Environmental impacts

Komet® a steel roof system manufactured by ArcelorMittal Construction for photovoltaic modules is designed to offer a high level of performance combined with a long-term warranty. It is the first simplified, integrated solution for mounting photovoltaic modules without the need for fixing rails and now holds a technical assessment certificate from the French construction industry body CSTB.

An innovative, certified solution

The patented Komet® system is a steel profile specifically designed for photovoltaic (PV) roofing. With this high-performance solution, PV modules can be easily integrated directly onto the steel profile, which constitutes a real innovation on the solar market. Furthermore, the thickness and the quality of selected coatings used guarantee water tightness and durability of the building.

Boasting the advantages of simplicity and modularity, and acknowledged for its quality and performance in use, Komet® 840 received in February a technical assessment certificate (no. 21/14-49) from the CSTB, the scientific and technical certification body in France.

Simplified integration with the roof: designed for the non-residential market, Komet® perfectly meets the requirements of new buildings and roofing renovation projects, be it in the field of industry, shopping centres or agriculture (storage).

Reliable, Moduble and simple

Due to the absence of intermediary mounting rail, the Komet® system is an easy-to-install and extremely competitive solution. Its limited number of components makes it very reliable and competitive, highly limiting risks at both supply and installation levels. Module mounting is technically independent from roof installation.

The fact that it is easy to install means that the services of a specialised installing company are not required: the installer simply positions the Komet® steel profile and then the PV company installs the PV panels using the special parts provided in the Komet® kit.

Superior mechanical performance, with guaranteed watertightness

The Komet® system has excellent mechanical performance, particularly in terms of the large spans possible between supports and the lack of any watertightness problems thanks to the use of casings covering relevant areas, without any intermediary system.

This solution offers a fully modular layout, with installation of either 54 or 60-cell PV modules in landscape orientation, and roof purlin spacing of up to 3.5 metres, depending on the specific case.

Furthermore, it is compatible with most ArcelorMittal Construction thermal/acoustic GlobalRoof solutions and can be combined with first-class electrical equipment to make a complete solar generator with optimised durability and performance.

Adapted to the construction market’s thermal regulations

The Komet® system was developed to take account of changes in French thermal regulations and reflects ArcelorMittal’s determination to meet the needs of the market and of its clients. RT 2012 requires that the primary energy consumption of new buildings should remain below the 50 kWh/m2/year threshold (compared with 150 kWh/m2/year in RT 2005).

The regulations are now being tightened up even more. The forthcoming RT 2015 will set the maximum at 30 kWh/m2/year and looking further ahead, to RT 2020, the positive-energy building (BEPOS) concept will encourage builders to erect buildings capable of producing more energy than they consume.

Tisséo bus depot in Toulouse opted for Komet®

The project, which was completed late 2014, involved the construction of buildings in Colomiers, in the south-west of France, mainly for the purposes of maintenance, repair and garaging of Tisséo buses (Tisséo is the commercial name of the public transport system in Toulouse and the surrounding area).

A solar photovoltaic electricity generating plant was installed on the roof of one of the buildings, with an installed power capacity of 80 kWp.

The Komet® system, which has been technically assessed by the CSTB, was selected for the job. This roofing system is installed in the same way as a conventional steel profile roof.  The casing formed by the ribbed steel profile acts as support rail for the PV modules, whilst also ensuring that the roof is watertight. Komet® has the advantage of being quick, easy and safe to install.


- Client: SMAT
- Consultancy firm: SNC Lavalin
- Architects: Claude Denu and Christian Paradon
- Installation company: SMAC Toulouse (roofing/cladding) and Eiffage Energie (photovoltaics)

In recent years there has been a steady growth in the number of wind-power generation projects around the globe: ArcelorMittal and Siemens cooperate to supply the next generation of wind farms.

ArcelorMittal is very active in the sector as a leading supplier of heavy plate for traditional welded towers and electrical steels for the turbines.

Siemens is a major player in the implementation of wind farms with more than 11,000 turbines installed worldwide. Although Siemens and ArcelorMittal already have a long history of cooperation, Siemens was looking for a long-term steel partner who could match their global footprint and provide them with the expertise and technical experience the company needed for success in the wind power segment. 

