{"id":15008,"date":"2023-12-01T13:26:10","date_gmt":"2023-12-01T13:26:10","guid":{"rendered":"https:\/\/smartairfilters.com\/uk\/?p=15008"},"modified":"2025-09-19T08:33:15","modified_gmt":"2025-09-19T08:33:15","slug":"cleanair-clinics","status":"publish","type":"post","link":"https:\/\/smartairfilters.com\/uk\/en\/cleanair-clinics\/","title":{"rendered":"The Air We Share - how to meet PHE guidelines for treatment rooms"},"content":{"rendered":"\n

Clean indoor air is not only essential for our health and wellbeing, it offers relief to asthma and allergies sufferers and reduces disease transmission. This is especially important in clinical rooms with no windows and limited airflow.<\/p>\n\n\n\n

In this article, we do a deep dive into how to meet Public Health England (PHE) guidelines to reduce airborne contaminants in treatment rooms.<\/p>\n\n\n\n

Good ventilation doesn't translate to good indoor air quality<\/h5>\n\n\n\n

Many UK hospitals rely heavily on natural ventilation as their main source of airflow in patient wards. However natural ventilation is highly dependent on weather conditions, the opening sizes of windows, doors or leakage etc making it uncertain and difficult to control<\/a><\/span>.<\/p>\n\n\n\n

Mechanical ventilation systems are more reliable. There are two types \u2013 recirculating ventilation and fresh air ventilation, which also delivers fresh air and is often counteracted with heating for thermal comfort (HVAC).<\/p>\n\n\n\n

The focus on mechanical ventilation has been considerable since the pandemic started. The HVAC solution for infection control in the UK is 'increased filtration' (requires a costly refit and lengthy construction work); or 'increased ventilation' (requires additional heating to compensate, leading to higher carbon emissions and energy costs). <\/p>\n\n\n\n

Although increasing ventilation is the only viable HVAC solution, at best it dilutes airborne particles rather than removes it and it also assumes 'good' outdoor air quality. So, if your goal is to reduce airborne infections and pollutants, then filtration needs to play a bigger role in healthcare settings<\/strong>. <\/p>\n\n\n\n

Understanding 'air changes' helps you find the right solution<\/h5>\n\n\n\n

Current UK healthcare guidance<\/span><\/a> for new buildings and major refurbishments specifies a minimum of 10 air changes per hour (ACH) for treatment rooms<\/em>. One ACH occurs when a volume of air delivered is equal to the volume of the room. <\/p>\n\n\n\n

However as fresh air enters and mixes with 'contaminated' air in the room, not all the contaminated air is removed by one air change<\/strong>. Under well-mixed conditions, one air change removes approximately 63.2% of air contaminants, and a second air change removes about 63.2% of what remains, and so on (let's refer to this as Contaminant Removal ACH for the purpose of this article).<\/p>\n\n\n\n

\"\"<\/td> <\/td>\"\"<\/td><\/tr>
Table source: <\/em>CDC - Guidelines for Environmental Infection Control in Health-Care Facilities<\/em><\/a><\/td> <\/em><\/td>Chart source: <\/em>Aerobiology and its Role in the Transmission of Infectious Diseases<\/em><\/a><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

This means that a room with 10 ACH can take 28 minutes to reduce the starting contaminant concentration by 99%.<\/p>\n\n\n\n

Exceeding PHE guidelines can reduce your bioburden<\/h5>\n\n\n\n

We're going to show you that it's not just possible to meet PHE guidelines for treatment room, it can be exceeded with low-cost portable filtration. <\/p>\n\n\n\n

1. Choose a Portable Air Cleaner that delivers the full ACH required by Public Health England<\/strong><\/p>\n\n\n\n

Not only can air cleaners deliver the equivalent ACH, it can do so at substantially lower energy costs and carbon footprint<\/a><\/span> than mechanical ventilation. It is also a cheaper solution that can be implemented within a week.<\/p>\n\n\n\n

2. Top up with the mechanical ventilation ACH to exceed guidelines<\/strong><\/p>\n\n\n\n

Ventilation is crucial, we are not suggesting here that it is a supplementary measure. Ventilation air changes should be based on room dimension\/occupants but consider filtration for particle removal - ie. use portable air cleaners to deliver the full<\/span><\/strong> PHE requirement. If your mechanical ventilation is functioning as required, then you have the added bonus of even more clean air! <\/p>\n\n\n\n

Before you start calculating your requirements, we recommend that you check \/ re-confirm the mechanical ventilation ACH. This recent research found airborne SARS-CoV-2 may transmit infection for nearly 5 hours<\/a><\/span> in a hospital setting where the HVAC 'should' have been delivering 6 ACH (note, ACH not validated by the researchers before commencing project).<\/p>\n\n\n\n

Combining ventilation and filtration<\/a><\/span> is the best way reduce bio-aerosols at source, but...<\/p>\n\n\n\n

...not all portable air cleaners are equal<\/h5>\n\n\n\n

To work out how to source a portable air cleaner to deliver the full ACH for your space, you will need to do a little bit of maths. Multiply your room volume (length x width x height) by the number of air changes recommended by PHE:<\/p>\n\n\n\n

Room volume x ACH = CADR<\/em><\/p>\n\n\n\n

This calculation shows you the minimum<\/em> Clean Air Delivery Rate (CADR) an air cleaner needs. Be mindful that most manufacturers only show the top speed CADR which will be too noisy<\/a><\/span> for continuous usage. To see how this works in practice, we are going to look at a dental treatment room scenario with 10 ACH, as per guidelines.<\/p>\n\n\n

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Practical example:<\/strong><\/h6>\n\n\n\n