Modern Building Services

12 MODERN BUILDING SERVICES JUNE 2022 FEATURE AIR CONDITIONING, COOLING & VENTILATION T he long-awaited revision to the HealthTechnical Memorandum03-01 (2021) gave greater insight and guidance to specifiers, installers, manufacturers and end-users on accepted specialist ventilation systems and design within healthcare buildings. However, there still needs to be objective consideration on themost suitable solution for each individual healthcare environment. In October 2020, the UK Government named 32 hospitals of the 40 originally announced in the 2019 manifesto, to be built by 2030, along with the addition of other frameworks designed to upgrade existing premises to current building standards. The building of new hospitals is not a quick process and like any construction project requires significant designing and development time prior to a brick being laid. With a new building design, it’s possible to incorporate current building legislation into both the budget and layout, so building services engineers can accommodate large, compliant Air Handling Units (AHUs) within the confines of the building, often due to the sheer size of these systems, other services and materials are subsequently fitted after the AHU integration. However, for the 1,229 live hospitals in the UK, installing a new AHU is simply not a luxury many can afford logistically and at times financially. So, can refurbishment be an option? Previously, with the introduction of Energy-Related Products (ErP) supported by the Ecodesign Directive (2009/125/EC) legislation in HVAC aiming to reduce the number of greenhouse gases and improve the efficiency of current systems, many users chose to make quick changes that yielded quick returns on investment. With ventilation systems, this typically included the changeover of belt-driven AC fans to direct drive EC plug fans as they account for approximately 40% of the electricity used in a ventilation system, new heating or cooling coils often operating at lower flow and return temperatures usually seen with the introduction of air- source heat pumps, moving away from gas-fired boilers or enhancing the control strategy to work on demand enable rather than 24/7 usage if it isn’t required. But June 2021’s updated HTM-03-01 guide, despite outlining Net Zero and Sustainability targets identifying the importance of ErP legislation, only allows for the refurbishment of systems that can be made “fully compliant with current standards” and “if it is not more than 10 years old” (HTM 03-01 Part A, item 4.71). Consideration should then be made to remodel plant rooms or create plant space to house the additional elements of the system, which if anyone in the industry is au fait with, is not an easy feat. Re-purpose or utilise an existing system If looking to re-purpose or utilise an existing system, maximising it’s potential for future use then there are a number of elements to consider. Firstly, is the existing system serving the same areas or zones as before? Referring to Appendix 2: Summary of design conditions, take for example an Infectious Disease Isolation room which may have been designed on 10-15 Air Changes per Hour (AC/H). If the system is now being remodeled alongside a departmental change, then the design flow rate requirements may be reduced. Secondly, ErP 2018 required minimum efficiencies achieved from the overall ventilation system and the heat recovery device being utilised. If an existing AHU installed in 2013 were to be refurbished, it’s quite JimNorris , National Head of Sales at VES says recent difficult years for the NHS havemade everybody acutely aware of the need for adequate ventilation and good indoor air quality to care for those who have been hospitalised. Ventilation in healthcare – replace or refurbish