Wednesday, 27 February 2013

Case study-Architect Sukhtej Gill's residence in Ludhiana ( Punjab)

Mr. Sukhtej Gill is an USGBC accredited LEED architect based in Ludhiana. He is always keen for in-detail discussion about Doors/Windows system. He needed something sustainable material for his own residence which provide quality with performance guaranteed

A common saying in the architect's field is Design follows Function. It becomes especially true when designing doors/ windows for an architect's own home. Here appropriate design needed with best performance. 

When mr. gill shared his architectural drawings , I realized & said to myself that for me & fabrication partner it is not going to be easy cake walk to convince him for size limitations ( by the way UPVC Doors/ windows needs to be strictly designed as per size limitations recommended by profile & fittings manufacturer otherwise it is complete waste of money & time ). As  he designed most of the door's height more than 8 ft or, 2440 mm.  We tried to convince him as not going more than 2440 mm height as it is not advisable as most of the doors fitting or, hardware locking mechanism comes with 2440 mm height & going beyond that is Indian Jugaad, not recommended by not only by profile manufacturer but also fittings manufacturer.ultimately Mr. Gill has freezed 2440 mm which we offered in SL 90 mm system.

There are other challenges in his office cum residence as most of the rooms were having large door opening specially south west facing where solar heat needs to be controlled & needs to have thermal insulation for winter. We suggested double glazing with neutral colored heat reflective glasses which he agreed. There were other challenges in while designing as he required 3-sided U-shape window for lounge area where we have suggested to use flat steel bar couplings to avoid deflection & make it as rigid as wall.

Rest is history. for us it is like a building a Taj Mahal by innovative & sustainable material like uPVC.Window and Doors, for some our work is " frame a view " , for us frame work for life......

Saturday, 16 February 2013

Case study-Mr. Saurabh Agarwal, MG Road, Gurgaon

Most of the time story is built around the house...but have you ever heard story is built around  doors/windows...yes it happened in gurgaon with Mr. Saurabh Agarwal working @ Google India. 

I remembered when he invited me to his home based in Essel tower on MG road. His first concern was  as he was originally from Kolkata & used to travel a lot from Delhi, he needed his home to be dust proof & also peace of mind by screeching noise created via sharp turning of metro rail & heavy traffic noise from Iffco crossing but poor aluminium windows/ doors which were having leakage at all corners are making their night worse to sleep & cleaning was arduous task. 
 What we have done... First we suggested them to have only casement or, openable doors/windows system all around the house as sliding doors/ windows can not be 100 % leakage proof...also we suggested to have acoustic glass ( Acoustic Laminated glass has high level of noise insulation upto 50 dB-Rw ).

But as usual first reaction of new customer i.e.Mr. Saurabh was that it is costlier & out of Budget...but don't he needs peace of mind, absolutely he needs but what about cheap competition as others were cheaper...we again worked on price & suggested 12 mm glass ( Rw ; C ,C tr- 35 dB ) with VEKA AD series ( acoustic design-Rw ; C, Ctr- 42 dB).  ( by the way it is a myth that double glazed glass is good for noise insulation as 12 mm glass has better noise insulation values than double glazed glass) but we did not compromised on fittings. Because only good  fittings makes uPVC doors & windows better product than wooden & aluminium windows....

Address- 903, PC-1, Essel Tower, MG Road, Gurgaon

Experience of making a house into a Home !
Bottom frame to make Home completely air-tight

Before Picture

Metro Track which brings screeching sound

Economical Door stopper suggested by Saurabh Agarwal

Feedback of Mr. Saurabh after 3 year 

Why uPVC Windows !

