1. An amber or blue light beacon conveys the warning that special care is to be taken.
2. The beacon must comply with the requirements of paragraphs 3 to 5.
3. The peak intensity of light emitted by the lens or lenses of each beacon must be—
(a)if the period between individual flashes does not exceed ¼ of a second, not less than 100 candela on the principal axis of the relevant lens;
(b)if the period between individual flashes exceeds ¼ of a second, not less than 2000 candela on the principal axis; or
(c)if the period between the cessation of a double flash and the start of the succeeding double flash exceeds ¼ of a second, not less than 1000 candela on the principal axis.
4. Each lens must be of such a shape and size that the perimeter of its area projected horizontally onto a vertical plane is capable of lying wholly inside a square having sides of 200 mm in length and wholly outside a square having sides of 100 mm in length.
5. The rate of flashing must not be less than 55 nor more than 150 individual or double flashes per minute.
6. General Directions 17 and 19 of the Schedule 13 General Directions apply to an amber light beacon.
7. General Directions 18 and 19 of the Schedule 13 General Directions apply to a blue light beacon.