Content with DTI

12 January 2022
We understand the difficulties by the end-users and purchasing departments in choosing the right components for different installation methods of High-strength structural bolting assemblies for preloading (HR). Different installation methods and product grades may require additional components like DTI washers, hardened washers, bolt face or nut face washers. Sometimes, the number and type of component change, depending on which part is rotated (the nut or the bolt head). We have prepared the HR configurator below to simplify this task.
Read more about BS EN 14399 (HR) Configurator

02 March 2021
When ordering Preloaded Assemblies (EN 14399-1) to be installed with Direct Tension Indicator Washers (DTI’s) , there are 4 different methods of how they can be installed. Depending on the access or preference, you may choose one method, over another. At the purchase stage, we may not know how you will be installing your assemblies. Please read below, as you may require an additional washer(s) to be purchased.
Read more about Do I need Bolt Face Washer or Nut Face Washer (EN 14399-9) with DTI's?

12 April 2016
Load curve graph for DTI for test compression loads at 0.40mm gap For use with bolts Compression load (kN) diameter Designation H8 Designation H10 M12 47-56 59-71 M16 88-106 110-132 M20 137-164 172-206 M22 170-204 212-254 M24 198-238 247-296 M27 257-308 321-385 M30 314-377 393-472 M36 458-550 572-688 According to EN 14399-9:2018, Table 4 DownloadPDF
Read more about BS EN 14399-9 Compression loads for DTI washers

08 April 2016
Direct Tension Indicators Washer – dimensions Dimensions of compressible washer-type direct tension indicator According to BS EN 14399-9:2018, Table 2 Size bolt diameter Internal diameter d1 External diameter d2 Thickness h1 Height over protrusion h2 Height of protrusions h3 Protrusion tangential diameter d3 Protrusion internal diameter d4 min max min max min max min max min M12 12,75 12,85 26,0 32,5 2,5 5,5 0,8 20,0 13,85 M16 16,75 16,85 35,0 36,8 3,0 6,0 0,8 25,0 17,85 M20 20,95 21,05 41,0 46,0 3,5 6,5 0,8 29,0 22,05 M22 23,05 23,15 46,5 50,6 4,0 7,0 0,8 33,0 24,15 M24 25,15 25,25 50,0 55,2 4,0 7,0 0,8 38,0 26,25 M27 28,30 28,40 54,0 62,1 4,0 7,0 0,8 43,0 29,40 M30 31,45 31,55 59,0 69,0 4,0 7,0 0,8 46,5 32,55 M36 37,75 37,85 78,0 83,0 4,0 7,5 0,8 56,0 38,85 Dimensions in millimetres DownloadPDF
Read more about BS EN 14399-9 Dimensions of Direct Tension Indicators washers

