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Expert ISO Assistance

Rob Kantner answers your questions:


Calibrate scale test weight? (3/11/09)

We use a platform scale as part of our receiving inspection process. It's checked and calibrated by our scale service quarterly. Once a week we check the scale with a 100lb test weight, just to make sure it's working correctly (i.e. within 2 pounds). Our assessor gave us an OFI that we should calibrate the test weight. Is this correct?

Well, you can't "calibrate" a test weight, per se. Calibration means adjusting the tool so that it's measuring correctly. The best you can do with a test weight is "verify" it. And yes, you could get it checked and verified and even certified by a calibration service. But I don't see the point in going to that expense and trouble. You're already having the scale checked and calibrated quarterly. All you're doing with the test weight is checking the scale. It's a preventive action. I assume that if the check shows the scale is faulty, it gets serviced and repaired by the scale company. In your system classify the test weight process as simply an "informal check" and you'll be fine.

Must we mark measuring devices? (1/19/09)

If you have a good covered system for guarding the expiring date of calibration equipment, is it still obligated to attach a label with the same information on the equipment itself?

If your system for tracking expiration of calibration intervals is absolutely bulletproof, you can get away without physically marking the devices. But you can expect an assessor to probe this closely. One pitfall is this: how easy is it for people who use the devices to determine whether they are within their calibration interval? They may easily be asked to demonstrate how to do that. It's a stretch, but in my opinion it would pass if there are no discernible lapses.

How can we cut calibration costs? (11/16/08)

We're a precision machine shop. Our shop people use their own measurement tools (mics, calipers, etc.). There are over 200 tools, and calibrating all of these is very expensive. What are some ways we can cut the cost? Besides not calibrating, of course?

Here are some options. ("Not calibrating" is not one of them.)

  • Reduce the population. Take a census and see how many duplicate instruments there are. Take duplicates out of the system and start a tool sharing arrangement among the operators.
  • Calibrate tools internally instead of contracting out. You'd need to invest in externally calibrated masters (gauge blocks, etc.), but calibrating internally can save a lot of money. Be sure to document calibration steps in work instructions, and maintain appropriate records.
  • Extend calibration interval. Our experience is the most companies calibrate more often than necessary. Calibration frequency depends on many factors, including instrument sensitivity and usage. You can with justification extend the interval of instruments that are seldom used; you can even calibrate before usage rather than at set intervals.

Should location template be calibrated / verified? (10/11/07)

We've made templates out of flat aluminum plate to locate holes in cabinets. Can we mark these templates "FOR REFERENCE ONLY" or do they need to be calibrated (verified to a drawing)? --R.M., Swainsboro, Georgia

In my opinion "For reference only" is a meaningless distinction. The question is, how critical are those hole locations. The tighter the tolerances and the greater the precision requirements, the more important it is for the template to be accurate. I would therefore recommend that you confirm them to the drawings (and keep a record of this) as part of your calibration process, prior to first use. If they are subject to wear and tear and damage of any kind, that confirmation should be repeated at set intervals.

What's the best way to test scales? (9/6/07)

I work for a 3rd party medical repair co and wondering what policies and procedures we need to follow when testing Medical physicians scales both analog and digital. We have seen competitors forms and wondering where they get all there info from. We use Calibrated test weights but we need to provide all our customers with the same documentation and don't know where to turn. Also, do different states require and conform to different guidelines?

Let me start with, I have no idea what (if any) state laws pertain to what you're doing. We operate in all kinds of industries and the issue of calibrating scales has never involved state laws as far as I know.

With that said: I assume the test weights you're using, which are calibrated, have certificates that trace their calibration to NIST (National Institutes of Standards and Technology). If you don't have such documentation of traceability, you need to get it. The service that calibrates your weights should give that to you as part of the cost of calibration.

Then when you calibrate someone else's equipment (such as physician's scales), you keep a record of: a) date; b) reading as found when you first put the test weight on the scale; c) reading after you adjust / calibrate the scale; d) identity of the test weight (serial number of whatever); e) identity of the person who did the calibration.

This is the basic / minimal information and it's a rudimentary way to proceed. I see no reason why your customers would not find it acceptable. Another approach would be to have your weights calibrated by your calibration service and then look at the documentation they give you.

What's the best way to test scales? (9/6/07)

I work for a 3rd party medical repair co and wondering what policies and procedures we need to follow when testing Medical physicians scales both analog and digital. We have seen competitors forms and wondering where they get all there info from. We use Calibrated test weights but we need to provide all our customers with the same documentation and don't know where to turn. Also, do different states require and conform to different guidelines?

Let me start with, I have no idea what (if any) state laws pertain to what you're doing. We operate in all kinds of industries and the issue of calibrating scales has never involved state laws as far as I know.

With that said: I assume the test weights you're using, which are calibrated, have certificates that trace their calibration to NIST (National Institutes of Standards and Technology). If you don't have such documentation of traceability, you need to get it. The service that calibrates your weights should give that to you as part of the cost of calibration.

