Calibration Fundamentals: The How-To Thread

[BradM]

Calibration seems to be growing in interest. To help provide assistance, here is some general information for some commonly asked questions.

1. I want to calibrate my devices in-house. What considerations should I take into account?

Starting a new calibration laboratory

2. Exactly what is meant by the term calibration. Is what I am doing considered calibration?

calibration versus verification


From the VIM ( International vocabulary of metrology — Basic and general concepts and associated terms):

2.39 (6.11)
Calibration​

operation that, under specified conditions, in a first step, establishes a relation between the quantity values with measurement uncertainties provided by measurement standards and corresponding indications with associated measurement uncertainties and, in a second step, uses this information to establish a relation for obtaining a measurement result from an indication​

NOTE 2 Calibration should not be confused with adjustment of a measuring system, often mistakenly called “self-calibration”, nor with verification of calibration.​

2.44
verification:

provision of objective evidence that a given item fulfils specified requirements.

3.11 (4.30)
adjustment of a measuring system

adjustment:

set of operations carried out on a measuring system so that it provides prescribed indications corresponding to given values of a quantity to be measured

3. Apart from Elsmar Cove, How can I expand my knowledge in calibration/metrology practices?

Joining NCSL international is an excellent start.

Here are some additional threads on training: Threads related to calibration and training

4. What should I consider when approaching/ addressing torque devices?

5. Any threads to assist with laying out the lab? related to lab layout here

 

[BradM]

Here is a good starting handbook for metrology, provided compliments of pangchiaboon:

http://elsmar.com/Forums/showpost.php?p=510212&postcount=3

 

[Richard Wilde]

Hi All,

The term calibration is used so that when people use the instrument they are guaranteed it meets their measuring requirements. For example, if it measures upto ISO standard which is relevant to the instrument.

However, you will need to check the date when it was last calibrated as they need to be calibrated at a minimum of a year (even if you dont use it regularly).

I hope this helps.

cheers.

 

[dwperron]

The term calibration does not guarantee that an instrument meets specifications, never mind measuring requirements.
It means that at some point the instrument was compared to standards and was found - at that point in time - to be within tolerance.

You keep mentioning "calibrated at a minimum of one year...". There is no standard out there that states this. The current standards all tell owners of test equipment to set calibration intervals based on analysis of calibration results and by their own risk assessment.