Abstract: A detonation manifold (30) for use with a separation device comprising an expansion member (10) disposed in a frangible joint (24), the expansion member comprising a flattened containment tube (20) having in cross section an oblong configuration having a major axis and a minor axis and having therein a detonation fuse (16). The manifold comprises a body portion (31) having at least one initiation port (32) for receiving an initiator device and at least one coupling flange (38) mounted on the body portion for engaging the expansion member and having a flange bore (40) for receiving the detonation fuse (16), the flange bore (40) being in detonation communication with the initiation port (32). The coupling flange (38) has in cross section an oblong configuration having a major axis and a minor axis and is dimensioned and configured so that the containment tube (20) can be flared for receiving the flange without significantly deforming the oblong configuration of the containment tube (20).