What is BS EN 14399-9 - Direct tension indicators about?
BS EN 14399 is a series of European standards on bolting assemblies that discusses the best procedures and specifications required for measuring direct tension on bolt and nut assemblies. BS EN 14399‑9 is the ninth part of a series of documents on high-strength structural bolting assemblies for preloading.
BS EN 14399-9 specifies, together with EN 14399-1 and EN 14399-2, the requirements for direct tension indicators, nut face washers (HN), and bolt face washers (HB) as part of high-strength structural bolting assemblies suitable for preloaded joints.
These direct tension indicators are specified as part of high-strength structural bolting assemblies of system HR or HV by EN 14399-3, EN 14399-4, EN 14399-7, or EN 14399-8, with nominal thread sizes M12 up to and including M36 and property classes 8.8/8 or 8.8/10 and 10.9/10.
BS EN 14399-9 specifies two-property designations H8 and H10 for direct tension indicators, together with general dimensions, tolerances, materials, and functional property/ies.
Bolting assemblies by BS EN 14399-9 have been designed to allow preloading of at least 0,7 fub × As1) according to EN 1993-1-8 (Eurocode 3) and to obtain ductility predominantly by plastic elongation of the bolt for system HR by EN 14399-3 or EN 14399-7, or by plastic deformation of the engaged threads for system HV by EN 14399-4 or EN 14399-8.
Bolting assemblies conforming to BS EN 14399-9 may include washer(s) according to EN 14399-6 or EN 14399-5 (under the nut only).
NOTE 1: Attention is drawn to the importance of ensuring that the bolting assemblies are correctly used if satisfactory results are to be obtained. For recommendations concerning the proper application, reference to EN 1090–2 is made.
NOTE 2: Direct tension indicators are also known as load indicating washers.
Who is BS EN 14399-9 - Direct tension indicators for?
BS EN 14399-9 on direct tension indicators for bolt and nut assemblies is relevant to:
- Manufacturer of bolt and nut assemblies
Why should you use BS EN 14399-9 - Direct tension indicators?
Direct tension indicators (known formerly as load indicating washers) used in conjunction with nut face washers (HN) and bolt face washers (HB) are load indicating devices that are placed under the bolt head or the nut. The direct tension indicators have protrusions on one face that compress under load and thus may be used to indicate that at least the required preload has been achieved in the bolting assembly.
BS EN 14399-9 navigates you through the specifications and reference standards for direct tension indicators, a functional test of direct tension indicators, test method for measuring compression loads (all finishes) on direct tension indicators.
As a user of BS EN 14399-9, you can be ensured of the requirements for direct tension indicators and can also measure preload that has been achieved in the bolting assembly. With obedience and compliance to BS EN 14399-9, you can efficiently manufacture high-quality bolt and nut assemblies. BS EN 14399-9 provides you with comprehensive information useful throughout the process of preload determination.
What’s changed since the last update?
BS EN 14399-9:2018 supersedes BS EN 14399-9:2009, which is withdrawn.
In comparison with EN 14399-9:2009, the following modifications have been made:
- Table 1 containing the overview of the composition of bolting assemblies and component marking has been revised
- The test method for measuring compression loads on direct tension indicators has been revised
- The suitability test for bolting assemblies including direct tension indicators has been revised
- Informative Annex A has been deleted
- Informative Annex on the use of direct tension indicators has been added
