uPVC Windows - bringing a whiff of fresh air to Indian constructions

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uPVC Windows � bringing a whiff of fresh air to Indian constructions

PVC (Polyvinyl Chloride Vinyl) is one of the three major thermoplastics- Polypropylene (PP), Polyethylene (PE) and PVC being manufactured and used across the globe. Globally, around 60% ('21 million metric tons) of PVC finds its way into infrastructure in the form of Water/SWR/ Plumbing/Drainage Pipes, Window & Door Profiles, Pre-fab Housing, Porta Cabins, False Ceilings, Wires & Cables, Floorings, Sidings & Claddings, Deckings, Fencing, Cable Trays & Channels, etc. thereby earning the sobriquet of �Infrastructure Plastic�. To make PVC useful for various applications, additives such as thermal stabilizers, lubricants, processing aids, colourants, UV stabilizers, Plasticisers, fillers, etc. are added to it before processing to ensure good mechanical properties and weatherability. Due to this process, called �Compounding�, PVC becomes a highly versatile plastic making its processing possible for the rigidest of products (unplasticised PVC, i.e. uPVC) to the softest (plasticised or flexible PVC, i.e. fPVC).
Windows in residential and commercial constructions in India have mainly been looked at merely as simple carpenter assembled contraptions to fill the aperture in the wall, and traditionally made of Mild Steel, Wood or Aluminium and simple float glass apart from some basic hardware such as handles, shoot-bolts, hinges, etc. Globally, windows have come a long way from being insignificant to being recognized as the single most important area in the envelope or shell of the building for preventing energy loss and providing inhabitant comfort. Apart from this, windows today also have to ensure low/high Solar Heat Gain (depending on climate) daylighting, noise attenuation, low dust ingress, air/water tightedness, aesthetics, low maintenance requirements, and the like. Accordingly, windows today are judged on the basis of following parameters :
uValue (W/m2K)
� This measures how well a window is able to prevent heat transfer across itself either from outside to inside , or vice-versa. The lower the u value, the better is the Windows insulating value. Today, State-of-the-art window making technology ensures u values of even 0.2 W/m2K, although this is not available in India yet.
Solar Heat Gain Coefficient (SHGC)
� This measures how well a window blocks heat caused by sunlight. It is expressed as a number between 0 and 1. The lower the SHGC, the less solar heat the window transmits.
Visible Transmittance (VT)
� This measures how much light comes through the window. VT is expressed as a number between 0 and 1 ; the higher the number, the more light is transmitted.
Air Leakage (AL) cfm/sq ft
� When air infilitrates through cracks in a window, heat gain from outside or cooling loss from inside can happen. AL rating is expressed as the equivalent cubic feet of air passing through a square foot of window area . The lower the value , the lesser the AL.
Water Tightedness
� This measures how much water can infilitrate through cracks/joints in a window . This is an important test for coastal and/or heavy rain areas.
Noise Attenuation or Reduction
� Due to their better sealability and product integrity, uPVC Windows ensure that noise from outside does not come into habitable area. This property is important for Hospitals, Hotels, Educational Institutions, Constructions close to noise centres, etc.
Wind Load Suitability
� Windows have to withstand higher wind loads particularly in windy locations, coastal areas , high rises, etc. uPVC Windows are designed and reinforced to withstand even 3000 Pascals of wind speed (equivalent to 245 km/hr of wind velocity).
In keeping up with the advancements in technology and how the rest of the world specifies windows to deliver far more than just filling the aperture in the wall, we in India also have to progress and go up the learning and value curve in Fenestration Products (broad term for products filling the openings in the Building Envelope or Shell) so that they can deliver higher inhabitant comfort , safety and aesthetics at affordable prices as well as restrict heat transfer/energy loss in commercial as well as residential air-conditioned spaces.
Based on the above and the fact that Indian Sub-Continent is designated into five distinct climatic zones, it is important to understand what windows are expected to deliver in each of the zones so as to improve overall inhabitant comfort as well as save energy by preventing heat gain or cooling loss, as the case may be (Table 1).
Table 1