Then when you calibrate someone else's equipment (such as physician's scales), you keep a record of: a) date; b) reading as found when you first put the test weight on the scale; c) reading after you adjust / calibrate the scale; d) identity of the test weight (serial number of whatever); e) identity of the person who did the calibration.

This is the basic / minimal information and it's a rudimentary way to proceed. I see no reason why your customers would not find it acceptable. Another approach would be to have your weights calibrated by your calibration service and then look at the documentation they give you.

Can we calibrate our own measuring devices? (5/3/06)

We currently use an outside source to calibrate our scales and lab equipment once per year. Can we purchase our own calibrated weights and calibrate the scales ourselves? If not, can we get a member of our organization certified and if so how would we go about it?

Yes, you can absolutely calibrate your own scales as long as the weights you use to calibrate them are certified and come with traceability to NIST standards. You obviously need to define the calibration intervals, procedure, and the amount of allowable error, and keep detailed records.

Maintenance manuals "for reference only"? (10/6/05)

I am the maintenance supervisor in an e-coat paint facility and we paint automotive parts. I am being told by our internal QS auditor that I must place a "For Reference Only" label on all manuals used to help understand and maintain equipment used in the production process. These manuals are supplied by the fabricators of said eqipment and not following the procedures of the manuals will result in early equipment failure and/or difficulty in trouble shooting equipment malfunctions. Are equipment manuals not considered control documents and is there any sensible reason for labeling them as a reference document? Thanks, D. Webster

From the information you supply, my opinion is that these manuals are essential to efficient process control and maintenance. They should be specifically referenced in the quality system documents (i.e. work instructions or procedures, whatever is relevant), and they should be controlled to assure that only the latest versions are in use. They should NOT be simply labeled "for reference only," which is a catch-all dodge sometimes used to avoid having to control documents that should be subject to control.

What must we calibrate? (4/26/05)

With reference to Article 7.6 (Control Monitoring Devices) of ISO-9000, I have a specific question in this regard. Is it a mandatory requirement to calibrate all measuring and test equipments and to certify these through a 3rd Party on periodic basis?

As far as to my understanding, only specific instruments and equipment requires calibration that are used for process variables measurements or are the requirement of customer as per his satisfaction. Considering the case of a Gas Processing Plant, I believe that calibration is mandatory for instruments like Gas Chromatographs, Laboratory instruments, Temperature, Pressure and Flow measuring instruments that affects the main process, Milli Amp current sources for calibration of Transmitters etc., however electrical measuring instruments like volt meters, ampere meters, ohm meters as well as relays test sets do not fall in the same category. This is because such electrical instruments are used only for checking the electrical parameters and nothing to do with process change. Also customer confidence is dependant of Gas quality and its characteristics, rather than the complete processing plant.

In large part you are correct in your statements about calibration. Here are my comments.

Measuring and test equipment that has an effect on the product/service you supply to your customer must be objectively verified and calibrated (where possible) so that the degree of measurement uncertainty is known.

The further away a measurement device is, in the process, from the product/service, the less critical this is. I believe, however, as a matter of principle, that if a measurement is worth doing, it's worth doing with a device that you can have confidence in because it's been objectively verified.

It is not necessarily required that this be done by a third party. If you have internal capability and certified / traceable measurement equipment to calibrate with, you can do it yourself. All such calibrations need to be traceable to national / international standards. For example, if you have hand held measurement tools (calipers, micrometers), you can calibrate them with a set of certified gauge blocks. This reduces the need for external calibration.

As for calibration interval, the Standard (7.6) says it's to be done on a scheduled basis "or prior to use." It should also be done if the device becomes suspect for some reason (i.e. damaged).

With respect to your statement about the gas processing plant, I agree with everything you say, except to reiterate that if it's not important that a measurement be done with verified equipment, why do the measurement at all?

Do it yourself calibration? (4/11/05)

We currently use an outside source to calibrate our lab and shipping scales once per year. Can we purchase our own calibrated weights and calibrate the scales ourselves? If not, can we get a member of our organization certified and if so how would we go about it? Thanks.

Yes, you can absolutely calibrate your own scales as long as the weights you use to calibrate them are certified and come with traceability to NIST standards. You obviously need to define the calibration intervals, procedure, and the amount of allowable error, and keep detailed records.

Preventive maintenance (2/19/05)

Would you please to explain about preventive maintenance parameter and if possible explanation with sample form maintenance according to Standard ISO 9001-2000. For your information today my company has been implemented ISO 9001-2000. Thank you for your information, and wait feedback from you, please send your suggestion by email. Best Regards, Isep Zaelani

Preventive maintenance means determining the routine steps that need to be taken on a regular basis to ensure that key settings are correct, fluids are at correct levels, friction points are lubed, belts are adjusted, etc.

The source for this information would be the service manuals or other documentation for the equipment.

