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.