can anybobody explain to me when and when not uncertainty can be put in a calibration certificate.is there any rules or law about the uncertainty?

There is one basic rule. It is that uncertainty must be reported unless there is an accepted Metrological equivalent. In the U.S. the equivalent is the 4:1 rules, specified in ANSI/NCSL Z540-1-1994, section 10.2.b. A U.S. based calibration lab can avoid reporting specific uncertainties IF a 4:1 can be maintained for the affected calibration area, AND the lab can put the evidence on the table for the accrediting body.

In the Phillipines, I do not know if the 4:1 or a similar rule is recognized. If no Metrological equivalent is recognized formally in the Phillipines, then you must report uncertainty.

Hope this helps.

Hershal

Hai

As in INDIA and the implementation of ISO/TS16949:2002 Or QS 9000 it is recommanding that the instrument calibrating external lab should be certified to NABL (which a set of labs approved by the INDIAN NATIONAL LAB ASSOCIATION).in NABl lab the calibrated instrument certificated should have Uncertinity value weather it is within or out of accpectance value.

Hope the info will be use full.

Expecting your feed back

REGARDS

R.L .SATTHISH KUMAR

thanks hershal & kumar for the info, it helped enlighten my mind. the 4:1 rule is also followed in the Philippines, but a lot of calibration certificates from local cal lab i've seen always shows the uncertainty value. are these cal labs credible? does that mean they are not 4:1 capable?