Abstract: A duct joining system for sealingly connecting plastic gas-conveying ducts is provided. The joining system comprises a receptacle attached to an end of a first duct and sealingly fastened thereto. The receptacle has a size and configuration which is adapted to mate with an end of a second duct. The second duct has a grippable surface extending along its length. The interior of the receptacle contains releasable gripping means and a sealing gasket. The gripping means engages with the surface of the second duct in order to urge the end of the second duct into sealing contact with the gasket.