BS EN STANDARDS
The launch of the European standards for design and fabrication (BS EN 1090-1 & 2) of Structural Steelwork, is associated with the introduction of a set of European standards harmonising the best of all European countries standards for non-preloadable (BS EN 15048) and preloadable (BS EN 14399) High Strength Structural bolting.
BS EN 14399 - 1 TO 10 HIGH STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING
BS EN 14399-1:2015
General Requirements
This European Standard specifies the general requirements for bolt/nut/washer(s) assemblies for high-strength structural bolting, which are suitable for preloading.
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The intended use of bolting assemblies in accordance with this European Standard is structural metallic
works.
BS EN 14399-2:2015
Suitability for Preloading
This European Standard specifies the technical requirements for high-strength structural bolting assemblies in order to ensure the suitability for preloading of bolted connections in metallic structures.
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A suitability test is specified to check the behaviour of the structural bolting assemblies so as to ensure that the required preload can be reliably obtained by the tightening methods specified in EN 1090-2 with sufficient margins against overtightening and against failure.
BS EN 14399-3:2015 System HR
Hexagon Bolt and Nut Assemblies
This European Standard specifies, together with EN 14399-1 and EN 14399-2, the requirements for assemblies of high-strength structural bolts and nuts of system HR suitable for preloaded joints with large widths across flats, thread sizes M12 to M36 and property classes 8.8/8 or 8.8/10 and 10.9/10.
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Bolting assemblies in accordance with this document have been designed to allow preloading according to EN 1993-1-8 (Eurocode 3) and to obtain ductility predominantly by plastic elongation of the bolt.
Click here for BS EN 14399 HR Preload Assembly Documentation
BS EN 14399-4:2015 System HV Hexagon Bolt and Nut Assemblies
This European Standard specifies together with EN 14399-1 and EN 14399-2, the requirements for assemblies of high-strength structural bolts and nuts of system HV suitable for preloaded joints with large widths across flats, thread sizes M12 to M36 and property classes 10.9/10.
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Bolting assemblies in accordance with this document have been designed to allow preloading according to EN 1993-1-8 (Eurocode 3) and to obtain ductility predominantly by plastic deformation of the engaged threads.
Click here for BS EN 14399 HV Preload Assembly Documentation
BS EN 14399-5:2015
Plain Washers
This European Standard specifies, together with EN 14399-1 and EN 14399-2, hardened and tempered plain washers intended for bolting assemblies with large series hexagon high-strength structural bolts and nuts with threads from M12 to M36 inclusive. Washers according to this standard can be applied under the nut only.
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Washers according to this standard are not intended to be used in direct contact with oversized or slotted holes.
BS EN 14399-6:2015
Plain Chamfered Washers
This European Standard specifies, together with EN 14399-1 and EN 14399-2, hardened and tempered chamfered plain washers with chamfer intended for bolting assemblies with large series hexagon high-strength structural bolts and nuts with thread sizes from M12 to M36 inclusive.
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Washers according to this standard are not intended to be used in direct contact with oversized or slotted holes.
BS EN 14399-7:2018 System HR Countersunk Head Bolt & Nut Assemblies
This European Standard specifies, together with EN 14399-1 and EN 14399-2, the requirements for assemblies of high-strength structural countersunk bolts and nuts of system HR suitable for preloaded joints with thread sizes M12 to M36 and property classes 8.8/8 or 8.8/10 and 10.9/10.
Bolting assemblies in accordance with this document have been designed to allow preloading according to EN 1993-1-8 (Eurocode 3) and to obtain ductility predominantly by plastic elongation of the bolt.
BS EN 14399-8:2018 System HV
Hexagon Fit Bolt and Nut Assemblies
This European Standard specifies together with EN 14399-1 and EN 14399-2, the requirements for assemblies of high-strength structural bolts and nuts of system HV suitable for preloaded joints with large width across flats, thread sizes M12 to M36 and property classes 10.9/10.
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Bolting assemblies (including fit bolts with nominal shank diameter d + 1 mm) in accordance with this document have been designed to allow preloading according to EN 1993-1-8 (Eurocode 3) and to obtain ductility predominantly by plastic deformation of the engaged threads.
BS EN 14399-9:2018 System HR or HV Direct Tension Indicators for Bolt & Nut Assemblies
This document 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 in accordance with 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 14399-10:2018 System HRC Bolt and Nut Assemblies with calibrated preload
This document specifies, together with EN 14399-1 and EN 14399-2, the requirements for assemblies of high-strength structural bolts and nuts of system HRC suitable for preloaded joints, with hexagon head (large width across flats), cup head or countersunk head, thread sizes M12 to M36 and property class 10.9/10.
Bolting assemblies in accordance with this document have been designed to allow preloading according to EN 1993-1-8 (Eurocode 3) and to obtain ductility predominantly by plastic elongation of the bolt.
Click here for BS EN 14399 HRC Preload Assembly Documentation
KEY NOTES
Under the European “CE” marking legislation for pre-Load structural bolting, there are three types of approved assemblies.
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BS EN 14399-3 HR Assemblies
Based on the historical British/French system, the BS EN 14399-3 “HR” assemblies are similar to the previous BS 4395 Part 1 & 2 assemblies and are less sensitive to over-tightening.
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BS EN 14399-4 HV Assemblies
Based on the historical German system, the BS EN 14399-4 “HV” assemblies are similar to the previous DIN 6914/15/16 assemblies which are more sensitive to over-tightening.
