TB 1--1520--238--20--100
b. Inspect the fire extinguisher tubes for corrosion --
(1) Inspect the outside of the tube and the inside near the "B nut" area for corrosion. If no corro-
sion is found, the tube may be reinstalled if no other rework is required IAW paragraph 8.a.
(2) If corrosion is present --
(a) Corrosion should be removed IAW paragraph 9.c to determine whether the tube can be
repaired or should be replaced.
(b) If the corrosion exceeds 10 percent (.003 inch) of the tube wall thickness, replace the tube
IAW paragraph 9.a.
c.
If the tube surfaces meet the inspection criteria in paragraphs 8.a and 8.b, the inspection is com-
plete.
d. The inspection criteria in paragraphs 8.a and 8.b will be added as an inspection requirement at
phase numbers 2 and 4 IAW paragraph 12.e.
Correction Procedures.
a. Fire extinguisher tube assemblies that exceed the damage and/or corrosion allowed in paragraphs
8.a and 8.b will be replaced IAW reference paragraph 13.c Task 12.38 or reference paragraph 13.a fire extin-
guisher system removal tasks.
b. Rework procedure --
(1) Apply MIL--C--10578, corrosion chemical treatment (Turco WO#1/phosphoric acid) to the
damaged surfaces, both inside and outside areas. Use an acid swabbing brush or equivalent.
WARNING
Chemicals/acids can burn eyes and skin. All personnel
must wear safety goggles and gloves when using
chemicals/acids. If contact is made with skin or eyes,
wash chemical off with water and seek medical aid.
Read and comply with chemical solvent label instruc-
tions and warnings.
(2) Allow the treatment to deoxidize for approximately 30 minutes.
(3) Rinse thoroughly with tap water an allow to air dry.
(4) Apply epoxy primer, MIL--P--23377, type 1 , class "C" or MIL--P--85582, type 1, class "C2"
to all deoxidized/damaged surfaces.
(5) Allow primer to dry and reinstall tube assembly per reference paragraph 13.c Task 12.39 or
reference paragraph 13.a fire extinguisher system installation tasks.
c.
Corrosion removal --
CAUTION
Do not use stong solvents (MEK, trichloroethane, etc.)
to clean the tube assemblies. Do not forcefully scrub
the surfaces to be inspected. Protect nearby wiring and
exposed parts from splashing or spillage of detergents
and cleaning compounds.
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