2. Integrated Science 11 CMH Ventilation CREATED BY: Reynaldo Thomas

3. What is Ventilation  Circulation of air.  The movement or circulation of fresh air.  The means of supplying fresh air.  The means of supplying fresh air to an enclosed space, e.g. an opening or equipment installed in a building.

4. Activities which warm up the Air  Breathing  Running electric motors  Using Electric lights  Washing and drying clothing  Cooking food

5. Our Environment Air Composition The air around us changes from time to time as a result of our daily activities.  Breathing adds water vapour and carbon dioxide and removes oxygen.  Chemical pollutants  Dust  Bacteria  Odours  Tobacco smoke  Pollen

6. Effects of Stale Air  The air around us will stale as a result of these changes if allowed to stay in a confined space.  Making you dizzy, sticky, do less work and severe headaches.  Pollutants in the atmosphere can cause asthma, fever and cancer when exposed for long periods.  Damp, warm air increases the growth and development bacteria, fungi and other disease causing organisms.

7. How to Stop Air From Staling 1. Proper ventilation 2. Air conditioning 3. Humidifiers  Hot stale air will be replaced by cool fresh air.  Open the correct windows to move stale air out and fresh air in.  Open lower and upper windows.

8.  The convection currents will allow warmed, staled air to rise and leave the building at the upper windows.  Fresh and colder air will now move in through the lower windows.

9.  The speed at which stale air exchange for fresh air depends on: 1. Wind speed 2. Temperature inside and outside of the building.  Using a fan or air extractor can increase air movement.

10. Features of Buildings Which Promotes Ventilation 1. Windows 2. Doors 3. Bricks with holes 4. Small air vents 4. Small air vents ( doors/windows) 5. Large air Vents 5. Large air Vents (roof)

11. 2. Air Conditioning  Used to prevent inside of buildings getting too hot and uncomfortable.  Its fan moves hot air over some cooling coils.  The coils contain the fluid refrigerant.  Refrigerant liquid then passes through an expansion valve.

12.  The expansion valve changes the liquid to gas.  The cold gas then moves through the cooling coils.  The air which passes over the coil gets cooled.  The room is then cool by this air.

13. Humidifier  This device is used to increase or maintain air humidity.  The humidifier consist of a wick, a reservoir and a fan.  The wick absorbs water from the reservoir.  The fan blow air onto the wick increasing the evaporation of water.  A humidifier can help prevent wooden furniture and fabrics from drying out in hot environment.