A hot tap housing for mounting over a main pipeline located underwater or in another restrictive environment adapted for use with a hot tap machine to connect a branch pipeline to the main pipeline. The hot tap housing includes a central housing section and a lateral housing section. The central housing section includes a central bore for receiving the main pipeline and first and second central housing grip and seal assemblies are mounted in the central housing bore for gripping and sealing off the main pipeline on either side of the lateral housing section. An access sealing assembly is mounted with the lateral housing section and includes an access sealing member which is movable in the lateral housing section bore into sealing engagement with the outer surface of the main pipeline in order to isolate an approximately circular area which is to be cut out and removed by a hot tap machine.
