Abstract: Structural honeycomb material is expanded to the open, hexagonally cellular state, by pulling it out in the expansion direction. It is then compressed across the expansion direction and fed through a throat where it undergoes further compression which creases the constituent material. On being allowed to re-expand, the material adopts a stable open-cellular state. The feeding of the material through the throat is accomplished by driving means which engages the material across the expansion direction. This is an improvement on feeding it between driving rollers having rotational axes parallel with the major axes of the cells. Satisfactory compression in the throat is more easily obtained, especially with small cell-sizes.

Abstract: The invention provides an assembly for accommodating service lines which comprises a length of ducting, a block of structural cellular material which fills the internal cross section of the ducting over at least a part of the length of the ducting, said block having cell walls which define cells which extend in the length direction of the ducting and on the cell walls a coating of intumescent material expandable to close the cells under fire conditions. With the block positioned where the ducting passes through a fire-resistant wall, the spread of fire through the ducting is usefully opposed. Using thermoplastic ducting, which has heretofore been contra-indicated, results superior to those obtainable with steel ducting are achieved.

Abstract: An apparatus for treating continuous unexpanded structural honeycomb material formed of permanently creasable material comprises rollers for drawing the material in the expansion direction whilst compressing it perpendicularly thereto so that it adopts a second unexpanded state. A guide receives the advancing material and permits slight re-expansion and a double acting severing device, e.g. a circular blade driven by a double-acting ram in forward and return strokes, severs the slightly re-expanded material to form cut lengths. The severing device may be located at the position of a guide of compact form, or at the outlet end of a guide in the form of a channel having at least one resilient wall. A receiving surface, formed in part by a conveyor belt may be provided to receive the cut lengths and allow them to expand. Guides for the expanded material may be arranged to discharge the expanded material from the receiving surface.