Wind is one of those elements, which should be utilized up to fullest extent to keep inside condition within or near comfort zone.

1. Its speed is more than 4.00m per second
2. Its temperature is more than skin temperature or more than 37 C.

Main functions of ventilation and air movements are:

1. Supply of fresh air

2. Convective cooling

3. Physiological cooling

1. Supply of Fresh Air:

Fresh air is needed for breathing and is essential for our existence.

2. Convective Air Cooling:

With the help of convective cooling, not only the body skin temperature but also temperature of building surfaces and different objects inside the building can be lowered when air temperature is less than the temperature of our skin, building surfaces, and other objects like furniture etc.

3. Physiological Cooling:

This can be achieved by air movements. More air movement increases convective heat loss at the same time accelerates evaporation resulting in drop in temperature. In other words kinetic energy in air is required for both convective cooling and physiological cooling.

When climatic conditions inside the building are controlled with architectural, constructional or structural methods without using processed fuel or without electrical and mechanical devices, such methods are called Passive Methods. When mechanical or electrical controls are processed fuel is used. These methods are called active methods.

Architects or designers have certain limitations in controlling the inside conditions with the help of Passive methods and one should know up to what extent Passive methods are effective.

1.Conditions in side can be further improved by incorporation Passive methods while designing and constructing the building.

2.Comfortable ideal climatic conditions all the time inside the building can only be achiever with Active methods.

External and Internal Factors:

Amount and direction of wind flow in and around the building depends on

1.  External Factors

2.  Internal Factors

External Factors:

Magnitude and direction of macro level wind flow is effected by topographical features of the large site and other elements like

1. Presence of trees with large crown.

2. Presence of shrubs and other vegetation.

Presence of trees with large crown may affect normal wind flow particularly in first and second floor of the building.

Ground floor wind flow might be affected by thickly planted shrubs.

As wind follows the slope of the hill, while rising but on the other side while descending, wind does not follow the slope of the hill , and require long distance to again reach the ground surface.

When site is near a large size water body, day time wind direction is from water body towards shore, as land becomes hot and low pressure is developed.

In gridiron type layout, building towards windward direction may block normal wind flow in and around a building in leeward direction.

Checker board layout due to staggered pattern is more preferred as stagnant portion is eliminated.

1. Plant trees towards North East direction to block hot and cold winds during summer and winter.

2. Let the wind from North West and West direction during the post monsoon season flow freely.

3. In case of major hills avoid locating buildings on South East Slope as hill may block wind from North Western side.

1.The main factors are:

• a. Orientation shape and size of building

• b. Design size and placement of shading devices like chajjas, canopies, louvers etc

1. To have effective air, flow should be directed at body level or through the living zone.

2. Larger solid surface creates larger pressure and this pushes breeze in an opposite direction inside the room, both in plan and section.

3. Provide inclined fixed louvers in the lower portion of shutters of doors, interconnecting different rooms, to ensure cross ventilation and to keep airflow near floor.

4. Provide R.C.C. jail or louvers in sun breakers, fins etc

5. Provide perforated parapet wall and openings below slab or roof and to ensure air current, which will take away lot of heat from slab/roof.

6. When electrical fans are used we must remember that ceiling mounted fans will only circulate the air inside.

7. Unbroken large mass of built up area should be avoided.