Market Leaders in Commercial Vehicle & Plant Safety Solutions

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Trailer Safety Park Valve

The Trailer Safety Park Valve

It is widely assumed that trailer spring brakes are applied simply by disconnecting the red (emergency) line and that the park button does nothing more than this. Not only is this assumption about the so-called fail safe nature of trailer brakes technically inaccurate, it could prove positively dangerous at the time a trailer is re-coupled.

The risks involved in failing to apply park brakes properly on motive units and trailers have been evident for some time, most starkly illustrated by fatal accidents. The Pownall Auto-Set Trailer Park Valve* can be manually operated at any time and does not prevent or relieve drivers of their duty to follow safe working practices.

However, should the driver 'forget', the Pownall Safety Park Valve automatically sets acting as a safety backup.

*For trailers fitted with air spring brakes.

UK Patent No. GB2310695

European Patent No. EP 0 792 783


  • Can be manually applied at any time
  • Sets automatically when Red line is disconnected should driver forget to apply
  • Eliminates trailer rollaway when coupling
  • Eliminates free standing trailer movement
  • Allows for trailer movement without connecting the emergency line
  • Supplied with safety warning decal

Available factory fitted to new trailers by all leading manufacturers.

Fleet Users include:

  • Sainsbury's
  • Tesco
  • Waitrose
  • Asda
  • and many, many more....



Pownall Security Systems Ltd

Tecnair Group

6 Station Road



Contact Pownall

Telephone:  +44 (0) 1623 490903


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Friday 08.00 - 12.00