18. — (1) Prima facie evidence of a standard specification may be given by the production of a copy thereof purporting to be published by or on behalf of the Authority.

(2) Section 6 of the Documentary Evidence Act, 1925 , shall apply to the printing, publication and tendering in evidence of documents purporting to be standard specifications as it applies to the official documents referred to in the said section 6 with the substitution, for references to the Stationery Office, of references to the Authority.