CIBSE Journal March 2025 by CPLOneGroup

cibse Journal

Entopia euphoria

The 2025 CIBSE Building Performance Champion is revealed

The

The National Rehabilitation Centre study Heat network conference highlights

Take a bow

Congratulations to all the winners of the CIBSE Building Performance Awards, held in London just as the Journal went to press. While print deadlines mean we cannot bring you pictures from the ceremony, we do have a summary of all the category winners on page 22.

The Entopia Building in Cambridge won the coveted CIBSE Building Performance Champion accolade and picked up the award for Project of the Year – Retrofit Workplaces. The judges called the project a trailblazer for large commercial buildings moving to net zero. Its measured energy use intensity (EUI) of 52kWh·m-² per year is comfortably below the pilot UK Net Zero Carbon Buildings Standard EUI limit for a new office, let alone a refurbished one.

It was a strong year for Max Fordham, which won Project of the Year –Residential with Agar Grove 1b and narrowly missed out on the award for Building Performance Consultancy of the Year (51-300 employees), which was won again by XCO2. There were two new categories at this year’s awards: Client of the Year, won by the London Borough of Islington; and Leadership, which was won by Swire Properties.

We will feature the Entopia Building in April’s issue, but this month, on page 30, we have a case study of the National Rehabilitation Centre (NRC), which aims to be the first hospital to achieve net zero under the NHS Net Zero Building Standard. As well as being sustainable, the hospital will enable patients to control their indoor environments through smart technology; personal tablets will be able to operate window blinds, room lighting and thermostats.

The NRC is situated in the grounds of an old country estate and has six air source heat pumps providing heating and cooling. If it had been in an urban area, it could have been connected to a heating and cooling network. As part of its support for heat network expansion, the government has just published 15 heat network zone opportunity reports that pinpoint where heat networks can deliver the lowest-cost low carbon heating. The growth in such networks is being supported by a new regulatory framework that is due to come into force from April. On page 46, we report from a recent CIBSE conference on residential heat networks, which uncovers the many opportunities and challenges in this sector.

l Alex Smith, editor asmith@cibsejournal.com

Contributors

Helen Sturdy Guidance on the application of the Building Safety Act for residential units across the NHS property estate

Editorial

Editor: Alex Smith

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Email: asmith@cibsejournal.com

Technical editor: Tim Dwyer

Reporter: Molly Tooher-Rudd

Designer: Kevin Reed

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This month’s

looks at the delivery of suitably ventilated built environments in tropical climates around the world

Kiru Balson Why building engineers should be encouraging the adoption of circular principles to slash whole life carbon

Calum Smith How the updated BS 9991 brings clarity to fire safety design in high-rise residential buildings

Tim Dwyer

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Journal production manager: Nicola Hurley Tel: +44 (0)208 772 3697, nhurley@cibse.org

Calum Smith on how the updated BS 9991:2024 will bring a new era of fire safety design for high-rise flats

A safer future for

New guidance has been issued on which buildings on hospital estates must meet the requirements of the Building Safety Act

WiBSE North West representative Rachael Gilbert on the conversations, connections and confidence built within the WiBSE community

CIBSE’s

The buildings, products and people that are setting benchmarks for excellence in building services engineering have been revealed

New Technical Notes from the Centre for Window and Cladding Technology are essential for modern façade design and construction

38 Why mainstream MEP can and should be circular

Building services engineers should be looking to be part of a genuinely circular construction industry that is fit for the future, says Max Fordham’s Kiru Balson

Technical

Air conditioning, heat networks and heat pumps

43 Breaking the ice

A new passive refrigerant flow control system aims to mitigate ice buildup on heat pumps, offering a simple approach to improving efficiency in extreme climates. Tim Dwyer reports 46 Countdown to regulation

A new regulatory framework will set minimum standards for heat networks. A recent CIBSE conference explored the challenges and opportunities. Alex Smith reports

47 Cooling without compromise

How EcoTechX’s CIBSE Awardwinning Optimum air conditioning system uses water to provide cooling, reducing embodied carbon and operational energy use

The National Rehabilitation Centre near Loughborough aims to meet the NHS Net Zero Building Standard and be a template for smart NHS buildings. Alex Smith reports 34 Take note: fire-safe façades

49 Delivering suitably ventilated built environments in tropical climates

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Heat networks face oversight as Lords back new rules

The upper house approves draft heat network regulations

The House of Lords has approved draft heat network regulations for customers. A committee of the upper house rubber-stamped the Heat Network (Market Framework) (Great Britain) Regulations 2025 on 3 February.

The regulations are designed to put customers of heat networks on a level playing field with those using other sources of heating, such as gas boilers, who have greater opportunities to switch suppliers.

The regulations ban the running of heat networks, which have hitherto been unregulated, without authorisation by the energy regulator Ofgem. Energy minister Lord

Hunt told fellow peers that existing heat networks will be ‘automatically’ authorised in order to phase in regulation of the market.

The new regulation extends the Energy Ombudsman’s redress scheme to heat network consumers from April this year. It will also ensure heat network customers have access to the advice and advocacy services on offer in the gas and electricity markets.

However, Ofgem’s regulation of heat networks will not kick in until 28 January 2026. Heat network operators will then have a year to obtain authorisation to operate.

For highlights of CIBSE’s Residential Heat Networks event last month, see page 46.

The Entopia Building’s champion performance

The Entopia Building has been named overall Building Performance Champion at the CIBSE Building Performance Awards. The office retrofit in Cambridge – by Max Fordham, Architype and BDP – also won Project of the Year - Retrofit Workplaces. The judges said the whole life building performance of Entopia was exceptional, despite a robust and challenging brief. The building is home to the Cambridge Institute for Sustainability Leadership. See page 20 for details of all the winners.

Government identifies £10bn of heat network opportunities

New reports from the Department for Energy Security and Net Zero (DESNZ) identify more than £10bn of immediate heat network investment opportunities, the Association for Decentralised Energy has estimated. DESNZ published

15 Heat network zone opportunity reports for English towns and cities. These pinpoint where heat networks can deliver the lowest-cost, low carbon heating in areas ranging in size from Birmingham and Sheffield to Canterbury and Cheltenham.

They also identify the key opportunities for initial heat network development within each zone. The reports, which have been prepared as part of the Heat Networks Zoning Pilot, are being used to inform the development of DESNZ’s zoning policy.

Timetable set for landlords to tackle damp and mould

Deputy Prime Minister announces rollout of Awaab’s Law

The government is to phase the introduction of Awaab’s Law to improve standards in social rented housing, focusing initially on measures to tackle damp and mould.

Deputy Prime Minister Angela Rayner has set out a timetable for implementing the legislation, which was introduced by the previous, Conservative, government after the uproar sparked by the death of two-year-old Awaab Ishak in 2020.

The toddler died from a severe respiratory condition resulting from prolonged exposure to mould in his Rochdale social rented flat.

Social landlords will be required, from October this year and within fixed timescales, to address damp and

mould that present a significant risk of harm to tenants. They will also have to address emergency repairs within 24 hours.

From 2026, landlords will have to address a wider range of hazards, which is expected to include: excess cold and excess heat; falls; structural collapse; fire, electrical and explosions; and hygiene hazards.

In 2027, Awaab’s Law will apply to the remaining hazards defined by the Housing Health and Safety Rating System, excluding overcrowding.

Rayner also pledged to consult in the coming months on legislation to require social landlords to carry out electrical safety checks at least every five years.

European heatwave deaths set to soar

An extra 2.3 million temperaturerelated deaths will occur in Europe’s main cities by the end of this century unless more action is taken to mitigate and adapt to global warming, researchers predict.

In a new paper, published in Nature Medicine, an assessment of 854 cities provides ‘clear evidence’ that temperature-related mortality will increase even under the ‘mildest’ climate change scenario. The net number of deaths increases substantially under ‘more extreme’ warming scenarios and the trend can only be reversed by ‘implausibly’ strong levels of adaptation in cities.

The findings reverse previous health-impact assessments of temperature-related deaths in Europe, which indicated that mortality attributable to cold is ‘much larger’ than that for heat.

Landlords must achieve Band C EPCs by 2030

The government is pressing ahead with its pledge to bring all private rented homes up to the Energy Performance Certificate (EPC) band C standard by 2030.

A consultation paper published last month sets out proposals for upgrading the energy efficiency of England’s privately rented dwellings.

For new lets, landlords will have until 2028 to comply with the band C requirements, and will be expected to spend up to £15,000 per property to bring them up to scratch – or £10,000 if the properties are in less-affluent housing markets.

Landlords renting out a noncompliant property for three months or more face fines of up to £4,000.

AI and diversity top agenda at ASHRAE Conference

Impact of US President also addressed at Orlando event

Major themes at the 2025 ASHRAE Winter Conference, held last month in Orlando, Florida, USA, included diversity and artificial intelligence (AI), and concerns were raised about the impact of Donald Trump’s presidency.

In his plenary address, Jeff Littleton, ASHRAE executive vice-president, acknowledged the potential impact of political changes in Washington DC on the Society’s operations. While ASHRAE is driven by science and engineering excellence, he emphasised that the organisation recognises its standards influence legislation and that it relies on partnerships with federal agencies.

Littleton said the withdrawal of some key government volunteers from

the conference was a concern, though the long-term impact remains uncertain. He reassured the audience that ASHRAE will continue to prioritise its state/local government outreach efforts.

ASHRAE President Dennis Knight highlighted a major milestone of his presidential year: the Women in ASHRAE Leadership Symposium. He introduced the Young Engineering Student in ASHRAE EmpowHERment Award, which recognises students who champion gender diversity.

AI was also a key theme, with the launch of ASHRAE’s Generative AI Task Group, bringing together experts from across various disciplines.

Sadler’s Wells leaps East

London Mayor Sir Sadiq Khan has officially opened the East End outpost of Sadler’s Wells. Designed by architects O’Donnell + Tuomey, working closely with engineers Buro Happold, Sadler’s Wells East boasts a 550-seat flexible theatre space and six studios for creating and developing dance productions. A crafted façade of hand-laid brick and clay-shingle tiles is designed to provide high environmental solar and thermal performance, as well as acoustic attenuation. The building is part of the East Bank zone of arts buildings that overlook the Queen Elizabeth Olympic Park.

BSR given £2m of extra funding to help ease planning delays

Government grant aims to ensure ‘greater timeliness and efficiency’ when signing off new tall buildings

The Building Safety Regulator (BSR) has been awarded £2m of additional funding by the government, to speed up the vetting of planning applications for new-build high-rise buildings.

In a written statement published on 13 February, housing minister Matthew Pennycook said the funding was designed to address industry concerns about ‘pinch points’ in the construction process by ensuring ‘greater timeliness and efficiency’ by the regulator when signing off new tall buildings.

The government’s move follows a call by the British Property Federation (BPF) for the Treasury to provide the BSR with additional resource to reduce delays and enable projects to move forward.

In its response to the Treasury’s upcoming comprehensive Spending Review, the BPF cites ‘extreme frustration’ among its members about the backlogs involved with applications going through the BSR.

HPA proposes annual service for heat pumps

A new set of annual service checklists has been launched by the Heat Pump Association (HPA) . The Air, Ground and Water to Water Heat Pump Annual Service Checklists have been developed by the HPA’s Technical Working Group, and outline the recommended minimum annual service checks for heat pump systems. They are designed to be a resource

where manufacturer-specific guidance on service and maintenance checks is unavailable and are not intended to replace these guidelines. However, the checklists seek to provide a useful reference point for reviewing the effective operation and longevity of heat pumps, enhancing consistency and reliability across the sector, the HPA says.

