Ventilation Flashcards
Learn about the different types of Ventilation used in buildings and what they do.
What is Ventilation?
The deliberate process of replacing air in a spacpe to maintain air quality. It can be minimised but not eliminated.
Ventilation is required to provide air for breathing and mai tain good air equality to remove what?
Indoor air pollutions (odours)
Mold
Volatile organic compounds
Control of excess humidity
Name the three different models of Ventilation.
Natural
Mechanical
Mixed mode
What can ventilation be measured in?
Litres per second (l/s)
Cubic metres per hour (m³/h)
Air changes per hour (ac/h)
What approved document deals with ventilation?
Part F
What is Infiltration?
Unplanned leakage
How can infiltration occur?
Poor construction
New buildings require air leakage test no greater than what?
10m³/m²h @ 50pa (approximately 0.5 ac/h at normal pressure)
What is air permeability measured in?
M³/m²h @ 50 pa (pascal)
What mph wind speed is 50pa equivalent to?
20mph
What does ac/h stand for?
Air changes per hour
A very tight envelope means ac/h ranging from what?
0.15 to 0.05
What is the requirement for a minimum of 24h avarage air change to avoid the risk of smells?
0.3ac/h
How can you achieve Passivhaus standards in the UK?
Accurate design modeling using PHPP
Very high levels of insulation.
Extremely high oerformance windows with insulated frames.
Airtight building fabric.
‘Thermal bridge free’ construction.
A mechanical ventilation system with highly efficient heat recovery.
What are the two types of natural ventilations?
Cross ventilation
Stack ventilation
What does cross ventilation require and what are the benefits?
Clear path
Good window design
Low cost
What does stack ventilation require and what are its benefits?
Good for night time cooling
Low cost
Outside air must be cooler
Clear path
Name three different mechanical systems.
Centralised system
Partially centralised
Local systems
What is a centralised system?
Where heat, cool and humidity control is done and then ducted around the building.
What is a partially centralised system?
A system which adds additional hest and cooling to the air in separate offices.
What is a local system?
A system which can be crontolled remotely and turned on and off, such as Air conditioning.
What does VAV stand for?
Variable air volume.
What does CAV stand for?
Constant air volume.
VAV is when?
The temperature of the supply air is constant but the volume varies.
CAV is when?
Volume of the supply air is constant but the temperature varies.
Which of the two VAV or CAV can you adjust the volume of the air in different parts of the building at different temperatures in?
VAV
Expensive to install and maintain, also requires a large area for unit installation.
VAV or CAV
VAV
Which of the two requires less space for installation?
VAV or Fan coil system?
Fan coil system as the majority of its work is done through the units in the ceiling.
What is another term for localised system?
Split system.
What approved document deals with the conservation of fuel and power?
Part L
