A septum-tied tube pack is provided that includes a first outer wall formed by a multiple of first connected radiuses. A second outer wall is formed by a multiple of second connected radiuses. A first end radius connects the first outer wall and the second outer wall. A second end radius connects the first outer wall and the second outer wall. A multiple of septum elements extend between the first outer wall and the second outer wall. A gas turbine engine is also provided that includes an engine case structure and a fluid conduit mounted to the engine case structure. The fluid conduit includes a septum-tied tube pack section.