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Up Topic Welding Industry / Inspection & Qualification / Tape measure verification
- - By jrw159 (*****) Date 03-06-2008 19:40
Recommended practices for verification of tape measures on a regular basis? This would be a requirement for IAS AISC ISO. Sorry about the spelling in the title of my last post "wich" I am sure will be overlooked.
Parent - - By eekpod (****) Date 03-06-2008 19:48
It could be conscrewed as a requirement of AISC, something to the effect that "All insturments involved in the verification of final inspection shall be traceable to a national standard".  It used to say that all instruments be traceable to NIST, but they changed it to a national standard to make it easier/ cheaper for fabricators to get this done.
So the short answer is yes, it's required per AISC.
Chris
Parent - By js55 (*****) Date 03-06-2008 19:50
There have been some extended discussions on this in the forum. You might try a search and see what you come up with.
Parent - - By jrw159 (*****) Date 03-06-2008 20:12
any recommendations on best process to use for the verification. It looks like we will do it on a weekly basis unless one gets dropped or somthing questionable happens to it before the week is up. I am thinking with a steel rule that has been verified. Then one would have to verify that on a bi-annual basis I would think.
Parent - - By js55 (*****) Date 03-06-2008 20:39
Witout getting too far back into opinions on this subject that I have already made clear in other threads, I would say IMO that tape measure verification is lame.
The only thing that ever goes wrong withem is the tab on the end. Keep your program as simple as possible with verification and re-certification as long term as the auditor will allow.
Drop it, throw it, hit it with a hammer, or run over it with a truck, when you pull the tape, if the tape is still together, it will still measure the same.
If the tab is busted, burn an inch.
Sarcasm not withstanding. Really, keep it simple.
Parent - - By jrw159 (*****) Date 03-06-2008 20:52
I totaly agree with keeping it as simple as possible. I just need to get somthing in place to satisfy auditors. Lovin it by the way.
Parent - - By js55 (*****) Date 03-06-2008 21:08
Do a search using terms such as verification, calibration, nist, tape measures, squares, etc., and you should get a good cross section of some of the participants programs and terms. There have been numerous discussions on this. Sometimes threads got hijacked on it.
Parent - By bmaas1 (***) Date 03-06-2008 21:28
All I do is when I issue a new tape I just quickly verify it with a verified 36" steel rule.  Done.  When it wears out I issue a new one.

Brian
Parent - By CWI555 (*****) Date 03-06-2008 22:15
My opinion.. I can understand verifying a tape measure initially. Once verified (as compared to one with a traceable standard) I can't say as I've ever witnessed one that shrank or enlarged to any signifigant digit.
Parent - By Joseph P. Kane (****) Date 03-07-2008 00:26
I have seen several layout tapes grow longer.  It happens when they use a spring tensioner or a 5 Kg. weight when they measure for layout or layout checking.  Now , these tapes are at least fifty feet and often as much as 100 meters.  The average tape ws probably a 50 meter, 1/2 inch wide flat tape, used in bridge fabrication.

I never could understand why the use of weights is required, if you can lay out the master tape and the target tape flat out on the same surface.  I do understand why it is necessary for surveyors tapes, because they are suspended in air and there is a catenary curve inaccurracy to deal with.  If all the tapes are steel, and you lay them out flat on a piece of steel, the coefficient of expansion should be the same.  Both tapes will be affected in the same amount.
Parent - - By Joseph P. Kane (****) Date 03-06-2008 23:07 Edited 03-07-2008 00:10
A few years ago. I received the NIST Tame Measure program from Chet Guilford.  I will attempt to attach it here.

