Ventilation: why so serious?

Published:  16 September, 2014

As we begin to make our homes more air tight and energy efficient, Kelly Butler asks if the industry is taking indoor air quality seriously enough

In recent weeks there has been a sharp upturn in media interest on the topic of air quality, specifically driven by the air pollution we suffered in the UK from early April.

Couple this with the EU Commission’s legal proceedings against the UK due to its failure to reduce levels of nitrogen dioxide (NO2) and we have a great platform for serious media attention.

And it is a serious issue. Poor air quality, either outdoor or indoor, can cause respiratory problems and even lead to asthma, yet we rarely talk about poor indoor air domestic pollution. We continue to seal our homes tight to save energy, but we also continue to neglect a regulated service for dwellings – ventilation. 

BEAMA has recognised the link between green building policies and potential health problems and worked with government to raise the profile of indoor air quality. The overall objective is to promote energy-efficient and healthy buildings, with BEAMA launching its Ventilate Right campaign later this year, bringing together health experts and members of the construction industry to significantly raise consumer awareness of the importance of ventilation.                             

A home should be green without turning black

Let’s go back a step to 2013. Green Refurbishment has been attracting lots of attention in the past year or so with the Green Deal and the news that energy saving measures can improve a property’s value by 14%. There is no doubt that green investment makes good sense for the customer.  However, we need to avoid health risks along the way and not just risks to the health of occupants, but also to the quality of the building itself. Progressive policies to insulate and seal our homes are excellent from an energy and carbon saving point of view, but we still need a supply of fresh air. 

The Royal Institute of Chartered Surveyors states that one in five UK homes are affected by condensation and mould growth. This is hardly surprising when you consider that four people living in a property can create 16 pints of moisture per week! This moisture is created by bathing, washing, cooking and breathing. If we fail to extract this moisture effectively and ensure an adequate supply of clean air, we run the risk of respiratory problems caused by allergen build-up and mould growth, or further refurbishment costs to tackle mould growth on walls, doors, ceilings and furniture.

The key risks

Heating and ventilation without insulation can lead to high running costs for the occupants. Cold surfaces such as single-glazed windows will attract moisture to them.

Heating and insulation with poor ventilation, on the other hand, can result in higher internal humidities. 

This allows moisture to form and in time mould spores to cultivate, causing damage to the building fabric and creating a risk to the health of the occupants, as seen in the picture above.

Higher internal humidities can result in larger house dust mite populations, with both the detritus from house dust mites and mould spores being potent airborne allergens. These allergens can trigger allergic symptoms such as rhinitis, conjunctivitis, eczema, coughing and wheezing. For a sensitised person, repeated exposure can lead to asthma, and it appears that the severity of the asthma intensifies with increasing humidity, house dust mite and mould levels.

Trapped humidity and stale air are at the heart of indoor air quality problems, so ventilation is essential in ensuring healthy living.

Reducing the risk

The minimum requirement is that there should be no visible sign of mould on external walls in a properly heated home with typical moisture production.  

Great care should be taken when insulating to ensure that consistent thermal performance is achieved. Even small variations in surface temperature can result in mould growth.

Air quality is tackled through the Building Regulations, which specifies seven litres/second/per person with a whole building ventilation rate not less than 0.5 air changes per hour. 

Any construction industry professional involved with refurbishment and building services specification should familiarise themselves with Part F of the Building Regulations and recognise that the simple solution to ensuring good indoor air quality and healthy living is high efficiency, continuous, ventilation as recommended in the BEAMA Green Deal Ventilation Guide www.beama.org.uk.

Kelly Butler is BEAMA’s marketing director

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