BS EN 1317 : Road Restraint Systems 1998

This is the European Code for all types of road restraint

• Safety Barriers
• Bridge Parapets
• Crash Cushions
• Arrester Beds
• Terminals and Transitions
• Pedestrian Parapets
• Pedestrian Guardrails

EN 1317 is a performance specification which lays down the requirements for vehicle containment and redirection. It will eventually be written in six parts but to date all are not approved.

There are currently eleven different tests for vehicles ranging from a 900kg car to a 38 tonne articulated HGV impacting at different angles and speeds. The restraint containment level is decided by passing two specified tests in achieving either Normal (N1 or N2), High (H1 H2 H3) or Very High Containment (H4a H4b).
The UK Highways Agency generally specifies Normal Containment (N2) containment for its Trunk Road and Motorway system. This may be raised to the higher containment levels dependant upon the degree of risk.

The major difference from the original British Standard BS 6779 (the old P1’s and P2’s) is the EN 1317 requirement to address passenger safety by the measurement of “Impact Severity Levels”. It is no longer acceptable just to contain and redirect an errant vehicle – it must now be achieved with a limit on the “damage” to passengers. Thus it is not just a matter of strength but a combination of factors in design to achieve containment and increased safety for passengers. Engineers can quite easily design for containment by increasing the structural capability of the restraint-- but this generally leads to a stiffer system and higher impact severity levels for the passenger. A very fine line exists between the right strength and the correct level of energy absorption – which has been proved in many such tests.

Bridge parapets in the UK have traditionally measured “wheel penetration” as a basis for approval- however because the European code applies to all types of road restraint this has been superseded by measuring “Working Width”. This is basically a dimension taken at test to determine the amount of deformation of the system which must be compatible with the available space or distance behind it i.e. to allow for lighting columns, bridge abutments, etc. Today road restraints are therefore specified as a combination of containment level and working width i.e. N2 –W4.

The BPL 100 series aluminium parapet system has achieved a Normal Containment qualification with a working width W4. BPL was the first company to achieve this milestone which others could not achieve for over two years.

Some of out competitors continue to try to detract from our success but we prefer not to respond to their unprofessional claims. We believe the valid opinions of the Highways Agency and Consulting Engineers are much more important. If you do have any questions relating to the performance of our products we will be very pleased to receive them via our email link

Indeed many highly qualified Engineers agree with our test reports and such evidence comes from the fact that over 70,000 metres of our parapet system is installed on 500 mm wide bridge plinths worldwide - including over 250 structures for the UK Highways Agency – amongst the world’s toughest authorities for safety standards.

One outstanding factor in our test report is the Class A Impact Severity Level – the safest possible qualification for vehicle passengers – and probably the most important.

 

The important opinions that matter come from the professional engineers who continue to approve and benefit with the inclusion of BPL aluminium parapets on their projects – see our list of completed contracts.