• Telescopic
• Yields under Strata movement
• Rapidly erected
• Recoverable
• No maintenance costs
• Adjustable in height and width
• Produced in Galvanised Mild Steel to prevent rust and corrosion
• No nuts & bolts used
• British & Overseas Patents applied for
• No welded parts

This design isolates the door assembly and supports from the stoppings by incorporating a rugged self-supporting frame. It is easy to erect and fit and allows integration with stoppings using standard components.

The frame comprises four channel sections with bolted corner joints. The three hinges on either side can be adjusted axially to control door seal compression. The top frame member has telescopic arms which are cemented into the roadway sides to anchor the assembly. the lower frame has facilities for floor bolting. If required assemblies can be provided to cater for rails. The 6mm thick doors are fitted with a heavy duty seal, 'pull-lift' decompression flap, handles and joint overlap. Detailed assembly instructions are provided. Standard assembly made to suit16'x12' arch with 7'x6' aperture.

The design is well proven and originated in the USA (Jack Kennedy Metal Products & Buildings Inc.). The standard assembly is designed for squarework raodways of heights between 2.2 and 3m and provides a double door size of nominally 12'x5' with an aperture of 3.67mx1.61m. Roadway widths above 5.2m can be accommodated. If necessary a 12'x6' door size to provide a further 305mm headroom can be supplied.

The door assembly comprises uprights or support props, a lintel and pair of doors.Uprights are 2.5" tube with a telescoped tube fitted with adjusting nut, floor and roof plates. The roof has an articulating facility. The lintel locates over the telescopic tube to provide an upper sealing face. The doors are a very strong box section form and include seals to effectively close centre joint and edges. A handle, ventilation pressure release flap and lifting lugs are also incorporated. Doors are hung on inclined and horizontally displaced hinges to provide an automatic self-closing action. The stopping assembly is completed using telescopic steel stoppings above the door lintel and either side of the door props to the extremes of the roadway width. Onsite assembly and fitting is very simple (instruction details provided).

Application is generally against negligible ventilation pressure, however they are suitable for operating pressure to 3"WG. The door frame is designed to yield under convergence without effecting the door function.