Air quality: a time for action

With an estimated 29,000 deaths a year from air pollution, The Environmental Audit Committee has issued its third report in five years calling for action to be taken. The report is calling for new schools, care homes and hospitals to be built far away from major roads.

With more than 1,000 schools already near major roads, it is suggested that it would make good economic sense to filter the air coming into the buildings.

“Experts believe that the figure of 29,000 is a robust figure, that is unacceptable. Those of us working in the built environment must play our part in addressing this,” said Ian Orme, head of BSRIA’s Sustainable Construction Group. “There is also a wider issue of air quality that we need to address; the environment in which people live and work plays a massive part in their wellbeing. As we have got better at making buildings airtight, it is BSRIA’s experience that there are often significant failures in the performance of ventilation systems leading to an unhealthy environment” Ian continued.

In BSRIA’s experience there are five main reasons for poor indoor air quality:

• Design: Impractical designs and/or designers “gaming” with calculations so as to demonstrate the standards are met.

• Construction/Installation: Ductwork can be prone to damage and the practical installation of ductwork, fans, and terminal units does not always equate to what was designed. BSRIA has come across instances of mechanical ventilation systems simply not being connected up to the power supply.

• Commissioning: Poor commissioning, such as ventilation dampers, sensors and controls can significantly affect performance. The current approved method of measuring air flow from low pressure ventilation systems is fundamentally flawed, so in practise it is difficult to identify the true situation in many buildings, even where a ventilation system has been properly commissioned.

• Maintenance: Poor maintenance of filters and sensors can have a significant impact on flow rates and the effectiveness of filtration. Design issues sometimes make cleaning of filters or their replacement or the cleaning of ductwork, somewhat problematic.

• Operation: Occupant effects such as not using the ventilation system as per the design intent, manual tampering of controls, sensors and dampers. Where mechanical ventilation works with trickle ventilators, they may be taped shut.