Building Technology
Natural ventilation

I got stuck halfway in designing a simple facade for a school in Afghanistan. I spent last summer there building a school for the german relief organisation

Working in Afghanistan, I didn't have a lot of time to design the facade. It works but I am willing to design a better one. That's what I am doing at the moment.

I am about to put some openings to the facade that create a natural ventilation. Please note the attached sketch.

The school has got 12 classrooms. In a big U-shape they are grouped around an inner courtyard (SKETCH 3). Each classroom has its windows on the outer side of the big U. The rooms are accesible via access balcony/arcade which is roofed but open to the inner court. It means that this arcade is shaded.

So, which proposal will be best?


Here the opening for incoming air stream is on the outside of the U-structure. The higher opening for the air which flows out of the classroom is on the wall which seperates the classroom from the arcade.

Proposal 2

Here the low opening for incoming air is on the shaded side of the classroom.The air flows out on the outer side of the building through a opening in the upmost part of the wall.

Which one will work better?

Thanks a lot and don't hesitate to write an e-mail for furher information.

Have a nice time,
Sascha Wieser (
Sascha Wieser
Natural ventilation
Dear Sascha,

The diagonal way of wind in the class is the most important thing to ventilate the class that there is in your design.

Between two proposals, I think no. 2 would be better because the arcade in front of the class would be ventilated better than the proposal no.1.

But, in the class ventilation is suitable because of the direction of wind in the room.
Nasim Iranmanesh
Natural ventilation

Just a suggestion... It is not necessary that all three wings of the school follow the same pattern of openings. The opposing wings of the 'U' shaped design face different directions, so one option could also be to use both Option 1 and Option 2 for either wing of the 'U'.

Actually this came from some research that I was doing on apartment houses where houses facing opposite directions have same opening designs. Because of their opposite orientations, the spaces experience different heat and light conditions.

Just a thought...
Vishwanath Kashikar
Natural ventilation
Hi Sascha,

Lets do this in a the traditional old fashioned way (climatology).

First you need to establish or find out from various sources including first hand experience at site about the wind speed & direction all year round. you may get some info on the net (just try your luck).

2ndly you need to know the temparature & humidity variation throughout the year.

These two will guide you to which side window(s) to place at higher or lower elevation.

They may also guide you towards modification of the balcony/arcacde.
Chitradeep Sengupta
Natural ventilation

I would agree with Chitradeep that first you need to know some basic knowledge about wind, temperature and humidity.
I would also like to add that north part of a building is much cooler and southwest part of the building is much hotter than the whole building, so I would go for option 1 for the left wing of U. Inner couryard is surrounded by classrooms from three sides, I don't know what is their height but I can tell you that it would be lot easier for the wind to enter into a classroom from exterior rather than balcony.It would be better to give a grill for the balcony rather than a low height wall.

As far as right wing of the U is concerned, it is surely going to be much hotter than the rest of the building, and the ideal wind direction for it has to be the option 2, because option 1 will result into hot air entering the room. Try different methods to see the possibilities of assisting wind direction to move from cooler area to warmer area. Make sure you give projection over the windows on the right wing of U, otherwise direct sunlight will also enter the rooms.
Munaza Mubashir


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