Abstract: A quick-access hinged lid assembly for flanged riser, having two-part clamp, having an inner face shaped to conform to the surface flanged riser, first clamp ring and second clamp ring are connected by a clamp hinge, a lid having an exterior surface and an interior sealing surface to abut the flanged riser exterior surface, wherein the interior sealing surface includes annular groove, gasket or o-ring positioned therein groove to seal flanged riser exterior surface and interior sealing surface, a lid hinge configured between clamp and lid, lid hinge having a swing bolt slot and pin bolt to provide adjustment of the lid to enable the lid to mate flat with flanged riser, swing bolts positioned on the perimeter and pivotable from the clamp ring with hand operable fasteners to press gasket between interior sealing surface of the lid and flanged riser exterior surface in a closed position.