5-30. TANK ASSEMBLY.
a. Cleaning and Inspection.
Drycleaning solvent normally has a flash point
of either 100 or 138 degrees F, depending-on the
type being used, but may flash at much lower tem-
peratures if contaminated with gasoline or jet
fuel. Avoid repeated and prolonged skin contact.
Do not use near open flame or excessive heat.
(1) The tank must be free of explosive vapors and thorough-
ly cleaned before any repairs are attempted; drain the tank of all
contents and open filler plug.
Allow filler to remain open for sever-
If compressed air is available, blow out the tank.
the tank interior with an approved solvent and dry thoroughly.
tions and procedures outlined in FM10-20 will be applied to the tank.
Areas of the tank to be subjected to severe heat must be cleaned to
the bare metal; use a stiff stainless steel wire brush or other suit-
able tool for this purpose.
Pay particular attention to the seams;
heat from a welding torch tends to volatilize tetraethyllead deposits
causing toxic fumes.
The tank exterior must be cleaned of all dirt,
sand, oil, or other foreign matter with a solution of trisodium phos-
phate (item 9, App. F), and water; rinse with plain water and dry,
Remove paint from any area to be welded.
Accumulation of fuel in the tank skids can be ignited
by a welding torch.
Before attempting any welding re-
pair, be sure the tank skids are equipped with drain
holes, and skids are purged and tested for removal of
(2) Tanks. Drill four 1/2 inch diameter drain holes and
four 1 1/2 inch doameter drain holes in each skid. Refer to figure 5-20
for locacion of drilling points. Vapor test the interior of each skid
using MSA Vapor Tester,
NSN 6665-00-664-4650, or equivalent. Purge skid
by steam cleaning, or other suitable method. Vapor test again and re-
purge as required to obtain a safe meter reading. Paint exposed metal
around holes in skids and leave holes open.
b. Welding Precautions.
(1) Completely drain all fuel from tank to be purged; be
sure the drained fuel is removed from the area where work will be
(a) Remove all fuel from floor; remove all fuel soaked
rags and waste from area.