Sciencemadness Discussion Board

Calibration Weights Classification for Balances

Mush - 1-2-2020 at 13:14

Calibration Weights Classification for Balances

https://laboratoryresource.com/?navaction=getitem&id=237

Laboratories concerned with quantitative analyses require stringent calibration of scales. Modern scales are easily calibrated and the accuracy of scales is largely dependent on the accuracy of the calibration weight. Modern scales electronically divide the calibration weight to obtain all smaller readings and this requires a perfectly balanced electronic circuit. For most accurate requirements check scales with a calibration weight of similar weight as the specimens under evaluation. Other impinging issues are magnetic properties of the calibration weight and weights handling and storage.

Accuracy of calibration weights are defined from the grades of stainless steel as well as other contributing factors. These different grades have different magnetization/accuracy (eg 8.0g/cm3). Most calibration weights are available with certificates.

Calibration Weight Classes

Class E1 These weights are the highest accuracy class, and are intended to be used for traceability between national mass standards and OIML
class E2 weights and lower. The maximum permissible error from nominal value at 1 kg is ±0.5 mg. Used as primary laboratory reference standard.

Class E2 Suitable for use for traceability of OIML class F1 weights and lower; also with OIML accuracy class I weighing instruments. The maximum permissible error from nominal value at 1 kg is ±1.6 mg. Used as a high precision standard for calibration of weights and special precision analytical instruments.

Class F1 Suitable for use for traceability of OIML class F2 weights and lower; also with OIML accuracy class I weighing instruments. The maximum permissible error from nominal value at 1 kg is ±5 mg. For the calibration of high accuracy class 2 balances.

Class F2 Suitable for use for traceability of OIML class M1 weights and lower; also with OIML accuracy class II weighing instruments. Intended for use in high value commercial transactions such as gold and precious stones. The maximum permissible error from nominal value at 1 kg is ±16 mg. Used as working standards for precision and analytical work, build-in weights, external weights to calibrate moderate precision balances.

Class M1 Suitable for use for traceability of OIML class M2 weights and lower; also with OIML accuracy class II weighing instruments. The maximum permissible error from nominal value at 1 kg is ±50 mg.

Class M2 Suitable for use for traceability of OIML class M3 weights; also with OIML accuracy class III weighing instruments. Intended for use in normal commercial transactions where goods are sold by weight. The maximum permissible error from nominal value at 1 kg is ±160 mg. Used for accuracy class III applications, industrial scales, dial scales, trip balances, platform scales

Class M3 Suitable for use with OIML accuracy class III or IIII weighing instruments. The maximum permissible error from nominal value at 1 kg is ±500 mg. May be used for accuracy class III L and IV.

DavidJR - 1-2-2020 at 18:24

Is there a reason for copy-pasting this here?

Sulaiman - 1-2-2020 at 22:15

You can also purchase class E0 Primary standards https://shop.haefner.de/kategorie.php

I have recently become interested in mass, weight, buoyancy etc.
Being separated from my hobby stuff for months, I bought a relatively cheap analytical balance,
and I've done a few VERY rough videos of checking the weight of cheap (Chinese via eBay) calibration weight kits.
https://www.youtube.com/channel/UCRL1WUCMm0AFuKhLkWRqQ7g
When I'm reunited with my stuff I intend to make several more crappy videos as I have M1 and F1 weight kits, 3x E2 weights, and various digital and mechanical scales to compare.
I'm currently making a video where I hope to demonstrate that Archimedes did not test the purity of gold in the way that you probably believe.

Mush, what is your interest in mass/weight ?
________________________
EDIT: per the comment below,
Class E0 weights are definitely not a Primary standard/reference, ... poor terminology, sorry :(
AFAIK, E0 are just the most accurate references commercially available.

[Edited on 3-2-2020 by Sulaiman]

unionised - 2-2-2020 at 02:29

Until recently, there was (by definition) exactly one primary standard.
https://en.wikipedia.org/wiki/International_Prototype_of_the...
and they won't sell it to you.

There is no longer a primary standard (other than the definition).

Mush - 9-2-2020 at 06:09

Quote: Originally posted by Sulaiman  
You can also purchase class E0 Primary standards https://shop.haefner.de/kategorie.php

I have recently become interested in mass, weight, buoyancy etc.
Being separated from my hobby stuff for months, I bought a relatively cheap analytical balance,
and I've done a few VERY rough videos of checking the weight of cheap (Chinese via eBay) calibration weight kits.
https://www.youtube.com/channel/UCRL1WUCMm0AFuKhLkWRqQ7g
When I'm reunited with my stuff I intend to make several more crappy videos as I have M1 and F1 weight kits, 3x E2 weights, and various digital and mechanical scales to compare.
I'm currently making a video where I hope to demonstrate that Archimedes did not test the purity of gold in the way that you probably believe.

Mush, what is your interest in mass/weight ?
________________________
EDIT: per the comment below,
Class E0 weights are definitely not a Primary standard/reference, ... poor terminology, sorry :(
AFAIK, E0 are just the most accurate references commercially available.

[Edited on 3-2-2020 by Sulaiman]


I just want to calibrate my budget analytical balance as accurate as possible for general analytical purposes.

[Edited on 9-2-2020 by Mush]

CharlieA - 9-2-2020 at 18:09

You really only need one very accurate (standard) weight (I know, mass, but I'm an old fart); then you reference all your other weights against that one.

Sulaiman - 9-2-2020 at 20:58

Quote: Originally posted by Mush  
I just want to calibrate my budget analytical balance as accurate as possible for general analytical purposes.
If you give details of the balance we can suggest suitable calibration requirements.

This OIML document is my primary reference source for calibration
Attachment: R076-1-e06.pdf (939kB)
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