FIRE EXTINGUISHING SYSTEM INSPECTION - continued
w. Check fire extinguisher tubes for corrosion.
(1) If corroded, remove tubes (para 12.38) and clean as follows:
Do not use strong 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.
Proper cleaning of the tube is necessary to determine the extent of corrosion damage and to determine
the appropriate corrective action.
(a) Remove built-up corrosion from tube with a non-metallic abrasive mat. Use mat (item 122, App F).
(b) Clean tubes with acetone. Use acetone (item 1A, App F) or equivalent.
(c) Corroded areas inside the tube that are not accessible require tube replacement.
(d) Visually inspect the cleaned area using a 5X magnifier. Ensure all corrosion is removed.
(e) After all corrosion has been removed, inspect for allowable damage.
1 If the repair exceeds 10 percent (0.003 INCH) of the tube wall thickness, replace tube.
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 instuctions and warnings.
(f) If damage is within allowable limits and all corrosion has been removed, apply corrosion removing
compound to the damaged surfaces, both inside and outside. Use corrosion removing compound
(item 64B, App F) and brush (item 34, App F) or equivalent.
(g) Allow the treatment to deoxidize for approximately 30 MINUTES.
(h) Rinse thoroughly with tap water and allow to air dry.
(i) Apply epoxy primer coating to all deoxidized/damaged surfaces. Use epoxy primer coating (item 77,
(j) Allow primer to dry and reinstall the tube (para 12.39).
END OF TASK