The fabric membrane
For its retractable fabric membrane, Saye-Roshan Co uses Germany’s Mehler Company’s productions. Mehler is one of the most authentic companies producing fabric membrane in the world.
Introducing Germany’s Mehler Co.
Germany’s Mehler Co. is one of the oldest European companies in the field of textile industry. By remarkable technological development in textile industry this company not only has used relevant up-to-date technologies but also has invented some innovative methods for producing incombustible fabrics. This company’s 60-year record in this field demonstrates the reliable background of a big producer of composite fabrics.
Here we list some of the accomplishments of this company:
– First producer of PVDF coverings which had weldability in VALMEX fabrics as final cover, in 1994.
-The introduction of AIRTEX, a layer manufactured for commercial advertisement digital print, by using new light materials and textile industry technologies, in 2004.
– Producing the first Polyester fabric covering with high chemical corrosion resistance, in 2005.
– Introducing composite covering for facades under the trade name TF400, in 2012.
– Registering the invention of membranes, which in them the ability of self-cleaning had been improved in comparison with similar cases, under the trade name of VALMEX, in 2014.
To get more information about technology used in fabric composite and Germany’s Mehler company’s productions visit its website: www.mehgies.com
The features of composite fabric of retractable roofs:
Coating Yarn Type: PVC
- The membrane is made of Acrylic Lacquer which as the final coating is anti-fungal and antimicrobial at both sides; This membrane is also UV resistant.
- Fire behavior: BS 7837، DIN 4102، NFP 92507 and M2 fire codes.
The regulations mentioned above measures the burning duration of the fabrics. For example when a fabric catches fire, the burning duration of the fabric is measured til it dies out. Then the result is compared with the determined standards, if the burning duration of the fabric is less than the standard time then the fabric would be safe according to the regulations. In other words, those fabrics that meet fire codes also catch fire but because of materials used in them die out soon.
- Total weight: 800 g/m²
- Tensile strength: 3000 N / 50 mm (in warp and weft directions)
- It means that if we put 3000 N Tensile stress on a 5-cm tape, it would break off.
- Shear strength: 300 N (in warp and weft directions)
- Adhesion: 20 N/cm
- Temperature resistance: -40 to +70C°
- With a dark membrane which reduce the light transmission to zero.
The link to download technical features of retractable roof’s fabric:
Material and the elements of retractable roof’s fabrics:
Composite fabrics are made of polyester and PVC yarn; Polyester yarn is used for producing tensile strength in composite covering from one hand, and PVC coating is used to protect polyester layer on the other hand. Tensile fabrics have versatile transparencies and different function in sunlight absorption, reflection and transmission. The amount of sunlight absorption, reflection and transmission depends on the thickness of the PVC coating in these kind of fabrics; and it ranges from 0 to 50 percent. Composite fabrics are produced in different tensile strengths. The difference between tensile strengths in composite fabrics depends on the yarn type and thickness of the coating from one hand and the number of the layers of the PVC coating on the other hand. Due to this, in any project the fabric is chosen corresponding to the limit load of that project calculated in the structural analysis.
Protection coating of fabrics used in textile structures:
In order to keep their durability and resistance, composite fabrics are covered with different layers which protect them. Among layers which are used for the final PVC coating in composite fabrics are PVF FILM, ACRYLIC, and PVDF.
PVDF layer is known as the most resistant coating of composite fabrics. Some specific features of the PVDF final layer are high fabric durability, bright and smooth surface, easy cleaning and high color fastness.
Color fastness of tent structure during the service time
One can compare the durability of PVDF coating with other coatings usually used in textile structures in the same condition. As the figure below shows PVDF coating keeps 80% of its primary brightness after 10 years, while the best kind of other coatings keeps only 20% of primary brightness and quality of fabrics in the same time.
More durability of fabrics used in textile structures:
More durability and resistance of these fabrics result from up-to-date processes of production and using modern technologies in the structure of tensile fabrics. Furthermore, repair and maintenance of composite fabrics is also a factor that increases these covering’s expected lifetime. Applying a PVC coating on the fabric protects it and increases the expected optimum functioning time.
Acrylic Lacquer final coating besides protecting PVC coating, by creating a smooth and bright surface and reflecting the light, reduce the absorbing of pollution to the minimum level and consequently increases fabric’s durability and expected lifetime. Moreover, the maintenance instructions presented for cleaning fabric surface help to keep fabric’s primary quality and consequently increases its expected lifetime.
To evaluate the flammability of a material we measure the burning duration of that material. PVC itself is flammable and dangerous, but in production of composite fabrics special additives are used which have very good deterrence quality against flame. Fabrics used for retractable roofs have such quality which is a very important characteristic.
These kinds of fabrics meet the regulations of fire safety. Mentioned regulations measures burning time of fabric. For example when a fabric catches fire, the burning duration of the fabric is measured til it dies out. Then the result is compared with the determined standards, if the burning duration of fabric is less than the standard time then the fabric would be safe according to the regulations. In other words, those fabrics that meet fire codes also catch fire but because of materials used in them die out soon.
The fabric of Saye-Roshan’s retractable roofs (FR700 opaque ORIENTAL 7209 0599 VALMEX ) is produced by Germany’s Mehler Co. This fabric’s thermal conductivity is less than 9 w/m.k (1 int surface emissivity). Opaqueness of retractable roofs’ fabric is that important feature which prevent the heat of sunlight to enter inside the automatic roof. Polyester texture of these fabrics is made of black membrane which prevents light transmission from the roof. Semi-matt fabrics are used for constructing tinsel textile structures and are not suitable for electric retractable roofs. But it is possible to install retractable roofs with translucent fabrics if costumers order so (due to specific architectural requirements).
Today, PVC is one of the best insulator materials in construction industry. Heat transfer amount of a retractable membrane roof is far less than a 10 mm glass surface.
Color fastness of retractable roof’s fabric:
For color fastness, the composite fabrics are coated with different layers protecting these kind of fabrics. PVF FILM, ACRYLIC, and PVDF are some of membranes used for final PVC coating. Using these membranes not only improves the color fastness in composite fabrics but also increases durability and the lifetime of fabric.
Light transmission of retractable roof’s fabric:
composite fabrics are usually produced opaque or translucent. In fabrics that transfer light the amount and percentage of light transmission are determined according to the thickness of PVC membrane. The light transmission amount in these kinds of fabrics can be increased by 50%. These type of fabrics are used for roofing environments in which light transmission amount and natural light use are important architectural factors of the place. Using a black membrane among different layers of matte fabrics have prevented light transmission in these kinds of fabrics. Heat transfer amount is a key factor for choosing fabrics in any particular project.