Calibration Procedure

In at the deep end eh?

Before anything else, most instrument manufacturers include the user manuals with the instruments. In fact, I've never had an instrument delivered that didn't have a user manual. That said, these documents must be around in your factory somewhere. Try and have a look first.

If the manuals are missing, misplaced, stolen, used for kindling or whatever, you can go to the instrument manufacturer's website. You didn't mention the brand of your instruments so I can't direct you. If you're familiar with Google, just type the instrument's brand name in the box and include "+manual" in your search.

Good luck.

Thanks very much. I have got some of the manuals. I was wondering is there any standard procedure/instructions to follow up in general for these type of instruments. As everything come under scruitiny by Auditors we would like to have one QA procedure for each test/calibrations.

Ah, okay, calibration audits are usually more concerned with two things:

1. Is the technician qualified to perform calibration?
2. Are your calibration instruments calibrated and traceable to international standards.

Basically, if you follow the calibration procedures stated in the manual, you're going to be fine. Now, all you need is to satisfy the two things I mentioned above.

Your technician should be trained and have a certificate to prove it. Your calibration instrument needs to have a certificate also. The certificate needs to show that the calibration can be traced to an international standard.

Great advice Vulcan!

milo

If you are performing the calibrations in-house, you obviously have staff with the necessary skills to carry out the work, and therefore, they should be able to write the calibration procedures in an SOP, using the vendors manuals. Otherwise, a contract calibration company will provide the calibration procedures they use for the various types of instruments. What is also important to include in your SOP are:

1. the roles and responsibilities of departments involved in the procedure (e.g. who performs the calibration, who reviews the calibration data, who approves the calibration and issues the calibration certificate and calibration labels, etc.)

2. The frequency of calibration and the calibration range.

3. the process for handling failed calibrations?

4. What test equipment is used for the calibration (you may have a seperate SOP/policy/process for dealing with calibration of your test equipment on site e.g. multimeters).

Essentially, auditors will look at your procedures and determine a) are they adequate and more importantly b) are you consistently adhering to them. Also, as Vulcan has pointed out, training records of individuals carrying out the calibrations is essential. If you can't prove that staff are trained to carry out the work correctly, you will be in a very bad place during inspections.

Just search to Google and youll get a lot of hits! Ü

BUt in searching you should also consider if the said procedure is ISA approved, or else your calibration done would be void or not accepted if your instruments or company would be audited by any organization which I think is required.

You can refer to the Website of the EA (European Accreditation) for the applicable examples amazing for You. Uncertainty is dealt with thoroughly and instruments calibration examples for use either as single or in coherent chain connection are also given therein.

Good Work,

Riccardo Tarelli

By the way:

In the USA there is an ISA organization that take care of some general problems of calibartion. I used some of their materials to write Procedures.

www.isa.org

Dear Sameer,

Firstly are you qualified to calibrate these instruments?. Do you have any training as I am an Instrument Engineer and know that these Instruments are fairly standard and I cannot believe that had you any kind of qualification or training that you would be asking how to calibrate them. It is dangerous to both yourself and others if you don't know what you are doing.

I also appreciate that due to the demographic timebomb that is currently hitting the western world that there is a masssive shortage of trained/qualified personnel within our industry.

The first thing to remember is that you never DIVE IN. Read the manuals that should have been provided with each instrument if not note the manufacturer and model number and surf the net for information regarding correct calibration procedures.

Lastly I have some literature that may be of assistance to you if you contact me on my e-mail address josephcowan@hotmail.co.uk and I can forward this to yourself at least it will let you know what is happening by providing you with the basic fundamentals of Instrumentation an control systems

Regards,

Joseph Cowan (E/I Commissioning Engineer)

Dear Joseph Cowan

Thanks for your kind reply and help extended to me. I have been working similar field for about three years. Recently I have been shifted to a new division and have got this prosposal. Also onsite calibration is new to me. What I was expecting by asking these query to this forum is to make my job easier and faster. Definitely I can prepare work procedure by referring respective manuals and standards. I already started preparing it according to the site requirement. Hope I could finish by another two to three days time.

I will be in touch with you if I stuck in between.

Thanks once again

with best regards

sameer

Dear Sameer,

As soon you have some experience in calibration field, I am sure, you will manage the situation. The only advise I would like to give you is as followed:

1. Have look on the ISO 17025 standard: "General requirements for the competence of testing and calibration laboratories". It will give you tips how to organize the calibration lab.

2. Before you start to do something, find the answer to the question: How should I perform the evaluation of measurement uncertainty and how deep I need to go with it?

With best regards,

Similani

OK, first in order to calibrate anything you're going to need to study ISO/IEC 17025, have the appropiate calibration standards (in your case, flow, conductivity, and pressure), and I suggest purchasing the Certified Calibration Technician (CCT) Primer from the Quality Council of Indiana, 602 West Paris Avenue, West Terre Haute, IN. 47885 USA, tel; 812-533-4215 or go to their website at www.qualitycouncil.com and find out how you can apply to take their tests.

Be prepared to study and even if you are an engineer you'll probably fail the first examinations. They aren't easy. I have a lot of respect for calibration techs and find their skills and training to be superior to many engineers I've had to work with.

That being said, conductivity standards are available from Cole-Parmer (look in Google), the pressure standard our techs use is a Druck DP 601 although there are probably equivalents from Omega, Merriam Instruments, and others. We have flow standards from Flowtech and Omega. You'll have to google up all these suppliers and look at their tech data to see which best fits your requirements.

If you are only charged with writing procedures talk to the manufacturers of your equipment. They may be able to provide you with written procedures which will pass the scrutiny of any auditor. If possible don't try to write calibration procedures from scratch. I know that to meet current ISO/IEC requirements, our procedures must follow a certain format and contain details about recording the environment during calibration, the technicians identity, standards used, their calibration dates, and other information.

You've entered into an esoteric (look that word up) world. It's best to let the experts lead you through it as another contributor suggested. Losing you way here can be disasterous for your project and perhaps your company.

Ref.- The purpose of this section is to outline the procedures for calibrating artifacts and instruments while guaranteeing the 'goodness' of the calibration results. Calibration is a measurement process that assigns values to the property of an artifact or to the response of an instrument relative to reference standards or to a designated measurement process. The purpose of calibration is to eliminate or reduce bias in the user's measurement system relative to the reference base. The calibration procedure compares an "unknown" or test item(s) or instrument with reference standards according to a specific algorithm.

See in this site: Calibration Procedure

Be sure your standards or other meters/instruments to compare with Device/Unit Under The Test/Calibration (DUT) have better accuracy. In mechanical world there was a rules of thumb that "standard" must be 10 times more accurate than calibrated instruments. In the time of digital electronics this rule (applied to electrical instruments, transmitters etc.) became 3 to 5 times factor.

Example: the transducer with its output accuracy 2 % must be tested/calibrated with an meter (e.g. milliampere meter) of at least 0.5 % accuracy. Extremaly hard are accuracy of 1 - 10 ppm (per million).

Fluke - Phillips have a v. good Intro Handbook of Theoretical Measurement/calibration Theory.