IJCA Vol 5 Issue 1 - Flipbook - Page 33
2026 | Volume 5, Issue 1
The International Journal of Conformity Assessment
Documentation. Implying complete, controlled
records that describe the calibration or
measurement process, conditions, and results.
Every link in the traceability chain must be
supported by documented and generally accepted
procedures, as well as calibration reports that
record what was done, who performed it, which
equipment was used, environmental conditions,
results, and associated uncertainties. Calibration
certificates, standard operating procedures (SOPs),
equipment records, and quality system documents
form the documentary evidence of traceability.
These records are reviewed during audits,
accreditation assessments, and technical reviews.
to preserve the traceability of the standard over
time and use. Calibration intervals are determined
based on factors such as drift behavior, frequency
and severity of use, environmental conditions,
criticality of the measurement, and historical
performance data. Regular recalibration confirms
that measurement performance and uncertainty
remain within acceptable limits. Laboratories
establish and periodically review a calibration
interval policy using a measurement assurance
system. Records of recalibration, trends, and
adjustments support decisions to tighten or
extend intervals and are often examined during
accreditation assessments or customer audits.
Competence. Demonstrated ability of personnel
and organizations to perform specific calibration
or measurement tasks correctly and reliably.
Technical competence includes qualified staff,
appropriate facilities, properly maintained
equipment, validated methods, and effective
quality controls. It provides assurance that the
documented procedures are actually implemented
as intended. Evidence of competence may
include staff training records, participation in
interlaboratory comparisons or proficiency testing,
and accreditation to relevant standards. Users rely
on this evidence when selecting laboratories to
support their traceability needs.
Measurement assurance. A systematic set of
activities designed to ensure the ongoing validity
of the measurement process and the reliability
of reported results. A measurement assurance
program must be established to ensure the validity
of the measurement process and the accuracy of
standard used.
Realization of SI Units. The establishment of primary
standards that embody the definitions of the SI
units and serve as the ultimate references for the
traceability chain. At the top of the chain, national
metrology institutes or equivalent bodies realize SI
units directly from physical phenomena or agreed
realizations. These primary standards anchor the
traceability chain and ensure global consistency
of measurements. Calibration laboratories derive
their reference standards from these primary
realizations, either directly or via recognized
reference laboratories. End users thereby obtain
results that are compatible with the SI and
comparable across borders and sectors
Periodic recalibration. Calibrations of standards
(and equipment where appropriate) must be
repeated at established and appropriate intervals
Each comparison relies on valid calibration
procedures and recorded results that show
how the work was done, who performed it, the
conditions of measurement, and the uncertainties
achieved. Technical competence—qualified
personnel, appropriate facilities, maintained
equipment, and sound methods—is assuring that
the written procedures are executed as intended.
Typical tools include check standards, control
charts, replicate measurements, interlaboratory
comparisons, and proficiency testing that monitor
bias, drift, and variability. A robust measurement
assurance program allows early detection of
problems that could affect traceability, such as
unexpected bias or equipment malfunction. It
supports decision-making about recalibration,
method improvement, and corrective actions,
and demonstrates that the laboratory maintains
metrological traceability in day-to-day operation,
not just on the calibration date. Every standard
and instrument must have determined an interval
of re-calibration that reflects drift behavior, usage,
criticality, and historical performance. Those
calibration intervals ensure that uncertainties
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