QS-9000 3rd edition - Laboratory Process Control - Temperature and Humidity

[Real Gagne]

Laboratory Process Control

According to QS-9000 3rd edition, we have to monitor the environmental conditions of our "In-House laboratory". We are a small company (about 70 employees) and we need an equipment to mainly monitor the temperature and humidity. We are doing basic inspections (calipers, micrometers, dial indicators) and we don't want to spend thousands of dollars for this equipment. Do you have suggestions (equipment specifications)?

Thanks.

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Real Gagne

[This message has been edited by Real Gagne (edited 03 January 2001).]

 

[Jerry Eldred]

The popular low-budget option is a temperaure and humidity chart recorder with LCD readout, detachable hygrometer probe (which I recommend, due to its ease of calibration - you'll find vendors to calibrate more readily than those without that probe). The vendors that come to mind are Omega Engineering, Dickson, Honeywell, Vaisala, General Eastern, ASL Inc. I am not advertising for any of them, and will refrain from trying to sell any of their specific units. If you want more detailed reply on that, please feel free to email me separately, and I'll try to give you some information.



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[David Mullins]

Dare I say - a wet & dry bulb thermometer!
Should give you about $985 change from one of those thousands.

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[Sam]

David, glad you said it first; That's exactly what I have used in the past. Works great.

 

[Ken K]

If you have access to a Fisher Scientific catalog, there are numerous listings for gages that will help you monitor lab conditions. Most of them are traceable to NIST standards.

 

[Ryan Wilde]

Originally posted by David Mullins:
Dare I say - a wet & dry bulb thermometer!
Should give you about $985 change from one of those thousands.

I have no familiarity with QS9000, but I do know that in the language of standards, monitor means "record". Therefore, the wet/dry bulb does not meet that requirement, unless someone performs a documented check every 10 minutes 24/7. The reasoning is simple - rate of change is by far more important to dimensional calibration than is the actual temperature. If your lab is turned down to say 60°F at night to save power, then turned up upon arrival, and it gets up to 73°F within an hour or so, you've added 13°F of uncertainty (Heretofore known as "slop") to any measurements you make.

Doesn't seem like much? Let's use a 24" set of calipers. In simple mathematics, the growth rate of 52100 steel is 6.4µin/in/°F. Therefore, 6.4E-6in * 24in * 13° = 0.0019968, or about 0.002" of possible "slop" that you've introduced. Last time I checked, the tolerance of a set of 24" calipers was 0.002".

I doubt that your lab is at this extreme, but the standard is just asking you to document, and therefore prove it.

Ryan