21 August 2015
Please find below documents as a part of our Technical Support section. If case of any further questions, please visit our Frequently Asked Questions (FAQ) section or contact with Andrews Fasteners Quality Department . BS EN 15048 Non-preloaded structural bolting assemblies (SB) Torque values prepared by W. Christie Guidance On The Tightening of Non-preloaded Fasteners Guide to Design Criteria for Bolted and Riveted Joints, Second Edition BS EN 14399 High-strength structural bolting assemblies for preloading (HR) BS EN 14399 (HR) Configurator Torque values for preload bolt assemblies with specified k-Class Bolt Length Calculator for HR Bolts and HR Countersunk Bolts (EN 14399-3/7) Thread Length (HR CSK) Calculator for bolts EN 14399-7 Thread Length (HR) Calculator for bolts EN 14399-3 Comparison of Tightening Methods of HSFG Bolts Detailed comparison of BS 4395 and BS EN 14399-3 & 6 Summary comparison of BS 4395 and BS EN 14399-3 & 6 Grip, Bolt Lengths and Hole Dimensions Guidance notes on the use of Preload Bolt Assemblies BS EN 14399 (HSFG) comparison as an alternative to ASTM HSFG See also: Preloaded assemblies k-Class K1 and K2 manufactured in the UK (from News ) BS EN 14399-9 Direct Tension Indicators Washers Instruction Manual for installing Preloaded (HSFG) bolting with TurnaSure Direct Tension Indicators Washers EN 14399-9 New Generation Direct Tension Indicators Squirter Type DTI performance results Preload Measurement and Comparison of Structural Bolts sets installed in Steel Connections with and without DTI Tests for stress relaxation over time 1963 to 1971 with CLI Fatigue tests on CLI CLI Washers-load gap relationship on unloading and loading DTI Case History - DTIs Save More than $150,000 Study discussing influence of load-indicating washers on bolt relaxation in joints subject to high prying forces Study on full flattening of Direct Tension Indicators in Shear Connections Study on curved protrusion DTIs design assembled without needing nut face or bolt face washers Impact of Variable Lubricity on Type 325 Structural DTIs Test Report for Accelerated Aging of Weathering Steel Joint using TurnaSure Weathering Steel Transverse Vibration Loosening Characteristics of High Strength Fastened Joints using DTIs Coating Trivalent passivation systems (Fasteners+Fixings Magaizne) The HDG (Hot Dip Galvanising) Coating (Source: galvanizeit.
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18 March 2015
Mechanical Properties BS EN 14399 Part 5: Plain Washer Mechanical Properties Requirement Vickers hardness 300 HV to 370 HV BS EN 14399-5: High-strength structural bolting assemblies for preloading. Plain washers BS EN 14399 Part 6: Plain Chamfered Washer Mechanical Properties Requirement Vickers hardness 300 HV to 370 HV BS EN 14399-6: High-strength structural bolting assemblies for preloading.
Read more about BS EN 14399 Mechanical properties for Washers

01 February 2015
Direct Tension Indicators Washers (BS EN 14399-9) Andrews Fasteners company in manufacturing Direct Tension Indicators Washers (DTI Washers) in well know in construction industry company based in United States – TurnaSure . All our washers are marked with our headmark FAST (previously AND.). Benefits of using Direct Tensions Indicators Washers: The use of DTIs is the simplest way of ensuring that bolting assemblies are tensioned properly; The use of DTIs saves cost on inspection ; No torque figures are required, only feeler gauges; Risk reduction on over tightening; DTIs are manufactured in compliance with EN 14399-9 and can be supplied with CE approved preload bolting assemblies; Unique curved protrusion design of Turnasure DTIs reduce necessary of using nut face / bolt face washers for 8.
Read more about Direct Tension Indicators Washers (BS EN 14399-9)

25 August 2014
BS EN 14399 High-strength structural bolting assemblies for preloading (HR) High-strength structural bolting assemblies for preloading Previously known as High Strength Friction Grip (HSFG) We are a manufacturer of UKCA & CE Marked pre-loaded fasteners to BS EN 14399. In our facility in Leeds, we can UKCA & CE Approve – assembly test to BS EN 14399-2 HR Assemblies from M12 to M36 up to grade 10.9. We are regularly independently assessed by Lloyd’s Register / LRQA, to make sure, that our company is fully compliant with BS EN 14399 requirements.
Read more about BS EN 14399 High-strength structural bolting assemblies for preloading (CE & UKCA Marked)

07 March 2013
Andrews Fasteners applied for change of approval to their current CE approval certificate covering EN 14399-1 preload bolting assemblies, to include DTIs (Direct Tension Indicators) in compliance with EN 14399-9. LRQA has conducted their necessary assessment in March to cover DTIs and following technical review of the audit documents the change of approval has been authorised and amended CE approval certificates have been issued covering DTIs to EN 14399-9. Andrews Fasteners is one of the first UK fastener companies to gain CE approval for the supply of DTIs ensuring that they remain at the forefront of CE approved fastener supply.
Read more about Andrews Fasteners applied for CE change of approval (DTI's)

20 June 2011
BCSA has released memorandum about CE marking of TCB (tension control bolts) and DTIs washers (direct tension indicators). Read more: BCSA Memorandum 53-10 TCB and DTI CE Approval
Read more about BCSA memorandum about CE marking of TCB and DTI's