Impact speed
The impact speed is how fast the vehicle is moving, free of the winch, just before first contact. It is measured, not assumed from the propulsion setting.
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 6.6 asks
Clause 6.6 sets the speed at which the vehicle must arrive. The definition is how fast it travels, free of the winch, at the moment before first contact. The method requires that figure to be measured and written down. The public preview does not show a tolerance in its visible pages, so this record states none. What the clause and the definition do establish is where the measurement belongs: the vehicle is free and at the stated speed before contact, not at the instant of contact and not after the barrier has begun to take energy out of it.
Why it matters
Speed is the variable a buyer is most likely to compare and least likely to check. A rating at 48 km/h and a rating at 64 km/h are different products in use, even when the barrier and the vehicle are the same. Because kinetic energy rises with the square of speed, a modest increase in approach speed is a large increase in the energy the barrier must absorb. The measurement point matters too. A speed taken from the winch setting, or from a point after the vehicle has struck the barrier, is not the impact speed the clause defines.
What good looks like
Ask how the speed was measured and where. Look for an independent speed trap or a calibrated measurement, not a setting on the propulsion equipment. Compare the rated speed with the realistic approach speed at the site, including any downhill gradient or run-up. Record the comparison in the assurance statement.
Evidence an assessor asks for
The reviewer will ask where the speed was measured. An answer that names the winch setting rather than the vehicle is not the clause.
- Speed record The measured speed, the method, the measurement points and the equipment calibration
- Video evidence The high-speed video covering the approach and the moment of contact
- Site speed assessment The realistic approach speed at the site, including gradient and run-up
- Comparison note The rated speed against the site speed, with the margin stated
Where it commonly fails
- The speed is taken from the propulsion equipment setting rather than measured on the vehicle
- The speed is measured after contact, when the barrier has already slowed the vehicle
- The site approach is downhill and the rated speed assumes a flat run-up
- The report gives a speed with no method and no calibration
What to do before the amendment publishes
Ask for the speed trace and the measurement points. Compare the rated speed with the site approach speed and record the margin or the gap.