Technician Proficiency Testing - Small Scale and Balances Laboratory

[Lorrie]

Hello all, please allow me to introduce myself. My name is Lorrie Blackburn; I'm the Quality Manager in a small scale lab that has recently received our 17025 accreditation. I happened upon this forum yesterday in a desperate search for an outside source of Proficiency Tests for scale technicians. At present, we are doing intra-laboratory Replicate Testing in lieu of Proficiency Testing, but we would like to participate in an inter-laboratory proficiency testing program. Unfortunately, I've not be able to find one that fits within our scope (scales and balances). If anyone can point me in the right direction, I'd really appreciate it.

 

[Ken K]

Hi Lorrie,

Here is a sight which may help you.

https://www.proficiency.org/

On the left side of the page click on NAPT Sponsored ILC / PTs and there is PT for scales and balances

 

[Lorrie]

Thanks, Ken. We have already signed up with NAPT for the tests they offer; however, our scope includes tanks, hoppers, and truck scales up to 24,000 lb; NAPT only offers testing for small scales (up to 20 lb) and balances. While it is unlikely that any of our truck scale customers will need accredited calibrations, we do have several pharmaceutical customers using tank scales; their calibrations need to be accredited, so we had to include this in our scope. Our accreditation body (Perry-Johnson Laboratories) has indicated that we need to proficiency test each segment of our scope on a regular basis, so we need to find some way of including these segments in our PT program.

 

[Ken K]

Lorrie, have you thought about setting up your own ILC/PT using ISO Guide 43-1 and 43-2?

You could use a local, if possible, calibration firm to run the PT with your lab.

 

[tomvehoski]

Lorrie,

I worked with a scale calibration company a few years ago on ISO 17025. Are you calibrating scales, or performing inspection/testing using them?

We claimed inter-lab proficiency testing was not possible in the scale calibration environment since:

1. The only public proficiency tests were for calibrating the weight standards themselves, not the scales as my client did.

2. It was not possible to circulate a scale among companies since moving a scale can cause damage and changes in calibration.

3. The last option would be to have a inter-lab comparison at my clients (or a neutral) site. Since it was really not desireable to have the competition in to see my clients process, and there were probably not other companies wishing to participate, it was not considered feasible.

We did do internal testing to technicians to ensure they were following the correct calibration process. I was also told by NIST (I believe) that the act of having an independent 3rd party auditor (i.e. your 17025 accrediation body) review your actions against your procedure could count as a proficiency test. (You might find a thread here concerning this back around mid 2001). I might have the e-mails from NIST in my archives - I will take a look over the weekend.

I also had another similar situation with a client last year. They calibrated the equipment they made at the customer site. Since they were the OEM, the were also the only company in existance that would calibrate the machines. They also had only one primary technician to service all of them. We got through the initial audit without having to do a PT, but the auditor did want to see something within a year. The plan was to have a technican from the supplier that built part of the equipment perform a calibration along with their own tech. Not sure if they ever did or not.

Hope this helps,

Tom

 

[Lorrie]

Lorrie,

We claimed inter-lab proficiency testing was not possible in the scale calibration environment since:

1. The only public proficiency tests were for calibrating the weight standards themselves, not the scales as my client did.

2. It was not possible to circulate a scale among companies since moving a scale can cause damage and changes in calibration.

3. The last option would be to have a inter-lab comparison at my clients (or a neutral) site. Since it was really not desireable to have the competition in to see my clients process, and there were probably not other companies wishing to participate, it was not considered feasible.

Tom, you hit the nail right on the head. We have considered setting up a test wherein we have ARTIFACTS of some sort (hunks of metal??) sent around to different scale calibration facilities wishing to participate in the test. The artifacts would have weights pre-certified by, perhaps, our state Dept. of Agriculture Standards Lab. Upon receipt, the technician would set up and calibrate their own scale, weigh the artifacts, record their results, and send the results back to the body administering the test for scoring purposes. The artifacts would then be sent on to the next test site. This would eliminate the problem of shipping a scale.

The problem: How do we insure the artifact is not damaged in shipping in such a manner as to change it's weight? If a piece gets dinged off the corner, it will obviously weigh less.

Does the Standard require that the body administering the test be certified or accredited in some fashion? For example, does NAPT have credentials that assure they know what they're doing? Or can we administer it ourselves?

Lorrie

 

[tomvehoski]

Tom, you hit the nail right on the head. We have considered setting up a test wherein we have ARTIFACTS of some sort (hunks of metal??) sent around to different scale calibration facilities wishing to participate in the test. The artifacts would have weights pre-certified by, perhaps, our state Dept. of Agriculture Standards Lab. Upon receipt, the technician would set up and calibrate their own scale, weigh the artifacts, record their results, and send the results back to the body administering the test for scoring purposes. The artifacts would then be sent on to the next test site. This would eliminate the problem of shipping a scale.

Lorrie

Lorrie,

I don't think this process for the test would work. The artifact would have to be the scale, not the weight. For example, we have a 100 pound weight. You calibrate and set up your digital scale with a resolution of .01 pounds and measure 100.55 pounds and report it. You send me the weight and I put it on my old mechanical scale with a 1 pound resolution and measure 101 pounds. The process for calibration is different, the capabilities of the measuring system are different, etc.

As I understand PT, if your business is calibrating micrometers, you get a set of micrometers to check, not a set of parts to measure.

I notice that NAPT does show two scales that they circulate, so perhaps it is now possible. What value that will add to your organization is another question.

Tom

 

[Hershal]

The NAPT scale and analytical balance tests (one in KY, one being negotiated for LA) will have the scale and the balance set up in a single location. The participating labs will come to that location, with just-calibrated mass standards. The scale and balance are the devices (not artifacts actually, since they are mechanical) and each lab will have time with the device(s). The scale and the balance are separate tests.

A high mass PT for the truck scales can be done the same way. It just takes a bit of work to coordinate....make sure set up and reporting is in accordance with Guide 43-1 and Guide 43-2.

Hershal