Beginning September 25th, 2015 ASTM International officially recognized the TNA Fastening System with it’s own specification;  ASTM F3148-15 Standard Specification for High Strength Structural Bolt Assemblies, Steel and Alloy Steel, 144ksi Minimum Tensile Strength, Inch Dimensions.

For us, this is a pinnacle moment in the development process.  No longer is TNA just a great idea.  Recognition by ASTM validates our own thinking that TNA is a valuable and useful addition to the structural bolting product mix.  Now users can identify and specify the TNA Fastening System according to its ASTM Designation knowing that the industry has reviewed, debated, and accepted the system based on its merit.

At Lejeune Bolt we have lived TNA for the past four years.  Through theory, R & D, Testing, and finally production we have moved forward with the singular idea that bringing TNA to market will revolutionize the way structural bolting is performed and viewed by the industry.  So it’s with sincere gratitude that we acknowledge those that have helped get TNA to this point and great pride that we now offer TNA to the public through this new standard.

Within the standard you will find all of the information required to specify TNA.  Included in the standard you will also find important additional information needed to implement the system.  In F3148 you will find Appendixes X1; Test and Installation Procedures for Torque-and-Angle Tensioning of Fixed Spline F3148 Assemblies.  In these Appendixes are the required Pre-Installation Verification Testing Procedure and the formal Installation Procedure.  This information is typically found in RCSC ” Specification for Structural Joints Using High-Strength Bolts”.  The dilemma we faced was the RCSC document was last published in 2014 and isn’t scheduled for additions and re-publication until 2020.  So for this interim period these procedures will be referenced from the ASTM document.  When the Torque-and-Angle installation method can be included in the next RCSC publication, it will be removed for the ASTM document.

To obtain your own copy of F3148 you can go to  For subscribers, the new standard can be downloaded as part of your subscription service.  If you’re not a subscriber, download your own copy from the ASTM site or contact LeJeune Bolt and we will provide a print copy free of charge.

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TNA is a registered trademark of LeJeune Bolt Company.  All rights resereved.