By David Brownstein

In 2017, Cundall’s Birmingham office underwent a significant expansion. We had previously occupied the 4th floor of 15 Colmore Row, however the need to accommodate our rapidly expanding business and the opportunity presented by a vacating tenant meant we were able to expand to the 5th floor as well.

Cundall are at the forefront of the health and wellbeing movement, which has been taking the construction industry by storm as more and more people begin to realise the benefits that healthy buildings give to their people and businesses. To properly reflect these values, we sought to put health and wellbeing front and centre in the development. Our London office became the first project in Europe to be certified under the WELL Building Standard, being awarded a Gold rating in 2016. We wanted to follow suit, but with a design that reflected the values specific to the Birmingham office.

A growing area of interest for Cundall, the construction industry and the wider public as well is that of indoor air quality. With the UK consistently breaching air quality limits, and the number of deaths and illnesses related to poor air quality in the tens of thousands, air quality formed a key part of the health & wellbeing strategy. To facilitate our goals, Cundall developed the IEQube system, a network of air quality sensors that are placed in ours as well as our clients offices. This enables minute-by-minute monitoring of key indoor air quality metrics such as carbon dioxide, volatile organic compounds and particular matter (PM10 & PM2.5). The readings can be remotely monitored and analysed.

We wanted to monitor three things:

  • Firstly, with construction occurring directly above us, and a 5m diameter hole being cut into the slab between the two floors, we wanted to determine whether this would have any impact on the occupants working below.
  • Secondly, we wanted to understand the Volatile Organic Compounds (VOC) concentrations immediately after construction, and how these changed over time as the materials ‘off-gassed’.
  • Thirdly, we wanted to ensure that the office achieved the intended performance and that all systems had been commissioned correctly. In particular, we were interested in the ventilation and the provision of fresh air.

Construction Phase

The air quality monitor was placed in the centre of the office space for the duration of the construction phase, prior to handover of the 5th floor. The graph below shows a timeline of several weeks where PM10 and PM2.5 were monitored. These are fine dust particles which can infiltrate the lungs and blood stream, causing long term complications. It was important that our staff were protected from this whilst the works were carried out.

The graph shows that, overall, the measures that our contractor put in place to minimise the spread of particulates were successful. Concentrations remained below WELL limits throughout most of the construction. The graph shows a number of brief spikes in levels. This was caused by the large hole being cut in the slab, as well as when fire protection surrounding the steel beams had to be removed. These works were programmed to occur overnight and at weekends, which minimised occupant exposure to the particulates.

Materials Off-Gassing

Once Cundall took occupation of the 5th floor, the air quality sensor was placed in the centre of the floor plate. The graph below shows VOC concentrations for the weeks immediately following that. As expected, the initial off-gassing of the materials following installation resulted in elevated VOC levels. However, the WELL Building Standard suggests a limit of no greater than 500 µg/m3. The initial concentrations in our office were around 35µg/m3. Several visitors to the space commented on how ‘fresh’ it smelled when compared to other projects. This is attributed to the low VOC content of the materials specified, which includes the Bolon flooring, acoustic baffles and the natural finishes applied to the wooden furniture.

As time went on and materials continued to off-gas, Total Volatile Organic Compounds(TVOC) concentrations fell. After a number of weeks, these settled at around 5 µg/m3, which is an order of magnitude below recommended limits.

Ventilation Performance

Carbon dioxide concentrations were monitored post-occupation of the 5th floor. Typical good practice CO2 concentration limits are around 800-1000ppm. Immediately, the monitoring showed alarmingly high concentrations of around 1600ppm. This was far higher than anticipated, particularly since the floor plate was only partially occupied.

After verifying the readings with another sensor and checking the records to ensure commissioning was carried out correctly, it turned out that the control system for the ventilation plant was not functioning correctly. This was a simple fix, and the following day CO2 concentrations fell to expected levels. Had we not caught this earlier, the elevation CO2 would have continued to cause occupants to feel drowsy and less productive, resulting in significant lost time for Cundall!

Monitoring of air quality played a significant role in validating the performance of our new office. Our air was telling us that our staff were safe from particulates during the construction, our materials were not compromising the air quality and our ventilation plant was not operating as it should have been. What is your air telling you?

To speak to us about our Air Quality Monitoring services, please contact Alan Fogarty (London), Paul Chatwin (Birmingham), Mariana Trusson (Edinburgh, Newcastle), David Clark (Australia), Amie Shuttleworth (Asia) and Hala Yousef (MENA).

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David Brownstein, Sustainable Cundall


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