Terms and definitions
The definitions fix the front face, the datum, the penetration distance and the debris threshold. Most rating disputes are arguments about those four things.
Basis. The public preview carries this clause. The clause number and defined terms are the standard's; the explanation is our own.
What clause 3 asks
The clause defines a vehicle security barrier as a barrier of the passive, active, portable or linear kind, placed to deny hostile vehicle access to a site. It defines the barrier foundation, the ground at the test site, the test vehicle, ballast, crew cab, day cab and unladen mass. It defines a datum, the point on the vehicle from which measurements are taken, and the barrier datum line: a ground mark set vertically under the most forward part of the structure that resists the hit. It defines impact, its speed and angle, the point aimed at and the point first touched. It defines the data record, penetration distance, major debris and the test house. Major debris is a piece of the barrier, the vehicle or the ballast weighing at least 2 kg.
Why it matters
The definitions are the contract inside the standard. The VSB datum line is measured at the foremost point of the structure that resists the impact, not at the foundation and not at the rear face. Penetration is the maximum perpendicular distance from that line to the vehicle datum point, or to the most distant point of the load bed or vehicle after a severe yaw. Major debris starts at 2 kg, which is lighter than the 25 kg threshold in PAS 68. A team that carries an old definition into a new report will produce a number that looks comparable and is not.
What good looks like
Build a one-page definitions sheet for the programme and use its terms in every specification, drawing and report. Mark the VSB datum line on the site drawing and on the product drawing. State the debris threshold in the specification. When a supplier quotes a penetration figure, ask which face it was measured from and whether the figure is dynamic or static.
Evidence an assessor asks for
The reviewer will ask from which face the penetration was measured and what counted as major debris. A vague answer undermines an otherwise good test.
- Definitions sheet The defined terms used in the programme, with the clause reference for each
- Datum drawing The VSB datum line and the vehicle datum point marked on the product and site drawings
- Measurement note A note per rating stating the face, the method and whether penetration is dynamic or static
- Debris threshold statement The 2 kg threshold stated in the specification and used in the report review
Where it commonly fails
- Penetration is measured from the rear face, as under PAS 68, and then presented as an ISO 22343-1 figure
- Major debris is counted at the PAS 68 threshold of 25 kg instead of the 2 kg used here
- The datum line is drawn at the foundation edge rather than the impact-resisting structure
- The vehicle datum point is assumed to be the bumper without checking the body type
What to do before the amendment publishes
Take the last three test reports and mark the datum line and the debris threshold on each. Where the report is silent, ask the test house to confirm in writing.
Read across
- 1 Scope
- 4 VSB performance requirement
- 6.3 Impact geometry
- 7.2 Classification code
- A-04 Datum point and reference marks
- A-06 Penetration and debris measurement