Desired Zonewise Window Performance in Indian Context
Climatic Zone	Solar Heat Gain (SHGC)	Heat Transfer (u value)	Air Tight	Water Tight	Heavy Squall &/or Rain	Comfortable to Touch	Noise Reduction	Dust Reduction	Condensation Free
Hot-Dry	Should Prevent	Low u value required	Yes	Yes	Should Withstand	Yes	Yes	Should not let in dust	NA
Humid-Warm	Should Prevent	Low u value required	Yes	Yes	Should Withstand	Yes	Yes	Should not let in dust	NA
Composite- Hot in Summer, Cold in Winter	Should Prevent in Summer, Allow in Winter	u value may not be as low as in above	Yes	Yes	Should Withstand	Yes	Yes	Should not let in dust	Yes in winter
Temperate	Should Prevent when hot, allow when cold	u value may not be as low as in above	Yes	Yes	Should Withstand	Yes	Yes	Should not let in dust	Yes
Cold	Should Allow	Low u value required	Yes	Yes	Should Withstand	Yes	Yes	Should not let in dust	Yes

Why uPVC Windows ?
uPVC Windows are widely used across the globe, from the deserts of Arizona to the coldest parts of Scandinavia/Russia, from the hot environs of Gulf to the tropics of Malaysia, Thailand as well as very extensively in China, S. Korea, Taiwan , and many more Geographies. In fact Europe and North America predominantly use only uPVC Windows in their residential constructions, for both new and replacement. This is due to their good aesthetics, durability, noise proofness, low maintenance requirement, best air & water tightedness, and their ability to provide excellent thermal insulation , thereby helping save air-conditioning power costs in homes, offices and commercial centres. uPVC Windows come with a very high-quality surface finish, soft-contoured profiles and a variety of styles to meet the needs of the most demanding architects, designers and users. The environmental benefit of using uPVC Windows instead of wood and metal windows is phenomenal. Due to their ability to conserve energy throughout their life-time (from raw-material stage to in-use stage), uPVC Windows are recognized as Green Windows thereby scoring over traditional wood and metal windows. uPVC Windows are the best fit for all weather conditions prevalent across India - from salty humid corrosive air of coastal areas to sub-zero temperatures of Ladakh to heavy rains of Cherrapunji to the hot dust storms of Central India to the cyclonic gale winds of Orissa coast to the extremely hot deserts of Thar in Rajasthan.
Given below are some of the Key Attributes and Value Proposition that uPVC Windows offer :
a) Do not allow rains to come in due to their double gasketting and water drainage design - Ideal for rainy and coastal locations
b) Do not let outside heat in (and vice-versa in cold climate) thereby providing inhabitant comfort & saving heating/cooling energy to the extent of 20-25% due to insulating multi-chambered profile and air-tight sealing design ; Also comfortable to touch in hot as well as cold climate; are condensation free � Ideal for cold locations. e.g. Siachen, as well as hot locations like Thar desert
c) Provide Sound & Dust insulation , reducing noise to the extent of 20-30 decibles thereby providing user comfort � Ideal for Schools, Colleges, Canteens & Messes, Hospitals , Community Centres, etc
d) Do not Rust, Corrode, Rot or Swell , are Termite proof, need no Painting � Ideal for coastal and rainy locations
e) Design flexibility and versatility - Any shape, form and size can be made; can be customized to blend with the architecture of the building
f) Stylish , elegant and aesthetically pleasing - Available in a choice of colours, printed patterns, laminates and colour- coordinated grilles (white is the best suited colour for Indian weather conditions)
g) Easy to fabricate, and install - Can be drilled, nailed, sawed, etc. and no finishing needed
h) Durable & Long Life - Have high impact strength, dimensional stability and weather stability ; Do not fade or get discoloured ; Water and chemical resistant ; No warpage or expansion/ contraction due to changes in humidity
i) Look new year after year - No paint or varnish needed; occasional cleaning with soap and water. In fact , if uPVC Windows are installed as replacement in old buildings, the buildings get a face-up and look almost new
j) Secure - Safety locking arrangements and metal reinforcements meet the common standards for forced-entry resistance
k) Meet stringent Fire safety requirements � PVC is inherently flame retardant, difficult to ignite and resists sustained burning
l) Convenient cleaning - Tilt in sashes allow for safe and easy cleaning from inside. Windows open effortlessly and balances never need adjusting
m) Act as Project Differentiator from a Builder�s perspective
n) Increase asset and resale value from a home-owner�s perspective
o) Save Forests and Environment - Replacement for Wood and Energy Intensive metals
p) Made from plentiful natural resource - 57% of PVC comes from common salt
q) Can be recycled at the end of their useful life