It doesn't engender a lot of confidence in NIST (10 meters = 25 feet)
Attachment: W-NISTTapeMeasureCalibrationRequirements-HB44-Final1.doc (37k)
Parent - - By James Corbin (**) Date 03-06-2008 23:25
I have used a "Calibration Station" i.e. a wall board with a calibrated 2' square that has its squareness checked, numbers checked and documented, traceable to NIST. Then its bolted to the board and top leveled with a calibrated level, traceable to NIST, so the shop personal can check their tape ends, squares & levels at least every month or more depending upon use. Document this check and your good to go. Also special postings procedures etc. can be placed there for the Weldors to check out. The AISC auditor loved it.
Parent - - By js55 (*****) Date 03-07-2008 14:14
Gerald makes an excellent point to moderate my position. An intitial verification does seem reasonable to me. And certainly is consistent with a simple system.
Parent - - By js55 (*****) Date 03-07-2008 14:32
Also, its interesting. We have certain, or many, subjects (this is one) that pop up over and over again, and certainly we all seem to get tired of them from time to to time, but each time something a little new seems to surface in the discussion.
Parent - - By jrw159 (*****) Date 03-07-2008 16:11
Very true. I have been using the search and there is already alot of information out there but a few new opinions in this one as well. Sorry for beating an apperantly dead horse. LOL
Parent - - By js55 (*****) Date 03-07-2008 16:26
Ain't no dead horse. Its just limpin.
Parent - - By jrw159 (*****) Date 03-07-2008 16:30
LMAO
Parent - - By jon20013 (*****) Date 03-08-2008 06:38
Its really a damned wonder we've ever managed to build anything in this country!  Can't imagine how all of the factories, nuclear power houses, refineries, hospitals, schools, skyscrapers, etc, etc, etc., were ever successfully built without the benefit of calibrating tape measures and the likes!  No, I don't think this is progress, I think its absolute insanity, QA insanity, just another thing to gig folks on that really amounts to nothing.
Parent - - By pipewelder_1999 (****) Date 03-08-2008 23:06
I have to agree. I rank this right up there with "Calibrated Welding Machines"
Parent - - By CHGuilford (****) Date 03-09-2008 02:32
When speaking of tapes manufactured to comply with NIST44 I agree that validating tapes is not so much of a necessity.  However, there are a lot of tapes being sold today that do not comply with any standard.  That is why we have chosen to supply all of the tapes used in production.  They come from one company and we have not had any problems with that brand.

We too are an AISC certified shop.  All we do is to validate new tapes for the 1st six feet to be within specs.  Those get a small sticker put on the back above the belt hook.  No other checks are made to those tapes except for having production people check that 12" is 12" on a steel rule we have fastened to the wall, for when the end hooks have been bent.  For us, tapes last 3 months on average, so we don't worry about them stretching.

Validation is done with a 100 ft tape we purchased that has been checked and is traceable to NIST standards.  That is used to validate a 30' tape which is used to check everything else.  The 30' tape gets rotated into QC use once a year.  The 30' tape also is used to check framing squares every 3 months (Pythagorean Theorum, or 3-4-5 triangle). 

It is simpler than it sounds.  Remember that AISC requires a calibration program but the fabricator determines what that is based on their needs.  It doesn't make sense to have a program that does not provide some assurance of accuracy, but a science project is not required.
Parent - - By jrw159 (*****) Date 03-10-2008 12:57
Gentlemen, I appreciate all the valuable opinions that have flooded back on an apperantly well discussed issue. I believe this is just a technicality, and as stated, we as a company have the choice of how we meet the standard. I personally equate it to a molehill that I do not want to make into a mountain. KISS/ Keep It Simple Stupid, seems to apply in this case. Again, thanks to all.
Parent - - By jwright650 (*****) Date 03-10-2008 13:12
I have verified/calibrated our inspector's tapelines here too per the AISC requirement that all tools used in final inspection need to be verified annually......so in doing so I did find that Craftsman tapes had a few discrepencies...the 100'ers were dead on for the full 100', but the 50'ers were an 1/8" off....and some of the off brand tapes were all over the place...some within the first few feet.
Parent - By eekpod (****) Date 03-10-2008 14:17
John, I'm glad you said that.  I had the same problem w/ the 50' craftsman, in fact I told our guys not to use them.  It's either the 30' or the 100' but not inbetween.  I haven't had any problems w/ the 30's or the 12' either.  Chris
Up Topic Welding Industry / Inspection & Qualification / Tape measure verification

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