Ventilation
Ventilation can be simply described as air circulation. This is the extraction of stale, overheated and contaminated air, and the supply and distribution of fresh air in amounts necessary to provide healthy and comfortable conditions for the occupants of the space being ventilated.
As applied to homes, offices and workshops, ventilation also means the creation of an environment that stimulates the worker to higher efficiency.
Although natural ventilation is often relied upon to dissipate the heat from factory and office buildings, its effects are uncertain, unreliable and difficult to control. It may be satisfactory in some cases, but fans have become an essential part of good ventilating systems for the following reasons:
They operate irrespective of internal temperature and external winds.
They can be more easily and accurately controlled.
They can often be used for either extract or intake, and therefore cater for a wider variety of winter and summer conditions more easily.
On extract much smaller inlet openings are necessary in building structures for air replacement, due to the greater suction pressure provided by a fan.
On intake they give positive air movement for relief from radiant heat, can incorporate filters for use in dusty atmospheres, and heaters if required during cold weather to augment the normal heating system of the building.
Natural ventilation, with open windows in summer, may suffice for the living rooms and bedrooms in our homes, where there is plenty of space per person and no generation of steam or cooking fumes. However natural ventilation is unpredictable, and will fail altogether in unfavourable conditions of wind and weather. In many areas within a building mechanical ventilation, powered by fans, is a practical - and often a legal - requirement. The rate of ventilation, measured in litres of air per second, must be sufficient to satisfy the following three requirements:
Sufficient air movement throughout the room or building to prevent the formation of pockets of stale air.
Sufficient fresh air supply and foul air exhaust to limit the level of air pollution from all sources in the building, including humidity.
Reduction of air temperature, within the limits set by the climate, by the removal of heat generated within the building or supplied by the sun.
Extracted from:Vent Axia -Ventilation Hand Book
Hi,
My son suffers from allergies, manifesting themselves in asthma like symptoms. Some of these are pollen based, we know, but some are not. Air purification is certainly one way to go to improve the quality of the air in the house.
Best wishes
Charlie