The first full-scale installation of the revolutionary new W50TB (Thermally Broken) steel window system has been successfully carried out as part of the extension and refurbishment of the Robert Hooke Science Centre at Westminster School, London, improving both the appearance and the thermal performance of the building.

Steel Window Association member, West Leigh, designed, manufactured and installed the £1million package on behalf the main contractor, while the London office of jmarchitects led the design and Contract Administration.

The thermally broken W50 steel window system, featuring innovative high density polyurethane isolators, offered the most cost-effective alternative for this challenging project. It was designed to meet key specification requirements, particularly in terms of thermal performance, replacing old medium steel section frames as well as secondary glazing from a later date.

Having been invited to tender, West Leigh carried out a detailed survey of the extensive 1920s building leading to the fabrication and fitting of the high performance, factory finished windows in a total of 162 openings. Such is the variation in size of the openings that only four of the frames had the same dimensions. There were also some very large units with one measuring 5.3 x 3.0 metres. All of them were glazed with Argon filled 28 mm IG units containing a 6mm toughened, Low-E inner pane and a 6.8mm clear laminated outer, with a warm edge spacer bar. They are finished in a RAL 9016 Traffic White matt polyester powder coat.

Mark Burgess, Director of jmarchitects, commented, “The Robert Hooke Science Centre had old, single glazed steel windows which, along with a cumbersome secondary glazing system, need replacing. The client was also very keen to improve the energy performance of the windows and the solution was to replace them with new high quality, durable, thermal broken steel windows which not only maintained the narrow sight lines of the frames but will also reduce energy consumption and last the school for a long time to come.”

The Steel Window Association’s members are able to offer a full selection of options for new build and replica refurbishment, as well as historic projects; including W20, W30, W40 and W50 frames able to comply with the requirements of Part L to the Building Regulations. Choosing an SWA member to manufacture and install your steel windows and doors ensures that you are receiving the highest standard of fabrication, Installation and customer service.

For further information on the Steel Window Association, please visit or call 020 8543 2841.


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