Pushing the Boundaries of Fire Protection in Complex Steel Structures

Intumescent coatings are a crucial part of any structural steel development, providing vital passive fire protection.

Appearing to all intents and purposes as an ordinary coating, with a thicker film, these coatings demonstrate unique properties.

However, their application can be a slow process for fabricators, adding time to any construction project, particularly so as the increasing use of complex steel structure design requires the use of new, high-performance coatings.

A series of chemical reactions swell the coating to many times the original thickness to provide an insulating char or foam.

In a standard cellulosic fire – when the fuels are wood, paper or plastic – an average piece of unprotected steel hits 500°C in just 13 minutes. Protected steel, however, can take as long as 120 minutes to reach this critical failure point.

Intumescent coatings are not a new technology. First developed in 1936, there are many types available. These can be divided into two main groups, thick film or thin film.

Thick film are epoxy-based coatings which are tough and durable, suitable for protecting against the severity of hydrocarbon fires Thin film coatings are solvent or water-based coatings mainly used to protect against cellulosic fire conditions.

The coating process is therefore a vital one, and is usually the responsibility of fabrication shops. The application process is the same for any such coating. Fabricated steel is blasted then primed, then following the primer application, the intumescent coating is applied. Subsequent coats are applied until the required film thickness is achieved.

Depending on the nature of the project being applied, there may be a top coat applied to the intumescent coating to provide external weather resistance.

Time and cost savings

Solvent-based coatings can take up to a week to reach full specified dry-film thickness, and can take a significant period of time before they can be exposed to the weather. This is a significant period of delay to be factored into any project.

Once coated, the steel is susceptible to mechanical damage at this stage, when being transported both in the shop and being erected at site.

It has long been recognised by the industry that it would be of real benefit to the fabrication companies and their customers if this process could somehow be accelerated.

As a result, Sherwin-Williams’ FIRETEX FX6000 was developed to meet these growing customer needs, in particular through improving productivity in a fabrication shop by reducing the amount of time taken to apply a full fire protection system.

Meeting the modern-day challenge

The process for fabrication companies with traditional products, and with the FIRETEX FX6000 product is very similar, up to a point. The basic blasting, priming and coating is undertaken as with any product.

However, FX6000 pushes the boundaries with an extremely fast cure, and with this new advantage, multiple coats of product can be applied in one day.

Traditional solvent-based coatings will dry based upon solvent evaporation from the applied coating. When these materials are applied at higher thicknesses – for instance to ensure increased time period fire protection – drying and handling times are significantly increased.

This new technology dries as a result of a chemical cross-link reaction rather than solvent evaporation. This chemical reaction proceeds at a rapid rate, which is what provides the FX6000 with its unique drying and handling properties, enabling multiple coats to be applied in a day.

The fast cure means that application can be completed in a much reduced time period, and the completed steel can be put into outdoor storage sooner, meaning that valuable shop space is not taken up and that production can carry on.

This also means that not only can a project be completed on the production line quicker, with higher productivity rates, it means the building owners can be assured of a faster turnaround and installation.

For many modern steel structural projects, this is a huge benefit especially with longer periods of fire protection being increasingly required.

Curing to a very hard, durable film, the added benefit of this breakthrough means there is more resistance to mechanical damage, with less time and money required to repair any damage that may be done to the fire protection, again reducing the costs associated with the total project.

With curing at lower temperatures than are required for adequate drying of solvent-based coatings in a fabrication paint shop, even heating costs can potentially be reduced.

As a very high volume solids product, FX6000 also offers a significant reduction in VOCs – volatile organic compounds – generated when the product is cured. This can offer a benefit to a steel fabricator and painter in terms of being beneficial for the solvent emissions directive.

A system for all reasons

This technology is starting to fast-forward many projects as modern steel structures built in major towns and cities in the UK and worldwide become more complex and the demands of project owners becomes more challenging.

 Sherwin-Williams has many years’ experience in manufacturing and supplying specialist intumescent coatings, and its family of FIRETEX FX System products has been used on landmark projects worldwide.

These have included a number of high-profile projects in London such as the The Shard, the Leadenhall Building, Heathrow T5, St Pancras Station and the Olympic Park.

Projects have also included Al Khifaf Etisalat Tower in Dubai, Turkey’s Sonkar Hilton Hotel, the Grand Mosque in Abu Dhabi and Azerbaijan’s Flame Towers. 

Sherwin-Williams, a global leader in the development, manufacture and sale of coatings and industrial-related products, is exhibiting at FIREX International 2016. Register here to attend Europe’s biggest annual trade show for the fire industry. And click here to book a meeting with the Sherwin-Williams team at the show.