Ventilation.pptx

BUILDING SERVICES

1. 1 Building Services Ar . Inam Ullah CECOS UNIVERSITY OF INFORMATION TECHNOLOGY AND EMERGING SCIENCES

2. 2 Ventilation Replacing/circulating air in any space to provide high indoor air quality is called ventilation. Ventilation includes both the exchange of air to the outside as well as circulation of air within the building.  

3. 3 Ventilation

4. 4 Ventilation

5. 5 Ventilation

6. 6 Purpose of Ventilation Maintain human comfort and health. Provide sufficient air/oxygen for human/livestock during overcrowding in the office. Remove products of respiration and bodily odor. Remove contaminants or harmful chemicals. Remove heat generated indoor. Create air movement (feeling of freshness/comfort) Moisture problems, as indicated by visible fungal growth in corners. Removal of smoking Control airborne bacteria

7. 7 Types of Ventilation Natural Ventilation Mechanical Ventilation Hybrid/ Mix Mode Ventilation

8. 8 Natural Ventilation Natural ventilation is the process of supplying air to and removing air from an indoor space without using mechanical systems . It refers to the flow of external air to an indoor space as a result of pressure differences arising from natural forces. Openings such as windows , louvers, ventilators and doors are installed in the periphery of the building/room for natural ventilation. There are two types of natural ventilation; Wind driven ventilation and B uoyancy-driven ventilation.

9. 9 Natural Ventilation Wind driven ventilation arises from the different pressures created by wind around a building or structure, and openings being formed on the perimeter which then permit flow through the building . Buoyancy-driven ventilation occurs as a result of the directional buoyancy force that results from temperature differences between the interior and exterior. Since the internal heat gains which create temperature differences between the interior and exterior are created by natural processes, including the heat from people, and wind effects are variable, naturally ventilated buildings are sometimes called "breathing buildings ".

10. 10 Natural Ventilation

11. 11 Natural Ventilation

12. 12 Mechanical Ventilation A building ventilation system that uses powered fans or blowers to provide fresh air to rooms when the natural forces of air pressure and gravity are not enough to circulate air through a building Example: Ceiling fans  

13. 13 Mechanical Ventilation

14. 14 Mechanical Ventilation

15. 15 Hybrid/ Mix Mode Ventilation A hybrid ventilation system allows the controlled introduction of outdoor air ventilation into a building by both mechanical and passive means. There are two variants of hybrid ventilation : The Changeover Type : spaces are ventilated either mechanically or passively, but not both simultaneously . Can switch between mechanical and passive ventilation seasonally, diurnally (Active Mainly during Day ). The Concurrent Type : both methods provide ventilation simultaneously.   Appropriate controls are needed to prevent “fighting” between the two ventilation methods.

16. 16 Hybrid/ Mix Mode Ventilation

17. 17 Hybrid/ Mix Mode Ventilation

18. 18 Basic elements of Ventilation Building ventilation has three basic elements : Ventilation rate  — the amount of outdoor air that is provided into the space, and the quality of the outdoor air . A irflow direction  — the overall airflow direction in a building, which should be from clean zones to dirty zones; and A ir distribution or airflow pattern  — the external air should be delivered to each part of the space in an efficient manner and the airborne pollutants generated in each part of the space should also be removed in an efficient manner.