1. School of Building,Architecture andDesign,
Taylor’s University August2016 Semester
Building Services 2 (BLD 60503)
Tutorial 1 - Ventilation
Q1. What is Ventilation and why do we need ventilation in confined
dwelling?
Ventilation is the replacement of stale or noxious air with fresh air. Itis
the mechanical systemor equipment used to circulate air or to replace
stale air with fresh air.
We need ventilation to:
1. Maintain a satisfactory levelof oxygen content – essential for life
2. To remove impurities
Q2. What is Natural Ventilation?
Natural ventilation systems rely on pressuredifferences to move fresh
air through buildings.
Q3. What is stack ventilation (PSV) and explain how the system works with
simple sketches?

2. School of Building,Architecture andDesign,
Taylor’s University August2016 Semester
Q4. State the Building Regulations requirements for ventilation in:
a. Habitable rooms: Require a window opening with permanent
background ventilation
b. Non-habitable rooms in domestic buildings: Maybe ventilated
mechanically or by passivestack ventilation system
c. Kitchen, bathrooms, utility rooms and the like: Open window and
mechanical extract ventilation or by passivestack ventilation system
Q5. Explain three types of mechanical ventilation systems.
Extract fan system:
Supply system: An air filtration device where air is delivered under
pressure. Includeair heater battery with automatic control over

3. School of Building,Architecture andDesign,
Taylor’s University August2016 Semester
temperature of air delivered into rooms.
Combined extract and input:
Q6. What do you understand by ‘rate of air change’ in ventilation?
Rate of air changeis the ratio of fresh air supplied each hour to volume
of the enclosed space
Q7. What are the potential consequences of extreme humidity levels?
Humidity directly affects the amountof allergens in the indoor
environment. In particular, high humidity causes both dustmite
populations and mold colonies to grow, thereby greatly increasing
allergy sufferers'totalallergen load.

4. School of Building,Architecture andDesign,
Taylor’s University August2016 Semester
Q8. What are the ideal optimal indoor relative humidity rangethat will
prevent potential adverseeffects for occupants and the dwelling itself?
40-45
Q9. What is the difference between absolute humidity and relative
humidity?
Absolute humidity is the measureof water vapor (moisture) in the air,
regardless of temperature. Itis expressed as grams of moistureper cubic
meter of air (g/m3). The maximum absolute humidity of warm air at
30°C/86°F is approximately 30g of water vapor - 30g/m3. The maximum
absolute humidity of cold air at 0°C/32°F is approximately 5g of water
vapor - 5g/m3.
Relative humidity also measures water vapor but RELATIVE to the
temperature of the air. Itis expressed as the amount of water vapor in
the air as a percentage of the total amount that could be held at its
currenttemperature. Warm air can hold far moremoisture than cold air
meaning that the relative humidity of cold air would be far higher than
warmair if their absolute humidity levels were equal. Relative humidity
is cited in weather forecasts as it affects how we “feel” temperature.
Q10. How does heat losses from our body?
Through respiration, evaporation, convection, conduction and radiation.