July 2003. Location: Silsden, West Yorkshire
The building consisted of three storeys constructed around a quadrangle. A two-storey section bisected the quadrangle to form a triangular piece of land at ground floor level.
The building had a steel frame and all floors were concrete, the upper two concrete floors being on steel decking. The first and second floors were clad with 70mm thick PIR Insulated Panels approved by LPCB to LPS 1181 Part 1 2003 as Grade EXT-B. At the time of the fire, the ground floor had a steel framework in place for cladding but no cladding had been fixed. All steel beams had been coated with an intumescent paint to give a standard of fire resistance of one hour.
The premises were still under construction when the fire occurred. At the date of the fire the ground floor was in use as a storage area for building materials. The fire occurred in stored materials (plastics and paints) in the open ground floor of one section of the building. Damage was caused to the steel beams that supported the first floor, the profiled steel sheets that rested on the beams and the concrete floor that had been laid on the profiled steel sheets.
The intensity of the fire was such that it had removed the intumescent coating to the beams supporting the first floor. Although rated to provide a one-hour standard of fire resistance the intumescent coating resisted the fire for less than half an hour in this fire. The beams had distorted and the concrete floor at first floor level had dipped above the fire. The expansion of the beams had pushed out the supporting columns. The concrete floor above had cracked due to the movement of the beams.
The fire played up the external facing of the building, affecting the panels on the first and second floors.
- There was no fire spread to the upper floors
- There was damage to the external skin of the cladding to the upper floors but no spread in the insulation of the wall panels and no fire spread to the eaves
- The exterior facing of the panels to the first and second floors was damaged by heat and smoke
In spite of the significant heat generated by this fire (sufficient to damage the intumescent coating and distort the steel beams); the orientation of the cladding panels (directly above the fire); and the fact that fire stopping was not in place; the cores of the panels, did not ignite, did not promote fire spread within the core or to the eaves and did not significantly contribute to the products of combustion. The panels on this project are approved by LPCB to LPS 1181 Part 1 2003 as Grade EXT-B.