Lightweight Solutions -  Textile Roofing in India

There is a great need to spread awareness about the applications of textiles in architecture, says Mr. Ravi Mehta of Sujan Impex which represents Ferrari, a French company in India.



Architectural Textiles is a fashionable shading concept that could be used for interior as well as exterior applications. While interior applications include stretched false ceilings, acoustic wall coverings & sun protection, exterior applications consists of light weight roofing structures & building facades. The exterior applications of this concept are very exciting because of the dynamic forms and the different possibilities to play with the lighting. With almost a decade of efforts in disseminating the message of light weight textile roofing the growth in this segment today is visible. Five years back, there weren't many companies in India which had the capability to execute these kinds of structures. Even if the architects loved the concept, they suspected the capability of execution. Sujan Impex represents Ferrari, the manufacturers of architectural textiles. With Ferrari's policy of not venturing into the forward integration of the product, Sujan Impex restricts itself as suppliers to the industry while still acting as a catalyst in promoting the concept of textile architecture, apart from supporting our customers to acquire knowledge and enabling them to execute the projects. This is achieved by organising annual workshops, providing guidance to source the software, & machines required, and also providing international contacts to acquire engineering knowhow, enabling our customers to execute textile architecture projects successfully.

In the last five to six years FERRARI has assisted many companies to achieve expertise to execute tensioned structure projects successfully. Structures ranging from small canopies of about 100 sq. mts. to large shopping mall roofs of up to 10000 sq. mtrs are being executed successfully in India. With the Indian market ready to take off, even a large MNC like Taiyo Membrane Corpn. is quite active in the Indian market and most of the projects executed by them like Mumbai & Hyderabad Airports are using FERRARI Membranes.

In India one of the pioneers in the field of membrane structures was Construction Catalysers of Pune. Dhananjay Dake started experimenting with fabric structures in the early nineties. One of the earliest structures done by Dake was for a petrol pump on the outskirts of Pune, with some locally available material. Unfortunately that did not last long as the fabric used could not sustain the external atmospheric conditions. One of the earliest large projects in India was the IL&FS Dome at BKC, where Dake got the membrane ready to install from Germany, as he realised that the locally available materials were not suitable for such applications. Once FERRARI entered the market in 1998-99, Construction Catalysers have executed some wonderful projects, as the right material was now available in India.

As other vendors acquired the expertise to execute membrane structures, today a large number of projects stand completed, or are under construction, like the Mumbai Domestic Airport, Santacruz, Mumbai International Airport, Sahar, Hyderabad Airport, Great India Place Mall Noida, Select City Walk New Delhi, Metro Walk Rohini New Delhi, Dreams Mall Bhandup, Crown Interiors Faridabad, Glomax Mall Kharghar, R City Mall Ghatkopar, Mumbai, Indore Cricket Stadium, Philips India courtyard Bangalore, Franklin Templeton Hyderabad, Mahindra World City Entrance Chennai, Mahindra International School, Chennai, Mantri Mall Bangalore, Express Mall, Chennai, and many many others.

Many sports facilities for the upcoming Commonwealth Games are going for this solution. Some of the prominent projects under execution are JN stadium New Delhi, Yamuna Sports Complex, Shivaji Stadium, SPM Swimming Pool Stadium, etc.

The benefits of using fabric are that it allows a lot of natural light to enter the building, resulting in a bright daylight atmosphere and warm ambience. At the same time, it does not allow too much heat into the buildings. Polycarbonate & Glass also allows natural light, but the problem is that it allows too much light which creates a glare on the eyes and at the same time transmit too much heat too. The air conditioning load required in such buildings is very high and yet the air conditioning is not very effective. In case of fabric you have the best of both worlds by having sufficient natural daylight, creating an ambient and festive atmosphere, yet not too hot to make the air-conditioning ineffective. FERRARI has now developed special LOW E membranes, which have a lower U value as compared to normal membranes, and therefore has a lower Solar factor, and yet allows natural light to come in. The Shanghai Exposition centre has used around 80,000 sq. mtrs of this material for the entire roofing of all the exhibition halls.