Government removes nuclear red tape

Rules limiting the number of sites where new nuclear power stations can be developed have been scrapped. A new planning framework for nuclear, unveiled by the Department for Energy Security and Net Zero last month, removes the existing list of eight sites where nuclear can be developed. The updated national policy statement also allows small modular reactors for the first time. There will, however, continue to be ‘robust criteria’ for nuclear reactor locations, including restrictions near densely populated areas and military activity.

Stoke-on-Trent signs heat network deal

SSE Energy Solutions has been named as Stoke-on-Trent City Council’s exclusive strategic energy partner for heat networks. Under a ‘comprehensive’ memorandum of understanding, the company and council will collaborate on mapping out the city’s wider path to net zero. This potentially encompasses a range of initiatives beyond heat networks, including renewable energy generation, such as solar and wind projects, and the creation of electric vehicle charging hubs across the city.

Analytics saves health group

£200,000

Private hospital provider Circle Health Group has solved 81% of its maintenance issues remotely since the establishment of a partnership with Schneider Electric eight years ago. More than three-quarters of the group’s 53 hospital sites have been connected by Schneider to an advanced analytics platform with round-the-clock remote maintenance support. A further 15% are due to be connected by the end of the current quarter. Schneider said the partnership has saved Circle more than £200,000 since 2018 by using artificial intelligence tools to remotely monitor equipment and systems.

News

The Eden in Manchester is the first office to have a Nabers UK 5.5* design rating

CIBSE focuses on building performance at Futurebuild

Sessions on Nabers UK and reimagining building performance will take place at ExCeL London in

CIBSE will be hosting sessions on Nabers UK and Building Performance Reimagined at the Futurebuild conference and exhibition taking place at ExCeL London from 4-6 March.

On the first day, CIBSE director of certification Kieran O’Brien will chair the session ‘Nabers UK: the power of data-driven building performance’. He will introduce Nabers UK and discuss why gaining an initial rating is crucial as the foundation for long-term performance enhancements.

Speakers from Aecom will share lessons and insights from the journey through the Design for

Training

Relaunch of cable sizing training

The cable sizing on-demand training course has been updated, and now features enhanced interactivity, a refreshed, user-friendly design, and new content to reflect current industry standards.

The Cable Sizing Overview module aims to give learners an understanding of the principles of cable sizing, the wiring regulations and their relevance to cable sizing, the typical design approach and sequence, and cable and wiring systems, and offers an introduction to the sizing template.

For most projects, cable sizing is undertaken using specialist software. The course will help designers understand the implications of the information put into the tool. For more information: bit.ly/CJCIBSCStr

March

Performance process into an operational Nabers rating, demonstrating how actionable data drives meaningful improvements.

CIBSE technical director Anastasia Mylona will chair the Building Performance Reimagined session on 6 March, when a panel will explore the future definition of ‘value’ in the built environment, and challenge assumptions about what ‘good’ looks like.

Futurebuild takes place from 4-6 March at ExCeL, London. For more information visit: www.futurebuild.co.uk Come and visit the CIBSE stand at L10. For full details and booking: www.cibse.org/training

Mechanical services explained 10-12 March

Advanced simulation modelling for design for performance 13-14 March

Low carbon consultant building design 18-19 March

Earthing and bonding systems 20 March

ISO 50001-2018 Energy management system

March

Electrical services explained 31 March – 2 April

Design of ductwork systems 4 April

April

Heat networks Code of Practice

April

Low and zero carbon energy

April

Low Carbon Consultant (LCC)

April

Data Centre Special Interest Group prepares for launch

The new CIBSE Data Centre Special Interest Group (SIG) is to hold its launch event on 5 March, in London.

The group brings together members from across the industry to collaborate on innovative, energyefficient design solutions for data centres, paving the way for more sustainable networks.

It will help maintain building professionals’ awareness of the zero carbon technologies, power systems, cooling methodologies and control architectures necessary to build and operate sustainable data centres.

The SIG will work with CIBSE to identify and support the research

required to fill knowledge gaps, and will propose and contribute to the development of new publications and existing guidance.

This month’s launch event will provide the opportunity to connect with others in the data centre sector, share thoughts, and contribute to the growth of the network.

Nominations for members of the SIG’s committee are invited at bit.ly/CJCDSIG25

The launch meeting will take place on 5 March, 17.30-19.00hrs at Aecom, Aldgate Tower, 2 Leman Street, London, E1 8FA and online. For more details, visit bit.ly/CJSigDC

In March

Conference

SoPHE 2025 Conference

27 March, London

This year’s event will focus on the challenges of water scarcity and water conservation brought on by climate change, and the innovative solutions for management. Register at bit.ly/CJSOPHE25

Technical

symposium

CIBSE IBPSA-England

Technical Symposium

24-25 April 2025, London

The symposium will have a range of peer-reviewed papers and presentations outlining the latest developments in practice, technology and policy, and highlight the latest guidance for building services engineers. The theme is ‘Fit for 2050 – Achieving net zero through intelligent, resilient and sustainable design in the built environment’.

Event

WiBSE Southern Supper Club

7 March, Brighton

WiBSE Southern’s first Supper Club event at Bill’s Brighton is in celebration of International Women’s Day. The evening aims to bring together women and gender-diverse people within the industry to create a supportive network as we navigate our careers. Register at www.cibse.org/events

Conference

CIBSE ANZ: Reimagining the engineer’s role in building performance

24 March, online

CIBSE President Fiona Cousins will present the Building Performance Reimagined report, and share her thoughts on how the role of building design professionals and building services designers could be reimagined to deliver a more sustainable future. Register at bit.ly/CIBSEAnz

Lighting news

Illuminating the future: balancing light and dark nightscapes

Join the Society of Light and Lighting (SLL) for a conference that dives into the complexities of night-time lighting. This event will feature experts from various fields, including environmental science, urban planning, criminology and social psychology, offering a balanced examination of the pros and cons of artificial light after dark. l 27 March, Senate House, University of London. www.cibse.org/sll-illuminatingthe-future

Jean Heap Bursary

The Jean Heap Bursary is open for applications, offering the successful applicant up to £4,000 in funding. To enter, submit a written paper, along with a short video, to outline your research proposal. The panel is looking for a lighting study or piece of research that will benefit SLL members and the wider industry. Deadline 7 May.

l Find out more and apply www.cibse.org/sll-jean-heap

Young Lighter 25

This competition is open to anyone with an interest in light and lighting, regardless of background or education. You don’t need to write an academic paper to enter; you simply have to submit six slides on an original and creative idea about any aspect of light, and be under 30 years old. This is a great opportunity to showcase your talent and vision to the lighting community and beyond. The winner will be awarded the prestigious title of SLL Young Lighter, plus £1,000. Each finalist will also receive a cash prize. The deadline is 28 April.

l Find out more and apply www.cibse.org/younglighter

First event at Aecom’s office in London on 5 March

CIBSE joins forces with UK Construction Week

CIBSE is partnering with UK Construction Week for its exhibition and conference at London’s ExCeL from 7-9 May. It will focus on topics such as the UK Net Zero Carbon Buildings Standard. l Visit ukconstructionweek.com

Call for volunteers to update TM39

TM39: Building energy metering is being updated and CIBSE is looking to form small groups to create content on: hardware meter selection, sizing and placement; installationcommissioning, verification and documentation; data collection systems; and data analysis methods and user engagement. l Contact TM39@cibse.org

Applications open for Ken Dale Travel Bursary

Up to £4,000 of travel expenses up for grabs for early career CIBSE Members

Are you ready to expand your horizons and influence the future of building services engineering?

The Ken Dale Travel Bursary offers up to £4,000 (or local equivalent) to support members of CIBSE in the first 10 years of their career to pursue international research that can make a real impact on the industry.

This unique opportunity allows you to spend three to four weeks abroad, exploring innovative engineering practices, sustainable technologies and global solutions that can shape the future of the built environment.

Last year’s winner, William Holley,

explored how heat pump technology is revolutionising sustainable energy infrastructure in countries such as Finland. Reflecting on his experience, ‘ Meeting with industry leaders such as Teemu Nieminen, at Fortum, and exploring groundbreaking projects first hand, has been an incredible opportunity to see how innovative technologies are transforming energy infrastructure on a global scale, ’ said Holley

The deadline for entries is 25 April. For more information on how to apply, visit go.cibse.org/ kendale2025-march-journal

New CIBSE associates and licentiates

ASSOCIATE

Cheeseman, Josephine

London, United Kingdom

Chow, Yip Fat

Warrington, United Kingdom

Fisher, William Manchester, United Kingdom

Gilbert, Rachael

Manchester, United Kingdom

Green, Tyla

Manchester, United Kingdom

Hamer, James

Morecambe, United Kingdom

Hart, Lawrence William Southampton, United Kingdom

Holton, Thomas

Chobham, United Kingdom

Jackson, Joseph Hale, United Kingdom

Jahangir, Ayad

Riyadh, Saudi Arabia

Lawman, Joshua Manchester, United Kingdom

Lawrance, Jacob

Nottingham, United Kingdom

Lord, Ryan

Westhoughton, United Kingdom

Metcalfe, Henry George Alexander

Swanley, United Kingdom

Min, Priscilla

London, United Kingdom

Nash, Matthew

Rochford, United Kingdom

Parker, Jacob

London, United Kingdom

Parkinson, Ross

Pontefract, United Kingdom

Pimm, Charlie

Solihull, United Kingdom

Prentice, Nathan

Doncaster, United Kingdom

Rahman, Dena

London, United Kingdom

Ritchie, James Hamilton

Swanley, United Kingdom

Sharman, Alex

Sunninghill, United Kingdom

Silao, Christian Ray

London, United Kingdom

Stevens, Chris

Glasgow, United Kingdom

Wood, James

Wigan, United Kingdom

LICENTIATE

Aldred, Daniel

Nottingham, United Kingdom

Barbieri, Luca

London, United Kingdom

Booth, Liam

Chesterfield, United Kingdom

Borun, Marta

Maidenhead, United Kingdom

Bowyer, Lydia

Leatherhead, United Kingdom

Connelly, Ciaran

Blackburn, United Kingdom

Ghanbariazarneir, Sharareh

London, United Kingdom

Godfrey, Philip Liverpool, United Kingdom

Glover, David

Stockport, United Kingdom

Hewitt, Samuel

Stockport, United Kingdom

Hogg, Charlie

Leatherhead, United Kingdom

Hull, Harrison

Elland, United Kingdom

Lambton, Joe

Leeds, United Kingdom

Lau, Sze Wing Erica

London, United Kingdom

Llewellyn, James

Cardiff, United Kingdom

Lonsdale, Sophie Louise

South Croydon, United Kingdom

McAslan, Andrew

Lytham Saint Annes, United Kingdom

Marklew, James Birmingham, United Kingdom

Matthews, Paul

Gidgegannup, Australia

Odey, Sylvia Yegra

London, United Kingdom

Parkington, Alfie

Manchester, United Kingdom

Penston, Connor

Mossley, United Kingdom

Plusciauskas, Dovydas

Ipswich, United Kingdom

Procter, Jack

Darwen, United Kingdom

Radev, Hristo

London, United Kingdom

Riggs, Melissa

St Ives, United Kingdom

Starkey, Kyle

Hemel Hempstead, United Kingdom

Taylor, David

Chepstow, United Kingdom

Thackray, Hannah

Menston, United Kingdom

Vincent, Alex

Grinstead, United Kingdom

Wall, Sam

Sheffield, United Kingdom

Ward, Simon

Rainow, United Kingdom

Whetham, Aidan

West Lothian, United Kingdom

Young, Samuel Bolton, United Kingdom

Barbara Lane to give conference keynote

Fire safety expert speaking at CIBSE Scotland Conference on 28 May

Expert witness to the Grenfell Tower Inquiry Barbara Lane is delivering the keynote address at the CIBSE Scotland Conference on 28 May.

