Traceability Overview
Doug Berg, Testing Program
Manager- PJLA
Presented-December 2009

ISO/IEC 17025 Calibration
Laboratories• 5.6.2.1.1 For calibration laboratories, the programme
for calibration of equipment shall be designed andoperated so as to ensure that calibrations andmeasurements made by the laboratory are traceable tothe International System of Units (SI) (Systèmeinternational d'unités). A calibration laboratory
establishes traceability of its own measurement
standards and measuring instruments to the SI bymeans of an unbroken chain of calibrations orcomparisons linking them to relevant primary
standards of the SI units of measurement.

ISO/IEC 17025 Calibration
Laboratories• 5.6.2.1.1 (cont’d) When using external calibration
services, traceability of measurement shall be assured
by the use of calibration services from laboratories
that can demonstrate competence, measurement
capability and traceability. The calibration
certificates issued by these laboratories shall containthe measurement results, including themeasurement uncertainty and/or a statement ofcompliance with an identified metrological
specification (see also 5.10.4.2).

ISO/IEC 17025 Calibration
Laboratories• But how does that align with the following…
••

5.10 Reporting the results
5.10.1 General
The results of each test, calibration, or series of tests or calibrations carried out by
the laboratory shall be reported accurately, clearly, unambiguously and objectively,
and in accordance with any specific instructions in the test or calibration methods.
The results shall be reported, usually in a test report or a calibration certificate (seeNote 1), and shall include all the information requested by the customer andnecessary for the interpretation of the test or calibration results and all informationrequired by the method used. This information is normally that required by 5.10.2,
and 5.10.3 or 5.10.4.
In the case of tests or calibrations performed for internal customers, or in the caseof a written agreement with the customer, the results may be reported in a
simplified way. Any information listed in 5.10.2 to 5.10.4 which is not reported tothe customer shall be readily available in the laboratory which carried out the tests
and/or calibrations.

ISO/IEC 17025 Calibration
Laboratories•

And the following …

•

5.10.2 Test reports and calibration certificates Each test report orcalibration certificate shall include at least the following information,
unless the laboratory has valid reasons for not doing so
5.10.4 Calibration certificates 5.10.4.1 In addition to the requirements listed
in 5.10.2, calibration certificates shall include the following, wherenecessary for the interpretation of calibration results:a) the conditions (e.g. environmental) under which the calibrations weremade that have an influence on the measurement results;b) the uncertainty of measurement and/or a statement of compliance with
an identified metrological specification or clauses thereof;c) evidence that the measurements are traceable (see Note 2 in 5.6.2.1.1).

•And then … just to cap it off….

ISO/IEC 17025 Calibration
Laboratories• And ….
• 5.10.4.2 The calibration certificate shall relate only toquantities and the results of functional tests. If a statement ofcompliance with a specification is made, this shall identify
which clauses of the specification are met or not met.
When a statement of compliance with a specification is madeomitting the measurement results and associated uncertainties,
the laboratory shall record those results and maintain them forpossible future reference.
When statements of compliance are made, the uncertainty ofmeasurement shall be taken into account.

ISO/IEC 17025 Calibration
Laboratories• 5.6.2.1.1 NOTE 1 Calibration laboratories fulfilling
the requirements of this International Standard areconsidered to be competent. A calibration certificate
bearing an accreditation body logo from a calibrationlaboratory accredited to this International Standard,
for the calibration concerned, is sufficient evidenceof traceability of the calibration data reported.
• What about reference to “accreditation to ISO/IEC
17025” or a “statement”?

ISO/IEC 17025 Calibration
Laboratories• 5.6.2.1.1 NOTE 4 The term “identified
metrological specification” means that it must
be clear from the calibration certificate which
specification the measurements have been
compared with, by including the specification
or by giving an unambiguous reference to thespecification.

