Steel structures' required fire and corrosion protection in Stockholm city center in a timeframe ten times shorter than they would have had before

Teknos' sales team found a solution to avoiding weeks of traffic disruption in central Stockholm caused by a construction site: using the correct intumescent coating for steel structures sped up the construction process remarkably.

Over the next five years, some of central Stockholm's old buildings will undergo renovation. The construction site offices installed for the duration of the work needed durable fire protection. By using Teknos intumescent coatings, it was possible to avoid installing fire boards – which would have taken three to four weeks – and to start construction earlier thereby minimizing the disruption caused to the city and its traffic and reducing excess costs.

Stockholm undergoing renovation

Over the next half-decade some of the old buildings surrounding the Sergels torg square in central Stockholm are scheduled for renovation. The lengthy renovation project for some of the old buildings surrounding the Sergels torg square requires the construction site office to be lifted into the air so that they do not disrupt traffic. This will be achieved by building steel structures to support the office. For safety reasons, the structures must be protected from fires to ensure that the steel cannot heat up and suffer a loss of strength in the event of a fire. Structures are protected using products such as intumescent coatings or fire boards. 

The load-bearing steel structures for the Stockholm site offices project were required to have a fire resistance class of R60. This class means that the structure must be able to withstand a fire for 60 minutes, which is estimated to be enough time to evacuate everyone. Furthermore, the coating system needed a corrosion protection class of C3, which is suitable for protecting structures from corrosion in urban environments.

The first method selected – installing fire boards– caused traffic disruption

In the first phase of the project, a single-coat epoxy paint was selected for corrosion protection. When the steel structure was installed, it was protected using fire boards. The structure met the requirements, but installing the fire boards meant using scaffolds for a period of three or four weeks. The installation caused major disruption to traffic in the area.

An intumescent coating had been an option from the very start of the project, but it was not chosen because the paint under consideration took far too long to dry and the paint shop could not manage the capacity it demanded for such large amounts of materials.

The fast-drying Hensotherm 910 KS intumescent coating enabled rapid installation and brought the construction forward by weeks

At just the right moment before the final phase of the project, the client consulted Teknos, and Business Development Manager Jan Nordmark offered an alternative intumescent coating. The paint in question was Hensotherm 910 KS, a solvent-free coating with an R60 fire protection class and a C3 corrosion protection class. As this paint dries in 24 hours, the paint shop was able to work efficiently and the steel structures were put in place quickly. Therefore, the construction project could start 3-4 weeks earlier. 

An efficient and successful project using Teknos' intumescent coating

The steel structures are now complete and the renovation project is in full swing. The customer is highly satisfied with the project. It has been a great success for everyone involved.

"If you ask me or Jan, our Teknos contact person, this is one of most fun projects currently underway. If we had used a conventional fire protection, we would never have been able to handle the deliveries on time due to the different panelling method and longer drying times. These are areas where Teknos' paint really stands out," says ProChroma's Björn Stam.

ASK FOR MORE INFORMATION

Janne Nordmark
Business Development Manager - Fire Protection 
Tel. +46 325 61 95 00
jan.nordmark[@]teknos.se

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"If we had used a conventional steel fire protection, we would never have been able to handle the deliveries on time due to the different panelling method and longer drying times. These are areas where Teknos' paint really stands out"

Björn Stam, ProChroma

Teknos & Hensel

Fighting Corrosion and Fire

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Sergels torg, Stockholm, Sweden

Steel stands have been erected in an area of over 6,000 square meters (1.5 acres), and 400 construction site offices have been fitted to the stands above ground level. 

ProChroma, Sweden, has supplied the customer with approximately 16 tons of intumescent coating.

Coating process

On the first day, the first batch of parts is coated. On the second day, the parts are inspected and additional coatings may be applied before the parts are collected and coatings of the next batch can begin. The coating is a dual-component paint applied at a temperature of 35–40°C. The minimum recommended spray pressure is 400 bar. At least two people are required to carry out the painting work. One person paints while the other is responsible for the tools and for mixing the paint. This is mainly due to the paint's usage time, which is less than 60 minutes. A single layer of paint is applied with a thickness of 2 mm, and this is inspected by taking a wet film measurement.

READ More about intumescent coatings