  • Weather Resistant Doors & Windows -More than any other building material, uPVC windows and doors have excellent material properties even after many years in use. As a matter of fact, they do not alter under extreme temperature or weathering.
  • High Security Doors & Windows – High-stability window and door profiles made of uPVC offer the best solution for increased safety. Special fittings and glazing, qualified window fabrication and expert installation offer an enhanced security at various levels.
  • Maintenance Free- UPVC window and door systems do not require regular repainting and expensive maintenance. They do not rot, warp nor corrode even in tropical and salty coastal climates. Therefore, their maintenance is reduced to simple cleaning and does not involve any further costs.
  • High Noise insulation- The protection against noise is an essential characteristic of a modern window in order to ensure a comfortable life both at home and in the office.
  • Efficient Thermal Insulation- No matter in which climate windows and doors are installed – they contribute to a cosy and comfortable atmosphere in your home. As the design prevents thermal bridging, the thermal insulating performance of the finished window is exceptionally good
  • Termite Resistance-In tropical climates wooden windows and doors are often destroyed by termites, whereas uPVC window and door systems are fully resistant to these insects. Thanks to the highly developed compound of uPVC windows and doors, termites are not able to attack to uPVC profiles.
  • Fire Resistance-Fire tests have shown that uPVC materials, being naturally flame retardant throughout their product life, will not cause, support or enhance the development of accidental fire. Unlike timber windows, the uPVC sections do not support combustion and are in fact self-extinguishing.
  • Maximum Water Tightness- UPVC window and door systems have been successfully used in swimming-pools, marine and ocean environments without detriment to the surface finish or performance. One of the main assets of window and door systems is their resistance to driving rain and their joint tightness.So Your Home stays absolutely dry however heavily it might be raining outside.
  • Durable Doors & Windows-The longevity and superior quality of this material has been conclusively proved for almost 40 years. UPVC material compound performs to worldwide standards for strength, durability, heat stability, colour retention, and termite resistance.All in all, an uPVC is virtually guaranteed to help you save plenty of time and money over long duration of its use.
  • Maximum Wind resistance- Due to their excellent material properties, uPVC window and door systems are ideal for being installed in buildings close to sea where they are permanently exposed to strong wind, heavy rain and salty air.
  • Rust resistance- Unlike metal windows, uPVC windows & doors are rust proof and resistant to atmospheric pollution ,including a range of acids & alkali.This also means they will also perform better than wooden doors & windows.
  • Dust Proofing-The sealing of uPVC windows & doors effectively stops dust drifting in from the outside, which drastically reduces the time you’ll spend cleaning your house.

Are uPVC Windows environmental safe?

Preserving the environment is one of the leading concerns, we, as a society, face today. Individuals and corporations alike must act responsibly and understand how the products they purchase and manufacture will affect the environment today and tomorrow. A number of factors can influence how “environmentally friendly” a product or industry is viewed. Those products and industries associated with recycling, energy efficiency and minimal waste disposal will have a definite advantage in the ever “greening” global marketplace. 

Plastic, once regarded as a substitute material that is used and thrown away, is becoming one of the most durable and widely recycled materials in the industry today. Plastic products have made an impact on modern medicine, global communications, transportation and food preservation. Plastics are also used in the preservation and protection of the environment in such ways as materials recycling and pollution prevention. Ironically, plastics, which were originally thought to be one of the larger of waste disposal problems, are now vital in the construction of material landfills. These facilities depend on plastic liners to protect groundwater by blocking toxic escape into the environment. Plastic drainage nets and textiles are used to remove the leachate and methane gas that collects inside the landfill, while plastic reinforcing materials and foam coverings save space, suppress odors and deter pests. Plastic products also conserve energy since they are lighter than alternative materials and use less fuel to transport. Plastic building components and insulation are extremely efficient in reducing conduction and infiltration into living spaces, lowering the amount of energy used for heating and cooling. Plastics generally require less energy to manufacture than equivalent products made of alternate materials. 

PVC is the world’s second most widely used plastic material. PVC, a non-hazardous white granular powder made from upvc chloride monomer, is fabricated into diverse upvc products having a variety of applications. upvc is predominantly used in construction and building applications that include window and door frames, sewer and water distribution pipe, drain, waste and vent plumbing pipe , flooring and wall coverings. upvc is an integral part in the manufacture of electrical wire and cable, packaging, furniture and coatings. A vast array of products found in the home and industry use upvc products because of their unique characteristics and low cost. Because most upvc applications are long-term uses that are not disposed of quickly, relatively little (about two and a half percent) is found in the waste stream. upvc is highly recyclable and can be incinerated safely without harm to the environment. Reground upvc is used to manufacture many items including mobile home skirting, PVC pipe and upvc siding. The small amount of upvc that is discarded is also environment-friendly. 

Studies conducted by independent bodies, such as the New York State Energy Research and Development Authority, have shown that the presence or absence of upvc waste in incinerator feed has no effect on the amount of dioxins produced by incinerators.* Dioxin production from any source can be minimized by carefully controlling incinerator operating conditions. pollution control equipment minimizes dioxin emissions, and scrubbers remove over 90 percent of the acid gases produced from the incineration. upvc also resists attack from the corrosive action of water and soil conditions typically found in landfills. It remains inert and will not leach harmful chemicals into groundwater. As the use of upvc and other plastics continues to increase, so does the need for continued research to develop more and stricter recycling programs and industry regulations.

