Tensile membrane action in slabs at high temperatures:

In the Cardington full-scale fire tests there had been a strong indication that concrete slabs survive to very high fire temperatures, maintaining the vertical compartmentation of a building, due to a self-equilibrating membrane action. This occurs at high deflections and represents the true ultimate condition in the fire Limit State. An improved slab formulation was researched and partially implemented.

The building layout comprises two main areas; a waste sorting hall (~ 650 m2 area) and the ATPP hall (~ 2000 m2). In the former, waste is delivered by Bristol County Council articulated lorries, directly onto a feed conveyor. Undesirable and recyclable material in the waste is removed and the residue transferred to a moving floor storage vessel. The remaining waste is then fed into the thermal processing hall via a conveyor belt system. The ATPP hall contains the pyrolysers, boilers and turbines i.e. the power producing plant.

A fire risk assessment was undertaken in order to identify the specific hazards & determine the level of acceptable risk; the main fire risk has been identified as the waste sorting hall. The facility is designed to have high levels of natural ventilation in order to minimise excessive heat build up – particularly in the ATPP hall. The walls incorporate a significant area of louvered air inlets, together with ridge vents in the roof (~ 13 m above ground level).