Unified System of Design Documentation

　　1.1. General provisions 1.1.1. The following shall be provided when developing the working drawings： а） Optimal application of standard and bought items， and also the items of commercial production， conforming to the modern technics level; b） Rationally bounded nomenclature of threads， slots and other design elements， their dimensions， coatings， etc.; c） Rationally bounded nomenclature of material grades and assortments， and also application of the cheapest and least scarce materials; d） The necessary degree of interchangeability， the most advantageous modes of the items production and repair， and also their maximal serviceability during the operation. 1.1.2. Interstate， state， national and branch standards and specifications may be referred to in the drawings， provided that they fully and uniquely specify the appropriate requirements. When there are references to specifications in the drawings for items of serial and mass production， these specifications shall be registered in accordance with the established procedure （in the states where state registration of specifications is obligatory）。 It is allowed to make references to technological instructions， provided that the requirements established in these instructions are unique and guarantee the required item quality; in this case the instructions shall be enclosed to the complete set of the item design documentation when transferring it to the other enterprise. Plant （corporation） standards may be referred to in the drawings for auxiliary process items. Separate clauses of standards， specifications and technological instructions may not be referred to. The whole document or its separate section may not be referred to in the drawing， if necessary. The documents， specifying the shape and dimensions of the item design elements （facet， thread， etc.）， may not be referred to， if there are no designations of these elements in appropriate standards. All the data for their production shall be specified in the drawings.