Lane is a Fellow in Arup’s global fire safety engineering practice and reported on the active and passive fire protection measures within Grenfell Tower at the inquiry.

Taking place at the University of Strathclyde’s TIC Building in Glasgow, the conference’s theme is ‘Safe

and sustainable futures’. It will feature speakers from across industry and the public sector, covering topics including: embodied carbon; the digital and information management requirements of building services and safety critical systems; and how Scotland’s Compliance Plan approach has contributed to safety, with case studies of current projects.

For more information, visit www.cibse.org/events

Nominations wanted for prestigious CIBSE medals

CIBSE medals recognise those who have demonstrated outstanding leadership, innovation and commitment across the built environment, including through CIBSE Regions, Special Interest Groups and Societies, and industry expertise. If you know someone who you think should be recognised for their excellence, nominate them for a medal.

Nominees must be an Affiliate, Licentiate, Associate, Member or Fellow of CIBSE - and before you start your medal proposal, please check that you have all the required information, including:

l Type of CIBSE medal for which they are being proposed

l Candidate’s full name, contact details and membership grade

l Justification statements with concrete examples, using quantifiable achievements, dates and detailed descriptions to substantiate claims

l Details and confirmation from four endorsers.

Nominations must be made by Friday 21 March.

Review the eligibility criteria and start your proposal at bit.ly/CJmed25

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Elevating education

CIBSE’s academic accreditation is key to creating relevant and engaging programmes for developing engineers, says Mitesh Chauhan, CIBSE senior accreditation and approvals officer

Accreditation plays a pivotal role in shaping the future of engineering education. CIBSE awards academic accreditation to higher education programmes in building services engineering that meet the UK Standard for Professional Engineering Competence (UK-SPEC). This standard is outlined by the Accreditation of Higher Education Programmes (AHEP) and ensures that courses align with industry and professional requirements.

The UK-SPEC is a framework that defines the expectations and criteria for professional registration, ensuring that engineers have the necessary skills, knowledge and experience to perform competently. It is also a benchmark for assessing the competence of engineers, which helps maintain high standards in the profession. This guarantees that graduates of CIBSE-accredited programmes meet the academic requirement for registration with the Engineering Council, paving the way for professional registration as a Chartered Engineer and full Member of CIBSE, Incorporated Engineer, or Associate Member or Engineering Technician Licentiate.

Insights from an accreditation moderator

Steve Hunt, of Steven Hunt Associates, details his experience as an accreditation moderator:

‘As an industry, we take it for granted that the qualifications candidates present are valid and of equal currency. I was extremely impressed with the depth of examination and the rigour employed by the accreditation body in ensuring that standards are maintained across the full range of available courses.

‘The industrialist representation within the process balances the needs of industry with the technical requirements of academia, while keeping it relevant and demonstrating to students the link between the two – and giving them a voice to influence progress.

‘It is refreshing to see the quality and strength of students representing the future of our industry emerging from these courses. This role provides the perfect opportunity to share your experiences for the benefit of the next generation of engineers.’

If you would like to help influence the future of building services engineering and become a moderator, or wish to know more about CIBSE Accreditation, please email partnership@cibse.org

The accreditation process

The accreditation process involves a thorough evaluation of programme content and delivery by a panel of trained and expert accreditors, who assess relevance, coherence, challenge, assessment, staffing, quality assurance and resources. They then make recommendations to the Academic Accreditation Committee (AAC), which is responsible for accreditation decisions.

Each panel consists of three members, including two academics and an industry expert. The industry expert will be a senior member working in industry who can assess the programme and its fitness for industry.

The AAC also oversees the policies and process for CIBSE Accreditation, and strategically supports the Engineering Council and CIBSE in improving the educational base for registration and membership.

Value of accreditation

Completing one of these courses improves graduate employability by demonstrating that students have developed the appropriate skills and knowledge for an engineering career and professional registration.

Additionally, students enrolled on a CIBSEaccredited academic programme can apply for CIBSE Student membership for free – one of the many benefits of being on an accredited degree.

Currently, CIBSE accredits 87 programmes across 24 educational providers. Each programme is accredited for a maximum of five years before requiring re-accreditation. Approximately 10-12 accreditation visits are conducted annually, including international visits to the United Arab Emirates and China.

The ACC constantly reviews its accreditation requirements, a recent addition being around climate change and sustainability.

This ensures that CIBSE-accredited engineering programmes prepare students to be future climate leaders by providing them with the knowledge, skills and mindset to address the climate emergency.

Energy efficiency, climate resilience and sustainability principles are now essential components of building services engineering education. l

Case study: Heriot-Watt University

Heriot-Watt University runs CIBSEaccredited programmes in the UK and Dubai, at undergraduate and postgraduate level. Accreditation plays a vital role in ensuring our programmes remain current and relevant, while providing an opportunity to engage with leading experts in the field.

Our most recent accreditation visits fell during the pandemic lockdown period, so took place primarily online, but we were able to supplement these digital meetings with in-person visits to campus in 2023. CIBSE was extremely helpful and flexible in navigating this added complexity, working through the means of providing digital documentation securely, and maintaining a really useful dialogue throughout the process.

Collating information for the panel, and presenting and discussing this, is a helpful team exercise for the staff,

requiring us to revisit mapping against criteria and articulate how courses link at each stage of study.

This time around, we were able to discuss with the panel the impact of the new AHEP criteria, and how that evolved our offering around equality, diversity and inclusivity, security, and design ‘optioneering’ for sustainability.

Our curricula have always been very multidisciplinary: our building services and architectural engineering students study alongside other construction disciplines at each stage, working with real-world scenarios on cross-disciplinary project work.

The importance of this can be tough to articulate to our internal auditors at the university, and CIBSE’s support of our approach gives us additional weight when arguing for points of value and quality in our programmes.

The process is very discursive

fully functionally

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and reciprocal; it’s an enlightening opportunity for professional dialogue, with a human face.

Students benefit, too. When the accreditation panel visited our campus, the CIBSE officer took the opportunity to meet with our first-year students and introduce CIBSE and student membership benefits directly to them, linking into the coursework for their class on addressing the climate emergency.

We’re delighted that this pays off as the students develop their careers in industry. Heriot-Watt graduates from the Edinburgh and Dubai campuses have recently been the proud recipients of CIBSE/ASHRAE graduate awards, and lead Young Engineers Network groups across the globe.

l By Alex MacLaren, Associate Professor in Architecture at Heriot Watt University

Clarifying fire safety

The updated BS 9991:2024 ushers in a new era of fire safety design for high-rise flats, with guidance on escape staircases, open-plan spaces, evacuation lifts, sprinklers, smoke control and care homes. Calum Smith explores the key updates

After three years of anticipation, the latest version of BS 9991:2024 Fire Safety in the Design, Management and Use of Residential Buildings – Code of Practice (bit.ly/CJBS9991) has been published. The draft version of the standard was first published in 2021, and the final version – published in November 2024 – has important implications for certain buildings.

It provides much-needed clarity on various elements that have long been considered ambiguous by designers, while also capturing several enhancements to bring the standard in line with wider industry developments.

This new standard supersedes BS 9991:2015 and should now be used as statutory guidance for residential projects in England, Wales and Northern Ireland. BS 9991 remains an alternative design standard to Approved Document B (for England), which provides guidance for the design of buildings to meet Part B – Fire Safety – requirements in Building Regulations. Although Approved Document B has been recommended by various relevant groups, such as the National Fire Chiefs Council and RIBA, it is not the most recent standard for designers.

Some of the BS9991 changes were aimed at making the guidance less England-centric. References to Approved Documents were removed as they only apply to England. A British Standard is intended to be applicable to the whole of the UK and we know other countries that base their own guidance on British Standards.

BS 9991 is applicable to residential blocks of flats up to 100m in height, where the structure is of traditional, non-combustible materials, such as steel and concrete. It also covers residential buildings that are not made of traditional, non-combustible materials, up to a height of 11m.

For advocates of sustainable building materials, this is promising, as

This latest version of the standard is more in line with industry expectations, providing guidance that will, hopefully, result in higher-quality fire safety design

beginning to be made, but the standard will, hopefully, continue changing and evolving to reach even greater heights in the future.

Internal planning of flats

For the design of open-plan flats, recommendations now incorporate a 1.8m clear zone around cooking equipment to allow occupants to escape through the living/dining space, as is established industrypractice.

In addition to this, the outdated and onerous requirement for enclosing kitchens in open-plan flats larger than 8m x 4m has been removed. New guidance now also recommends that charging points for mobility scooters or electric wheelchairs are not located in an apartment’s entrance hallway.

Evacuation lifts

Where a residential building provides lifts, it is now required to also provide evacuation lifts. This is another welcome addition for inclusive design, as BS 9991 goes beyond comparable upcoming Approved Document B amendments. The standard goes into detail on the specifications needed to implement these accessibility features successfully.

Design of common escape routes

it increases the possibility of using materials such as mass timber and timber frame. It also unlocks potential for a greater volume of quality housing to be built in very tall buildings.

The changes outlined below are undoubtedly a positive step forward in enhancing fire safety. Currently, this represents the highest standard of fire safety, featuring clearer guidance, increased emphasis on accessible design, and a broader scope in this year’s edition. The right changes are

BS 9991 recommends that any residential building with a storey height above 18m should have at least two escape staircases. This brings it into alignment with upcoming amendments to Approved Document B. A single-stair approach is still acceptable for buildings less than 18m.

In the previous iteration, BS 9991:2015, the diagrams for common escape routes in Figures 6 and 7 were inadequate, and failed to cover many situations where the internal corridor design was more complicated. The new standard provides additional clear example arrangements, giving designers more certainty going forward.

Suppression

Sprinkler protection is now required in all residential buildings above 11m, bringing BS 9991 in line with Approved Document B. However, it still allows buildings up to 30m with sprinklers to be provided with 60 minutes of structural fire resistance, instead of 90 minutes.

References to the BS 8458 standard relating to water-mist systems in residential buildings have been removed from BS 9991, which, by omission, means residential buildings should be protected with sprinkler systems. Where water mist is proposed, therefore, it is now considered a fully fireengineered solution that will be a derogation from guidance.

Residential building smoke control

For buildings more than 18m in height, only natural or mechanical smoke shafts are now recommended, and external automatic opening vents direct to the outside of the building will not be acceptable. Above 30m in height, only mechanical smoke shafts (either extraction or pressurisation) should be used for the protection of stair lobbies, and natural smoke shafts in these circumstances will no longer be acceptable.

Guidance for care homes

Sprinklers will be required in all care homes regardless of storey height and should either be in accordance with BS 9251:2021 or BS EN 12845:2015.

There are specific recommendations for maximum travel distances in care homes depending on the dependency of residents. For low- and mediumdependency residents, travel distances to the nearest relative place of safety should be 15m for single-direction escape and 32m for multi-direction escape. For high-dependency residents, this is 12m and 25m respectively.

This latest version of the standard is more in line with industry expectations, providing guidance that will, hopefully, result in higher-quality fire safety design. This should lead to greater consideration of inclusive design and sustainable material selection options for the workplace. l

l Calum Smith is a senior engineer at Cundall

Decarbonising British Land’s HQ

BReplacing gas boilers with heat pumps at British Land’s York House office in London is reaping benefits, says Mitsubishi Electric’s Graham Temple

ritish Land’s flagship head office, York House, is benefiting from new heat pump technology that has fully replaced the use of gas.

This was part of a wider goal to reduce operational carbon by 75% and energy use by 25% by 2030. The result is a building in which heat pumps deliver a reduction of more than 400,000kWh in energy use year on year – all achieved in a central London retrofit project, where roof space for plant was at a premium.

