Business Development Manager, AACS Limited
The latest guidance from HSE on Air Conditioning and Ventilation
The risk of air conditioning spreading coronavirus (COVID-19) in the workplace is extremely low as long as there is an adequate supply of fresh air and ventilation.
You can continue using most types of air conditioning system as normal. But, if you use a centralised ventilation system that removes and circulates air to different rooms it is recommended that you turn off re-circulation and use a fresh air supply.
You do not need to adjust air conditioning systems that mix some of the extracted air with fresh air and return it to the room as this increases the fresh air ventilation rate. Also, you do not need to adjust systems in individual rooms or portable units as these operate on 100% re-circulation. You should still however maintain a good supply of fresh air ventilation in the room.
Employers must, by law, ensure an adequate supply of fresh air in the workplace and this has not changed.
Good ventilation can help reduce the risk of spreading coronavirus, so focus on improving general ventilation, preferably through fresh air or mechanical systems.
Where possible, consider ways to maintain and increase the supply of fresh air, for example, by opening windows and doors (unless fire doors).
Also consider if you can improve the circulation of outside air and prevent pockets of stagnant air in occupied spaces.
Director at AACS Limited
The work of building services specialists was acknowledged by various government departments and building clients as providing vital support for critical operations like the NHS and food suppliers during the Covid-19 crisis.
The Department for Business, Energy and Industrial Strategy (BEIS) said building maintenance should continue as normal during the period when the country was in lockdown and was “helping to save lives” by keeping hospitals, care facilities, schools and supermarkets operating.
There were some early rumours that air conditioning and ventilation could help to spread the virus, but it was quickly established that this was not the case. On the contrary, it became clear that these systems could play an important role in helping to deal with the problem.
REHVA, the European Federation of HVAC associations, explained that Covid-19, unlike some other viruses, is largely resistant to environmental changes and susceptible only to high relative humidity above 80% and temperatures above 30°C. Therefore, humidification, air conditioning and duct cleaning had no practical effect on its transmission.
However, there were certain adjustments facilities managers could make that would further reduce the risk of transmission. For example, by switching air handling units (AHUs) to full fresh air mode and temporarily disabling recirculation with heat recovery, facilities managers could ensure potentially contaminated air was not recirculated in occupied spaces.
Building users were urged to keep up air change rates – even in partially occupied buildings – as this would minimise the risk of moisture, which could contain the virus, settling on internal surfaces.
indoor air can often be between 5 and 13 times more polluted than outdoor air due to a cocktail of contaminants
Monitoring and maintaining for health
However, good maintenance strategies should not just be deployed in response to a pandemic. There is a wider lesson to be learned about how building services maintenance can safeguard the health and wellbeing of building occupants at any time.
According to the Royal College of Paediatrics and Child Health (RCPCH) and the Royal College of Physicians (RCP) indoor air can often be between 5 and 13 times more polluted than outdoor air due to a cocktail of contaminants including smoke, damp, traffic fumes, chemical aerosols and particulates from wood burning.
This is known to be contributing to a dramatic rise in the number of asthma sufferers and is also linked to other allergic conditions including conjunctivitis, dermatitis and eczema. It also has a particularly unwelcome impact on the health of children.
Schools, care homes and healthcare facilities are areas of particular concern. In these buildings it is crucial that the air conditioning systems are continuously monitored to ensure they are delivering the right conditions for health and wellbeing – and that regular maintenance is carried out to keep them operating reliably and efficiently to minimise running costs.
This is also the best way to extend the operating life of these critical assets and minimise costly repairs and system downtime. It will also flag up the need for regular maintenance activities such as disinfection and chlorination to kill viruses and bacteria, preventing airborne cross contamination.
Duct cleaning also removes unwanted substances such as debris and dust from ductwork and sanitising prevents mould building up in the system. Duct and air sampling ensures good quality air is circulated through the HVAC units. Humidifiers should also be checked to maintain relative humidity levels are in line with recommendations for minimising airborne viruses.
