Projects and Features
Fasteners and Bolts
Structural bolts are one of the key elements of a steel frame and their manufacturers and suppliers form an important part of the steel construction supply chain.
Structural bolts play a vital role in steel construction, as the majority of steelwork projects will always have an abundance of bolted connections. For this reason, bolts or fasteners are considered to be one of the key structural elements in a steel frame and vital to a structure’s safety and speed of completion.
To keep the UK and Irish markets adequately supplied with structural bolts requires an extensive network of manufacturers, suppliers and distributors spread throughout the British Isles. This important supply network also has tentacles that stretch around the globe as many of the products are manufactured and sourced from overseas.
The most popular bolt sizes in the UK and Irish markets are typically M20 (20mm diameter) up to M24 (24mm diameter) units, with lengths between 50mm and 100mm. However, the product range also includes diameter sizes up to and beyond 100mm and suppliers can manufacture and procure bespoke sized bolts for a particular project.
Bolt suppliers will also stock, and in some cases manufacture, various associated products such as nuts, washers, machine screws and studs.
Advancements in the sector have included colour coding. In a safety critical industry, such as steel construction, the colour coding of bags has also meant a safer work place as it has lessened the chances of someone using the wrong bolt. The practice of putting one size of bolt only in a unique coloured bag is now nearly universal and has helped erectors and project teams identify the correct item more quickly.
The BCSA has an established Working Group for Fasteners. Its aim is to support suppliers and manufacturers of bolts to spread best practice throughout the steel construction supply chain.
One of the aims of the Working Group is to assure specifiers of bolts that they are buying products from companies with strict quality control procedures in place. By purchasing bolts from BCSA industry members, customers can also be assured that the products are of the highest standard and CE Marked.
Bolt suppliers’ UK premises are all certified for CE Marking, while having ISO 9001 means strict quality control is in place and guaranteed from point of manufacture all the way to the construction site. Regular contact and visits to overseas facilities means companies’ factories are producing bolts to the highest standards, wherever they are located.
In regard to future advancements the European standard for the manufacture of both non-preloaded and preloaded fasteners are being revised [see box]. The harmonised (CE Marking) standard for preloaded bolts, BS EN 14399-1, has been updated and cited in the Official Journal of the European Union (OJEU). Bolt manufacturers have until the 8th April 2017 to put in place the necessary factory production control system for CE Marking as this is when the cited standard will become mandatory.
Other parts of BS EN 14399 ‘High-strength structural bolting assemblies for preloading’ are also being revisited and these include:
- BS EN 14399-7 – Part 7: System HR, Countersunk head bolt and nut assemblies
- BS EN 14399-8 – Part 8: System HV, Hexagon fit bolt and nut assemblies
- BS EN 14399-9 – Part 9: System HR or HV, Direct tension indicators for bolt and nut assemblies
- BS EN 14399-10 – Part 10: System HRC, Bolt and nut assemblies with calibrated preload.
The standards for non-preloaded bolts are also being revised including the harmonised (CE Marking) Standard BS EN 15048-1. This standard has been approved by the CEN Committee but has not been cited in the OJEU. However, it is anticipated that it will be cited in April 2017.
Sponsors: Structural fasteners
BAPP Group of Companies,
Tension Control Bolts Ltd