A friend of mine asked me that the other day and I really don't know. I always thought they were a pass/fail type of thing. Does anyone do these?
I calibrated the anti-static strap testers but not the straps themselves.
If you mean like the heel straps then no. On a wrist strap I have there is about 1 Megohm resistance in the lead, ditto the floor plate to tester lead. I would think testing the strap confirms that is OK.
You "could" calibrate the 1M resistor in the wrist strap but there is a problem with that. If you were to sticker the strap the user may think it is OK to use. If the strap is not properly placed on the wrist a good connection may not be achieved and static discharge could still be an issue. This is why wrist strap testers are used because it checks continuity from the strap to the individual. A better way of "Calibrating" the strap is to put a "Cal Before Use" on it and have operators right down their name and time everytime the strap was checked on the wrist strap checker.
I reviewed (but did not study) several quality standards regarding wrist straps and ESD protection. There are many quality standards regarding this. When I reviewed them I found they were all written in way that gave quite a bit of leeway to the using organization on how they are interpreted. If the standard is intended for a lot of different industries that makes a lot of sense.
If you need the accountability I think having a log is a good solution.
The only requirement for a company that I did jobs for was that the straps were tested by a wrist/foot strap tester. The company had an ESD Clean room and they were really intent on the testers to be calibrated. They were made by Desco and we used a specific resistance standard from Desco (mainly for convenience reasons). The straps, in my opinion, should be verified by the testers each time before use and therefor do not need calibration.
Here is the unit that I've worked on: http://desco.descoindustries.com/DescoCatalog/Wrist-Strap-Foot-Wear-Testers/Combo-Tester-X3/19278/ (http://desco.descoindustries.com/DescoCatalog/Wrist-Strap-Foot-Wear-Testers/Combo-Tester-X3/19278/).
This is about the best thing I can think of as far as calibration of wrist straps.
The tester is the only way I know to test the wrist straps. We have a daily log to record pass / fail
I have never heard of "anit-static straps.
Quote from: NC-Cals on 09-15-2016 -- 10:00:37
I have never heard of "anit-static straps.
Also known as wrist straps, here's a little wiki for assistance
https://en.wikipedia.org/wiki/Antistatic_device#Antistatic_mat
Griff, I think NC-Cals was stressing the way anit was spelled.
Quote from: PurelyNonsense on 09-19-2016 -- 05:26:03
Griff, I think NC-Cals was stressing the way anit was spelled.
I should never type when I'm short on coffee...