Discover how one can improve noise free comfort at home………..

Noise is increasing day-by-day, especially in metros, and is adversely contributing to the health of people. From hearing loss to sudden change in behavioral pattern, doctors say, noise pollution is just adding to the existing stress levels.And those who gets it a lot, doctors say suffer from fatigue, lack of concentration, irritability, tinnitus (constant ringing sounds), and gradual hearing loss among other health problem. “Over- exposure to loud sound can result in temporary or permanent hearing loss is gradual, it leads to headache and fatigue. As the person is not to able to hear properly, he has to strain more to hear which often leads to headache and lack of concentration, “said Dr. Atul Mittal Senior consultant surgeon, ENT, Max Healthcare. (Source : Times of India : New Delhi Edition published : 7 April 2007)

However with proper glass & window combination you can protect your home from this disturbance and reduce noise pollution thanks to  uPVC window! At here, working with different specialists creates many opportunities to learn from each other. Sometimes one forgets that engineers, architects & consultants who know everything about dark matters as wind loads in glass or intricacies of structural elements may not have a clue about the acoustic performance of a window.
That’s why these questions keep coming to my desk (remember I’m a professional in the Glazing world): what effect does glass thickness have in the acoustics of a double glass unit? Or what matters more in the acoustical performance of insulated glass: the thickness in a monolithic pane, the effect of lamination or the dimension of the cavity? Here you will find some answers to these questions. As usual a number of hidden surprises will come out from the data mining.
Noise explained
Sound, a form of energy, is caused by molecules vibrating in a gas, liquid or solid. These vibrations are known as sound waves.The frequency or pitch of a noise, measured in hertz, is the number of sound waves emitted per second. High pitched sounds are carried by short sound waves and low pitched noises by longer waves. The actual level or intensity of noise is measured in decibels (dB).
Improving acoustic insulation
Acoustic insulation works by reducing a sound wave’s energy with proper combination of glass & window. The acoustic insulation properties of a window are measured with the ‘R’ sound reduction index. For example, a window with an R of 20 decibels should reduce a 60 dB outside traffic noise level to 40 dB within the room.
Noise pollution can be in any combination of low, medium or high frequency sounds. Some types of frequencies are easier to block or reduce. High pitched sounds (carried by short sound waves) are easier to absorb but reducing low frequency noise such as traffic can be more difficult. It is important to select the acoustic insulation properties of the window required according to the frequency or pitch of the noise to be blocked, as well as the desired number of decibels to be reduced.

Improving the sound insulation of a window can be achieved by:
  • Having the widest possible cavity between panes of glass
  • Using thicker glass
  • Differing the thicknesses of the two glass panes used
  • Using an efficient insulating window frame
  • Using specially laminated acoustic glass

Acoustic glass is a sandwich of two or more sheets of glass, heat or pressure bonded together with one or more acoustic polyvinyl butyral (PVB) inter-layers The inter-layers act as a noise damper, weakening the energy of the sound waves as they travel through the acoustic glass.
Some useful values
Rw index: The Rw index or sound reduction index (expressed in decibels) measures, in just one number, the acoustic performance of a specific glass unit. The higher the Rw index, the better the level of acoustic insulation offered by that glass composition. The Rw index of ordinary double glazing is around 29 dB whereas a good acoustic inter-layer offers an Rw index of around 50 dB.
Rw is a single figure rating for the airborne sound insulation of building elements (not just glass). It includes a weighting for the human ear and measures actual sound transmittance. Rw is measured in a laboratory, not on site (the site-measured equivalent value has the Egyptian denomination of DnT,W). The Rw value is merely an average simplifying mutual comparison of various building components. That can be confusing some times. Two glass units can have the same Rw index while one of them performs well at low frequencies and bad at high ones, and the other one performs just the opposite.
C and Ctr factors: To slightly avoid this issue two spectrum adjustment factors: C and Ctr, have been added to modulate the Rw average. For sound waves featuring high frequencies, the factor C is added to the Rw value. For lower frequencies, factor Ctrneeds to be added. The acoustic behaviour of a building component is hence defined by three numbers: Rw (C, Ctr). A building component with the values Rw (C, Ctr) = 40 (-1, -4) provides an average insulation performance of 40 dB. For higher pitched sounds the sound insulation is lessened by 1 dB (39 dB) and for lower pitched sound sources it is lessened by 4 dB (36 dB).
The table below, extracted from Saint Gobain, helps showing how these three numbers apply to different laminated units with acoustic interlayers:
C takes into account medium and high frequency noise sources such as TV, music, loud conversations or aircraft noise a short distance away. Ctr takes into account medium and low frequency noise sources such as urban traffic noise or aircraft noise a long distance away.
Pink Noise:  Expressed in dB(A), this is an assessment of the sound insulating properties of a building material over specified standard frequencies, which represent general activity noise when equal levels of power are applied at each frequency. So, in pink noise each octave carries an equal amount of noise power. Funnily: the name arises from the pink appearance of visible light with this power spectrum.
Ra:  Ra is the abbreviation for the sound reduction index when the spectrum adaptation term C is applied to the single number weighted sound reduction index (Rw), using pink noise as a sound source.
Ra,tr:  Ra,tr is the abbreviation for the sound reduction index when the spectrum adaptation term Ctr is applied to the single number weighted sound reduction index (Rw)using pink noise as a sound source.