The five-storey, multi-tenanted office building in Marylebone previously relied on gas boilers for heating, and requires 24-hour cooling, with extended fresh air requirements.

The new equipment includes two Climaveneta i-FX-Q2GO5 chillers, with a combined heating capacity of 1,113kW and a combined cooling capacity of 1,250kW.

Working with the chillers is an EW-HT/0612 water-towater heat pump, which raises the flow temperature from 50°C to 65°C. This meant the existing heat emitters could be used, saving time and costs.

This was the first building for which British Land has achieved a full gas removal using heat pump technology. Previous projects – such as British Land’s first installation of an air source heat pump at 350 Euston Road in 2014 – have been hybrid, with gas retained.

The design for this solution was provided by Twenty One Engineering. Its starting point was identifying the peak load to increase efficiency, with the principle of using a 95% peak load to minimise equipment size and optimise project costs.

The building is controlled with a demand-driven strategy, meaning it isn’t allowed to get cold, which reduces the time needed to heat it and maximises the efficiency of the heat pumps.

Installation work was completed by Nationwide Air Conditioning in an operational building, within normal office hours, so nearby apartments were not disturbed. This meant the office was fully occupied; however, most of the work occurred on the roof, so the building occupants were not aware of it. (See ‘British Land’s heat pump retrofit at York House’, CIBSE Journal, Feb 2025, bit.ly/437JwwX)

l Graham Temple is marketing manager at Mitsubishi Electric

Decarbonisation of Heating and Cooling

21 May 2025 The Congress Centre, London

Taking a lead on Decarbonisation

TimeAgenda Session Title

09:00Registration

09:30Session 1 The Future of Cooling

10:45Break

12:15Lunch

11:00Session 2 Decarbonisation of Heating Systems

13:15Session 3 Heat Networks

14:30Break

14:45Session 4

16:00Session 5 Case Studies

17:00Close

Register Now

A safer future for NHS estates

The complexity of hospital estates makes it particularly challenging for NHS Trusts to meet the requirements of the Building Safety Act. The NHS has issued guidance in response, and published key resources around competency and the golden thread

The Building Safety Act (BSA), introduced in response to the Grenfell Tower fire, is a significant legislative change to building safety that impacts new and existing hospital buildings during design and construction.

The act requires greater accountability and responsibility over a building’s life-cycle, and has new responsibilities for stakeholders involved with the design and construction of new and existing buildings. It has also introduced accountable persons and principal accountable persons for occupied buildings higher than 18 metres or seven storeys with residential accommodation, known as higher-risk buildings (HRBs). Hospital buildings within scope include key worker and student accommodation, but not patient wards or on-call rooms.

The Building Safety Regulator (BSR) oversees all buildings, particularly the safety of HRBs. For HRBs, there is a requirement to apply to the BSR for building control approval where any building work is proposed. Under the new regime, a much larger amount of information needs to be submitted.

For hospital trusts, this is resulting in additional costs and major delays to projects, as construction cannot start until design approval has been given.

NHS England (NHSE) ProCure23 is supporting the NHS to interpret the BSA. It recognised that the legislation was difficult to apply to hospital sites, which are complex, often consisting of multiple connected buildings with varying heights and uses.

To help hospital trusts comply with the new requirements, NHSE has published several NHS-specific guidance documents. These include a National Estates Technical Bulletin (NETB) on the Building Safety Act1, which offers detailed guidance on the application of the BSA to hospital trusts. Importantly, the NETB provides

an explanation and examples of the provisions that allow complex hospital sites to be split into independent sections. To do so, buildings on the estate must have their own entrance/ exit and not be connected to any other sections with residential units. The test to determine whether a building is classified as a HRB can then be applied to these sections.

For those parts of a site not subject to the HRB regime, traditional and faster building control approval routes can be taken. This should assist trusts and contractors, as well as local authorities, which, in some instances, wrongly categorise existing buildings as HRBs and refuse to submit or accept building control applications.

The NETB is backed by the NHSE ProCure23 BSA Support Document, which includes 21 hospital-specific scenarios, flowcharts, workflows, and guidance to help trusts understand the nuances of their site.

Competency is a key focus for ensuring building safety. The new Part 2A inserted into the Building Regulations 2010 introduces a new competency regime to ensure that all individuals involved in the design, construction and management of buildings are adequately trained and competent in

terms of skills, knowledge, experience and behaviours.

NHSE’s ProCure23 has developed a simple Competency Checklist toolkit that covers Construction Design Management and BSA requirements. It has been validated by the Royal Institution of Chartered Surveyors for credibility and effectiveness, and is endorsed by the BSR and Local Authority Building Control.

To support the safe operation of hospital buildings, information is crucial. Working with the Construction Leadership Council (CLC), NHSE ProCure23 teams have adopted the principles of the CLC’s Golden Thread guidance2. This provides essential advice on maintaining a golden thread of information throughout the lifecycle of a building – an approach emphasised in the BSA – and is applicable to hospital buildings. The approach has been reflected in the latest ProCure23 workflows and BIM templates.

To understand BSA requirements fully, it is recommended that hospital trusts appoint advisers to support them and define the extents of HRBs and independent sections on hospital estates. l

l By Louise Mansfield, legal director at Bevan Brittan; Andrew Rolf, healthcare technical advisory lead at Mott MacDonald; and Helen Sturdy MCIBSE, head of construction and ProCure23 lead at NHS England

References:

1 National Estates Technical Bulletin 2024/2: Building Safety Act 2022 – application to healthcare buildings, Ref PRN01337, bit.ly/CJNETB242

2 Construction Leadership Council: Delivering the Golden Thread: Guidance for dutyholders and accountable persons bit.ly/CJCLCGT (August 2024)

Building Performance Award winners 2025

CIBSE has revealed the buildings, products and people that are setting the benchmarks for excellence in building services engineering

Building Performance Champion and Project of the Year – Retrofit Workplaces

Winner: The Entopia Building – Max Fordham, Architype and BDP

The judges described the whole life building performance of Entopia as exceptional. Despite what they called an ‘incredibly robust and challenging brief’, the winning team delivered an exemplary retrofit of a five-storey 1930s telephone exchange that had levels of performance comparable with a brand-new office building.

The Entopia retrofit shows that, with ingenuity and collaboration, it is possible to deliver healthy, highperformance buildings on a typical refurbishment budget.

‘It’s a great example for others to learn from,’ said the judges, who called the project a trailblazer for large commercial buildings moving to net zero.

The project team achieved high levels of user satisfaction and comfort, as well as outstanding measured building performance. This was exemplified by achieving EnerPHit

Classic, Well Gold and Breeam Outstanding standards. Improving the thermal fabric performance reduced the amount of plant required significantly. A highly efficient MVHR ventilation system maintains thermal comfort, while night-time purge ventilation helps minimise mechanical cooling. A reversible heat pump in the central AHU provides any necessary cooling and mitigates the risk of overheating in future climate scenarios.

The measured energy use intensity of 52kWh·m-² per year compares well with the 75kWh·m-² per year target for 2025 new-build offices, laid out by LETI and RIBA 2030.

The design included careful consideration of whole life carbon, and 48% of materials specified were bio-based. Project of the Year – Retrofit Workplaces sponsored by Crane Fluid Systems

Engineer of the Year

Sponsor: Ideal Heating Commercial

Winner: Volkan Doda, head of design technologies, Atelier Ten

Volkan Doda stood out for his ability to ‘bridge gaps between academia, constant learning and highperformance building design’, said the judges.

Doda combines deep technical knowledge with an ‘empathetic communication style’, they added, translating complex ideas into actionable solutions for clients, collaborators and his team. At Atelier Ten, he leads a culture of collaboration and mentorship through initiatives such as cross-discipline expert practices and weekly knowledge-sharing sessions. Under his leadership, expert practice groups research, develop and embed the latest approaches organisation-wide.

Project of the Year – New-build Workplaces

Sponsor: Crane Fluid Systems

Winner: Globe Point, Temple – Hoare Lea

Globe Point is a landmark project in Temple, Leeds, transforming a triangular site into a Grade A office space prioritising sustainability, occupant wellbeing and energy performance. The judges praised Hoare Lea’s ‘ability to demonstrate in-use performance’ – recognised by Well, Nabers and Breeam certifications – and ‘great use of a digital twin to improve energy performance’.

The all-electric Globe Point operates on 100% renewable energy and achieves top sustainability certifications, including Breeam Excellent, Nabers 4.5 stars, and WiredScore Platinum, with a focus on tenant engagement and performance monitoring.

Project of the Year – Residential

Sponsor: Crane Fluid Systems

Winner: Agar Grove 1b – Max Fordham

In a competitive field, the judges praised Agar Grove 1b for its exemplary application of design best practice on a large scale. They highlighted the focus on building performance and commitment to the local community. The project, part of the UK’s largest Passivhaus housing scheme, includes 34 council and 23 private homes.

Max Fordham adopted a passive-first M&E design, achieving 70% energy efficiency. The energy source is currently gas, but future plans include heat pumps. Resident surveys showed high satisfaction, and the design considered overheating risks, passive ventilation and noise mitigation for optimal comfort. Highly commended: Brambles - Bere Architects

Project of the Year – Portfolio Workplaces

Sponsor: Crane Fluid Systems

Winner: Cathedral Hill Industrial Estate – SRE

The judges praised the Cathedral Hill Industrial Estate deep retrofit as an ‘outstanding example of how regeneration can benefit businesses and the environment’. Achieving operational net zero, the £10.6m refurbishment increased rental value by 220% and the site is now fully tenanted, with a waiting list.

Improvements included enhanced insulation, heat pumps, Tesla Powerwall batteries for solar energy storage, and sustainable material reuse. The project’s upfront carbon emissions were only 281 kgCO₂ m-² GIA. Highly commended – Aldar energy retrofit, grfn

Building Performance Consultancy (over 300 employees)

Sponsor: ABB

Winner: AtkinsRéalis

With a focus on decarbonisation and post-occupancy evaluation (POE), AtkinsRéalis won with a ‘very strong entry’. Its decarbonisation tool assessed more than 3,000 buildings in 12 months, saving £1.54bn and helping to reduce its own carbon footprint by 55% since 2019.

Judges praised its strong POE strategy, supported by its Azolla tool, which benchmarks projects against sustainable frameworks. ED&I policies ‘expand beyond company borders’, impacting supply chains and clients. Named a Top 50 Employer for Gender Equality, it also achieved Clear Assured Platinum Accreditation.

Highly commended: Buro Happold

Building Performance Consultancy (up to 50 employees)

Sponsor: Mitsubishi Electric Winner: Cyclone Energy Group

Cyclone Energy Group was praised for its innovative approaches, including its use of geo-exchange systems in two high-rise residential projects – the first of their kind in the US. The company’s post-occupancy evaluation of more than 51 projects was also ‘very impressive for a business of this size’, the judges added, while its impactful outreach, volunteer service day, and efforts to educate architects on decarbonisation also stood out.

The 28-person consultancy optimises building performance across life-cycle stages, using tools such as AI drones and virtual reality. It fosters diversity with blind recruitment and inspires through STEM events.

Building Performance Consultancy (51-300 employees)

Sponsor: Airflow Winner: XCO2

‘A truly global approach to sustainability’ earned XCO2 a record fourth consecutive win. The firm has worked in nearly 50 countries, tailoring designs to diverse climates and communities. Landmark projects include work on a passive-designed monastic school in the Himalayas and assessing climate change risks in the Galapagos.

Among the company’s key efforts are championing net zero, material reuse and social change. Its highlights include AI energy modelling with UCL and pioneering pre-demolition audits for material reuse.

