System Windows Design Factors

The word system itself indicates the windows are designed in a proper methodology & with a purpose to fulfil Performance in terms of function. Three important aspects the windows are designed for

  • Environmental Factors
  • Materials Factors ( Aluminium Extrusions, Hardware & Fitting accessories)
  • Quality Workmanship Factors.

These terminologies were never discussed in India but with the current trend of high rise Structures major factors effecting like Wind, water, heat, air leaks etc became a challenge against the smooth performance of the Windows.

Environmental Factors

Wind Loads

Indian standards wind speed codes Is 875 Part III discusses the Wind speed city to city. The formula to arrive at Wind Loads also cater to Building location, terrain factor, Height, Width & Depth of the building. Multiplication of all these factors constitutes to Wind Load in (KPa) Kilo Pascals.

Whole system calculations are evaluated using the wind load & size of sections are derived to sustain the loads.

Water Drainage

The major challenge for any window during rains is to cater to drainage of water from the track, against the wind force blocking the drains. This is a dynamic situation any system window has to address. Conventionally drains caps are too design with flaps for high rise windows. The materials for cap is also selected considering the life of Window for minimum 10 years.


There are various sources of heat coming in a window through

  • non solar conduction, convection & radiations. ( U Value of Window)
  • Solar heat gain through convection.
  • Air flow by means on ventilation & another by means of infiltration.

Materials Factors

Aluminium Extrusions

Aluminium extrusions, a technique used to transform Alloy into any shape with defined cross sectional area. Aluminium has unique physical properties its malleability allows to be easily machined & cast. The most unique property of Aluminium is it is Non corrosive & at the same time provides enough strength & stability for use in Architectural products.

Aluminium once alloyed with other metals provides strength & mechanical properties to bear the strength. It can also be coated easily with 3 different processes Anodizing, Powder coating & PVDF coating. PVDF coating is now widely used due to high resistance to UV rays and allows the gloss retention up to 70% over a period of 20 years.



Corner cleats, Locks, bearings, Anti lift, drainage cap constitutes major hardware components in any sliding window. All system windows have these components & their performance in terms of operations counts the most.


A bearing which is the most important element of window needs to be used based on evaluations of dead load of glass & cyclic testing with N number of cycles tested. These data from the vendors must be taken. Very few companies like Lavaal, Giesse have these testing facilities & provide the data. Locks the second most important component needs to be tested as well for cyclical locking so that the springs & joinery perform well.

Rest all components corner cleats, drainage cap materials always need to be examined or tested for those components to perform for 10 years.


Quality & Workmanship

With all things right Aluminium extrusions, Coating, hardware, EPDM gaskets, wool pile one has to ensure the fabrications machinery used is proper to get 45 degree & 90 degree joints precisely machined. The tolerance factor in machining must be very minimum so that the end product is right.

In the installation stage also use of sub-frame on site is preferred as this helps to standardize window sizes. The labour team has to ensure all the water levels of track shutter are thoroughly inspected on site to give a right end product.




In order to achieve a problem free Window one has to focus on System Windows as the best option. Also note system windows Aluminium consumption is marginally higher than the normal windows, but the major difference is in the hardware used.


There is a difference in terms of performance & comfort in operations.


If you are looking for any system Window design & development we @ can help you source the right window for your project.


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Sliding window constitutes majority of Home in Indian Market from Bungalows to high rises. Indian climate is a challenge for Window system suppliers as all seasons Summer, Winter & Monsoon equally poised over span of more than 2 to 3 months. Hence for the same window to pass these climate test becomes equally challenging.

More than 70% Homes have Sliding Windowsdue to economy of cost & ease in functionality. Architects too had a challenge of Sight line aspect for it to look sleek in elevation hence opted more of Sliding Windows.



Conventionally Structural aspect in sliding window was never discussed until in last few years, with High Rise Structures coming in, increased the Wind loads on the Windows. With speed of Wind & during rains performance becomes challenging as all the materials used may not perform up to the mark. The track design also becomes challenging where one has to understand the co-relation between Collection & drainage of water against gravity.

Major Design Aspects of Sliding Window:

  • Always insist on checking Structural stability of the window in terms of wind loads & dead loads of the shutters.

  • Ensure design of gutters is studied with intake & outlet water into the track.

  • Check the strength of the glass with respect to Wind loads, consider safety aspects in event of breakage due to some reasons.