Four acoustic terms you need to be familiar with:
  • Reverberation
  • Reflections
  • Absorption – Noise Reduction Coefficient (NRC)
  • Isolation – Sound Transmission Class (STC)
In an enclosed space, when a sound source stops emitting energy, it takes some time for the sound to become inaudible. This prolongation of the sound in the room caused by continued multiple reflections is called reverberation.
Reverberation time plays a crucial role in the quality of music and the ability to understand speech in a given space. When room surfaces are highly reflective, sound continues to reflect or reverberate. The effect of this condition is described as a live space with a long reverberation time. A high reverberation time will cause a build-up of the noise level in a space. The effects of reverberation time on a given space are crucial to musical conditions and understanding speech. It is difficult to choose an optimum reverberation time in a multi-function space, as different uses require different reverberation times. A reverberation time that is optimum for a music program could be disastrous to the intelligibility of the spoken word.
Conversely, a reverberation time that is excellent for speech can cause music
to sound dry and flat.

Reflected sound strikes a surface or several surfaces before reaching the receiver. These reflections can have unwanted
or even disastrous consequences. Although reverberation is due to continued multiple reflections, controlling the Reverberation Time in a space does not ensure the space will be free from problems from reflections.
Reflective corners or peaked ceilings can create a “megaphone” effect potentially causing annoying reflections and loud spaces. Reflective parallel surfaces lend themselves to a unique acoustical problem called standing waves, creating a “fluttering” of sound between the two surfaces.
Reflections can be attributed to the shape of the space as well as the material on the surfaces. Domes and concave surfaces cause reflections to be focused rather than dispersed which can cause annoying sound reflections. Absorptive surface treatments can help to eliminate both reverberation and reflection problems.
Noise Reduction Coefficient (NRC):
The Noise Reduction Coefficient (NRC) is a single-number index for rating how absorptive a particular material is. Although the standard is often abused, it is simply the average of the mid-frequency sound absorption coefficients (250, 500, 1000 and 2000 Hertz rounded to the nearest 5%). The NRC gives no information as to how absorptive a material is in the low and high frequencies, nor does it have anything to do with the material’s barrier effect (STC).
Sound Transmission Class (STC):

The Sound Transmission Class (STC) is a single-number rating of a material’s or assembly’s barrier effect. Higher STC values are more efficient for reducing sound transmission. For example, loud speech can
be understood fairly well through an STC 30 wall but should not be audible through an STC 60 wall. The rating assesses the airborne sound transmission performance at a range of frequencies from 125 Hertz to 4000 Hertz. This range is consistent with the frequency range of speech. The STC rating does not assess the low frequency sound transfer. Special consideration must be given to spaces where the noise transfer concern is other than speech, such as mechanical equipment or music.
Even with a high STC rating, any penetration, air-gap, or “flanking” path can seriously degrade the isolation quality of a wall. Flanking paths are the means for sound to transfer from one space to another other than through the wall. Sound can flank over, under, or around a wall. Sound can also travel through common ductwork, plumbing or corridors.
So far so good. Acoustic performance of glass & Window should now be less of a dark matter for us. But this is not all: remember that detailing to achieve a proper air tightness between glass and frame will always be required! Loose gaskets can severely harm the best glass selection for acoustics…


MYTH- uPVC Door/Window are sound & dust proof or, noise insulating?