For Siemens, one of the prime considerations was the ability of their steel supplier to guarantee stable lead times. With wind towers using up to 180 tonnes of heavy plate and up to 175 individual turbines in a wind farm, the logistics of ensuring just-in-time deliveries of steel are critical for success. The heavy plate is used to construct both the tower and, in offshore installations, the jackets that keep the turbine stable on the sea floor.

Global customer team

To meet the Siemens challenge, ArcelorMittal established a global customer team including technical experts, representatives from the mills, and marketing and sales personnel. This team worked closely together to respond quickly to the customer’s requirements – imperative in such a complicated supply chain. The team also undertook research and development activities in order to maximise cost savings for the client.

ArcelorMittal is already a well-regarded supplier of heavy plate from a number of our mills around the world. One of the largest is AcelorMittal Gijón in Spain, ideally situated to meet Siemens European needs.

In November 2010, Siemens placed a trial order for heavy plate to build 21 wind towers at the Hill of Towie Wind Farm in Scotland. Thanks to the work of the ArcelorMittal customer team and the Gijón mill, the first plates were shipped in January 2011.

With the success of the first order, Siemens placed an additional order for hot rolled coils of high strength steel to build a new generation of ‘shell’ towers. Unlike other wind towers, shell towers can be higher than normal and are held together using bolts rather than welding.

Production and processing

To answer the growing demand from Siemens in Northern Europe, an entirely new supply chain was developed and implemented. All supplying units (including external suppliers) were extensively audited by Siemens before they could be integrated into the supply chain.

ArcelorMittal also took on the challenge of both producing and processing the heavy plate. Processing is handled by ArcelorMittal’s partners who are located close to our Gijón mill. Together we have built a competitive offer for Siemens which is unbeatable in terms of quality. The added value ArcelorMittal and our partners are able to offer also creates significant cost savings for Siemens.

As a result of this cooperation, Siemens and ArcelorMittal agreed on a long-term contract for the supply of heavy plate for Siemens’ wind turbine needs at the end of 2011. The agreement was possible thanks to ArcelorMittal’s proven ability to understand and meet the customer’s needs, our global footprint, and speed of delivery. ArcelorMittal and Siemens are now working closely together to build the next generation of wind-power plants.

End of November 2012, the first part of new containment structure for the defunct reactor in Chernobyl was put into place. 21 years of planning preceeded the construction of this new “Sarcophagus” that will encase the reactor number 4 and the old containment structure and will be finished in late 2015. ArcelorMittal provided steel for this milestone project.

When on April 26th in 1986 a great explosion followed by a fire was registered at the Chernobyl Nuclear Power Plant, a large quantity of radioactive particles was released into the air. Now, almost 27 years later, the world is still dealing with the consequences.

Immediately after the accident a protection to contain the contamination was built, the so called “Object Shelter” sarcophagus encases the unit 4 of the Chernobyl plant. Now, this concrete and steel structure shows worrying signs of deteriorations and is feared to collapse.

At the moment, the New Safe Confinement  is under construction right next to the Chernobyl site and once it is finished it will be slid into place on rails, encasing the reactor 4 and the old containment structure in order to ensure the radioactive material cannot be released. 21 years of planning preceeded the actual project – the most effective longterm solutions to safeguard the defunct nuclear power plant had to be investigated.

When completed, this New Safe Confinement structure will take the form of a giant arch, with 150 m lenght and 105 m height, creating thus a span of 257m. The frame of this arch will consist of a tubular steel lattice secured by two longintudinal concrete beams and will support the two layers of steel cladding. For the next 100 years, this cladding will ensure that no residual radioactive material can escape the reactor core.

ArcelorMittal was involved with various teams of different departments: the International Construction Team of ArcelorMittal Distribution Solutions, ArcelorMittal Construction Poland, ArcelorMittal FCE Poland and ArcelorMittal Kryviy Rih supplied in total 164.000 tonnes of steel:

- 12.000 tonnes of rebar (40mm) for the foundations
- 91.000 sqm of steel profiles for external supporting deck
- 73.000 sqm of profiles for the internal supporting deck  
- 106.000 m Omega purlins