This document has been prepared by DIN Standards Committee "Chemical Apparatus Engineering (FNCA)" and specifies the arrangement and design (dimensions, semi-finished products, fasteners and materials) of stairs at stationary accesses to process apparatus. The stairs are usually used for inspection and maintenance work on these apparatuses. This standard applies to stair constructions based on the rated loads for platforms according to DIN 28017-1 and for stair steps according to DIN EN ISO 14122-3. DIN 28017-2 is used as the basis for railings. Applicability shall be checked for enamelled, lined or coated apparatus as well as apparatus made of non-ferrous metals or of plastics. DIN EN ISO 14122-3 applies to stairs on mechanical equipment and structural installations. Committee NA 012-00-01 AA "Anlagenteile" ("Process equipment") of the Standards Committee Chemical Apparatus (FNCA) at DIN is responsible for this standard.