1-6
by the user and the calibration interval (each use—daily, weekly, every 100 hours—each overhaul, and so
forth) is indicated in the Metrology Requirements List (METRL).
The USER CALIBRATION label, shown in view D of figure 1-1, has black lettering and a white
background and is affixed when the calibration is performed by the user; however, this label is not
replaced at each calibration. When the label is first attached to the instrument, it is annotated as to the
appropriate calibration interval. Records of calibrations performed, when other than each time used,
should be by normal maintenance practices; that is, in the maintenance log, on maintenance action forms,
and so forth.
Inactive—Calibrate Before Use Label
In the event that an individual instrument due for recalibration will not be used for some time in the
future, you may indefinitely postpone the recalibration by affixing an inactive label to the instrument. As
shown in view E of figure 1-1, the INACTIVE—CALIBRATE BEFORE USE label has green lettering
and a white background. The INACTIVE label remains on the instrument until it is recalibrated. The
instrument is not to be used while bearing this label.
Calibration Not Required Label
Test equipment standards and T&ME not requiring calibration are shown as CALIBRATION NOT
REQUIRED. This label, shown in view F of figure 1-1, has orange letters and a white background. It is
attached to and should remain on the instrument indefinitely unless its calibration requirements change. If
the instrument is not listed in METRL, you should use the following criteria when placing instruments in
the CALIBRATION NOT REQUIRED category:
Instrument does not make quantitative measurements nor provide quantified outputs.
The device is "fail-safe"; that is, operation beyond specified tolerances will be apparent to the
user.
All measurement/stimulus circuits are monitored during use by calibrated instruments or are
dependent on external known or calibrated sources for performance within required limits. (When
determining that an instrument falls into the CALIBRATION NOT REQUIRED category, you
should annotate the label as to the authority for the decision, such as METRL, technical manual,
letter or message from higher authority.)
Rejected—refer To Attached Tag Label
In the event that an instrument fails to meet the acceptance criteria during calibration and cannot be
adequately repaired, a REJECTED—REFER TO ATTACHED TAG label is placed on the instrument and
all other servicing labels removed. This label, as shown in view G of figure 1-1, has black letters and a
red background. In addition to the REJECTED label, a REJECTED tag, giving the reason for rejection
and other information as required, is attached to the instrument. Both the label and tag remain on the
instrument until it is repaired and recalibrated. The instrument is not to be used while bearing a
REJECTED label.
Calibration Void If Seal Broken Label
The CALIBRATION VOID IF SEAL BROKEN label, shown in view H of figure 1-1, has black
letters and a white background. It is placed over readily accessible (usually exterior) adjustments to
prevent tampering by the user when such tampering could affect the calibration. The label should not be
