and may be on-conditional replacement or hard-time
following definitions are provided to clarify age
replacement.
control, acceptance life, shelf life, and service life:
Age control--The efforts made during
Rejection Standards
manufacture, purchase, and the storage of age-sensitive
items and parts made from natural or synthetic rubber
Rejection and replacement of hose or hose
materials to assure conformance to the applicable
assemblies after inspections are based on the standards
material and performance specifications. Age control is
normally specified in the applicable maintenance
further defined in terms of acceptance life and shelf life.
instruction manual, maintenance requirement cards,
and depot-level specifications. Where rejection
Acceptance life--The period of time from cure
standards are not specifically outlined or if doubt exists
date to the procuring activity's (organizational-,
as to the acceptability of a hose or hose assembly,
intermediate-, or depot-level activity) date of
replace the hose or hose assembly.
acceptance.
NOTE: Teflon (PTFE) hose assemblies are
Shelf life--The period of time from the date of
replaced only on a conditional basis.
acceptance or delivery by the organizational-,
intermediate-, or depot-level activity to the date of use.
Storage
Service life--The period of time from the date
Hose and hose assemblies fabricated from
of installation to the date of removal. Installation date
age-sensitive materials are subject to deterioration by
of the hose or hose assemblies must be identified by a
oxygen, ozone, sunlight, heat, moisture, or other
tag. See figure 10-5.
environmental factors. These types of hoses and hose
Acceptance Life and Shelf Life for Synthetic
assemblies should be stored in a dark, cool, dry place
Rubber Hose and Hose Assemblies
protected from circulating air, sunlight, fuel, oil, water,
dust, and ozone (ozone may be generated in an
The acceptance life (MIL-STD-1523) and shelf life
atmosphere where electricity is discharged through
(DOD 4140.27M) for synthetic rubber hose and hose
oxygen or ambient air). Store hose or hose assemblies
assemblies are established as follows:
by sealing both ends of bulk hose. Cap or plug each
hose or hose assembly. Store hose or hose assemblies
Synthetic rubber hose, bulk or assembly, must
on racks that support and protect them. Store hose or
not exceed 8 years (32 quarters) from the cure date,
hose assemblies so that the oldest items are issued first.
which must be stenciled on the rubber covering of the
bulk hose or provided on an identification band on the
metal braid hose or on the hose assemblies.
CAUTION
Synthetic rubber hose and hose assemblies must
Do not store hose or hose assemblies in piles.
not exceed 5 years (20 quarters) from the date of
Improper storage will cause accelerated deterioration
delivery to the organizational-, intermediate-, or
due to both heat and moisture factors.
depot-level activity. The repair activity maintains a
record of delivery dates for bulk hose and hose
assemblies to monitor shelf life expiration dates.
Q10-1. What are the two basic types of hose used in
military aircraft and related equipment?
NOTE: Teflon (PTFE) rubber hose and hose
assemblies do not have shelf life limitations.
Q10-2. What material is used to cover a Teflon
hose?
Service Life for Synthetic Rubber Hose Assemblies
Q10-3. How is a synthetic rubber hose identified?
Service life is 7 years (28 quarters) for synthetic
Q10-4. A hose fitting consists of what separate parts?
rubber hoses in critical applications; that is, medium-
Q10-5. What color is an aluminum alloy 2024 hose
and high-pressure synthetic rubber hoses exposed to
fitting?
heat, weather, or fuel.
Q10-6. How are commercially manufactured hose
NOTE: Service life for Teflon (PTFE) hose
assemblies identified?
assemblies is determined by Cognizant Field Activity
10-23