Modern Building Services

FEATURE INDOOR AIR QUALITY MODERN BUILDING SERVICES NOVEMBER 2022 33 If you have good outdoor air quality and a naturally ventilated space, allowing large volumes of air to pass through the building will inevitably provide good IAQ, but during heating and cooling season, that air needs to be tempered before it is then exhausted from the building. Conversely, if you have to provide high levels of filtration to the incoming air because outdoor air quality is bad, feeding the pressure drop from the filters (and therefore energy use) into the platform gives valuable insight into the HVAC efficiency. If IAQ is exceptionally good, the platform can identify over- ventilated areas and adjustments to the HVAC system or levels of infiltration can be made. The rise of hybrid working has presented a significant opportunity to save money on filter replacements in buildings with demand-controlled ventilation. A rule of thumb 3/6 month filter change, is potentially highly wasteful. If the total supply air volume and filter dust loading are measured, optimal filter change points can be modelled, and the filters changed on a schedule that optimises energy, labour, and material costs. User prompts If the only ventilation to a building is via opening windows, users that are expected to operate the windows need to knowwhen it’s appropriate and necessary to open a window. Automated indicator lights linked to both indoor and outdoor air quality sensors are the ultimate solution as these will decide via their logic whether it is beneficial to open the window or not. A simpler to deploy solution is via CO2 sensors that indicate to the users of the space that they need to ventilate through a combination of visual displays and audible alarms. It is important that any audible alarm settings can be adjusted so that they do not become so intrusive that the whole system is disregarded. Automation Relying on users to regulate ventilation effectively via windows was shown to be a pipedream during the pandemic. A lack of knowledge around its importance, lack of prioritisation or concerns over energy use often prevent user-controlled ventilation systems from being used. A sensor can communicate overall air quality in a similar format to the EPC-style graphics that people are familiar with. Collating all the measured parameters into a single Air Quality Index keeps communication simple. On top of the clear communication, the a unit also has the ability to control a standalone air purifier via a relay, or to control a fan. With covid-19 being treated as something that happened in the past by a lot of people, as mentioned it is important that the industry now works hard to keep indoor air quality front of mind. Good communication and providing valuable insights will be key to keeping end users engaged in this important issue. More information can be found at www.arm-environments.com