Vented gas riser apparatus

摘要

A vented gas riser for use in a system for conducting pressurized gas through a gas carrier pipe from a gas supply source line located below ground level to a delivery point disposed above ground is provided. A fluid tight gas riser protective casing is disposed around said carrier pipe and creates a gas escape passageway in an elongate annular space between the carrier pipe and the casing. Any gas which leaks from the gas carrier pipe is captured in the gas escape passageway. A riser transition head, which includes at least one vent passageway, provides a fluid connection with said gas escape passageway and with the atmosphere such that any gas which leaks in the vicinity of the gas escape passageway can escape through the at least one vent into the atmosphere.