Highly commended – Max Fordham

Product or Innovation of the Year –Air Quality

Sponsor: CIBSE Patrons

Winner: The Pluvo Column – Pluvo

Judges called the Pluvo Column an ‘innovative solution to air quality in transport hubs’, and praised ‘a highquality submission supported by robust research’.

The 2.7m-tall air purifying system doubles as an LED advertising display. Designed for air pollution hot spots, it filters up to 99.5% of pollutants, creating clean air zones within a 20-60m radius.

The Pluvo has a small footprint, low power draw, and is controlled by internet of things devices for energy efficiency. A six-month trial near London’s North Circular showed significant reductions in pollutants, making it a scalable solution.

Product or Innovation of the Year – Wellbeing

Winner: Nature Connect – Signify

Signify’s NatureConnect earned judges’ praise for its scientifically supported design, addressing the need for enhanced lighting in spaces with limited natural daylight.

The system recreates daylight indoors, mimicking natural light’s appearance and effects. Its dynamic Day Rhythm feature adjusts brightness and colour temperature to align with circadian cycles, boosting mood, productivity and sleep quality.

Meeting EN17037 and Well standards, NatureConnect’s real-world application includes Edge Amsterdam West building and Battersea Power Station’s IWG offices.

Product or Innovation of the Year –Thermal Comfort

Winner: Optimum Air Conditioning System –EcoTechX

EcoTechX’s air conditioning system ‘demonstrated genuine innovation with broad applicability across property types and use cases’, said the judges.

The novel indirect evaporative cooler (NIEC) uses water’s natural cooling properties, achieving thermal comfort at 22°C without chemical refrigerants or high energy use. Operating via a humidifier and heat exchanger, the NIEC reduces energy consumption by 65% and can cut capital costs by 50%. It integrates with existing systems, boosting efficiency by up to 45%. Highly commended: Passive Cooling Double-skin Roof - Universidad de Sevilla

Collaboration

Winner: L&G’s Symphony Model – Legal & General, Demand Logic, Bellrock and partners Sponsor: CIBSE Life-cycle Carbon Assessment Training

Judges hailed L&G’s Symphony Model as ‘a gamechanging tool for optimising building performance’, commended for its collaborative, replicable approach that benefits clients and teams.

This data-driven strategy enhances health, wellbeing, energy efficiency and sustainability. Supported by the Symphony Academy, which trains teams in digital skills, the model uses tools such as Demand Logic to analyse HVAC data, flagging issues resolved via Bellrock’s software. Over six months in 2023, 87.5% of 2,941 incidents were fixed remotely, saving 300,000kWh and £208,450. The model aims to cover L&G’s full portfolio.

Best Digital Innovation –Project Delivery

Winner: Sydney Airport International Terminal T1 chilled water plant optimisation – A. G. Coombs Group, Exergenics

Sydney Airport, with A. G. Coombs and Exergenics, optimised Terminal 1’s chilled water plant using advanced machine learning and predictive control. They enhanced chiller, pump and cooling tower efficiency through measures such as dynamic condenser water resets and demand-based setpoints. The project reduced energy consumption by 890,094kWh, cut GHG emissions by 704tCO2 and achieved energy cost savings of $124,600 (£98,000) over nine months. Highly commended: Paper Trails to Digital Triumphs – Savills

Best Digital Innovation –Organisational Strategy

Winner: Cyclops – Foster + Partners

The judges said Foster + Partners’ software tool Cyclops has the potential to revolutionise the way software is used in our industry.

Cyclops integrates real-time environmental simulations into the design process, addressing timeconsuming cycles and interoperability challenges. The tool supports 17 types of analysis, including daylight metrics, sunlight hours and radiation. It is up to 10,000 times faster than traditional tools, reducing project analysis turnaround from days to hours. Judges praised its user-centric approach, and potential to transform data accessibility and decision-making.

Building Performance Awards Winners

Leadership

Winner: Swire Properties

Swire Properties’ ‘demonstration of global leadership’ –notably through research with leading academics on embodied and whole life carbon metrics – impressed the judges. Its portfolio spans Hong Kong, Chinese Mainland, Southeast Asia and the US, and encompasses 24.4 million sq ft of mixed-use developments.

The company’s 1.5°C-aligned Science Based Targets led to a 29% reduction in Scope 1 and 2 emissions, and a 40% drop in Scope 3 carbon intensity by 2023, surpassing its 2025 goals. Key initiatives such as Two Taikoo Place achieved a 17% reduction in embodied carbon. Swire also contributes to global sustainability frameworks. Highly commended: Andy Jackson, head of Central London operations and UK engineering – Savills

Learning and Development

Sponsor: BCIA

Winner: The ZERO Teaching and Internship Programme on zero carbon energy buildings –ZERO Institute, University of Oxford

The ZERO Internship Programme combines advanced teaching with real-world projects to drive Oxford’s net zero transition. Judges praised its potential to operate in more cities and communities, and noted overwhelmingly positive student feedback.

Led by Professor Jesús Lizana, the programme trains future MEP engineering leaders through degree courses, summer schools and internships. Launched in May 2024, it cut an estimated 5,395.5kgCO₂e in its first year. Highly commended: Building Safety Act training and assessment - Hoare Lea

Client of the Year

Winner: London Borough of Islington (LBI)

LBI’s ‘comprehensive approach to decarbonisation, social values and energy performance metrics’ earned praise from the judges, who highlighted the borough’s drive for a ‘more equal future’.

Its Net Zero 2030 vision includes the delivery of more than 50 projects such as the Waste Recycling Centre redevelopment, with full electrification, 852 solar panels generating 348,658kWh, and 92.5% construction waste recycling. Its collaborative efforts prioritise efficiency and emissions reduction, aided by tools such as Navigator.

Community initiatives raised £13,000 for charities and supported schools, and LBI shares expertise via events, case studies and Salix bulletins.

CIBSE Embodied Carbon Award –Products and Systems: for Manufacturers and Suppliers

Sponsor: CIBSE Certification Ltd

Winner: Apollo Fire Detectors

Apollo Fire Detectors won for its efforts to measure and reduce embodied carbon in its products. The company assessed nearly 100 products using CIBSE TM65, completed life-cycle assessments for 32, and is finalising Environmental Product Declarations for four.

Product redesigns have achieved significant reductions and manufacturing improvements have lowered embodied carbon by 114,453kgCO₂e over a building’s life. Apollo’s dissemination of data advances industry knowledge and emphasises collaborative system design for carbon reduction.

CIBSE Embodied Carbon Award –Services and Projects: for Consultants

Sponsor: CMR

Winner: Q Sustain

The judges commended Q Sustain for ‘providing clear, quantifiable evidence of the added value and whole life carbon reductions achieved’ through its retrofit of the lighting at Birmingham New Street Station.

Tasked with replacing 891 fluorescent lights, Q Sustain instead retrofitted luminaires by replacing gear trays, reducing material use and embodied carbon. This saved 163 tonnes of CO₂e (39% of whole life emissions) and cut annual energy use by 67 tonnes of CO₂e. The retrofit enhanced lighting quality by 150%, minimised disruption, and future-proofed the system. Highly commended: Aecom

Facilities Management

Sponsor: Gratte Brothers Group

Winner: 20 Fenchurch Street – Savills

Savills won for its energy-saving achievements at 20 Fenchurch Street. The judges recognised how ‘a proactive approach to FM can yield dividends over a relatively short timeframe’. In 2023, gas consumption fell by 10.6%, electricity by 5.3%, and water use by 21.8%, despite occupancy increasing by a third. Carbon emissions were reduced through recommissioning systems, optimising controls and engaging occupants. Project Go Dark cut lighting use, while an ‘energy Strava’ tool ranked tenant energy performance anonymously. Recycling exceeded 75%, and the team is aiming for Breeam Outstanding In Use certification.

Net zero healing

The National Rehabilitation Centre near Loughborough is being designed to achieve the new NHS Net Zero Building Standard and be a template for a new generation of smart buildings in the NHS. Alex Smith reports

The NHS National Rehabilitation Centre (NRC) is a pioneering facility designed to provide intense rehabilitation programmes for up to 750 patients each year, to increase their chances of returning to life and work.

Currently being constructed at Stanford Hall near Loughborough by the Nottingham University Hospitals NHS Trust, the £105m building is the first hospital in the UK to target net zero under the NHS Net Zero Building Standard (NHS-NZBS). It is all-electric and features three R454 air source heat pumps (ASHPs) and 900m2 of solar panels, which are predicted to provide 10% of the building’s energy needs.

The centre is pioneering a new interoperable building management system to demonstrate how smart technology could be incorporated into new and existing NHS hospitals and facilities. This is designed to talk to buildings’ engineering systems and, crucially, enable staff and patients to talk to it, literally, through voice-activated environmental controls.

‘We want to give the patients autonomy to

Project team

Client: Nottingham University Hospitals NHS Trust MEP engineer, civil and structural engineer, and net zero carbon consultant: Arup Architect: Ryder Architects Main contractor: Integrated Health Projects (joint venture between Sir Robert McAlpine and Vinci Construction) MEP contractor: T Clarke

be as comfortable as possible in their environment,’ says Ryan McCormack, head of programme construction and commercial for the NRC.

This pioneering new building was given the go ahead in September 2023. Its architectural design, however – including its irregular zig-zag, three-storey central spine, orientated along an east-west axis –had been conceived in 2016. The spine is home to the building’s double-height reception, while its ground floor contains the specialist treatment and clinic facilities, two gyms, a dining room and an innovation suite, which are housed in a series of pavilions projecting from the crooked core. The upper floors have a patient lounge and sleeping accommodation, arranged in individual rooms.

There is a separate energy centre building, and landscaped gardens surround the facility to further enhance patient wellbeing.

The NRC was granted planning consent in 2018. In the period between this and the scheme being given the go-ahead, NHS England made a commitment to reduce the

The NRC is on the Stanford Hall estate, home of the Defence and National Rehabilitation Centre

carbon footprint for its estate, targeting an 80% emissions reduction by 2028-32, and net zero emissions by 2040. The NHS-NZBS –published in February 2023 and referenced in the pilot version of the UK Net Zero Carbon Buildings Standard – is designed to meet that commitment.

It was decided that the NRC would retrospectively target net zero carbon under this standard. This was an additional challenge because the building’s irregular form – with its projecting pavilions of clinics and specialist treatment rooms designed to foster collaboration and innovative treatments –increased the surface area of the building envelope significantly.

‘The design team had to pay additional attention to insulation and airtightness to minimise any heat losses,’ says McCormack.

Non-combustible, structurally insulated panels (SIPs) provide a high-performance, thermally efficient and airtight envelope, and help the scheme to comply with modern methods of construction targets in the government’s New Hospital Programme. The SIPs are clad in low embodied carbon fibre-cement panels.

In addition, the roof accommodates 900m2 of photovoltaic panels, estimated to produce around 185MWh of electricity per year.

The building’s low carbon design is further enhanced through the use of post-tensioned concrete to form the upper floor slabs. This has comparatively lower embodied carbon compared with conventional concrete floor slabs. A concrete raft slab forms the foundations and ground floor, and avoids the cost and high embodied carbon associated

Lessons learned from trialling digital technologies at Linden House

l Smart hospitals require a large increase in connected devices, and many existing buildings don’t have enough power, data or containment to do this without considerable work.

l Aligning stakeholders to enable works to be completed at a convenient time, to minimise interruption to clinical operations, is challenging and causes delays.

