Jewelry vs. Normal Laboratory Balances - Accuracy and calibration

[shaker2051]

Hi GUYS
I work in pharmaceutical company. It would be a great help if someone could tell me the difference between jewelry and normal lab. balances regarding Accuracy and calibration. Some mix-up during ordering some balances and the ones that we got (pharmaceutical co.) are mettler jewelry balances. Is it Ok to use them after in-house Cal.? Is there any guideline prohibiting using them in pharmaceuticals?
Thank you All in Advance.

 

[Ninja]

To a large degree, the difference is in INTENDED use...not in function.

If it mesures what you need to measure, and does so as accurately and repeatably as you need...there's no issue.
(Accuracy by calibration, of course).

If there is any doubt, which there seems to be since you have posted, be sure to calibrate and verify/validate across the entire range of the balance to put your mind at rest.

The only thing that I would take care for is if they are PORTABLE jewelry balances...some customers, especially automotive, require recalibration if the balance is moved...and portable gets sticky pretty quick.

Due to the intended uses for a jewelry balance, they sometimes lack functions often needed by a laboratory (access doors, change of weighing pan, etc.) Check to make sure you can do everything you need to do on the scale ...

HTH

 

[dwperron]

The biggest difference with your jewelry scale is that it is most probably "Legal for Trade" or NTEP approved. Here is a brief explanation:

NTEP stands for National Type Evaluation Program, which is a non-profit corporation. Scales and other weighing equipment that are NTEP approved have been tested and evaluated to ensure they meet all government standards and requirements. The government standards are set by the NIST (National Institute of Standards and Technology), and are listed in their NIST Handbook 44 The NIST standards cover every aspect of an NTEP approved scale from capacity, accuracy, effects on the scale from temperature and humidity, and even how the manufacturers label is to appear on the scale. It is the standards in the NIST Handbook 44 that your local Weights and Measures inspector(s) will typically use when inspecting your scale and certifying it for use. Each NTEP approved scale will have an NTEP certificate or conformance number listed on it so that your local inspector can obtain a copy of the conformance certificate, and verify that the brand and model of your scale was manufactured within NIST standards.

These scales meet the requirements for commercial sales, there is no problem in using them for other purposes as well. There is no reason why they cannot be calibrated in house as long as you are not using them commercially.