DIN EN 14399-9:2009-07

This document specifies, together with EN 14399-1, the requirements for assemblies of high-strength structural bolts and nuts of system HR or HV and requirements for the general dimensions, tolerances, materials and performance for two grades, H8 and H10, of compressible washer-type direct tension indicators, nut face washers and bolt face washers suitable for preloaded joints with large widths across flats, thread sizes M12 to M36 and property classes 8.8/8, 8.8/10 and 10.9/10. Bolt and nut assemblies to this document have been designed to allow preloading of at least 0,7 fub × As ) according to EN 1993-1-8 (Eurocode 3) and to obtain ductility predominantly by plastic elongation of the bolt for system HR according to EN 14399-3 or by plastic deformation of the engaged threads for system HV according to EN 14399-4; also countersunk and fit bolts according to EN 14399-7 and -8 respectively. The purpose of indicators is to show that a defined preload is achieved in the bolt and it can be used alone or else with bolt face washers or nut face washers conforming to this standard. Note: Compressible washer-type direct tension indicators are also known as load indicating washers.