[vc_custom_heading text=”An Exclusive Insight from our Head of Built Environment,
Bernard Hornung” font_container=”tag:h2|text_align:center” use_theme_fonts=”yes”]
Ventilation plays a critical role in protecting our physical and cognitive health – the built environment and health outcomes are inherently linked. This is particularly important to note in the context of the Covid-19 pandemic, for which ventilation has been highlighted as an essential way of reducing impacts and spread of the disease. In the UK 70% of us spend 90% of our time indoors. As such, it is vital that the quality of the air we spend the majority of our time in, is not detrimental to our health.
Indoor air quality (IAQ) can be impacted by a range of factors – from airborne contaminants, pollutants, water vapour and the ability for passive and mechanical ventilation to draw fresh air from the outside and circulate it around a building. Poor ventilation – especially in residential, commercial or industrial buildings where pollutants are regularly introduced into the internal built environment – can result in poor extraction of contaminants and pollutants, and an inability to effectively dilute these contaminants and pollutants with fresh clean air. As a result, poorly designed and poorly implemented ventilation can result in poor indoor air quality.
The NHS associates poor ventilation and poor IAQ with Sick Building Syndrome (SBS), which can cause headaches, cold symptoms, irritated skin, sore eyes, tiredness and concentration difficulties – negatively affecting the health and productivity of those who reside or work within such a structure. Furthermore, a study carried out by researchers from Monodraught and The University of Reading School of Construction Management and Engineering, found that “low ventilation rates in classrooms significantly reduce pupils attention and vigilance, and negatively affect memory and concentration.” However, these conditions and negative outcomes are not just the result of historic building design failures. As the industry has been pushed forward by regulation, the airtightness of buildings has improved as building designers and construction firms strive to improve the energy efficiency of a structure.
There are arguments to suggest that by improving airtightness you also reduce passive venting – potentially reducing IAQ in a building which has inadequate ventilation to make up for the loss in air flow. My arguments are that air flow needs to be considered at the design stage and controlled. Unwanted infiltration and exfiltration of air through air leaks is a high risk method of increasing ventilation in any building. In a heavily polluted urban environment, and in a pandemic, this now equates to an open sewer.
The government’s own review into Building Regulations 2010 highlighted that only 3 homes out of the total of 80 new homes that were monitored met the governments standard for ventilation – underperforming design and especially lacking within bedrooms.
This shows how different building regulations can counteract each other and lead to poor building design, but it also highlights the need for evidence based and innovative building design solutions to ensure that new buildings – while energy efficient – are adequately ventilated to prevent the negative health outcomes associated with poor IAQ.
By late January 2020 it was accepted that the airborne transmission of aerosols was the primary cause of the rapid spread of Coronavirus infection, and as this virus evolves evidence confirms that it and its variants are increasingly airborne. To physically remove this hazard from the Built Environment will require more frequent air changes per hour than is currently recommended, and the implementation of a ventilation plan for every occupied building to enable clean air circulation. Covid infection is a significant health risk, ventilation and air filtration are key components of a layered approach towards risk reduction from the transmission of airborne infectious diseases. Such an approach also includes vaccines, masking, physical distancing and other controls on occupancy and testing. Adequate ventilation is also critical for maintaining healthy indoor clean air quality, conversely unoccupied buildings are generally safer if kept airtight to ensure that in the event of an outbreak of fire, the building in question is not replenished with a fresh supply of oxygen.
The requirement to maintain ICU Hospital Wards in negative pressure, by quickly detecting, locating, and quantifying air leaks as small as those with a diameter of 0.5mm, whilst the ICU Ward is occupied, resulted in a Government Emergency Response Award being granted to Coltraco Ultrasonics, and their successful development of the Portascanner Covid-19, followed shortly thereafter by their successful development of the Portascanner Airtight 520, the latter for use in broader applications throughout the entirety of the Built Environment. These lightweight instruments can be used by any competent person.
Both these successful technologies have their origins in the Portascanner Watertight, designed, manufactured and supplied by Coltraco Ultrasonics, primarily to enhance the ease and accuracy with which critical watertight, airtight, or weather-tight seals, can be inspected for leak sites or areas of reduced compression in the seal. This proven technology is already to be found in use throughout the world, and has been for well over 30 years.
Buildings which achieve higher levels of airtightness tend to also be built and executed to a much higher quality level. Whilst airtightness is essential to ensure thermal and acoustic insulation performs to its optimum designed level, to reduce the risk of condensation it must also be combined with an effective ventilation strategy for the building in question. At its most basic airtightness aims to eliminate any unintended gaps or cracks in the external fabric of the building. Ventilation focuses on replacing the stale, and possibly infected indoor air, with fresh outdoor clean air, to meet the occupants needs. Airtightness and a complementary ventilation plan, are both critical to make any further meaningful progress to end the current rapid spread of Covid-19, within Hospitals, and indeed within the entire Built Environment.Professor Catherine Noakes spoke on Tuesday 2 February at 12 noon on a webinar hosted by BESA – the Building Engineering Services Association.
Here is a synopsis of the webinar from the BESA website;
The pandemic has shown the true value of good ventilation systems in buildings. Always an area ripe for the worst kind of value engineering, there is a newfound respect for a poorly understood area of building engineering services.
Professor Cath Noakes, who studies how air moves and the infection risk associated with different ventilation systems will be joining us for this webinar. Early in the pandemic, she was invited to join the government’s Scientific Advisory Group for Emergencies, SAGE and was asked to study the transmission routes for Covid-19.
Bernard Hornung is grateful to Professor Catherine Noakes OBE and to Breathing City for being able to attend their seminars and to contribute towards their vital work on ventilation.