Bad air days

CIBSE’s forthcoming TM40 uses the WHO’s maximum concentration guidelines. CIBSE advice is that these guidelines should be seen as ‘interim and tentative’, and design and maintenance teams should remain informed of indoor air quality standards and regulations that are likely to be developed in the future. Ultimately good IAQ will depend on a good ventilation strategy supported by monitoring cleaning and maintenance.

Poor maintenance issues that can lead to IAQ issues highlighted in TM40 include:

• Badly maintained combustion equipment, such as boilers, which can lead to carbon monoxide poisoning
• Filters not being changed
• Unclean ductwork which could introduce pollutants and smells into a space
• Poorly drained condensate spans in air-handling units and fan coil units, creating the conditions for microbial growth

CIBSE Guide M provides details on scheduling of inspections and maintenance activities for all types of environment.

According to TM40, various measures can be explored to improve IAQ. These include reducing pollutants at source to reduce occupants’ exposure to them. In mechanically ventilated buildings, for example, one solution might be to install air filters, while on naturally ventilated buildings operators should consider reviewing the feasibility of ventilating through openings on less exposed façades.

Flushing the building, or the affected rooms, should help dissipate emissions if high VOC levels are identified in a building in the early stages of occupancy after construction, refurbishment, fit-out or installation of new furniture. CIBSE suggests that flushing could be repeated for the first few months of occupation, particularly if formaldehyde levels are found to be high.

Likewise, if high VOCs are identified in a ‘settled’ building, TM40 suggests this could be due to occupants’ products and equipment, or the use of cleaning products emitting high levels of VOCs. TM40 proposes that occupants should switch to low-emitting cleaning products, and that consideration should be given to cleaning at night rather than in the morning just before the office is occupied. Similarly, polluting equipment such as printers should be relocated, ideally to unoccupied areas with adequate ventilation.

Once sources of pollution have been reduced or controlled as much as possible, the provision of adequate ventilation should be checked. According to TM40, this should include “checking the operation of existing ventilation systems, the ventilation rates being delivered and controls in relation to occupancy patterns; systems should be recommissioned and remediation measures carried out if needed”.

Currently there are several voluntary schemes which require indoor air quality to be tested. These include Building Research Establishment Environmental Assessment Method (BREEAM), LEED and WELL, all of which set a VOC limit of 500µg/m3, while both the existing and new draft Approved Document F recommend 300µg/m3. In addition, WELL requires VOC considerations to continue after the fit-out is complete; it requires constant monitoring and testing of IAQ.

WELL CERTIFICATION
When engineering consultancy Cundall moved its London office, it used the opportunity to trial WELL certification on its new workspace. In fact, Cundall’s new office was the first in Europe to gain WELL Certification, achieving Gold.

As part of the WELL certification process, Cundall focused attention on IAQ, including the specification of low-emission materials and finishes. Despite this, one early IAQ test showed VOC levels at almost three times those allowed by WELL. After investigation, it was found that levels were high because the building had been cleaned the night before using products with a high VOC content. The findings serve to highlight the need to consider whole building operations to achieve indoor air quality, including regular testing and monitoring.

Cundall has since been monitoring the impact of the WELL measures on its workforce. The findings are impressive: according to the organisation it has seen a 50 per cent drop in absenteeism compared to the year before the move, and a 27 per cent reduction in staff turnover.

The evidence from Cundall suggests that a healthy workplace is an environment in which people can thrive. While a healthy workplace is not necessarily a productive workplace, to be productive office workers need to be and feel well.

Designing the workplace to support people’s wellbeing makes business sense, as even a modest improvement in employee wellness will have positive financial implications for a business. Research demonstrates that cognitive performance scores of participants who work in improved indoor environments with low levels of volatile organic compounds and higher ventilation rates are, on average, double those of participants who work in conventional environments.

For more information please visit the CIBSE website www.CIBSE.org