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BS EN 14399-10 HRC Assemblies
Based on the historical Japanese system, the BS EN 14399-10 “HRC” assemblies are designed totally to be Installed using a specific type of torque wrench.
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It is essential, that the bolt and nut components from all three of the above assemblies are only incorporated as specified in the relevant standards as mixing of bolts and nuts is not allowed.
There are four methods of Installation allowed under the existing European fabrication standard BS EN 1090-2:2018 for tightening.
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​Torque method, section 8.5.3
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Combined method, section 8.5.4
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Torque Wrench method, section 8.5.5
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Direct tension indicator method, section 8.5.6 + BS EN 14399-9
The direct tension indicator (DTI) method is mainly popular in the UK, however it is becoming a preferred method throughout Europe due to the fact that it gives a specific measurement system to ensure that pre-load is achieved.
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The requirements for “CE” marking of pre-load fasteners assemblies, are given in BS EN 14399-1.
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These pre-load assemblies have major advantages where vibration is present, however the slip between joining parts must be avoided as the applied load through the joint frequently changes from a positive to a negative value, otherwise standard, non pre-load, grade 8.8SB assemblies will prove more economical.
History and related standards
The above series of European standards were first introduced in 2005 when they superseded BS 4395-1:1969 and BS 4395-2:1969, which have been declared obsolescent since September 2007, together with BS 449 and BS 5950, which were withdrawn upon publication of Eurocode 3.
Cross-references
EN 1090-2, EN 26157-1, EN ISO 225, EN ISO 898-1, EN ISO 898-2, EN ISO 3269, EN ISO 4759-1, EN ISO 4759-3, EN ISO 6157-2, EN ISO 6507-1, EN ISO 6508-1, EN ISO 7500-1, EN ISO 10684, EN ISO 17668, ISO 261, ISO 888, ISO 965-2, ISO 965-5, ISO 3508.
BS EN 15048 1 & 2 NON-PRELOADED STRUCTURAL BOLTING ASSEMBLIES
EN 15048 contains regulations governing products used for the design, calculation and manufacture of non-preloaded bolt connections for Steel and Aluminium Structures.
Part 1 sets out the general requirements and Part 2 the suitability testing required.
BS EN 15048-1:2007
General Requirements
This part of this European Standard specifies the general requirements for the components of bolt/nut/washer
assemblies for non-preloaded structural bolting and for the assemblies themselves. It applies to bolts (including screws, studs and stud bolts) and nuts made of carbon steel, alloy steel and stainless steel.
BS EN 15048-2:2007
Suitability Test
This part of this European Standard specifies a tensile test for bolt/nut assemblies to guarantee their suitability for non-preloaded bolted connections in civil engineering structures. It applies to assemblies of bolts, nuts (and washers if required) with dimensional and mechanical characteristics as specified in EN 15048-1.
History and related standards
EN 1090-1 sets the requirements for CE marking for steel and aluminium bearing construction parts with references for implementation to EN 1090-2 and EN 1090-3. EN 1090-2 describes the bolt connectors in which reference is made to standard EN 15048 for non-preloaded structural bolts and EN 14399 for preloaded bolts.
Cross-references
EN 1090-2, EN 1993-1-8, EN 10045-1, EN 10204, EN ISO 898-1, EN ISO 898-2, EN ISO 3506-1, EN ISO 3506-2, EN ISO 6507-1, EN ISO 7500-1, EN ISO 9001, ISO 273, ISO 6892.
Please note: All preload and non-preload bolt assemblies are sensitive to differences in manufacture and lubrication. Therefore it is important that the assembly is supplied by one single manufacturer only, who is responsible for the function of the assembly. For the same reason, it is important that the coating of the assembly is under the control of one manufacturer.
Beside the mechanical properties of the components, the functionality of the assembly requires that the specific assembly can be achieved if tightened with a suitable procedure. For this purpose a test method for the suitability of the components for preloading and non-preload was created within the standard (BS EN 14399-2 & BS EN 15048-2), which will demonstrate whether the function of the assembly is fulfilled. From 1 July 2014, it became a legal requirement under BS EN 1090 for all parts of a bearing steel structure to bear the CE mark for both preloaded and non-preloaded assemblies.
New requirements were introduced when the UK left the European Union that these parts are to carry the UKCA mark when placed on the UK market. There has been a transition period in place since January 2021 where either mark can be used but the UKCA mark will become compulsory in the UK after 30 June 2025.
Please note: It is crucial to ensure bolting assemblies are correctly used if satisfactory results are to be obtained. For recommendations concerning proper application, refer to EN 1090-2. General requirements and suitability for preloading are specified in EN 14399-2. Also note that the fact that the assemblies may be subject to plastic strains during tightening means that bolts and nuts that have been fully preloaded must not be re-used once removed.
BS EN 1090-1, 2 & 3
BS EN 1090-1, 2 & 3 are harmonised standards which covers the Design of Steel and Aluminium. Structures with Products within this scope that must be CE marked when released to the market. BS EN 1090 consists of 3 parts.
BS EN 1090-1:2009 + A1:2011
Covers the requirements for conformity assessment including instructions on how to CE mark products.
BS EN 1090-2:2018+A1:2024
Covers the technical requirements for Steel Structures.
BS EN 1090-3:2019
Covers the technical requirements for Aluminium Structures.
For a more in-depth detail of the EN 1090 standard head to the BSI website via this link