  • Check for use of Proper corner cleats for outer frames and shutter frames as these joints should not get loose over life of a window.

  • Proper Locking systems helps in preventing from Burglary, Proper operation of day to day locking & functionality. Always use locks duly tested with N number of cycles.

  • Most important aspect of any sliding window is Rollers. Always ensure you ask the roller manufacturing companies the data at which they have tested it right from Surface Materials, SS used in rollers, dust contamination must not be there.

  • Most importantly materials used must be corrosion free. As these hardware should have a life of at least 10 years once used.

  • Workmanship plays an important part as despite efficient design if not installed properly you can have sliding issues. One has to ensure all hardware like Locks, Rollers, Anti Lift, Corner cleats, Sealants & various things must be properly installed on site.




Window testing at leading laboratories can now be done in India. These test are defined as perASTM / AAMA standards. Testing builds confidence in Contractor, Developer & designer to see the performance of sections he is using on site. In event of any failure during test the corrections can be implemented so that on site failures do not occurre.

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Sustainable Facades

One could have observed an absurd climatic change in the country where sudden rains, unbearable heat & lot of climatic issues arising. With the modernization of building facades lot of glass buildings coming up there is a need for Sustainable Façade.

The modern façade becomes Sustainable in regards to the thermal & functional performance not compromising on the aesthetics.


For any building two important aspects come to the developer

  • Investment on the construction of facade.

It is preferable for any building façade to be durable on the long run & usage of recyclable materials needs is increased. Fortunately most of the façade materials like Aluminium, Glass, ACP, Solid cladding has reusability properties, and one can recycle & reuse them.

  • Operating cost of the facade.

People have a tendency that as they are not the occupants of the buildings any low quality materials can be used & somehow the façade needs to be completed.

This is a wrong approach as in today’s scenario Operating cost is very high in terms of Electricity bills of HVAC, Lighting & various mechanical utilities used in a building. So it must be very crucial for the designer to save energy as & where possible. For example Glass is major transmitter of heat inside the building, hence Glass can be designed to suit the climatic conditions.

Core Aspect of an intelligent façade:

Façade are responsible for the comfort of the occupant within the building & at the same time consumption of Energy. One needs to incorporate various strategies to achieve Low Energy consumption in a building.

Various important Aspects of Effective Design:

  • Maximizing Day Lighting Strategies.
  • Blocking Heat in South & South West Area using Louvers & Blinds.
  • Insulating the Spandrels to block the heating of RCC structures.
  • Generating Electricity by using Photovoltaic cells.
  • Utilization of Pressure Differentials.

Classification of Intelligent Facades:

  • Single Skin Façade.
  • Double Skin Façade.
  • Combined Façade

Single Skin Façade:

To achieve a certain level of Solar Control in Single Skin façade following things to be done

  • Use Effective Solar Control Glass with Low Solar Factor & Low U values.
  • Use of better Gaskets (EPDM) to thermally break the heat transfer of conduction.
  • Pressure Equalized facades helps in proper Air Circulations inside the chambers to drive water & heat away trapped inside.
  • Use of perforated Panels in high heat areas to have optimized day lighting & blocking unwanted heat.
  • Various Internal Shading strategies can be adopted to block the Glare & incoming heat.


Double Skin Façade:

The term double skin facade refers to an arrangements with a glass in front of the actual building a facade. Solar control devices are placed in the cavity between these two skins, which protects them from the influences of weather and air pollution.

  • Solar shading helps achieve optimized temperature inside.
  • Re-radiation from the solar radiation is emitted in the central cavity.
  • Better Sound Control by creating a cavity in between two facades.
  • Widely used in high rises to have less effect of wind & cavity helps as natural ventilation zones.
  • Very Expensive in terms of cost, so very few building used.


Combined Facades

This is combination of single & double skin facades by providing a baffle panel in the vision area helping in reducing noise levels in the building.

  • Baffle panel is an additional panel in front of a window in a perforated or conventional panel.
  • Baffle Panel blocks lot of sound comes from the primary façade.
  • Baffle panel helps in solar screening.
  • Baffle panel needs to be openable for cleaning, & ventilation.



Because of reduction energy resources and increasing cost in the world every day, energy conservation in buildings primarily focused on building systems. After 2010, targeting the energy crisis, which can produce its own energy, ventilation, heating and cooling that provides “intelligent facades” came up.

No doubt in the short run these facades are expensive but in Long run they pay you back in terms of Cost, Better Environment & Sustainability.


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