Compact Power is planning the construction of a Waste-to-Energy facility, to be located at Avonmouth, Bristol. The Advanced Thermal Processing Plant (ATPP) will process around 30,000 tonnes Bristol’s non-recyclable household waste and 1,000 tonnes of special waste per annum and generate ~ 2.5 MW of renewable power and heat for local businesses.

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).

Halcrow developed a fire safety strategy based on project-specific considerations regarding the site, building, plant design layout & operating requirements. In particular, the Client required a solution that did not include automatic fire sprinklers because of concerns over the reliability of the mains water supply. A key element of the analysis was a parametric zone modelling study of natural smoke venting through the ridge vents; the results demonstrated that the natural ventilation scheme was effective in preventing ‘smoke-logging’ at low level for a range of design fires from 2.5-100 MW.