6. The barriers shall be as light as possible but shall also be strong enough to prevent distortion or fracture likely to be caused by wind pressure. The barriers shall be at least 125mm deep at their mid-point and at least 75mm deep at their tip.
6. The barriers shall be as light as possible but shall also be strong enough to prevent distortion or fracture likely to be caused by wind pressure. The barriers shall be at least 125mm deep at their mid-point and at least 75mm deep at their tip.