(a) Descriptions and specifications shall be sufficiently restricted or specific so as to exclude cheap or inferior commodities which are not suitable or practicable for the purpose for which they are to be used, but at no time shall they be so specific in detail as to restrict or eliminate competitive bidding of any items of comparable quality and coming within a reasonably close price range.
(b) Brand names may be used to simplify or indicate the general description of the commodities required, but at no time, except for repair parts or items for use with existing equipment and machines or other health aids requested by a professional employee, shall such names be used to indicate any preference or to prevent bidding on commodities of like quality and coming within reasonably close price range.