Specifying Temporary Barriers for Workzone Safety

What must be taken into account when specifying barriers or a VRS (Vehicle Restraint System) for a workzone is the following:

  • The Size of vehicle that must be stopped
  • The Speed of the traffic around the project
  • What is the likely angle of Impact
  • The available Space for movement of the VRS
  • How much deflection can I allow in the system

The “norm” for barrier specification in South Africa stems from SANRAL’s choice of an H1 containment level on the Gauteng Freeway Improvement Project (GFIP), but this should be looked at as part of the baseline risk assessment for the project. Recently on a dangerous section of the N1 below the Hugenot Tunnel a containment level of H4b was specified for the temporary barriers

Once it has been determined what the suitable containment level, and working width is required for the project, the  specification for the project should read something like the below, merely a suggestion of course:
“Suitable movable vehicle restraint system, complying to SANS51317 with a containment level of X and working width of Y, installed as per the crash test.”

With X and Y being determined by the baseline risk assessment.

This allows the contractor to choose from a host of systems regardless of supplier that comply, and ensures both a fair tender and a suitable system being used during the contract.Performance class-img