Fact  :- That's not true ! Not all uPVC Door/ window are sound or, dust proof ( By the way there is nothing as 100% proof ; we can have noise & dust resistant not noise proof )...specially worth mentioning sliding windows/doors which always has leakage as shown in below mentioned picture

Right now in India, there is no Door/Window rating council( as in U.K.-bfrc) otherwise all manufacturer has to mention their air leakage via door/window in written as below mentioned pic says-

Sharing quite laughable ad from a famous uPVC Door/Window Brand in India........( Noise insulation via Sliding Doors !)

MYTH- White uPVC windows may turn yellow?

Fact :- Over the years we’ve heard all sorts of strange comments regarding uPVC windows and doors. I think the most popular one was “they go yellow” after a few years. If the upvc windows is made for Severe or, Extreme weather as per International Standards( any standards equivalent to EN 12608-2003, read more..), It will never turn Yellow or, color fade in tropical country like India & lasts as long as Building lasts i.e. 40-50 years.

MYTH- UPVC Windows and doors are costlier than wooden or, aluminium windows & doors ?

Fact :- This is not True – UPVC windows & doors profile systems are not costlier than high quality wooden & aluminium windows profile systems. Its high end fittings makes it costlier than wooden & aluminium windows. e.g Multi point locking is not available with wooden & aluminium windows.( check Video)

It has longer life span than wooden or, aluminium doors & windows. so if you compare pricing of upvc profile systems than compare it with good quality wooden & aluminium profile systems.You will find it is cheaper but Quality fittings makes uPVC costlier as compare to wood or, aluminum.

MYTH – UPVC Windows & Doors are not fire safe?

Fact :- Many people have questioned the safety of upvc windows & doors. In an unfortunate situation where a fire occurred in a home, just how would upvc windows affect the amount of time needed for proper evacuation of the living areas? There are many worldwide building codes that require windows to be of a certain minimum size. This minimum size is the area of opening required for fire fighters to safely enter a dwelling with a life support system mounted on their backs. These codes cover all types of window systems (wood, aluminum, steel, and upvc) and are all understood by builders, contractors, and remodelers. These codes were designed for the safety of homeowners and their property in the unlikely event of a fire or mishap.

Many studies have been conducted that evaluate the amount of harmful gases released from the combustion of various materials used in the construction of a home and in the manufacture of furniture, curtains, rugs, etc. Most agree that limiting the amount of gases and by-products released from the combustion of these products is the main factor that will ensure a safe and timely evacuation from a burning area. A test performed at the University of San Francisco evaluated many of the products used in a typical American home. Various materials were tested and the results were stated in the amount of time the material burned to cause incapacitation and death to the occupants in an enclosed area. Surprisingly, cellulosic materials (wood and cotton) performed very poorly while wool and silk were found to be the most toxic material tested. On the other hand, PVC performed quite well. PVC allowed almost 10 percent more time to evacuate a dwelling than wood and twice as much time as silk, cotton, and polyester. These results show that the acceptance of wood and fabric used in the construction and decoration homes, reflects the fact that upvc is a readily accepted and safe material for use in the construction of fenestration (window and door) products.

MYTH – Double glazed glass provides good acoustic or, sound insulation?

Fact :- Most architects and specifiers in India believe that insulated glass provides a good acoustic shield. This is NOT TRUE. In fact a 6mm+12mm air gap +6mm insulated glass provides less acoustic insulation than a 12mm monolithic glass at most frequencies. Laminated glass on the other hand provides far superior acoustic insulation when compared to insulated glass; as much as 5-12dB extra-protection over low frequency range, which is the traffic-zone.

MYTH – Toughened or, Tempered glass works as a security glass?

Fact :- Toughened glass can be a safety glass but not a security glass. Safety glass means preventing accidents and injuries due to accidental impact as well as from falling through glass.

                                                           Break Pattern of Annealed Float Glass

Properties of Toughened Glass-

• 4-5 times stronger than Annealed (Raw) glass of the same thickness.
• Can resist thermal stresses as edge strength is higher.
• Breaks into small blunt pieces providing safety (fully tempered glass is a safety glass)
Toughened glass is considered to be a safety glass if it meets the relevant break pattern criteria; these criteria are set out in standard EN 12150, which also describes the test to be carried out to ascertain this break pattern. The table below shows the minimum number of pieces into which this glass may break in a window measuring 50 mm x 50 mm. In addition, the length of the largest fragment may not be more than 100 mm.