Typically the steps are outlined on a checklist that is completed to document that all the steps were completed. These are kept as records.

Instrument "self calibration"? (12/1/04)

Rob, one supplier of these LIDAR (Laser light detection and ranging) devices claims their hand held devices are self- calibrating for distance and speed measurements when enforcing traffic laws.

They base this claim on three to four totally internal self-tests or self-checks when the devices are powered up in the first part of an operational shift.

For example 1) they perform an "All Eights" tests to make sure the number eight appears on all the LED readouts, and 2) they point the Lidar device at a stationary object some distance away and require that it display a zero speed reading.

Would you question their self-calibration claim?

Even without knowing the technical intricacies, I find this claim of "calibration" to be highly questionable. True calibration / verification would confirm the instrument's accuracy measuring the speed of something in motion. The fact that its test shows the instrument capable of showing certain numbers on the read-out, and confirming that something is standing still, does not, to my mind, confirm that the instrument is capable of accurately measuring what it is intended to measure, i.e., something in motion.

What Is "Key Process Equipment"?

The company I work for has just started on ISO/TS 16949. We are a third tier supplier. A question has come up on the preventative maintenance section. It reads the supplier shall identify key process equipment. We are basically a job shop and have several machines of the same type with similiar set-ups. What I'm trying to find out is that if we had a machine (or several) break down it would not prevent us from meeting our customers piece requirement. So is key process equipment, all production machinery or only critical equipment such as air compressors that would stop all operations.

Well, you can try to make that argument. The safest and most conservative approach is to include all production equipment. That approach enables you to avoid lengthy arguments, justifications, nit-picking, etc. at audit time and it is the way the most conservative auditors interpret the Standard. Personally I don't understand why anyone would overlook / ignore routine preventive maintenance anyway. If the machine isn't important to maintain, it isn't important enough to keep in service. Just my opinion.

Must Shipping Scales Be Calibrated?

We are a vender for computerized shipping systems. We have a customer beginning the ISO certification. They use scales for UPS shipping. Do theses scales have to be calibrated for ISO? If so, how often do they have to be calibrated?

Yes, the scales need to be calibrated, if the weight information is being used to come up with billing to customers. If the weight is only advisory, and the actual charge to the customer comes from some other source (i.e. UPS itself), then you could probably avoid calibrating those scales, but you'd have to be prepared for an argument (or at least a vigorous discussion) with assessors.

On the calibration interval, start with the manufacturer's recommendation (which is no doubt too often) and then adjust it based on documented historical experience.

We Don't Have To Calibrate EVERYTHING--Do We?

If we're doing a thorough final inspection with calibrated inspection equipment, does inspection equipment used earlier in the process need to be calibrated also?

Read the Standard. Devices used to "demonstrate conformance to requirements" must be "controlled and calibrated." The Standard does not distinguish between devices used at the end (final inspection) and devices used elsewhere.

So the answer is yes. And it makes sense. "Calibration" (really "confirmation") gives us confidence in the results of inspections.

What point is there in using a device in which you lack confidence? Why do the inspection at all?

Certainly, final inspections are important. They're meant to prevent nonconforming product from reaching customers. But in-process inspections are important, too. They're done to a) catch nonconforming product as close to the "cause" as possible, and b) to prevent nonconforming material from progressing further, which can be a waste of resources. If it's important to do in-process inspections (and make decisions based on the results), it's essential that they be carried out with calibrated instruments

Sticker and Snicker

I worked for a company that's ISO/TS 16949 certified.My wife and I were employed by the same company.We were Gauge techs we took care of both engine and transmission gauges. The plant manager of engines released all but one gauge tech which made it hard to keep up with gauges. Transmission asked their gauge tech to forge gauge records before the audit. I've seen all this happen and much more and this company still has it's certification.16949 to me is a joke unless controlled by quality person and not just someone trying to make a buck.

I have seen / heard this so many times. In many ways quality systems, audits, certification, etc. rely on honesty and honor. Any system can be defeated if management is corrupt enough to want to do that. It's so unfortunate because management is in effect teaching employees to be dishonest also.

I infer from your note that you and your wife don't work there any more. If so, good. Management that will lie about its quality system is in actuality lying to its customers, and management that will lie to its customers will lie to anyone -- including employees. You don't need to be involved in that. Just my .02 worth.

Auditing Calibration

The company I work for is currently in the process of ISO/TS 16949 training for approval by the the the first of the year. I have been delegated Quality Auditor for the Quality Control Lab. What are some of the common mistakes or problems that an outside auditor find most often? Thanks, in advance.

Calibration / verification of lab test equipment is a huge and target rich environment for auditors. Make sure your system is up to snuff and covers all of the equipment (and all the requirements in 7.6). Make sure there are work instructions covering calibration of equipment that you verify in-house.

Often, labs have formalized test procedures but then ALSO have unformalized, "back door" test procedures too. You want to make sure that these are gotten rid of or brought formally into the system.