Abstract: A concentric insulating tubular conduit string, including a separation joint comprising first and second couplings with concentric tubular sleeve members extending therebetween, is disclosed. An insulating conduit incorporating this integral separation joint could be employed for the delivery of a heated fluid, such as steam, through the conduit to the producing formation therebelow. The inner and outer tubular sleeves of the separation joint may be prestressed in tension and compression between axially spaced coupling members used to join the separation joint to the tubular conduit. One sleeve which may be prestressed in tension threadably engages both the upper and lower coupling members. The other sleeve which may be prestressed in compression threadably engages only one of the coupling members and abuts the other coupling member to carry compressive loads.