MIL-STD-1411 Inspection And Maintenance Of Compressed Gas CylindersThis standard defines the requirements and procedures for the inspection, maintenance, and charging of government-owned cylinders by gas suppliers. This standard is intended to assure that the cylinders are serviced to meet safety standards and to assure that the quality of the gas supplied is not degraded by a government container. This standard is also applicable to cylinders that require reconditioning, repair, and rebuilding to assure a level of renewal that meets the needs of the government and industry in gas handling. This standard is also to be a guide when cylinders are sorted, graded, and classified for storage, salvage, or disposal in depot facilities.

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MIL-STD-1411B

5.3.2.6.4 Valve replacement and disposal. Improper or rejected valves that cannot be reconditioned shall be condemned and replaced (see 5.3.2.1) with valves in accordance with

A-A-59860. Condemned valves shall be returned to the government for disposal. A simple control may be achieved by tying the unrepairable valve to the installed new valve to be returned with the service cylinder.

5.3.2.6.5 Cylinder plugs in lieu of valve. When specified by the PID, tapered plugs or plugs with flange and gasket shall be installed in the cylinder neck opening. Plugs shall have national gas threads provided with wrench flats for easy removal. The plug must effect an airtight seal to preserve the internal surfaces of the cylinder from oxidation and corrosion in storage.

5.3.3 General maintenance of acetylene cylinders. Acetylene cylinders accepted shall be scheduled for maintenance as follows:

a. The acetone shall be adjusted to reflect the marked tare weight of the cylinder

(see 5.3.3.1).

b. PRDs shall be CG-3 with a fusible metal plug with a melting point of 212 °F (see

5.2.3, 5.2.4, and 5.3.2.6.2).

c. Valves shall be maintained in accordance with 5.3.2.6.

d. The external cylinder surfaces shall be maintained in accordance with 5.3.6. e. The valve protection cap shall be maintained in accordance with 5.3.6.1.

5.3.3.1 Acetone adjustment. Excessive weight is indicative of water absorption by the acetone in the filler. Poor acetylene absorption is another indication of water vapor trapped in the porous filler. Either condition requires bleeding of the acetylene gas, heat evaporation of the acetone, baking dry the porous filler, and recharging with dry acetone to the tare weight of the cylinder. A low tare weight indicates excessive corrosion and wasting of the steel cylinder or loss of acetone by fast withdrawal of the acetylene by the user. Each cylinder shall be weighed and checked against its marked tare weight.

a. Cylinders under weight will require adjustment of the acetone in quantities up to 20 percent of the authorized weight of the acetone charge. Cylinders with greater deficiencies shall be rejected and returned to the government for disposition.

b. Cylinder over weight may be handled by the contractor's standard practice for removing excess acetone or small accumulations of moisture. Cylinders with excess moisture heavy enough to inhibit the absorption of acetylene shall be rejected and returned to the government for disposition.