Impact geometry
The test sets a target impact point, an initial contact point and an impact angle greater than zero and up to 90 degrees. At 90 degrees the two points coincide.
Basis. The public preview stops before this clause; the page states the published structure and the public guidance. The clause number and defined terms are the standard's; the explanation is our own.
What clause 6.3 asks
Clause 6.3 fixes where the vehicle is aimed and how it meets the barrier. The target point is where the vehicle's long centre line crosses the chosen lateral position on the impact face. The first-contact point is where the two actually meet. The angle lies above zero and at or below 90 degrees, measured in plan between the barrier datum line and the path the vehicle takes. Above 45 degrees the test house aligns the vehicle to the target point; at 45 or below it aligns to the first-contact point. At a right angle the two points coincide.
Why it matters
Geometry is not a detail. A barrier rated at 90 degrees has been hit square on. A site where the approach curves, or where the barrier sits at an angle to the road, presents an oblique impact that the square test does not represent. The clause gives the test house a repeatable way to set the vehicle and gives the buyer a way to compare a rating with the site. It also explains why two ratings that look similar can differ: one may be at 90 degrees and the other at 45, and the energy delivered to the barrier is not the same.
What good looks like
Draw the approach path and the barrier line on the site plan and measure the angle. Compare it with the angle in the rating. Where the site angle is not covered by the test, ask for a test at that angle or record the residual risk. Check that the target point is on the part of the barrier designed to take the impact, not on a gate post, a sign or a weak panel.
Evidence an assessor asks for
The reviewer will ask whether the site approach matches the tested angle. A 90 degree rating on a 30 degree approach is a gap the buyer has to close.
- Geometry drawing The approach path, the barrier line and the impact angle drawn to scale on the site plan
- Set-out record The aimed point and the first-contact point marked and photographed before the test
- Angle calculation The measured angle, the method and the equipment accuracy
- Site comparison The site angle against the tested angle, with the residual risk where they differ
- Barrier face drawing The impact face and the part of the barrier designed to resist the impact
Where it commonly fails
- The site has a curved approach and the only rating is at 90 degrees
- The target point is set on a decorative panel rather than the structural face
- The angle is measured to the rear face or the foundation edge rather than the datum line
- The test report gives an angle but no drawing, so the geometry cannot be checked
What to do before the amendment publishes
Measure the approach angle at each site and list it beside the rating. Where the two differ, decide whether to test, to change the layout or to record the residual risk.