Stainless Steel Manhole Insert Specifications

1. The insert

1.1 The insert body shall be manufactured of 16 gauge 304 Stainless Steel. The insert shall have a straight side design to allow a loose fit into the ring for easy removal. The manufacturer shall present load test verification showing a test failure in excess of 3,000 lbs. The insert shall be custom made to fit the manhole frame, outside diameter and inside diameter.

2 The Gasket

2.1 The gasket shall be made of closed cell neoprene and shall have a pressure-sensitive adhesive on one side. The gasket shall have a minimum total thickness of 1/8 inch. The gasket is to be installed by the manufacturer.

3 The Handle

3.1 The insert shall have a handle made of 1/4” plastic coated 304 stainless steel cable installed in the bottom of the insert. The handle shall be attached with two 304 stainless steel round head bolts with flat washers and self-locking nuts. The handle shall be capable of withstanding a pull force of 500 lbs.

4 Relief Valve

4.1 The gas relief valve shall be designed to release at a pressure of 0.5 to 1.5 psi and have a water leak down rate no greater than 5 gallons per 24 hours. The valve shall be installed in the insert by means of a hole tapped in the insert by the manufacturer. The valve shall be made of Nitrile or similar rubber.

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