PREFORMED H O S E A S S E M B L I E S . --
Medium-pressure Teflon hose assemblies are
sometimes preformed to clear obstructions and to make
connections using the shortest possible hose length.
Since preforming permits tighter bends that eliminate
the need for special elbows, preformed hose assemblies
save space and weight. Preformed hose assemblies
must be procured from a qualified commercial source
(source code P series). When preformed hose
assemblies are unavailable and could cause a work
Figure 10-15.--Firesleeve.
stoppage, fabrication by depot and intermediate
or similar synthetic bristle brush that has a
maintenance is authorized.
corrosion-resistant core. Brush the core and at least the
PROTECTIVE COVERS.--Some hose assem-
first inch of hose with a brush that has a diameter of at
blies are located in areas where temperatures exceed
least 1/16 inch larger than the fitting bore. Flush the
the capabilities of the hose material. Protective
hose or hose assembly with MIL-PRF-680, type II, or
firesleeves (covers) should be installed (fig. 10-15) over
equivalent. Drain the cleaning fluid and blow-dry with
these hose assemblies. Firesleeves do not increase the
dry, filtered, oil-free air or nitrogen. Install the
service temperature of hoses, but protect the hose from
protective closures if the hose or hose assembly is not to
direct fire long enough to allow the appropriate action
be cleaned further or proof tested immediately.
to be taken. The sleeve is composed of fiber glass. It is
impregnated and overlaid with a flame-resistant
Proof Pressure Testing
silicone rubber.
Hose assemblies must be proof pressure tested after
Cleaning
fabrication. Ballistic and oxygen hose assemblies must
be cleaned and tested by qualified aviation equipment
Fabricated hose assemblies should be cleaned and
personnel in accordance with NAVAIR 13-1-6-4 before
visually inspected for foreign material before and after
installation in weapons systems.
proof testing. Cleaning should be done with cleaning
Observe all safety rules when you proof pressure
fluid or a detergent solution.
test hose assemblies, and proceed as follows to proof
In cleaning hose or hose assemblies, the cleaning
pressure test hose assemblies. Clean hose assembly.
procedures used depend upon the cleaning material
Select test media from table 10-3. Select proof
selected for cleaning. The preferred cleaning method is
pressure. See table 10-4, which is a section of the
one that also uses the preferred cleaning material,
typical hose assembly proof pressure test data sheet.
MIL-PRF-680, type II.
Test one hose assembly at a time. Several hose
assemblies that require the same proof pressures may
be tested together, if they are connected in series with
CAUTION
adapters.
Oxygen hose assemblies must be cleaned and
Unless otherwise directed, a manifold hose
tested by qualified aviation equipment personnel in
assembly that contains different sizes or types of hose
accordance with NAVAIR 13-1-6-4 before
will be tested at the lowest proof pressure required by
installation in weapons systems. Degreasing Solvent
any one size or type contained in the manifold. Arrange
MIL-PRF-680 is combustible and should be kept
hose assemblies as close to the horizontal position as
away from open flames. It should be used in a
possible. Allow trapped air to escape when testing hose
well-ventilated area. Personnel should wear rubber
assemblies in a liquid test medium. When testing an air
gloves and chemical or splashproof goggles. Avoid
or gas medium, test hose assemblies underwater so that
skin contact. Consult with the local safety office
trapped air can escape from the hose's braided outer
regarding respiratory protection.
covers. Hose assemblies with a firesleeve do not require
the underwater test. Tighten the pressure cap. Apply
proof pressure for a minimum of 30 seconds, but no
Immerse or flush the hose or hose assembly using
longer than 5 minutes. Check leakage while
MIL-PRF-680, type II, solvent or equivalent. Brush the
maintaining proof pressure.
exterior of the hose or hose assembly with a nylon
10-12
