This standard applies to the manufacture and installation of electrical measuring systems and instruments utilizing radioactive sources (radiometric gauges) and which is intended to measure other quantities (for example, level, density, thickness, flow rate). It does not apply to portable equipment and equipment operated with X-ray tubes, but it can be analogously applicable to these gauges. The object of the standard is to specify constructional requirements for the instrumentation, a guideline for its installation as well as a uniform system classification coding. The object of the standard is to specify constructional requirements for the design of instruments utilizing radioactive sources in regard of radiation protection. It does not take into account mechanical or electrical hazards. The following modifications have been made with respect to DIN EN 60405 (VDE 0412-1):2007-12: a) replacement of the term "dose rate" with "radiation protection class" for unchanged values; dose rate 1 is not permitted and definition of radiation protection class 7 or E (see 4.4); b) regarding EMC reference to the standards of series IEC 61326; c) alphabetical sorting of the English terms in clause 3; d) extended fire resistance classes in accordance with 6.5; e) in 7.3, addition of the requirement for indication if the source is in protected position for the additional shielding housings of gauges of category B; f) in 7.3, specification of colours for indication of the shutter position; g) in 7.4, addition of an alternative colour for the warning lights; h) in 8.2, the requirement for the determination of the dose rate values between source and detector housing at distances lower or equal 10 cm and closed shutter have been deleted; i) changed classification code in accordance with 10.1. The responsible committee is DKE/K 967 "Mess-, Steuer- und Regelungstechnik im Zusammenhang mit ionisierender Strahlung" ("Measuring, control and regulatory technology in connection with ionizing radiation") of the DKE (German Commission for Electrical, Electronic and Information Technologies) at DIN and VDE.