Page:UK Traffic Signs Manual - Chapter 8 - Part 2- Traffic Safety Measures and Signs for Road Works and Temporary Situations) - Operations 2009.pdf/201

 The system shall be designed and installed in such a way that any malfunction within it has no influence whatsoever on the operation of any aspect of the standard vehicle braking systems. The only result would be the illumination of a warning light in the vehicle cab.

The design and installation of the impact braking system shall not have any influence on the effects of a fault within the standard vehicle braking systems.

The impact braking system shall never take an air supply from the input side of the four-circuit protection valve.

If the impact braking system takes an air supply from the service brake system then it shall be isolated from the service brake by means of a dual circuit protection valve.

Electrical or magnetic fields shall not adversely affect the operation of the impact braking system. It also shall not emit electrical or magnetic fields that could adversely affect other vehicle systems. This should be demonstrated in accordance with Directive 95/54/EC (Official Journal of the European Communities, No. L 266, 8 November 1995) or Directive 2004/104/EC (Official Journal of the European Communities, No. L 337, 14 October 2004).

The impact braking system shall be insensitive to power line transient signals. This should be tested in accordance with ISO 7637.

The impact brake system shall be equipped with a control to enable the system to be released and reset manually after an accident. This control should be clearly marked and positioned in an easily accessible place. It shall not be possible to reset the impact braking system unless the parking brake has been applied.

The impact braking system shall be fitted or modified only by qualified personnel approved by the manufacturer of the system.

All wiring and components should conform to the requirements of BS EN 60068 with regard to protection from environmental factors such as vibration and humidity.

All components and subsystems shall be insensitive to temperature within the range –20º C to +50º C. This is of particular importance to the impact sensor if it is of the rubber air-filled tube type.

The system shall be insensitive to accelerations of less than ±1 g horizontally and ±4 g vertically.

The impact sensor will be exposed to a harsh working environment. It shall be extremely rugged, durable and resistant to physical damage.

The mechanical integrity of components, wiring and piping in the impact braking system shall be at least as good as that of the standard vehicle braking system. Pipes should be resistant to rupture and both pipes and wiring should be routed carefully to avoid fretting.

Components should either be designed for the life of the system or should have a service or replacement interval marked on them or published as part of a comprehensive aftercare manual. 199