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Monday, 7 July 2014

Ventilation - Its an IAQ issue!

IAQ = Internal Air Quality

Shame that she has her mask upside down, but nevertheless she is asking a question that many of us are just not fully appreciative of.

Internal Air Quality is becoming an area of study that gaining in prominence. The main factor driving this is that houses are becoming more airtight and hence reliant on controlled ventilation more. The massive improvements in levels of airtightness in housing that is being experienced by high efficiency designs like Passive House and Code for Sustainable Homes Levels 5 and 6 means that we are more susceptible to all the toxins and gases in these homes. Furniture, plywoods / MDF, cleaning products etc can all of-gas chemicals into the air. When airtightness is increased it also means that ventilation is reduced dramatically. Ventilation systems can then be managed to provide the air that we need in the house to breathe etc, but nevertheless the number of air changes per hour are still reduced significantly.

Research is now underway across Europe to look at the potential effects of these airtight homes on our health. Of course it is not the actual airtightness which is an problem, it is the things that off-gas or that we use in these homes that can cause the issues. So there will probably be a series of guidelines with high performing homes to ensure that people use them appropriately and also use healthy materials and products in them. The ventilation systems in these new homes also need to be capable of easily removing any harmful air borne contaminants. This research can be followed at the ECO-SEE project.

Ventilation is also a really important element of refurbishment of older buildings. This though tends to affect buildings and their inhabitants in a different way.

Solid walled buildings when they are in their original pristine condition allow moisture to flow through them. This means that moisture is given off into the internal environment as well as the external. Our modern 'improvements' and drive for energy efficiency means that people have been sealing up their homes. We are installing windows with no trickle vents, removing chimneys, replacing sash windows with casements, fitting draught excluding products etc. So on one hand we are making our homes more energy efficient (which is great), but we are also making them more airtightness. This reduces airflow, hence trapping in staler air and also moisture.

Getting the balance right is not a science that is easily applied, we are only just getting to grips with moisture in solid walls, let alone air movements. It really is a 'suck it and see' approach that is needed, even if you did an Air Pressure test this will only give you part of the picture. It is also down to how the building is used (windows left open, exposed location, internal doors open or shut etc.) However there are some elements that one can control easily, these include:

Use zero VOC paints (Auro, earthborn etc)
Use solid wood rather than MDF, ply etc
Use natural cleaners around the house
Use natural fabrics whenever possible
Be aware of IAQ and take appropriate actions when required (open trickle vents etc)
Minimise use of sprays and aerosols
Get a spider plant - many plants absorb toxins and impurities from the air

If you do have a problem with IAQ then it might also be worth looking at the Auro Airfresh Wall Paint product as this has a catalyst in it to help remove certain elements from the air. Note that we can supply all Auro and earthborn products.