Natural materials are designed to make spaces feel less clinical and more comfortable

l Different areas of the hospital have different infrastructure; lead-lined areas such as theatres and the emergency department mean additional network infrastructure is required.

l Changes to current processes need to be supported until new technology is truly embedded into daily practices.

l Staff engagement in the design process is essential. Digitally disenfranchised groups should not be further isolated by implementation of technology.

l Technologies such as nurse call and CCTV, security and access control cut across organisational structures, so it takes time to clarify which departments are responsible for which systems.

l Life-cycle costs need to be fully understood and mapped out, including battery changes for the Internet of Things and the true costs of cloud data.

l NHS governance processes are not agile, which restricts the ability to implement innovation at pace.

A visualisation of the dining room

NHS-NZBS targets for NRC

l Regulated operational carbon:

58.8 kWh·m-² GIA per year

l Unregulated operational carbon:

42.6 kWh·m-² GIA per year

l Embodied carbon: 391 kg CO2e·m-2 GIA

with a piled substructure. Although concrete is used throughout the building, its associated thermal mass was shown to have little effect on the overall building energy demand compared with other measures.

At RIBA Stages 2 and 4, building services engineers Arup undertook extensive design modelling to determine the impact of various passive design interventions. These included the use of high-performance glazing and solar shading on the south elevation to keep cooling loads to a minimum.

To target the NHS-NZBS, Arup developed an all-electric building services solution for the NRC, which factored in future changes to the climate over the lifetime of the building. As such, heating and cooling are provided by three R454 ASHPs, each capable of producing 439kW of cooling and 337kW of heating. For cooling, the energy efficiency ratio is 3.12 at 100% load and the low-temperature hot water coefficient of performance (COP) is 2.69 at 100% charge.

Dynamic simulation modelling was used to identify the times and conditions under which simultaneous loads occur, so that waste heat from the provision of cooling can be reused to provide heating, increasing system efficiency and enabling seasonal efficiencies in line with

the net zero standard’s performance targets.

The lower-temperature heating circuit is kept separate from the higher-temperature domestic hot water (DHW) circuit to maximise system efficiencies. Six (CO2 refrigerant) ASHPs provide a total of 100kW of heat at a COP of 2.25 @ -5°C and a COP of 3.1 @ 10°C.

To further improve efficiencies, the DHW system incorporates thermal stores to meet hot-water demand at peak times without having to oversize the heat pumps. These stores also help to reduce heatpump cycling.

Mechanical ventilation with heat recovery is used for all spaces, with the exception of the isolation suites used for infectious patients. CO2 sensors located throughout the building deliver a demand-driven ventilation strategy, with systems ramping up and down accordingly as people move around the building. ‘If it’s hot within the building, or we have high levels of CO2, then we have the ability to measure that and control the ventilation,’ explains McCormack.

To give patients and clinicians additional control over their environment, and to reduce energy use, some areas of the building incorporate openable windows as part of a mixed-mode ventilation solution.

The centre is also designed to ensure high levels of daylight. To minimise energy consumption, the LED lighting system is linked to both occupancy and daylight-level sensors. ‘If it’s light outside, we don’t want the lights on in the building,’ McCormack says.

Critically, patients are given control over the environment in their rooms through a digital tablet. As well as facilitating traditional entertainment streaming and phone calls, the tablet allows patients to control their window blinds, room lighting and temperature using voice control. ‘We’re looking at features to make controls as accessible for as many patients at NRC as possible,’ says Lisa Yates, digital strategy lead at Nottingham University Hospitals NHS Trust.

Backup generator

The NRC uses a large diesel-fed emergency backup generator. The use of batteries and other energy-storage devices were discounted because of the reliability of the technology and available space and infrastructure on site. It is hoped that when cost-effective, low carbon alternatives are commercially available, these would replace the diesel generator.

Patients are due to start moving into the building in summer 2025

The tablet will also feed into the nurse call system to enable patients to request drinks and choose menus, or to be repositioned.

Crucially for this facility, the tablet has the capability to guide patients through exercises, via games and other apps, to help speed up their rehabilitation.

The tablet is just one of 50 technologies that have been identified for new NHS buildings. Rather than install all of them at the NRC, however, the design team decided to focus on technologies that would be most beneficial in hastening recovery and improving the patient and staff experience.

To help identify these technologies, the hospital trust carried out trials at its current neuro-rehabilitation unit, the 25bed Linden Lodge in Nottingham.

‘Until a technology has been implemented in a real, live, patient environment, we don’t fully know how it is going to work, and we need that feedback from patients and staff,’ says Yates.

‘The main point is to trial the proof of concept: do they deliver on the benefits we think they will, because we need to be confident in our procurement decisions for the NRC and, ultimately, for the trust.’

As a result of the trial, other digital technologies adopted include:

l A digital twin of the building to allow staff to identify, in real time, where a piece of equipment is within the building using an app with which they are familiar

l Digital signage so staff can see which rooms are available

l Artificial intelligence-enhanced CCTV that features ‘digital tripwires’ to help keep patients with cognitive impairment from absconding.

As well as gathering feedback on technologies that would be most appropriate for the NRC, the Linden Lodge trial also provided valuable insight into the challenges of installing the technologies in new and existing buildings - see panel, ‘General lessons learned from trialling technologies at Linden House’.

‘We've learned a lot about the constraints from being able to install these technologies in an existing estate – which will be the case for a lot of hospitals going forward, because they are not all going to go into brand-new shiny buildings,’ says Yates.

The NRC is set to receive its first patients later this year, at which point the design team will be able to establish whether the actual energy consumed by the building falls within the prescribed limits of the NHS-NZBS (see panel, ‘NHSNZBS carbon limits’). Dynamic simulation modelling and whole life carbon analysis throughout the design phase strongly suggest it will. l

The building is orientated along the east-west axis

Take note: fire-safe façades

New Technical Notes from the Centre for Window and Cladding Technology are essential reading for anyone involved in the design and construction of modern façades. By

David Metcalfe

, director at CWCT

Ensuring fire safety in façade design is critical, yet existing guidance in Approved Document B often requires careful interpretation. To bring much-needed clarity, the Centre for Window and Cladding Technology (CWCT) has recently published two new Technical Notes on the fire performance of façades: TN113 – Fire performance of façades – Introduction; and TN114 – Fire performance of façades – Use of combustible materials.

These are the first two Technical Notes in a series of four that replace previous guidance contained in CWCT TN98. (See panel, ‘Technical Notes’.) This series is intended to provide those who design and construct façades in the UK with an introduction to the regulations and associated guidance relating to fire performance, and how the regulations can be met in the design and construction of modern façades. They also provide useful information for building designers and fire engineers on fire-related requirements for façades.

We have engaged widely in the preparation of these Technical Notes, including with the Building Safety Regulator in England and the Scottish Building Standards Division, both of

Technical Notes

Available now

TN113 – Fire performance of façades – Introduction

TN114 – Fire performance of façades – Use of combustible materials

Coming in 2025

TN115, Fire performance of façades – Application to curtain walling

TN116, Fire performance of façades – Application to built-up walls

which provided feedback on the Notes. This article summarises TN113 and TN114, and previews TN115 and TN116, which are due for publication later this year.

TN113 – Fire performance of façades

This Technical Note provides an introduction to the building regulations relating to fire in England and the associated statutory guidance in Approved Document B. Requirements in other countries of the UK may differ and key differences are described in an annex.

UK Building Regulations require buildings to be designed and constructed to limit the spread of fire:

l Within the building

l Over the external walls of the building

l From one building to another.

They also require provision for warning and escape in case of fire. Satisfying these requirements will affect the design of the façade and TN113 provides an introduction to these requirements.

The Building Regulations give minimum requirements to ensure life safety. These are

generally in functional terms, with Approved Documents providing practical guidance that would normally satisfy the functional requirements. Approved Document B (ADB) covers fire.

There are five functional requirements relating to fire performance (B1 to B5), and TN113 summarises these, highlighting the influence they may have on the design and construction of the façade.

It is important to note that the façade cannot be designed in isolation – the design of the façade is affected by decisions about the design of the building. Therefore, a fire strategy needs to be developed by the building designer/fire engineer, with requirements communicated to the façade designer. It should also be noted that the requirements may exceed the recommendations given in ADB to reduce the risk of property damage in fire. These include:

l Any requirements for the façade to be fire-resisting

l Identification of compartment walls/floors to allow design of interfaces

l Limitations on reaction to fire of materials that exceed limits in ADB

l Provisions relating to escape routes that affect the façade.

There are also minimum recommendations in ADB that should be met in relation to:

l Provision of cavity barriers

l Limits on the reaction to fire of materials.

TN113 also describes reaction to fire testing, and highlights the importance of ensuring that

Buildings where at least part used for residential purpose¹

l All materials A2-s1, d0 or better other than permitted exemptions (Reg 7(2), Reg 7(3))

l Also applies to specified attachments

l Note ‘Additional considerations’ (ADB1 cl 10.21)

l External surfaces A2-s1, d0 or betterC (ADB1 cl 10.5)

l Insulation products, filler materials and so on A2-s1, d0 or better⁴ (ADB1 cl 10.7)

l External surfaces A2-s1, d0 or betterC (ADB1 cl 10.5)

l Balconies to be composed of A2-s1, d0 materials other than specified exceptions or to have a soffit achieving REI 30 composed of A2-s1, d0 materials and any materials of Class B-s1, d0 or worse to be interrupted by a 300mm wide strip of A2-s1, d0 material at compartment boundaries (ADB1 cl 10.10)

l External surfaces A2-s1, d0 or betterC (ADB1 cl 10.5)

l External surfaces B-s3, d2 or betterC (ADB1 cl 10.5)

l No specific recommendations (ADB1 cl 10.5)

materials and products are tested in a way that is representative of how they will be used as part of the façade.

Materials and products can be tested in different configurations. It is therefore crucial that those specifying and selecting façade materials understand how products and assemblies have been tested, to ensure that the tested configuration covers the proposed use. A product may give different classifications for different configurations.

TN114 – Use of combustible materials

TN114 provides a detailed interpretation of the various recommendations given in Building Regulations ADB relating to the reaction to fire of materials and products used in the external wall.

In isolation, the different recommendations appear straightforward. However, when considered collectively, and with regulation 7(2), guidance is required to help provide logical conclusions.

While the regulations and guidance discussed in TN114 allow combustible materials to be used in certain situations, it is generally considered that minimising the use of combustible materials in the external wall will lead to the lowest risk of external fire spread.

This simple view does not, however, take account of other performance aspects of the façade, which must also be met, and which may require the use of combustible materials.

As a general rule, where less combustible materials are available without compromising other aspects of performance, it will almost always be appropriate to use them in

Figure 1: Summary flow chart from TN114

Figure 2: Measurement of height for ‘external surfaces’ (from Approved Document B)

Height of top floor³ 18m or more above ground (relevant buildings)

Façades Fire safety guidance

preference to a more combustible alternative.

Extensive guidance and interpretation in relation to regulation 7(2) and modern façades is already provided by a joint CWCT and CIBSE's Society of Façade Engineering (SFE) document, updated in 2023. This guidance is freely available (bit.ly/CJCWCTSFEfire) and should be read in conjunction with TN114.

Guidance in TN114

TN114 provides flow charts (see Figure 1) that summarise the recommendations given in ADB regarding combustible materials. These provide a very useful reference, but care is still required. They should be read in conjunction with the specific clauses in ADB, given in the flow charts, for the full context of the

Future works – TN115, TN116

TN115 will cover the performance of curtain walls. The key consideration in relation to curtain walls is fire stopping: how it is tested, how it should be used and how it will perform.

In a change from our previous guidance, we are proposing that curtain wall fire stops are tested in accordance with BS EN 1364-4.

To provide the flexibility to account for curtain wall designs and building uses, we are recommending a hierarchical approach to the use of fire stops. This ranges from using the fire stop within the direct field of application of the standard through to a fully fireengineered solution, to the design of the compartmentation.

