14.23 The minimum recommended dimensions for mounting triangular signs and roundels on grey or yellow backing boards are shown in figure 14-8. Where the supplementary plate is wider than the sign, the space between the vertical edge of the plate and the edge of the backing board should match the space below the plate, i.e. 0.075 H or 0.075 D as appropriate. Where the width of the plate is equal to or greater than the minimum width of backing board required for the sign, the backing board can be flush with the plate at the sides and bottom. Where triangular and roundel signs are mounted one above the other, the vertical space between them should
14.24 Where a speed limit roundel to diagram 670 or 671 is mounted on a grey or yellow backing board with the speed camera repeater sign to diagram 879, special design rules apply. These are shown in figure 14-9. The smallest prescribed sign to diagram 879 is used with the 300mm diameter roundel. Larger roundels are mounted with a sign to diagram 879 which is proportionally smaller but within the range of prescribed sizes.
138
