Built to withstand considerable wind loads at Liverpool Docks

The challenge

Wood Pellet fuels needed to be kept dry to avoid spontaneous combustion in prevailing winds during freight delivery and offload.


The solution

To install a bespoke structure, designed to cover a substantial bulk hopper and withstand winds up to 93mph.

Key facts 

  • Bulk hopper 9m x 9m
  • 18m above ground
  • Wheel-mounted roof trusses
  • 3 phase electric motor
  • Rack & pinion system

Project overview

In addition to conventional fuels E.ON Energy is involved in renewables and wood pellet fuels. At its bulk terminal in Liverpool’s Bootle Docks it receives wood pellets in bulk freight ships and needs to offload them in the shortest time using a bulk hopper 9m x 9m which loads three freight trains every day. 

The organic wood pellets have to be kept dry to avoid problems of spontaneous combustion caused by dampness due to rainwater.  E.ON decided that the hopper had to be covered when not being filled and looked for a suitable method to cover the mouth but, at a height of 18m above the ground in the docks, the wind loads are considerable. 

CopriSystems were able to design a bespoke structure consisting of roof trusses mounted on wheels joined in a longitudinal frame to give rigidity. Each wheel had an anti lift bracket running in a track mounted to the top frame of the hopper.  The entire roof, covered with a heavy duty PVC coated polyester fabric, secured at frequent intervals, was operated by means of a 3 phase electric motor on each side driving a rack and pinion system. The whole structure was designed to stand up to wind speeds of 42.3m/sec (93mph) to conform with British and Euro Standard BSEN 1991-1-4.