Pownall Case Studies

QUARRY DUMPER ROLLAWAY FATALITY:

Incident: A dumper being repaired following an electrical breakdown rolled with fatal consequences. Apparently, the park brake was not applied. To test the repair the engine was started and left running while final work was being completed. As brake system air pressure built up with the park brake not applied the spring brake actuator released and the dumper rolled with fatal consequences. In our opinion there were three contributing factors in this incident, loss of electrical power, driver error, and loss of brake system air.

Solutions: Following enquires from the group tasked by the HSE to find a solution to help prevent similar incidents in the future. Pownall proposed two products, firstly the Sentinel Duo electro pneumatic park brake not applied alarm, which warns drivers if they attempt to exit the vehicle without having first applied the park brake, additionally it warns if the park brake is unapplied with electrical power isolated. In this particular incident the warning would have activated as soon as the electrical power loss occurred and continue the warning until the park brake had been applied or system air depleted at which point the spring brake actuator applies the brake (see below).

The second proposal being the Pownall Sentinel low air cut off valve. This valve is mounted in the cab and shuts off the air supply to the park brake control valve and thus spring brake actuators when supply air pressure to the park brake control valve drops below a set point. Once tripped, the valve is manually reset by the driver once system air pressure is restored. The low air trip point is critical in order to ensure that maximum possible spring park brake efficiency is maintained.

FALL PREVENTION FROM BAKERY TAIL LIFT:

Problem: Delivery drivers walking backwards dragging bread baskets on to moving floor tail lift and falling of the back.

Solution: Tactile underfoot matting to warn of the approach of an open lift edge. Please see TredAlert product.

MOBILE LIBRARY & EXHIBITION UNIT ROLLAWAY PREVENTION:

Problem: A local authority safety risk assessment highlighted the potential risk of a playing child releasing the park brake on mobile library’s and requested the body builder, xxx to fit a device to prevent a possible occurrence.

Solution: A Pownall Ultra air brake locking valve, fitted with an air horn tamper alert that sounds should the park brake control valve be released while the vehicle parked.

OPERATED PLANT SEAT BELT MONITORING:

Problem: Tarmac found that although instructed, some drivers were not using the seat belts and management found the situation difficult to monitor.

Solution: Pownall proposed and then provided seat belt status systems which provide visual confirmation to management that the seat belt is fastened. Management are now able to monitor drivers from a distance without having to stop the vehicles in order to carry out spot checks.

Land fill operator Biffa and contractors now fit Pownall seat belt status indicators, which are available with several options.

DUMPER RAISED BODY COLLISIONS:

Problem: Tarmac had experienced damage and driver injuries caused by collision with overhead constructions and objects such as conveyors and electricity supplies caused by dumper drivers forgetting the body is raised and driving off despite having standard height warning devices fitted.

Solution: Pownall proposed, then manufactured a body raised interlock system to address the problem. The system locks the vehicles brakes while the body is raised but does not interfere with normal operation allowing deliberate movement but preventing the driver from just driving off with the body raised. An additional benefit is the reduced risk of tip over’s. Articulated dumpers are known to tip over when driven on uneven rough ground with the body raised due to the now high centre of gravity.