The applications where membranes structures are widely used are Airports, Metro Stations, Stadiums, Shopping Mall Atriums, Restaurants & Cafeterias and such other public spaces. In Residences they can be used for skylights, car parks etc.

Textile Façade

A very innovative use of a textile mesh is for building facades. Use of fabric as a external façade skin, has many advantages such as:

1. It reduces heat gain tremendously reducing air-conditioning costs substantially. A case study in an old existing building in California shows, that the energy bill was reduced more than 60% by using a skin of façade mesh on the exterior.
2. It can be used as a medium of communication to display logos, advertising, or simply beautiful graphics, as the mesh is digitally printable.
3. Facades can be easily given 3D forms, and along with innovative lighting, the building can be completely transformed, at a low cost and in quick time. Existing buildings can be transformed without major structural changes.

Precontraint technology

FERRARI fabrics are manufactured using the patented Precontraint technology. Precontraint in French means prestressed in English. This technology was developed by FERRARI to eliminate the problem of elongation under load. High tenacity Polyester yarn which is used in the weaving has some elasticity, and when subjected to stress can elongate. Use of Precontraint technology ensures that the fabric is stretched during the process of coating in both warp & weft direction, which eliminates the possibility of further elongation under load. Fabrics which do not use the precontraint technology have an irregular elongation across warp & weft, and the level of elongation which is called creep, is also very high. Structures made with such fabrics tend to lose the tension after some time, and need periodic re-tensioning, which can be avoided using FERRARI's Precontraint technology. FERRARI membranes have a residual elongation of less than 1% in both directions, which ensures dimensional stability in the fabric. Precontraint also make the yarns very flat ensuring thicker coating of PVC for the same thicknes of fabric, providing higher longevity to the fabric.

On top of the PVC coating, there is a PVDF topcoat which can be a high concentrated PVDF or an alloy of PVDF and acrylic. Most fabrics use a low PVDF concentration, making the fabric weldable without abrasion of the PVDF topcoat, since PVDF does not allow HF welding. However FERRARI has pioneered the technology of High concentration PVDF coating, which makes it more expensive at the manufacturing stage. However, the advantage is that it provides very high level of dirt repellent properties, and make the fabric non-stick to atmospheric dust & pollution.

Maintenance of these fabrics is very easy and a spray of water is good enough to remove all the settled dust. In tropical countries like India, where the rains are quite heavy even in case no maintenance has been done, 3 months in the year the membrane will be automatically washed with the rainwater.

Choosing the right fabricator for the membrane is very important, as designing & engineering of membrane structures is a much specialised field requiring special skill sets & infrastructure. A comprehensive software makes this task easier, as it can help you to do form finding, the load analysis for steel & membrane, and then generating the cutting patterns to achieve the desired form. Most serious players have an automatic plotting & cutting machine, which plots and cuts the fabric as per the patterns provided by the software.

Ferrari conducts a one-week workshop every year in July in France to educate participants on good manufacturing & installation practices, and to impart basic knowledge on textile architecture. We also conduct modelling workshops & arrange lectures for students of architectural colleges in India.

As far as sustainability goes, Ferrari jointly with Solway has developed a technology, which is a closed loop recycling technology. It does not release any effluent during the process of recycling. Effluents discharged during recycling are harmful to the environment and closed loop technology ensures that the discarded membrane get converted back into PVC and polyester, without discharge of any harmful effluents. Already a commercial scale plant is operational in Italy, and FERRARI is the only company today which undertakes to accept the membrane back for disposal at no cost to the customer at the end of its lifecycle, ensuring these fabrics do not end up in landfills. With this technology PVC coated fabrics which once upon a time were looked at as environmentaly unfriendly, have now become acceptable as environmentally friendly. Normally such roofs have a life span of 20 to 25 years.

Factors that make Fabric structures Green and environmentally friendly are:

1. Completely recyclable with a closed loop process.
2. Light Efficient & heat efficient making the space covered less energy demanding.
3. Reduces steel consumption on the structure due to lightweight in nature.
4. Construction & Deconstruction is fast and consuming lower resources.

Looking at all the advantages in terms of aesthetics, energy efficiency, recyclability, etc., I am sure Textile architecture has a great future in India, as it has in the rest of the world.