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UN/DOT Closure Requirements

Per 49 CFR 178.2(c)(1)(ii), the below listed closure and gasket information should be followed

Metal 31A and 31B Closure Descriptions

2″ and 3″ threaded fittings with all gasket materials except Teflon

3/8-1/2 rotations beyond full/solid gasket contact or minimum torque value of 30 ft-lbs

2″ and 3″ threaded fittings with Teflon gasket

1/8-3/16 rotations beyond full/solid gasket contact or minimum torque value of 60 ft-lbs

22″ drum rings with multiseal gasket

Seat the ring by striking with non-sparking mallet such as a rubber mallet around the circumference of the ring. Tighten the 5/8” bolt and then restrike the ring with the mallet. Alternate between tightening and striking until the bolt tightening resistance does not change (NOTE: The ring ends should be approximately 3/8″ apart and must not meet)

Rotationally Molded 31H2 and 31HA1 Closure Descriptions

6″ cap, all gasket material

1/8 – 1/16 rotation beyond contact

2″ NPS (NPT) threaded bung plugs, pressure/vacuum relief vents

3/8 – 1/2 rotation beyond contact

All bottom drain valves

(NOTE:  Not to be screwed in until 0.5 – 3 threads remain visible.) The exterior compression clamp should be tightened until it cannot be rotated around the tabulation. A leak test per 49 CFR 178.813 is required after valve installation

Blowmolded 31HA1, 31HG1 and 31HH1 Closure Descriptions

6″ cap, all gasket material

Rotation beyond contact or torque to 55ft lbs

2″ NPS (NPT) threaded bung plugs, pressure/vacuum relief vents

3/8 – 1/2 rotation beyond contact or torque to 55ft lbs

Valve nut

1/8 rotation beyond contact or torque to 55ft lbs

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UN/DOT Closure Instructions

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