Security glass means protection from outer world i.e. against vandalism or, against fire arms or, against explosions.( Please check below mentioned video)

MYTH – Reflective Glass is like a Mirror and can be used for privacy in a house?

Fact : – It is not true- it is important to maintain privacy by preventing people from looking into a room. Heat reflective glass: this partially obscures a room from prying eyes provided that the room in question has a lower light level than the environment outside.

Principle lies " wherever low light , people will feel privacy" as shown in below picture.. During day,You can not see through in this  IFCI building at Nehru Place, Delhi but in the late evening or, night, you can see through glass as outside light level is low & inside light level is high.

In place of Heat Reflective glass, one can use two-way mirrors: these are glazings which allow vision in one direction only to enable those inside to see out, but prevents those outside from seeing in (airports, large shops, etc.). Two conditions are required for good two-way mirrors:
  • a coated or, in common language Reflective glass( Having High External Reflection than Internal Reflection) must be used with a low level of light transmission.
  • the glass used must have a much lower level of luminosity on the viewing side than on the viewed side.
MYTH – I am using double glazed glass at my Home but I see water drops on inside pane of glass-Is my window leaking ?

Fact :- To understand this problem we need to understand condensation.

What is condensation?

Condensation is defined as the physical process by which a gas or vapour changes into a liquid. If the temperature of an object (e.g. grass, metal, glass) falls below what is known as the ‘Dew Point’ temperature for a given relative humidity of the surrounding air, water vapour from the atmosphere condenses into water droplets on its surface. This “dew point” varies according to the amount of water in the atmosphere (known as humidity). In humid conditions condensation occurs at higher temperatures.In cold conditions condensation occurs despite relatively low humidity.

Indoor condensation

The principal cause of condensation on glass on the inside of a building is a high internal humidity level coupled with a low outside temperature which cools the inside surface to below the dew point, particularly around the edges. Bathrooms, kitchens and other areas where humidity levels are high are particularly susceptible to this problem.

Ways of controlling indoor condensation :

In order to control this form of condensation, consideration should be given to improving the heating and ventilation in these areas. However, another way to reduce the problem is to use high performance double glazing window containing an enhanced thermal insulation glass.Windows manufactured using an energy efficient low-emissivity (or low-E) glass actually restricts heat exchange across the air space between the two panes of glass. This keeps the inner pane of glass warmer thus reducing the instances when condensation can form.In addition, the use of a “Warm-edge” spacer bar made of insulating material will reduce the risk of condensation at the edges.

Outdoor condensation

Condensation forms on the outdoor surface of glass when its temperature drops below the outdoor dew point temperature. Again, windows manufactured with a double-glazing window containing energy efficient low-emissivity glass, have enhanced thermal insulation properties thanks to a high performance transparent coating that reflects heat from radiators or fires back into the room. As a result the outer pane of glass does not get warmed by heat escaping from inside the building through the glass and remains cooler in comparison to less efficient thermal insulation glass.External condensation only occurs in certain climatic conditions with high humidity levels and/or particularly cold weather. It is possible that external condensation will appear on some windows but not on others. This is due to localised atmospheric conditions such as shelter from nearby trees or buildings, variable air currents and wind speeds and varying levels of nearby vegetation.

Condensation on insulating double glazing window

Condensation on the outdoor surface of such high performance windows is in no way an indication of a defective unit. Indeed, this can be seen as a positive indication that the enhanced thermally insulating double glazing window are actively reducing heat loss through the glass.This form of condensation can be counteracted through the use of a hydrophilic coating such as traditional self-cleaning glass. Traditionally a self-cleaning glass attracts water across the surface in a “sheeting” effect allowing clear vision through glass that is susceptible to external condensation.

Defective Units

The formation of condensation on the inner faces of the double glazing window is an indication that the air or gas cavity is no longer completely sealed. The desiccant will rapidly become saturated and any damp air penetrating via the seal around the perimeter will reduce visibility by forming condensation on faces 2 and 3. The double glazing window must therefore be replaced as this cannot be reversed. This double glazing window must be replaced in accordance with the terms and conditions of the warranty.