InterBolt receives DNV approval

InterBolt utilises a gauge pin at the heart of its bolt load sensor. To fit the gauge pin into a standard bolt or stud, a small modification to the fastener needs to be made. We often get customers asking if this modification could have an adverse impact on their fasteners.

We recently appointed DNV to conduct an independent, third-party review of our manufacturing process to confirm that our modified fasteners still meet the requirements of ISO898-1 (most common international bolting standard). DNV is recognised as the leading player in risk assessment and certification, with many wind turbine OEMs using them to approve new designs so their approval is seen as the gold standard in the industries we operate in.

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Following extensive evaluations of the InterBolt manufacturing process, DNV concluded that the bolt modification process, testing procedure and documentation resulted in InterBolts meeting all the requirements of ISO898-1. This makes InterBolt the first and only embedded bolt load monitoring company to have their design externally verified.

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The boring bit:

The governing code for the structural verification was ISO 898-1:2013 - Mechanical properties of fasteners made of carbon steel and alloy steel - Part 1: Bolts, screws and studs with specified property classes - Coarse thread and fine pitch thread.

Codes used for reference were;

? EN 14399-4:2015 - High-strength structural bolting assemblies for preloading - Part 4: System HV - Hexagon bolt and nut assemblies

? ISO 225:2010 - Fasteners - Bolts, screws, studs and nuts - Symbols and descriptions of dimensions

? ISO 261:1998 - ISO general purpose metric screw threads - General plan

? ISO 724:1993 - ISO general purpose metric screw threads - Basic dimensions

? ISO 965-1:2013 - ISO general purpose metric screw threads - Tolerances - Part 1: Principles and basic data

? ISO 965-2:2013 - ISO general purpose metric screw threads - Tolerances - Part 2: Limits of sizes for general purpose external and internal screw threads - Medium quality

? ISO 68-1:1998 - ISO general purpose screw threads - Basic profile - Part 1: Metric screw threads

? ISO 6892-1:2019 - Metallic materials - Tensile testing - Part 1: Method of test at room temperature

? ISO 6157-1:1988 - Fasteners - Surface discontinuities - Part 1: Bolts, screws and studs for general requirements

? ISO 3269:2019 - Fasteners - Acceptance inspection