TM 10-4930-236-13&P
a.
Cleaning Exterior. Wash all exterior surfaces with a solution oftrisodium-phosphate and water; rinse thoroughly and
dry. Parts removed during disassembly may be cleaned by immersing in or wiping with dry cleaning solvent.
b.
Safetv Precautions.
(1 ) The tank being purged must have a static ground during all operations. Caution should be taken with all tools and
metal objects around the tank to ensure no spark will be made.
(2) Conduct a combustible vapor test reading prior to purging the tank, using a combustion vapor tester.
(3) Only personnel thoroughly instructedin the proper handling and reading of the combustion vapor tester will
conduct vapor tests.
(4) Conduct a combustible vapor test reading immediately after purging. Under no circumstances will repair of the
tank begin untli declared safe by safety personnel.
(5) Discontinue all operations if an electrical storm is threatening or in progress.
(6) Eliminate conditions that could cause explosions.
c.
Safety precautions for personnel.
(1) Personnel engaged in purging operations will not wear wool, ylon, silk, rayon or other similar static electricity
generating clothing.
(2) Clean cotton clothing with no metal buttons or fittings will be worn. All contents will be removed from pockets.
(3) Rubber boots will be worn.
(4) Cotton rags will be used for cleaning. Material that may generate static electricity will not be used
d.
Purging procedures.
(1) Completely drain all liquid from the tank to be purged. Be sure the drained liquid is removed from the area where
work will be performed. Remove all flammable liquid from the floor and liquid-soaked waste from the area.
(2) Remove all accessory items that might entrap liquid and close or seal all drains.
(3) Fill the tank and overflow with cold water for five minutes. Drain the tank completely.
(4) Conduct a combustible vapor test reading to determine if the tank is safe to repair. If combustible vapor test
reading indicates tank is not safe, repeat purging procedure until safety personnel determine tank is safe to repair.
e.
Inspection of the Tank Assembly.
(1) Check the tank for the condition of the paint.
(2) Check the tank for dents that require repairs. Check dents on welds for breaks in the weld seam Check for any
damage or wear that has caused a rupture or leak.
(3) Check the interior of the tank for general cleanliness and the presence of contaminants.
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