This document applies to accessible technical ceilings and grids in meeting rooms as well as in entertainment and production sites for scenic representations. Establishments of this type are, for example, theatres, multi-purpose and exhibition halls, studios for film, television and radio, performance and scenery areas in the following facilities: concert halls, schools, exhibitions, bars, nightclubs, outdoor stages and rooms for shows, events, cabarets, vaudeville stages. For the purposes of this document, technical ceilings are working surfaces for technical personnel for operation and maintenance of stage and lighting equipment as well as other event technology equipment, which extend across several levels depending on the structural design. They can also fulfil functional requirements for mechanical equipment. Operation mechanical and technical lighting equipment in the area of technical ceilings result in particular hazards which are considered in this document. Technical ceilings include, for example, fly lofts, grid ceilings, ceiling flaps, tension wire ceilings and web ceilings. Usually they are arranged both above surfaces used by persons or spectators, and above areas for scenic representations and their side surfaces. This document can also be used for the design and dimensioning of work galleries, connection and access bridges. This document does not apply for working platform nets made of safety nets according to DIN EN 1263-1. This document contains terms and definitions for technical ceilings which have been prepared, among others, on the basis of terms and definitions in DIN 15560-45:1992-12. This document has been prepared by Working Committee NA 149-00-06 AA "Einrichtungen und Arbeitsmittel" ("Work equipment and installations") at the Entertainment Technology, Photography and Cinematography Standards Committee at DIN German Institute for Standardization. Representatives of German Social Accident Insurance (DGUV) have been involved in the preparation as staff at NA 149-00-06 AA.