date, often long in advance of the completion of working drawings, This was of primary importance because of the distances separating Jobsite from points of supply and because many construction material items were not available from stock, The second purpose was to achieve uniformity of equipment and materials at the various locations on Jobsite, Here, being able to pro- cure materials and equipment well in advance of the completion of working drawings, or in advance of the requirements of construction schedules, aided in establishing the uniformity and interchangeability of equipment and machinery used on various locations at Jobsite, For example, by the use of a Purchase Specification, the procurement of an item of equipment for one site could be effected in time to meet the construction schedules, and at the same time procurement could be made of similar or identical items for other sites, well in advance of requirements. The third objective was to issue specifications as required by construction schedules in such form as would allow their subsequent embodiment in a single, comprehensive unit. The Purchase Specifications were later incorporated into the final Construction Specifications (General Specifications) . Purchase Specifications for construction operations were supplemented by the inclusion on the working drawing of considerably more specification material than is ordinarily included on the drawings. It is believed that the use of Purchase Specifications aided in the achievement of availability and uniformity of materials and in clarity and conciseness of specifications to an extent that the ordinary methods of specification preparation could not have approached, In general, the criteria to which the Purchase Specifications were written were those followed in the preparation of the General Specifications. The basic requirements included the provisions that specifications he +e government standards or to other avplicable, recognized standards; that proprietary names to designate types or standards of quality be avoided where practical; and that the speci- fications be prepared so as to result in open competitive bidding among a minimum of three qualified vendors. Because of climatic conditions at the Jobsite, it was of primary importance that materials used in the permanent construction be inherently resistant to or suitably processed against extremes of heat, humidity, and sait spray. In addition to this requirement, a short delivery period was often essential for the maintenance of construction schedules at Jobsite, The combination of these two conditions required that a greater than normal amount of time be spent in the preparation of Purchase Specifications, For many items, an exhaustive survey of available materials was necessary before the specification writing could be begun, 5-18