Mean time between failure (MTBF) for the purifier shall
be not less than 1500 hours (see 6.3)
3 6 1.1 Failure. For purposes of reliability calculation, the purifier is
in a failed state if it cannot be started, or if a malfunction occurs that forces
the purifier to be shut down prior to the completion of its scheduled test time or
operating time. In addition, the purifier shall be considered to fail if the
capacity (see 3,4.1) or the quality of purification (see 4.6 8) is not in accor-
dance with the requirements specified, even if the unit has not experienced a
forced shutdown. Failures shall be classified as either relevant or nonrelevant.
Only relevant failures shall be chargeable for verifying reliability requirements.
(a) Relevant failures are caused by:
Equipment design defects.
Equipment manufacturing defects,
All other causes not specifically listed as non-relevant
(b) Non-relevant failures are caused by:
Accident, mishandling, or improper storage
Operator or procedural error
External test equipment or- facility failures
Drawing, maintenance manual, or other documentation errors,
provided prompt correction is shown to eliminate future
similar failures (this shall not be construed to include
Failures of multiple, simultaneous or immediately sequential
nature (only the initial failure shall be counted in such
Direct result of relevant or non-relevant failures of another
item of equipment (secondary failures)
Improper maintenance induced failures
Foreign object damage, unless caused by failure of protective
device built into seller's equipment.
220.127.116.11 Failure mode, effects and criticality analysis (FMECA).
shall be performed (see 6 3 and 6 10)
3.6.2 Maintainability. Mean time to repair (MTTR) for the purifier shall
not exceed 10 hours (see 6.3)
Identification plates shall be furnished on each
3.7 Identification plates.
purifier and shall be type A or B in accordance with MIL-P-15024 and
MIL-P-15024/5, except that plastic Identification plates are not acceptable
Identification plates shall be secured to equipment with corrosion-reslscan~
Purifier identification plates shall
3.7.1 Identification information.
contain the following information.