HOSPITALS & HEALTHCARE
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The role of ventilation in improving the nation’s health
Roy Jones, technical director at Gilberts Blackpool, the independent air movement specialist, discusses the role of ventilation in improving the nation’s health
A
t the beginning of the year, the Government announced its plans for a revised hospital building programme, as part of its rebuilding
of the NHS strategy. As a result, over the next five years alone, construction will start on 16 new hospitals1
.
Underpinning the programme is a new Hospitals 2.0 principle, a standardised approach to the design and construction, designed to deliver sustainable buildings that play a part in reducing the nation’s carbon footprint: hospitals represent 4+% of UK greenhouse gases.2
Inevitably, ventilation is a
fundamental element of that. The most recent relevant guidance- Health Technical Manual HTM03-01 Part A3
promotes
natural ventilation as the default for hospitals. Yet it acknowledges this is not always appropriate nor practical in today’s health environments and accepts, in order of priority, mixed mode then mechanical ventilation. It stresses the importance of the resilience of the ventilation, with updated guidance on airflow rates, air quality and filtration. This is in response to both protecting patients post Covid, and the ambition to be net zero by 2050. The ultimate aim is to provide appropriate ventilation with the least energy. HTM03-01 further advises cross-reference with CIBSE Guide B and CIBSE Manual AM13 (Mixed Mode Ventilation Systems). Finding practical, energy-efficient solutions to maintain the high standards of ventilation required in such critical settings is a challenge. We have to balance air changes- a minimum 10l/p/s- in such a way to avoid draughts, alongside noise, air pressure within specific rooms and risk of fire with so many highly combustible liquids and gases in the building. Filtration is also required to ensure good ventilation is critical: 11% of infections resulting from surgical intervention are caused by airborne micro- organisms4
.
The very diversity of room usage within a hospital means one must address numerous different considerations to maintain the airflow and air quality within each space. As a rule of thumb, the grilles and diffusers need to be positioned to achieve required supply air changes (up to 35/hour in a brain surgery operating suite for example5
and extract Gilberts Royal Preston Hospital Intervention Radiology Gilberts zip diffusers lab
Gilberts rutherford diagnostic centre reception
disruption. To cite an example, they were chosen for a High Dependency Unit for Wirral University Teaching Hospital Trust where up to 0.47m3/s supply airflow and up to 0.82m3/s exhaust airflow was required, providing the high room air change rates necessary to quicky remove airborne pollutants before pollutants could disperse and contaminate. Do note though that operating suites have specific
airflow away and prevent any uncontrolled airflow, without unnecessary ‘dumping’ or draughts. All whilst considering pressure differentials, humidity, temperature and noise. This tends to mean- but is not always the case- high level supply and low-level extract, for example in challenging spaces such as operating theatres. In our experience, perforated face diffusers- whether swirl or laminar- are an ideal solution for many areas within healthcare environments, from radiology suites to wards. Care needs to be taken in their positioning, to avoid any potential for stagnant zones if they are too far apart, and to avoid excess turbulence if too close: where diffuser airstreams meet, individual velocity of <0.25m/3 is generally advised.
Whilst the laminar option creates a curtain effect,
forcing the air down and away, perforated swirls deliver the high airflow with minimal turbulence of the air, The perforated face delivers maximum diffusion and rapid entrainment with minimum air
criteria. Perforated laminar flow panels provides a continuous, consistent flow of air which thus eliminates opportunity for airborne pollutants to enter supply air streams. Thus, it is very relevant for hospitals in sensitive areas such as laboratories and operating theatres. HTM03-01 does say that air convergence from a grid of diffusers above the table is also acceptable within operating theatres. Our research would indicate there is a risk with this configuration for the air be redirected back over the patient increasing the potential risk of contamination. However, provided care is taken in the precise positioning of the diffusers, any risk can be minimised. This is detailed in our specialist guidance document which proposes different solutions to the same problem6
.
Use of software modelling such as computational fluid dynamics is, we would suggest, more critical than ever when designing for a healthcare environment. Such technology (such as that available in Gilberts’ in-house test facility) can be invaluable in validating the airflow to ensure as clean an environment as possible, to encourage the recovery of patients and the continued health & wellbeing of the staff.
(1)
https://www.gov.uk/government/publications/new-hospital-programme-review-outcome/new-hospital-programme-plan-for-implementation (2)
https://www.fph.org.uk/media/3126/k9-fph-sig-nhs-carbon-footprint-final.pdf (3)
https://www.england.nhs.uk/wp-content/uploads/2021/05/HTM0301-PartA-accessible-F6.pdf (4)
https://pmc.ncbi.nlm.nih.gov/articles/PMC8243999/ (5)
https://www.england.nhs.uk/wp-content/uploads/2021/05/HTM0301-PartB-accessible-F6.pdf (6)
https://gilbertsblackpool.com/wp-content/uploads/2022/11/SERIES-Operating-Theatres-Sept-2022.pdf
16 May 2025
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