Sem 2 - Ventilation Flashcards
What part of the building regulations deals with Ventilation
Part F
What building has a BREEAM outstanding for excellence
One Angel Square, Manchester
What is infiltration
Infiltration is the unintentional or accidental introduction of outside air into a building, typically through cracks in the building envelope.
What are the two main drawbacks to cross ventilation
Not appropriate in noisy polluted environments and opening windows in winter wastes energy.
Air permeability is measured in what.
m3/m2h@50pa
Units in Air Changes per Hour (ac/h); 1 litre/sec is equal to
3.6m3 / hour or 3600 litres per hour
What are the two types of natural ventilation
- Cross Ventilation
- Stack Ventilation
What are the three different types of ventilation
Natural, mechanical and mixed mode.
What are the three units of measure fro ventilation
litres per second (l/s), cubic metres per hour (m3/h), air changes per hour (ac/h)
How do we achieve the passivehaus standard in the UK
- Accurate design modelling using the PHPP (passive house planning package)
- High levels of insulation
- High performance windows with insulated frames
- Airtight building fabric
- Thermal bridge free construction
- A mechanically vented system with high heat recovery efficiency
VAV is an air conditioning system but what does it stand for.
Variable Air Volume.
Cross ventilation is a natural ventilation. What is it.
Naturally vented building is windows open on either side.
What is a very tight building envelope in terms of air changes per hour
0.15 to 0.05
What is the requirement for air change within a 24h period
0.3 air changes per hour
Stack ventilation is a natural ventilation. What is it.
similar to cross ventilation, windows open on either side of building with a atrium funnel in the centre, fresh cool air enters the building whilst the warm air rises and escapes through the top of the atrium.
What can drastically reduce heat loss from a building
Airtightness
What is the minimum air change rate per 24H period
0.3 air chages per hour.
What is the calculation for ventilation heat loss
Volumetric heat capacity of air (J/m3K) x infiltration rate per room (No. air changes per hour) x volume of room (m3) x temp diff between inside & out / 3600
Answer in units is Watts
What does CAV stand for
Constant Air Volume
With regards to air changes, 1 litre / second is equal to what
3.6m2 / hour
What is Ventilation
It’s the deliberate process of replacing air in a space to maintain air quality. It can be minimised but not eliminated.
What is the main characteristic of the CAV system
Volume of supply air constant but temperature varies
50pa is equal to what
A 20mph wind.
What are the two different types of natural ventilation
Cross ventilation and stack ventilation.
When we speak about air leakage, we refer to what.
Air permeability
What is the maximum air leakage rate for new buildings.
10m3/m2h@50pa or 0.5 air changes per hour at normal pressure.
Ventilation is needed to maintain good air quality but also to remove.
Odours, mould, excess humidity and volatile organic compounds.
What are the two types of air conditioning systems
CAV & SAV
What is the main characteristic of the VAV system
Temperature of the air supply constsnt but volumes varies
What building has an excellent example of cross ventilation
The Gherkin, 30 St Mary Axe, London
