Cleaner air - outside and in

Cleaner air - outside and in © Land Securities

Concern over the air quality inside buildings is now receiving similar attention to that which outdoor air quality received in the 1970s – and it’s another area in which nonwoven-based filter media are cleaning up.

A growing body of scientific evidence indicates that the air within homes and other buildings can be even more polluted than the outdoor air in even the largest and most industrialised cities.

In addition, those exposed to indoor air pollutants for the longest periods of time are often those most susceptible to the effects of pollution, such as the young, the elderly, and the chronically ill – especially those suffering from respiratory or cardiovascular disease.

Acceptable indoor air quality (IAQ) is defined by the Standard 62 Ventilation for Acceptable Indoor Air Quality as determined by ASHRAE.

Founded in 1894, ASHRAE is an international organisation with over 50,000 members whose mission is to advance heating, ventilation, air conditioning and refrigeration services through research, standards writing, publishing and continuing education.

Its definition of acceptable indoor air quality is “air in which there are no known contaminants at harmful concentrations and with which a substantial majority of the people exposed do not express dissatisfaction”.

Poor IAQ is caused by airborne particulates and gases or vapours which adversely affect occupant health and comfort, the building structure or its furnishings. Some IAQ problems are so harmful that the entire structure can be defined as a ‘sick building’.

Many of the environmental pollutants are new and are the result of changes in HVAC (heating, ventilation and air conditioning) system design and operating practices. Others have existed for years, but health-conscious building occupants are now complaining about them.

Poor IAQ has been shown to result in an increased incidence of illness and absenteeism, reduced productivity, irritability, complaints about building odours and stuffiness, as well as health problems. These may include allergies, coughing, diarrhoea, eye, nose and throat irritation, fatigue, general respiratory problems, headaches, nausea, dizziness, runny nose and skin irritation.

EN 13779

Consequently, the European standard EN 13779 has been established to achieve the realisation of a comfortable and healthy indoor climate with acceptable installation and operating costs.

The required filter performance for the achievement of a good indoor air quality is specified, taking into account the quality of the outdoor air. This is classified in three categories, from ODA1, i.e. clean air with temporary pollution such as pollen, to ODA3 with high concentrations of gas and particles. Indoor air, however, is classified from IDA1 (high air quality) to IDA 4 (low air quality).

German first

Five years ago, the Berlin Marriott Hotel became the first hotel in Germany to consistently implement the recommendations in respect of IDA1 for EN 13779 in all areas.

With more than 2,900 hotels, Marriott International is one of the world’s leading chains. The five-star Berlin Marriott is located in the inner city, directly on the Potsdamer Platz.

With such a city centre location with a high volume of traffic, the outdoor air quality ODA3 is measured. Specifically, this means frequently exceeding EU threshold values and guideline values of environmental protection in the concentrations of particulate matter (PM10), ozone, nitrogen dioxide etc.

This conflicts with the high standards of the Berlin Marriott Hotel, which aims to guarantee its guests the best indoor air quality (IDA 1).

In addition to a good particulate matter filtration, the DIN EN 13779 recommends using gas filtration in cities to improve the IAQ.

A filter made from a unique media of nonwoven fibreglass and activated carbon – with rapid adsorption dynamics – has been provided to provide unique particle and gas filtration.  This media has a low pressure drop, good filter efficiency and also efficiently eliminates particulate matter, ozone and any fumes caused by traffic. In addition, it can be used without major effort in existing or new filter installations in place of conventional pocket and compact filters.

To achieve DIN EN 13779 IDA1, the conversion to an additional gas filtration level did not entail any major conversion work and the pocket filters previously employed could be replaced without any problems by the new media in the second filter stage.

The improved indoor air is perceived as a qualitative added value of the hotel for guests and also portrayed as such. In collaboration with the filter producer, the Berlin Marriott Hotel has therefore created a joint flyer which is displayed in all guest rooms.

Land Securities

Over in the UK, meanwhile, the country’s largest property management company, Land Securities, is saving an estimated £250,000 and 650 tonnes of CO2 by installing low energy air filters

Land Securities now owns and manages more than 29 million square feet of commercial property – from London offices and high street shops to major shopping centres and out-of-town retail parks.

A filtration company was initially asked to evaluate the effect of installing low energy air filters in the air conditioning system of its London buildings, and a suitable site was identified at New Street Square in the heart of the City. In July 2009, the company’s engineering staff completed a detailed evaluation of the air filters within one of the air conditioning systems.

This evaluation involved collecting performance details on the standard air filters in use at the time, and comparing them to an alternative selection of new, low-energy air filters.

It identified the following savings:

  • Replacement air filters  – 15% reduction;
  • Labour to change filters  –  64% reduction;
  • Energy to move air through the filters  – 16% reduction; and,
  • Tonnes of CO2 – 16% reduction.

These savings were achieved by fitting low-energy nonwoven air filters into the existing filter holding frames as part of the normal maintenance regime.  No further investment was required.

Prior to this implementation, the air filters were routinely replaced as part of an established Planned Preventative Maintenance (PPM) regime. During this trial project the filter supplier demonstrated that using low-energy air filters not only reduced the energy consumed, but also doubled the service life of the filters. Consequently, the annual air filter cost was reduced, together with a corresponding reduction in labour and waste costs.

Crucially, because the way in which the low-energy air filters are engineered, the air being supplied into the buildings is now much cleaner – a four-fold decrease in the amount of particulate in the air has been noted.

Land Securities has subsequently rolled out the replacement filter scheme across all its properties across London.



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