For further details of the approach being proposed, please see ‘Fire and façades: key guidance’, CIBSE Journal , June 2023, bit.ly/40LSA7O TN116 will cover built-up walls. Among the issues being considered are:

l How can cavity barriers be tested when the rainscreen fails before the end of the test?

l Is the spread of cold smoke prior to the activation of open-state cavity barriers an issue?

l The applicability of testing in accordance with BS 8414.

Height of top storey excludes roof-top plant areas and any top storeys consisting exclusively of plantrooms

Height of top storey measured from upper floor surface of top floor to ground level on lowest side of building

for ‘materials and products’ (from Approved Document B)

recommendations. In relation to ‘external surfaces’, we define what is meant by an external surface and then where the recommendations for external surfaces apply. This sounds straightforward, but when considered with other recommendations, illogical conclusions could be drawn, whereby the recommendations for lower-risk buildings could be more onerous than those for relevant buildings. We provide a pragmatic interpretation that avoids this.

The recommendations for ‘materials and products’ are relatively straightforward; however, there is still some confusion over the definition of a ‘filler material’. This has particular implications for laminated glass, and we explore this issue in the Technical Note.

Two further Technical Notes, TN115 and TN116, are in preparation and there are a number of outstanding issues that we are working hard to address (see panel, ‘Future works - TN115, TN116’).

Conclusion

If you have any experience of the issues raised, we would welcome your feedback. Please email cwct@cwct.co.uk with any details that you can share. CWCT/SFE regulation 7(2) guidance

The fire performance of façades remains a key industry challenge. Our two new Technical Notes provide guidance on the general requirements relating to the façade and then go into detail regarding the use of combustible materials.

Regardless of the interpretations provided, the risk of fire spread because of the specific materials used, and their extent and arrangement, should be considered on a project-by-project basis, to ensure that the functional requirements of the Building Regulations are met. l

TN113 and 114 are available from the CWCT website: bit.ly/CJCWCTTNs

Figure 3: Measurement of height

Roof

Shaping a net zero future

Fit for 2050 is the theme of the 2025 CIBSE Technical Symposium, which will be co-organised by CIBSE and IBPSA-England. Here are four topical papers that give a flavour of the event at UCL on 24-25 April

There are only two months to go until the CIBSE Technical Symposium, which this year takes place on 24-25 April at UCL’s Bentham House, in London. CIBSE has partnered with the International Building Performance Simulation AssociationEngland (IBPSA-England) to combine the CIBSE Technical Symposium and IBPSA-England‘s biennial Building Simulation and Optimisation event. The theme is ‘Fit for 2050 – achieving net zero through intelligent, resilient and sustainable design in the built environment’. Below are details of four presentations on embodied carbon in heat networks, artificial intelligence, building resilience, and heating system performance.

Embodied carbon in heat networks

Carbon Trust manager Dr Akos Revesz MCIBSE will present the paper ‘Evaluating embodied carbon in heat network projects: current practices and future directions’. Revesz’ work highlights the need to assess the embodied carbon impacts in heat networks, and he calls for comprehensive evaluations for a more accurate whole life carbon perspective.

Machine learning and decarbonisation

Stantec’s Arash Izadpanah’s review paper, ‘A comprehensive review of machine learning approaches for decarbonisation and energy efficiency in the UK building sector’, highlights the significant potential of machine learning techniques in enhancing building energy management and decarbonisation in the UK.

more information and to book your place, visit www.cibse.org/ technicalsymposium

Building resilience and climate extremes

Dr Simona Bianca, post-doctoral research fellow at Delft University of Technology, highlights the urgent need to improve building resilience against climate extremes in her paper ‘A quantitative approach to resilience design of building façades against heatwaves and floods’. The author introduces a framework using computational simulations, machine learning models and sensitivity analysis, to select and quantify the resilience of façade systems.

Primed for heat pumps

Laurence Childs, doctoral researcher at UCL, will present the study ‘Do existing radiators perform as expected?’. The research reveals discrepancies between survey estimates and data-driven estimates from heat-meter data that could complicate the effective sizing of radiators for heat pumps (see ‘Primed for heat pumps’, CIBSE Journal, February 2025). l

Why mainstream MEP can and should be circular

Building services engineers should be looking to be part of a genuinely circular construction industry that is fit for the future, says Max Fordham’s Kiru Balson

There is an adage that states ‘if you can’t grow it, you have to mine it’ - but can this go on forever? The Global Resources Outlook 2024, by the UN Environment Programme, sent a stark message that global resource consumption has tripled in the past 50 years. This is expected to double in the next 35 years and, along with it, the wider negative environmental impacts.

In 2020, 10% of global resource extraction (9.6 billion tonnes) accounted for iron, aluminium, copper and other non-ferrous metals. Energy transmission and storage infrastructure will require a significant quantity of metals. The responsible use of resources that have already been mined and are currently in use is critical.

A circular economy model aims to reduce the need for new materials and reduce waste. It does this by keeping materials in use for longer through reuse, refurbishment, repair and by using secondary recycled materials. The sixth Climate Change Committee report, from 2020, includes resource efficiency as a key policy and estimates an annual UK emissions reduction of 8 million tonnes of CO2e by 2035. Efficiency measures include optimisation of design through reduced material inputs, more reuse and recycling, and increasing product lifespan.

The MEP sector must take an active role in the solution by enabling the decarbonisation of the construction sector. Manufacturers of MEP equipment rely, fundamentally, on the global supply chain for various minerals and metals, and are exposed to critical shortages and market volatility. Production supply chains are long, with individual parts sourced from third parties, then assembled and delivered semi-finished, or finished, for installation on site. The rate of technological development and shorter replacement cycles means manufacturers, as well as the construction industry, hold the responsibility for managing the resource flow.

At Max Fordham, our experience shows that it is possible to mainstream MEP repair and reuse, not just for historic conservation reasons, but in everyday practice. This will help scale up knowledge and confidence in doing this more commonly in the sector.

The Passivhaus EnerPHit-certified deep

retrofit of The Entopia Building in Cambridge championed efficiency of resource use, as well as operational energy performance. The client’s commitment helped the team to identify ways to overcome risks and accept reuse of the building’s original MEP equipment. Reused items included elements of the generator systems, electrical sub-mains, principal drainage stacks, lightning protection, and lifts. The scheme also reused elements sourced from elsewhere, such as LED lighting in the main office areas, the steel frame for the PV canopy, and raised access flooring. Reuse of MEP equipment required a higher level of coordination, from early design through to construction. The overall upfront embodied carbon savings, at a building level, from the reuse of these MEP items was minimal compared with the savings from the use of reclaimed structural steel or raised access flooring. So why do it?

The driver was to minimise the wider environmental impact (more than just carbon)

A generator being removed from a former Debenhams store in Manchester will be reused in a railway museum

and be an example for resource efficiency within a commercial refurbishment scheme. The project team overcame common challenges with reuse by acquiring the maintenance records, assessing the condition of the equipment, and undertaking the necessary tests to provide warranty.

Typically, when a building is refurbished or demolished, most MEP items are marked for recycling. It can be challenging to track the waste-processing routes once an item leaves the site. Manufacturer takeback schemes are available, such as Grundfos, which supplied 10,000 circulator pumps to heat pump maker NIBE with remanufactured, reused rotors. However, these schemes are embryonic: what can we do about equipment that is in good condition, but no longer needed in a specific building, if the manufacturers are not interested?

Another Max Fordham project is the Rylands Building, in Manchester, which is currently in construction. We developed a detailed materialreuse strategy for this refurbishment and conversion of the Grade II-listed warehouse building (most recently a Debenhams) into 43,300m2 of retail and office space, .

More than 20 tonnes of steel from MEP items have been carefully stripped out for reuse by others, thereby avoiding 68 tonnes of carbon emissions. This equates to ~40% of annual operational carbon emissions from a typical 10,000m2 GIA new-build office building.

More than 600 existing LED spotlights were assessed, recovered and sent to EGG Lighting for remanufacturing, saving 14 tonnes of CO2e and 644kg of electronic waste (see Figure 1). Products were fully disassembled and cleaned, reassembled as per BS 8887-221, with new electrical components, including new LED drivers and track adapters. The lights are now available to buy with full CE marking, fiveyear warranty and a digital passport; some have already been installed in other buildings,

OMICRON Zero

TM65 assessment: remanufactured vs new equivalent

Figure 1: Embodied carbon savings as a result of 600 LED spotlights from the Rylands Building being recovered and remanufactured

including at the London School of Architecture.

From nine redundant escalators, the team recovered 12.6 tonnes of steel, including escalator treads, pit covers, electrical boxes, drive rims and guides, for reuse within the escalator maintenance and repair sector.

The most logistically complex deconstruction was the removal of two generators, which required cutting open a roof and closing a road to allow a crane to lift them out (see image) and load them onto a truck for reuse at Carnforth Station Heritage Centre in Lancashire.

Material efficiency and managing fragility in the supply chain should be high on the agenda for the building services sector. For existing buildings, an early design-stage condition survey of existing equipment via installers, and mapping items that can be reused or remanufactured, is the first step. It will help to build the practical information required at the detailed design stage, overcome the challenges of availability of existing data, and manage contractors’ risk allowances at procurement stage.

Although it’s challenging to deliver, if all in the industry work together, we can build a genuinely circular construction industry fit for the future. l

l Kiru Balson is whole life carbon and circular economy leader at Max Fordham

• Eurovent certified performance

• First air-source multifunctional heat pump and chiller unit using propane as a near zero GWP, natural refrigerant solution.

Kiru Balson

Carrier launches AquaSnap

61AQ propane heat pump

Carrier has unveiled its first hightemperature air source reversible heat pump for commercial applications that uses natural refrigerant R290 (propane).

The AquaSnap 61AQ delivers high-temperature heating up to 75°C at outdoor temperatures as low as -7°C and operates efficiently in extreme conditions down to -25°C, says the manufacturer.

The heat pump has variable speed compressors, EC fans and optional variable-speed pumps, which can save energy because they adjust their speed to match the heating or cooling demand.

A seasonal coefficient of performance (SCOP) of up to

4.2 is claimed for the heat pump, 30% above European Ecodesign requirements. Noise-reduction technologies have resulted in noise levels of 78dBA, which is 10dBA lower than the Ecodesign standard.

A monobloc version has capacity from 40kW to 140kW, while the modular version –allowing the connection of up to four units – extends the capacity range to 560kW.

R290 has a global warming potential of just 0.02, but is a flammable refrigerant, so Carrier has grouped refrigerant components into a dedicated, insulated enclosure in the heat pump to minimise risk.

Its SmartVu controls enable real-time monitoring of the system and the integration of boilers, domestic hot water and

two heating zones, with customisable schedules and Legionella prevention.

The heat pump’s ability to deliver high-temperature heating at very low outdoor temperatures means a heating system is less likely to need another heat source, such as a gas or electric boiler.

New Panasonic cascade manager offers energy efficient control

Panasonic’s new cascade manager system, the Aquarea Cascade Edge, claims to provide seamless management of heating, cooling and domestic hot water.

Featuring P-Smart Edge and P-Smart Nexus, the solution enables remote monitoring and control via smartphones, tablets or laptops.

Available in two models supporting up to

10 units, Panasonic says the system ensures energy efficiency.

Units in cascade can be controlled and managed online by P-Smart Edge, which negates the need to be on site by providing local web visualisation of the units and remote management of the system.

P-Smart Nexus offers global supervision of multiple sites with 24/7 monitoring.

