metrology laboratory, but i can't remember it.

Thank you.

P.S.: I am working in automotive industry, the lab. is equipped with CMM machines.


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I really don't know of specific requirements for laboratory environments. The standards require that the environments be adequate for the work being done in them. This means you choose temperature (actual and stability), humidity, cleanliness, etc. based on the level and type of calibration being performed. And you need to monitor your environment.

There are recommendations. The best is NCSLI RP-14 Guide to Selecting Standards Laboratory Environments. They have suggestions based on types of work performed. Other documents include ISO 554 and ISA-RP52.1.

A suggestion is to evaluate the specifications of the equipment used in your lab. There are normally environmental ranges attached to the tolerances, and if you go beyond these you must account for environmental contributors to your uncertainties. If you can stay within the environmental requirements of your equipment it will save you a lot of work compensating for it.


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In my experience, the labs usually stay at 68 +/- 2 deg. If its outside that, then Zeiss will not guarantee the calibration on my CMM. I've worked in that temp range since 1998 with no issues. Humidly is not a major factor for my work here. Only temps


Most title blocks on prints reference ANSI Y14.5 M or whatever the latest spec is. In the first few pages of that spec it states that all measurements are valid at 68°F ±2° or 20°C ±1°. If measurements are not recorded at this temperature range then one must calculate and compensate for thermo-expansion.

This is the key reason why QA Labs are maintained at 68°F.
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