Ajish,

for other than class 7 it shall be as below

Specifications for placards ( 5.3.1.2)

.1 Be not less than 250 mm by 250 mm, with a line running 12.5 mm inside the edge and
parallel with it. In the upper half of the placard the line shall have the same colour as
the symbol and in the lower half it shall have the same colour as the figure in the
bottom corner;

.2 Correspond to the label for the class of the dangerous goods in question with respect to
colour and symbol; and

.3 Display the number of the class or division (and for goods in class 1, the compatibility
group letter) of the dangerous goods in question in the bottom corner for
the corresponding label, in digits not less than 25 mm high.