A cost-effective, low-maintenance, lightweight, strong, versatile and fully recyclable material — unplasticised polyvinyl chloride (uPVC) — is making construction eco-friendly and sustainable. We take a look at its properties and usage in the building and construction industry:
Manufacturing process
A by-product of the petrochemical industry, uPVC is known as a thermo-plastic. Principal architect of Shripal and Venkat Architects, Shripal Munshi explains the process and says molten PVC is passed through dies and profiles created which are then cut, fusion-welded and screwed together to make doors and windows. It is derived from ethylene (from natural gas) and chlorine (from salt water). Stabilisers are added to improve the resistance of uPVCs to heat and sunlight. New generation stabilisers are based on calcium.
What makes it popular?
uPVCs are seen as a more sustainable choice as they are unlikely to be affected by climate change over longer period of time. S Kalidoss, GM-Projects, House of Hiranandani, says the industry has gradually embraced uPVC as it is more durable and energy-efficient. Apart from being versatile, uPVC products can withstand plumbing and draining more efficiently than conventional pipes (GI, stoneware, RCC) because of minimal frictional losses. Also, uPVC pipes are easy to use and can endure high operating pressures. “The products are resistant to sunlight, oxidation and a variety of chemicals. They are resistant to fire, frost, electricity, and do not react adversely with any building material,” Kalidoss says. uPVS products are also priced cheaper in comparison to solid wood windows doors, wood clad windows and doors, Italian aluminium wood windows, and aluminium thermal break windows.
The material is dust-proofand is a product for extreme conditions. It scores over aluminium in terms of sound insulation, heat reduction and fire resistance. “uPVC windows and doors have a greater energy saving potential than any other window material and rank at the top of the league in eco-efficiency analyses,” says Munshi. They have the highest thermal insulation property compared to other framing materials like aluminium, wood and their extrusion process is relatively energy-efficient when compared with aluminium.
Utility range
uPVC has multiple uses, and not restricted only to the construction sector.
In the construction industry, uPVC is primarily used for windows, doors, water pipelines, irrigation pipes, sanitary pipes, plumbing pipes, water tank, partition panels, temporary shelters, RCC formwork shuttering materials, and false ceilings. In the transportation industry, it is used externally to make vehicle bodies, caravans and is also used internally to create plastic aesthetics. In the retail sector, sale displays, storage racks, ticket strips and poster grippers are produced from uPVC.
N. Kalyanaraman, General Manager-Technical, Navin’s Housing, says uPVC is apt for projects in areas situated close to the sea. “As it doesn’t get corroded, it is easier to use. It is also easy to use since it is lightweight. Windows and doors are manufactured with UPVC which are cut to the required size and joined with fusion welding. Necessary hardware, glass, and gaskets are then fixed.”
uPVC as a green material
Based on the physical and chemical properties, it is proven that uPVC is a green material. One of the major benefits is that these products can be fully recycled and reused for production. The products are recyclable and can be reshaped into new products at high temperatures. Shushmul Maheshwari of RNCOS says, “At the end of their life they can be converted into other useful products, even the waste material generated during manufacturing can be reprocessed, thereby helping in creating a reliable and sustainable future.”
Munshi explains that 57 per cent of the basic PVC molecule is derived from salt, an element in plentiful supply with an estimated 50 quadrillion (one thousand million) tonnes of dissolved salt in the world’s seas alone, with the remainder from oil. “PVC is inert; a quality that makes it ideal for use in medical products and environments, and the modern production process for PVC is also environmentally friendly.” An average European PVC production plant would need to be operating for 30,000 years to produce the same amount of dioxins generated on one bonfire night.
Today, doors and windows are indispensable energy saving components, says Chandan Jain, MD, Vijay Shanthi Builders. uPVC has low thermal conductivity, which makes it impervious to heat transfer and the use of energy-efficient windows and doors can help reduce your energy bills by almost 7-15 per cent. “uPVC doors and windows have three energy-saving features that minimise the cost of heating and cooling,” he says. As per a research conducted by RNCOS, uPVC windows and doors are economical and help in monetary saving on the cooling or heating bill. They help save around 20 per cent on the bill if the structure is fully equipped with uPVC windows and doors.
In addition to this, uPVC can replace the wood and is considered as popular framing material. Its manufacturing is relatively energy-efficient as compared to aluminium production. Its sealing quality keeps environmental pollutants like sound, dust and smoke out of home, reducing health hazards and improving environmental quality inside the home. T. Chitty Babu of Akshaya says uPVC is an excellent alternative to timber, steel, and aluminium. “It is a by-product of the petroleum cracking process, and thus, wastages are minimised. While everyone says plastic is not a ‘green’ product, recycling uPVC is possible.”
Disadvantages
Although the material has a number of benefits, it has its downsides too. uPVC has a low strength to weight ratio, and while the extrusion process is energy efficient, it is also toxic. It does not have the same life as aluminium or steel, and often discolours because of lack of appropriate additives and protection against UV light exposure. Yaazhini Ramchandran, a designer at Shripal and Venkat Architects, says uPVC is not recommended for use above 70°C, although it can withstand 80°C for short periods. The material is sensitive to UV and oxidative degradation. It has limited thermal capability and has a higher density than many plastics.
Similar materials
While none of the modern construction materials are a match to uPVC, there are a few that have similar benefits. Glass Fibre Reinforced Concrete (GFRC) and Fibre Reinforced Plastics (FRP) could be used. HDPE pipes, aluminium panels, calcium silicate boards, gypsum, and fiber plastics are other alternatives
WHY IS uPVC POPULAR?
High mechanical strength and durability
Hygienic means of fluid transportation
Resistant to fungi and are not subject to contamination
Resistant to most concentrations of acids, alkalis, organic chemicals, oils and fats
Flexible to withstand deformation due to earth movements
Low density, making it cheaper to transport and easier to install
Fire resistant and self-extinguishing
Has good insulating properties
Low thermal conductivity
Recyclable and reusable
