Device Orientation

40 Holborn Viaduct, London

  • Client: Castlemore Securities
  • Architect: Rolfe Judd
  • Construction Manager: Balfour Beatty Construction
  • Scope of Works
  • Intumescent Paint Systems: 25,000m² Nullifire System S707 Intumescent coatings
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40 Holborn Viaduct is a high specification office building occupying a prominent site at the western gateway to the City of London. Designed by Architect Rolfe Judd’s, 40 Holborn Viaduct is a 235,000ft², 12-storey office building, including three basement levels, and retail units at ground level facing on to Holborn Circus.

High specification, high profile projects generally require high quality products and this scheme was no exception. Situated in the heart of the city, meant that the application of the structural fire protection system had to be sympathetic to the local environment, whilst also meeting Balfour Beatty’s strict budget constraints. Sharpfibre were approached early on to offer a number of solutions to satisfy the fire protection criteria. With the structural steel members being delivered to site in a primed condition to receive a highly decorative finish, meant that the obvious choice would be to apply an intumescent coating throughout the building. However, the odours associated with high performance Intumescent paint systems meant that the choice of paint system must be water-based. Sharpfibre approached supply chain partner Nullifire whose water-based systems are fast and easy to apply to in-situ steelwork, by spray or brush, and safe to use even in confined spaces. They are environmentally friendly and have no solvent odours and were therefore suitable for this application.

Unlike other intumescent paint systems, the Nullifire System S coatings dry quickly to a smooth, hard finish, minimising the risk of damage. This enabled Sharpfibre to offer Balfour Beatty reduced application times by up to a half, thereby reducing the cost of installation and allowing faster access for following trades, mitigating the potential of any delays.

Product Information

Intumescent Paint Systems
Thin film applied Intumescent paint is a fast method of providing up to 120 minutes fire protection to structural steelwork. Intumescent coatings provide an appearance similar to that of paint, with basic to high gloss finishes now available.  At ambient temperatures Intumescent paint systems remains stable. However in a fire condition, the increase in temperature activates a chemical reaction which then causes the intumescent coating to expand many times its original thickness.

This expansion provides an insulating foam-like coating or “char”. It is this “char” that provides the fire protection to the steel work which, in some instances, can be up to 50 times its initial applied thickness. Therefore, secondary casings applied to the steel members must allow for expansion to ensure the intumescent paint system performs correctly.

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