Comparison of uPVC with other framing materials
		uPVC	Wood	Aluminum	Steel
Raw Material		Made from 57% common salt, unlimited availability	Limited availability due to environmental concern	Extracted from Bauxite ore � limited availability	Extracted from Iron Ore
Energy Consumption		Low Embodied energy, Low energy consumption during extrusion	Low Energy consumption similar to PVC	High Embodied energy, 7.5 times high energy consumption during extrusion	Higher than PVC but lower than luminium
Convenience in Installation		Easy	Fair	Fair	Poor
Usage	Does it Peel corrode, rot or wrap in bad weather	Never	Yes	Yes	Yes
Does heat or cold transmit through the material	No	Only if kept dry	Yes	Yes
Is it cool all year?	Yes	Only if kept dry	No	No
Will it require painting or other maintainace?	Never	Only if kept dry	Yes if scratched	Yes
Will scratches show as a different colour under the paint	No	Yes	Yes	Yes
Does soap and water cleaning make material look new again	Yes	No	No	No
Aesthetics	Excellent	Good	Good	Poor
Waste Disposal		up to 99% after seperation from Hardware and reinforcement	Recycling difficult as profiles are treated with paint, silicon and various protection coatings	Separation of Alu and plastic parts difficult	Low value
Life Time		50-100 years. PVC windows are in market since 50 years	Have to be painted & maintained	40 Years with adequate surface coatings	5-10 years with maintenance
Flash Ignition Temp.		400 o C	210 o C
Self Ignition Temp.		450 o C	400 o C
Needle Flame Test		Non-Ignitable	Ignitable in < 20 sec.

Indian Development on Building Code:
The issuance of first ever Energy Conservation Building Code (ECBC) by Bureau of Energy Efficiency, Ministry of Power, Govt. of India in May�07 was long awaited. The code is applicable to Building Envelope and four other areas of building construction.(HVAC, Service Hot Water Heating & Pumping, Interior & Exterior lighting, Electrical Power & Motors). ECBC 2007 has recommended the use of Energy Saving, low u value uPVC Windows in Indian constructions . uPVC Windows fit the bill perfectly , thereby helping to save both Energy & Environment.
In fact, a case-study undertaken in Europe in 2006 ( Potential to Save Energy through use of Modern Window Systems in Europe � By Marcus Hermes ) concluded that if energy-inefficient Windows are replaced by energy efficient uPVC Windows , Europe will be able to meet emission norms of Green House Gases (GHG) set as per Kyoto Protocol within lesser number of years without touching any other area for curtailing energy consumption.

Conclusion:
uPVC Windows are increasingly becoming the material of choice for achieving economic and environmental balance as well as meeting higher demands on inhabitant comfort . With natural resources dwindling fast, traditional products are becoming more expensive. At the same time the requirement of building materials is increasing many folds. uPVC Windows and other PVC Products are making an enormous contribution to many different aspects of infrastructure development and hence need to be on every Architects, Interior Decorators or Builders radar screen.
(Source: Ravi Koul Jalali & Aruna Kumari , HOBD-Polymers, Reliance Inds. Ltd.)