Wording and size of lettering. Such signs shall be worded
in plainly legible block letters with the word "EXIT" for exit signs and the
words "TO EXIT" with a suitable pointer or arrow indicating the direction
of exit for directional signs. Letters for signs shall be conspicuous, readily
discernible and at least six (6) inches high, except that for internally illuminated
signs, the height of such letters shall be at least four and one-half (4 1/2)
inches.