Thanks to the availability of connected tools, continuous monitoring can be carried out remotely so potential problems are spotted before they arise.
good maintenance strategies should not just be deployed in response to a pandemic. There is a wider lesson to be learned about how building services maintenance can safeguard the health and wellbeing of building occupants at any time.
Technical innovation for long term efficiency
Our supplier Daikin continue to push the boundaries of technical innovation to improve the long-term operating efficiency of our installations. For example, they recently launched a new generation of water-cooled centrifugal compressor chillers, which provide better energy efficiency thanks to the inclusion of a new refrigerant cooled inverter drive.
Available in a wide range of cooling capacities and component combinations, Daikin's new B Vintage chillers have been designed to deliver optimal performance at both full and part-loads. They can also operate with a choice of refrigerant to help building users meet targets for reducing the global warming potential (GWP) of their installations.
Daikin AHUs also meet client requirements for air quality and energy efficiency through accurate sizing and using technical innovations like EC fans. Fan power is specifically referenced in revised ErP legislation so is another design aspect that should not be ignored by specifiers. This also calls for multiple fan systems to build in redundancy so is as much about reliability and peace of mind as improving efficiency.
The country’s problems with air pollution and the increasing publicity around the transmission of disease means this aspect of building engineering is under the microscope. Fortunately, the air conditioning and ventilation sectors have a range of solutions available to help building owners and managers maintain safer, healthier and more comfortable conditions for occupants – delivering better and more cost-effective outcomes for all.
Business Development Manager, AACS Limited
Delivering and maintaining a high level of indoor air quality has never been such a high priority. This is because long-term exposure to air pollution can cause or exacerbate chronic conditions, such as cardiovascular and respiratory diseases, as well as potentially affecting a person’s mental health and well-being. While there are numerous factors that contribute to the creation of a pleasant, clean and healthy internal environment, such as lighting, humidity, temperature and air quality, effective building ventilation is perhaps the cornerstone of good building health.
Fundamentally, ventilation aims to remove stale indoor air and replace it with ‘fresh’ outdoor air. Ventilation systems are designed to extract water vapour, airborne pollutants (from both inside and outside pollution sources) and odours, control humidity and maintain good indoor air quality.
In order for a building ventilation system to be truly effective and perform as the original design intended, it has to be commissioned correctly, and have a regular maintenance and cleaning programme in place.
Air pollution from both outdoor and indoor sources represents the single largest environmental risk to health globally” - World Health Organisation (WHO)
Installation and commissioning
It is crucial that the system is installed according to the manufacturers’ recommendations and commissioned in line with the final design specification. While last-minute changes during on-site installation, such as varying pipe lengths, for example, may seem minor, it can in fact have a significant impact on the system’s overall performance and energy efficiency. Consequently, this can also affect the building’s indoor air quality. That’s why it’s so important to use an experienced installer, who is approved to install the chosen manufacturer’s ventilation system.
Maintaining your ventilation system
Once ventilation is installed and commissioned, regular maintenance is essential in order to ensure the system continues to deliver a high level of performance, and this should form part of the building’s overall HVAC service regime. It is not a case of simply installing the system and then forgetting about it.
Given the system’s role of extracting airborne pollutants and providing a continuous supply of ‘fresh’ air, regular cleaning of a building’s ventilation is particularly important, as build-up of dust and dirt can affect the system’s ability to maintain indoor air quality. While HVAC units are fitted with filters, primarily to keep the system free of dust (as well as removing particulate matter from supply air), there is still more that can be done.
For example, regularly checking the supply intake and exhausts for signs of dirt build-up, pollution or contamination, or damage from weather or animals is good practice, as is inspecting the ductwork and indoor units. Any dust should be removed from the ductwork, with particular attention to the filters, heating and cooling coils and any change of direction in the ducting.
It is also recommended that on a regular basis filters are cleaned and replaced, indoor units are cleaned and the dust boxes of those fitted with auto-cleaning systems emptied.
For further guidance, BS EN 15780: 2011: Ventilation for Buildings. Ductwork. Cleanliness of Ventilation Systems specifies acceptable cleanliness levels for supply, recirculation and extract air, grouped into three classes – Low, Medium and High – depending on the use of the internal space.