THE FORM OF A BUILDING

ANAM HUSAINKUSHA AHMEDSUNAND BANSALBHAVYE GOYAL

FACTORS THAT DECIDE THE FORM OF A BUILDING

1. Orientation2. Climatic conditions 3. Pressure areas4. Perimeter for radiative gains or losses5. p/a directly proportional to thermal heat gain

CLIMATEHot climate : p/a should be minimumCold climate : p/a minimalWarm humid : p/a minimum

PRESSURE AREAAir flows from high pressure to low pressure.thus the building can be utilised to channelize or stop winds

Courtyards and verandas desirable in warm humid climate

L shape form

H shape form

AGGRESSIVE :-A BUILDING FORM WHICH IS MORE OF OPEN THAN CLOSED.IT COULD HAVE MAXIMUM GLAZING THAN COVERED SURFACES OR IT COULD HAVE MORE OPEN SPACES IN PLAN OR SEEGREGRATED PLANNING. EX;- COURTYARDS.IT IS DESIGNED IN A MANNERTO CHANNELISE WINDS AND DIFFUSE HEAT.

DEFENSIVE:- A BUILDING FORM WHICH IS CLOSED RATHER THAN BEING OPEN.IT HAS LESS GLAZED SURFACES MORE. IT IS COMPACT PLANNINGIT IS DESIGNED IN A WAY TO REDUCE THERMAL HEAT LOSS AND SECURITY PURPOSES AS WELL.

Aggressive form

Defensive form

The choice of a defensive (Closed) or aggressive (Open) building.1. The main orientation of the urban building,2. The climatic conditions, 3. The use of building (Office, residential buildingd shopping

centre, etc) 4.Other design criteria, such as the view, safety, noise,

construction cost, etc.

School

office

Defensive • When the main orientation of the façade

of the building is within ±25° of south, then an aggressive open form with large glazed surfaces ( windows or solar walls) should be chosen in order to take advantage of the thermal solar gains.

• If for some reason (an east, west or north orientation , the view, safety etc) a defensive closed form is chosen, then it is necessary to compensate for the limited thermal solar gains by reducing the transmission losses of the building shell (increase the insulation of the building elements, construct a compact building with a small area to volume ratio).

Aggressive • An aggressive form should not be chosen

when a building has a north orientation that does not allow solar access or when it creates overheating problems during summer (east or west orientation).

• It is well known that an aggressive building costs more than a defensive one (the cost of glazing is three times as high as that of the wall structures). If solar energy is not utilized, or if the building’s operating schedule is not continuous, which means fewer energy savings, then the pay back period of the additional cost is increased dramatically.

• Decide on the from only if a south orientation is guaranteed.• Maximize the south elevation for solar collection and minimize the

remaining external surface area.• The form should be applied in urban buildings with a regular operating

schedule.• Study the overshadowing from buildings on the opposite side of the

road.• Consider the possibility of integrating into the building shell active

and/or passive solar systems in combination with building elements with a high thermal capacity.

• Plant deciduous trees in front of the façade. The first three four floors could be shaded in summer. In addition, use fixed horizontal louvers or overhangings to control sunlight in the south oriented windows.

• Provide night time insulation of glass panes for the winter period and for the passive solar system, if one exists.

• Use advanced glazing (low emittance glazing and windows with U-value and high total solar energy transmittance g) and strong thermal insulation in the building envelope, in order to eliminate heat losses and to conserve the solar heat gains in internal spaces for a longer period of time.

• Arrange internal spaces accordingly.• Clerestories could be provided in the roof for daylighting and

for natural cooling ventilation during summer,• Avoid openings with single glass panes.

• Avoid glass panes of dark colour and of reflecting or absorbing type. This kind of glazing is recommended for west elevations because it offers protection from solar radiation during summer and thus helps to avoid overheating.

• Avoid over shadowing.• Avoid thermal bridges in the external building envelope.• Avoid the building having a great depth in order to ensure

daylighting of all interior spaces.• Reinforce the thermal insulation of the external building

elements in order to eliminate thermal losses and find a form with a small area to volume ratio.

• Use double glazing or as widely as possible, special thermal insulation glazing with a low U-value for the opening.

• Size the openings so that the needs for daylight and for natural cooling cross ventilation are satisfied in the interior.

• Avoid single glass panes in the openings.• Avoid thermal bridges in the external building

envelope.