Pandemic turns spotlight on indoor air quality

Controlling airborne contaminants while simultaneously maintaining healthy temperatures and humidity levels has never been more important in healthcare buildings, says James Henley*.

The work of building services specialists and facilities managers is increasingly being measured in terms of human health. At a recent industry conference, they were recognised as “physicians of the future” by an international authority on virus transmission.

This increased recognition can be linked directly to the Covid-19 crisis, which focussed unprecedented attention on how air conditioning and mechanical ventilation systems manage air quality alongside temperature and humidity to keep people healthy.

The government’s SAGE advisory group has also called for a national strategy on building ventilation following research from Cambridge University, which recommended that air change rates should be adequate to keep carbon dioxide levels below 800 parts per million. This can be used as an indicator that indoor air is being refreshed often and well enough to minimise the risk of transmission rates from airborne viruses and other pollutants.

Systems that manage air change rates, filter outside air and control both temperature and humidity will be increasingly vital as the country learns more about the airborne nature of Covid-19 and other viruses. Their importance in controlling relative humidity (RH) has also been stressed by Dr Stephanie Taylor from Harvard Medical School, who believes it is the key to preparing buildings for future health challenges too.

She says managing the indoor environment was “the best medicine for treatment and prevention” and her research identified an RH ‘sweet spot’ between 40% and 60%. Air that is too dry, which we often experience indoors during the winter, will allow viruses to thrive and be more active.

Indoor air quality – a public health emergency

Even before the pandemic, poor air quality was labelled a “public health emergency” by the World Health Organisation (WHO); and the British Lung Foundation identified a particular threat to hospitals and healthcare facilities in its Toxic Air at the Door of the NHS report. This revealed that more than 2,000 GP surgeries and 248 hospitals in the UK are in locations where air pollution is above WHO recommended contamination limits.

As a result, opening a window in search of ‘natural ventilation’ could expose occupants to the harmful effects of outdoor air pollution.  Indoor air is often many times more polluted than outdoor air due to the increased concentration in a confined space and the mixture and combination of pollutants from both internal and external sources. This strengthens the case for a more controlled indoor environment – particularly in urban settings – where mechanical systems manage the air quality.

‘Smart’ connected technologies

The ‘lockdown’ periods also proved how much activity could be carried out from home or from mobile workstations without any loss of productivity – including the means to keep vital support systems operating for the NHS. Building engineers rapidly increased the use of digital tools capable of assessing the condition of equipment from a remote location – making it possible to repair and maintain systems even when physical access was severely restricted.

Thanks to the increasing availability of ‘smart’ connected technologies, our industry is now much better prepared for any future lockdowns and for those instances when restrictions make it difficult to get engineers to site.

Continuous monitoring of the different contributors to poor indoor air quality (IAQ) also allows facilities managers to anticipate potential problems. They can manage potential breakdowns or analyse why critical plant, like a chiller or air handling system, is not achieving its design capacity or efficiency. This may be because the refrigerant charge is low or operating pressures have become too high, for example, with the FM alerted before the problem becomes serious – leading to a potentially expensive breakdown.

Wireless networks make it possible to configure, commission and control complex systems, which also gives engineers the ability to gather performance data and analyse the individual pieces of equipment that consume the most energy, such as fans and chillers. This is an increasingly important consideration for NHS estates managers, who are under pressure to reduce running costs while also maintaining good quality indoor environments.

Smart, connected systems also allow building services designers to match conditions more closely to the comfort and health requirements of occupants because the performance of heating, cooling and ventilation equipment can be adjusted without the need for any physical intervention.

Integrated systems meet health needs

Being able to deploy the very latest in wireless technology underpinning a robust and reliable communication network also makes it possible to create a more integrated system that will both maintain comfortable temperatures and RH while minimising airborne contaminants through adequate air change rates and the use of the appropriate filtration.

Once the system has been designed and installed, however, it needs to be maintained to continue operating properly. Performance will slip gradually over time if any system, however sophisticated, is not regularly monitored.

Using a system like Daikin Applied’s DoS (Daikin on Site) remote monitoring means FMs benefit from a system that is constantly monitored so any performance or safety risks are detected at the earliest possible moment. This allows them to keep the system running as it was intended, which is particularly valuable in a critical facility like a hospital.

DoS can obtain live operational data from the building and combine it with statistical predictions using Trend Analysis. This allows the engineering team to develop a preventative maintenance schedule to ensure the maximum efficiency and reliability of critical equipment, avoiding costly downtime and major repairs.

Daikin Applied UK have supplied ovedaikinr 1000 AHUs to healthcare facilities nationally and internationally, giving the company a wealth of knowledge and expertise when it comes to product benefits and future developments.

Daikin Applied UK also offers high care/clean room technology solutions that deliver the sterile environments needed by critical areas like operating theatres and pharmaceutical production facilities. Its full system approach includes delivering solutions to control air pressure, temperature, moisture, and filtration systems to protect against fine dust, skin particles and bacteria.

*James Henley is product development manager at Daikin Applied UK.

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