ISO/IEC 17025 Testing
Laboratories• 5.6.2.2.1 For testing laboratories, the requirements given in
5.6.2.1 apply for measuring and test equipment withmeasuring functions used, unless it has been established thatthe associated contribution from the calibration contributes
little to the total uncertainty of the test result. When thissituation arises, the laboratory shall ensure that the equipmentused can provide the uncertainty of measurement needed.
• NOTE The extent to which the requirements in 5.6.2.1 should
be followed depends on the relative contribution of thecalibration uncertainty to the total uncertainty. If calibration isthe dominant factor, the requirements should be strictlyfollowed.

NIST Website
Check out the NIST web site forTraceability…supplemental materials• http://ts.nist.gov/Traceability/SupplMatls/suppl_matls_for_nist_policy_rev.cfm

NIST … “Traceability”• "the property of the result of a measurement or thevalue of a standard whereby it can be related to statedreferences, usually national or international standards,
through an unbroken chain of comparisons, all having
stated uncertainties."• “It is important to note that traceability is the propertyof the result of a measurement, not of an instrument
or calibration report or laboratory. It is not achievedby following any one particular procedure or using
special equipment. “NIST … Who is Responsible?
• Who is responsible for supporting claims oftraceability? The provider of the result of ameasurement or value of a standard isresponsible for supporting its claim of thetraceability of that result or value. This is thecase whether that provider is NIST or anotherorganization.

NIST … Who is Responsible?
• Who is responsible for assessing the validityof claims of traceability? The user of theresult of a measurement or value of a standard
is responsible for assessing the validity of aclaim of traceability. However, as discussed …
above, the provider is responsible forproviding the necessary information that theuser assesses.

NIST Traceability … What is Needed?
•What do I need to do to support a claim of traceability? To support aclaim, the provider of a measurement result or value of a standard must
document the measurement process or system used to establish the claim
and provide a description of the chain of comparisons that were used toestablish a connection to a particular stated reference. There are several
common elements to all valid statements or claims of traceability:–––––

a clearly defined particular quantity that has been measured a complete
description of the measurement system or working standard used to performthe measurement
a stated measurement result or value, with a documented uncertainty
a complete specification of the stated reference at the time the measurement
system or working standards compared to it
an internal measurement assurance program for establishing the status of themeasurement system orworking standard at all times pertinent to the claim of traceability
an internal measurement assurance program for establishing the status of thestated reference at the time hat the measurement system or working standardwas compared toNIST ..Internal Measurement
Assurance Program• An internal measurement assurance
program may be quite simple or very
complex, the level or rigor to be determined
depending on the level of uncertainty at issue
and what is needed to demonstrate its
credibility. Users of a measurement result areresponsible for determining what is adequate
to meet their needs.

NIST … NIST Report Numbers
Sufficient?
• Is a NIST Test Report Number sufficientevidence of traceability? Test report numbers
issued by NIST are used solely foradministrative purposes. Although they often
uniquely identify documents that bearevidence of traceability, test report numbers
themselves do not address the issues listed inII.B.1 above, and should not be considered as
the sole evidence of traceability.

NIST … and Accreditation•

Given that NIST operates the National Voluntary Laboratory
Accreditation Program (NVLAP), does this mean that NIST stands
behind claims of traceability made by NVLAP-accredited labs? No.
More specifically, laboratory accreditation, whether conducted byNIST/NVLAP or any other recognized accreditation body, is a finding of alaboratory’s competence and capability to provide scientifically sound andappropriate measurement services within their scope of accreditation.
Embedded in the process is an evaluation of the lab’s ability to achieve andmaintain traceability for the accredited services. Accreditation to ISO/IEC
Guide 25, now replaced with international standard ISO/IEC 17025:
General requirements for the competence of testing and calibrationlaboratories, determines that a laboratory has all of the necessary facilities,
equipment, standards, procedures, uncertainty analyses, personnel, etc.,
which make it capable of providing traceable measurement results.
Laboratory accreditation does not speak to the specifics of any individual
measurement result but to the overall capability of a lab to provide theservice.