Abstract: Method and apparatus for internally sealing live low pressure residential gas supply lines, including gas main tap and associated fittings, by applying sealant to the inside surface of the gas line. Sealing assemblies allow tapping and insertion of tools without gas escape to atmosphere, as well as application of sealant under gas pressure passed through a supply line which has the ability to rotate in order to feed itself through elbows and fittings to the point where sealing is required, as well as achieve uniform spray coverage of the target pipe's inner surface with sealant.