Heat pump sales and training jumped in 2024

There was a record number of heat pump sales and individuals training to install the technology in 2024. New data from the Heat Pump Association (HPA) shows a 63% increase in hydronic heat pump sales, to 98,469. This follows a

‘modest’ 4% growth in sales between 2022 and 2023, says the HPA. The association’s figures also show that 9,062 people successfully completed a recognised heat pump training qualification last year – a 15% increase on 2023

levels. Last year’s increased level of deployment should provide ‘enhanced confidence’ to the market that the sector is well placed to meet expected increases in demand for heat pumps in the coming years, the HPA said.

Breaking the ice: a novel defrosting solution for heat pumps

Heat pump performance in sub-zero conditions is significantly challenged because of cumulative freezing. A new passive refrigerant flow control system aims to mitigate ice buildup, offering a simple yet effective approach to improving efficiency in extreme climates. Tim Dwyer reports

As global decarbonisation efforts drive the shift away from gas boilers, heat pumps are becoming an increasingly popular alternative in many parts of the world where the climate has made successful implementation extremely challenging.

The performance and reliability of air source heat pumps, for example, are significantly challenged in cold climates, where low ambient temperatures lead to reduced airflow and cumulative freezing.

At extremely low temperatures, heat pumps operate with low evaporation pressure and a high compression ratio, further straining system efficiency.

Externally, snow and ice accumulate on the outdoor unit, restricting airflow and exacerbating heat-transfer issues. A critical problem arises when defrosting water refreezes in the lower sections of the outdoor heat exchanger, leading to cumulative freezing that degrades heating performance and system reliability.

Conventional solutions, such as reverse-cycle defrosting and modifications to heat exchanger design, have limitations. Methods such as

bypassing refrigerant from the compressor to melt ice introduce additional material costs and complex control requirements, highlighting the need for more effective and efficient defrosting strategies.

The paper ‘A study on cumulative freezing prevention structure of a heat

pump system’1, presented by Junghoon Ha at the recent Orlando ASHRAE meeting, proposed a novel, passive solution to prevent cumulative freezing in residential air conditioning (RAC) heat pumps.

The design enhances de-icing performance by selectively controlling refrigerant flow in the lower section of the outdoor heat exchanger. During heating mode, specific tubes at the bottom of the heat exchanger remain inactive, reducing condensate formation and minimising the risk of freezing. In defrosting and cooling modes, hightemperature refrigerant is redirected to these tubes to aid in ice removal.

A key feature of this design is a check valve positioned before the refrigerant enters the outdoor heat

Table

Heat pumps Defrosting

exchanger. This prevents refrigerant from reaching the lower section during heating, effectively reducing frost accumulation. However, a limited number of lower-section passes remain active to maintain system stability.

The structure is optimised to ensure a balanced heating load per tube pass while maintaining a simple control logic, making it practical and cost-effective for RAC.

The proposed design was validated through software simulations and experimental testing on a split-type heat pump system. Performance was assessed using the air enthalpy method, calculated by airflow rate and dry/wet bulb sensors, with evaluations conducted under various operating conditions as shown in Table 1.

Thermocouples and a camera were used to monitor temperatures and

Further work

To develop this work further, the authors suggest the need for:

l Long-term field testing to evaluate system durability and sustained performance over extended periods

l Comprehensive cost analysis to quantify economic benefits compared with existing defrosting solutions

l Scalability assessment to determine the feasibility of applying this design to larger heat pump systems.

detect cumulative freezing.

The modified heat pump design demonstrated a significantly longer heating operation time compared with a conventional system during cumulative freezing tests. After four cycles, cumulative freezing was observed in the typical heat pump, whereas the new design remained free of ice following defrosting.

Performance analysis revealed that the new system achieved slightly higher heating efficiency, attributed to improved mass flux at the distributor. Reducing the number of lower heat exchanger tube passes from two to one probably altered the refrigerant flow pattern, leading to more effective distribution within the cone-type refrigerant distributor used in the system.

Cooling tests further validated the design’s effectiveness. By incorporating a capillary tube at the inlet of the heat exchanger pass during cooling operation, the system maintained uniform refrigerant temperatures across all passes, ensuring a balanced heat load and optimised performance.

A field test was conducted in Alaska, starting in January 2024, to assess the reliability of the new heat pump in very cold conditions. After two weeks of operation in temperatures ranging from -42°C to -30°C, ice accumulated at the bottom of the outdoor heat exchanger, but it did not propagate to the upper section. The combination of low temperatures and high winter humidity contributed to ice formation at the lower part of the heat

• R290 refrigerant with heating up to 85°C

• Exceptional efficiency with high COP

• Cascadable up to 16 units

• Three models: 30kW, 50kW, 100kW

www.modutherm.co.uk

Lower part pass

Distributor

Schematic of the cumulative freezing prevention structure in the new

exchanger, yet the heat pump system continued to operate without any issues.

This work appears to introduce a promising solution for improving the performance and reliability of heat pump systems in cold climates. The authors claim that the proposed simple, passive design offers a costeffective and easily implementable approach for residential air conditioning units, supporting the broader adoption of heat pump technology as a sustainable heating alternative. l

l About the paper’s authors Junghoon Ha, Jiwon Jang, Dongsoo Moon, Jungtack Lee, Juhyok Kim, Suchang Woo, Simwon Chin are engineers from LG Electronics, specialising in the heat pumps used in this research. Sunwoo Kim is an associate professor at University of Alaska Fairbanks in the Department of Engineering

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Countdown to regulation

A new regulatory framework, due in January 2026, will require all heat networks to meet minimum technical standards. A recent CIBSE conference looked at the challenges and opportunities for operators and consumers. Alex Smith reports

With new mandatory heat network standards due to come into force for operators in less than a year, CIBSE co-hosted a timely one-day conference on residential heat networks last month, in London.

The Heat Networks (Market Framework) (Great Britain) Regulations will require new and existing heat networks to meet minimum technical standards for design, installation and operation, as described in the Heat Network Technical Assurance Scheme (HNTAS). They are set to come into force on 1 April 2025, when the energy ombudsman will start handling disputes and Citizens Advice will begin offering support to customers. The authorisation regime is due to start on 27 January 2026, and heat network operators and suppliers must obtain authorisation to operate by 27 January 2026.

Experts at the conference, cohosted by CIBSE’s Heat Networks and HVAC Groups and Yen London, examined the challenges and opportunities for residential heat networks. Rachel Mills OBE, director at Chirpy Heat, opened by reporting on positive customer feedback from

the Heat Network Consumer and Operator Survey 2022. She said heat network consumers reported a median annual heating and hot-water cost of £600, £360 lower than for non-heat network consumers. They were also more satisfied with their heating – 74% compared with 67% – but outages were more common among heat network customers, with 25% complaining about heating in the previous 12 months.

HNTAS will help address technical issues, said Mills, but she is concerned about the cost: ‘I think it’s going to be an exceptionally expensive journey.’

FairHeat senior engineer Lucy Sherburn discussed HNTAS, which is due to go out for consultation later this year. She identified issues that were leading to poor outcomes for customers, including oversizing, unnecessary complexity, poor water quality, poor commissioning, high heat losses, no meters and data. ‘The aim of HNTAS is to prevent these poor outcomes from occurring,’ said Sherburn.

Heat Trust chief executive Stephen Knight also highlighted issues faced by consumers, including the high cost of heat, system inefficiency, reliability issues, non-compliance with metering

Regulations will bring about annual monitoring of heat networks

regulations, and not being able to change suppliers. ‘All these issues drive the need for regulation,’ he said.

FairHeat senior engineer Ellen Hassett spoke of the Heat Network Optimisation Guide (HNOG), which is aimed at the 14,000 existing heat networks. She said there was a lack of guidance for improving performance and HNOG aimed to close this gap.

Beata Blachut, head of strategic business development at SAV Systems, looked at the benefits of designing energy centres with large delta T air source heat pumps. She explained that heat pumps using natural refrigerant were much more efficient than those using synthetic refrigerants at a high delta T, resulting in an increased coefficient of performance, from about 2.7 to 3.3. A higher delta T also gives more opportunity to increase thermal storage, said Blachut.

Tom Vosper, strategic project manager – heat networks at the London Borough of Southwark, gave an overview of the council’s strategy of modernising heat networks to provide 17,000 connected households with low carbon, low-cost heat. The council installed three ‘large-scale’ open water ground source heat pumps (GSHPs) on existing heat networks after analysis identified the best locations for boreholes. Two 600kW open water GSHPs on the Newington Estate have led to the rapid decarbonisation of 430 properties and improved air quality.

In the final presentations, Dr Gabriel Gallagher MCIBSE, managing director at Sustainable Energy, spoke about design optimisation of residential networks using dynamic simulations, and Michael Moggeridge, MD of Qvantum, looked at the benefits of in-apartment water source heat pump systems providing heating and cooling. l

For more on YEN London visit bit.ly/ CJYenLon and for CIBSE’s HVAC and Heat Network groups visit bit.ly/CJSIG

Cooling without compromise

EcoTechX’s CIBSE Award-winning Optimum air conditioning system uses water, not refrigerant, to provide cooling, which not only reduces embodied carbon, but also cuts operational energy use by up to 65%

Judges at the CIBSE Building Performance Awards praised EcoTechX’s Optimum air conditioning system for ‘demonstrating genuine innovation with broad applicability across property types’, and it took the award for Product or Innovation of the YearThermal Comfort.

The system’s novel indirect evaporative cooler (NIEC), developed by EcoTechX, is an energy-efficient cooling system designed to improve building performance while reducing environmental impact.

Unlike traditional air conditioning (AC) systems, the NIEC uses water’s natural cooling properties to reduce indoor air temperatures without chemical refrigerants or high energy consumption.

It achieves indoor temperatures of approximately 22°C, ideal for occupant comfort and equipment performance, and it reduces air temperature without adding moisture, thereby maintaining indoor humidity levels.

The system consumes up to 65% less energy than conventional AC systems and has a 50% lower capital cost. Its ability to integrate with existing systems as a pre-cooler also boosts energy efficiency by up to 45%.

The system uses the evaporative cooling potential of water and features a heat exchanger and humidifier. Air used for cooling the supply air, known as working air, is humidified to increase its moisture content in an external humidifier before being directed into the heat exchanger’s wet channels. The supply air flows through adjacent dry channels, where it loses sensible heat to the cool, humidified working air. The working air is subsequently discharged outdoors, while supply air is directed to the building. As the dry and wet working airstreams remain separate, the humidity of the supply air remains unaffected.

The NIEC tackles two key

challenges in cooling systems: reducing operational energy consumption and eliminating chemical refrigerants. With a plug-and-play modular design, minimal maintenance requirements and low embodied carbon, the NIEC –using recyclable materials, such as plastic for heat exchangers – delivers operational and life-cycle sustainability.

System applications

A 10kW NIEC was installed at the Centenary Business Centre in Nuneaton, to maintain an indoor temperature of 22°C, and resulted in a 65% reduction in energy consumption compared with traditional AC units. Life-cycle analysis showed it had 50% lower capital costs.

In a data centre installation, the NIEC was used as a pre-cooler alongside existing vapour compression chillers, and reduced air temperature from 38°C to 23°C. It achieved a coefficient of performance (COP) of 12-15 compared with the COP of 3-4 in a typical AC system. The final reduction in temperature was managed by conventional AC.

An AI control strategy optimises the distribution of air between the NIEC and AC system based on outdoor conditions. The hybrid system improved energy efficiency by 45%. EcoTechX paid close attention to minimising whole life carbon, and opted for environmentally friendly materials and locally available components that

minimised the carbon footprint associated with transportation. The system features a plastic heat exchanger, chosen not only for its durability and ability to handle various water qualities without cleaning, but also for its lower embodied carbon compared with metals.

Whole life carbon methodologies, such as CIBSE TM65 Basic Level, were used to assess and minimise embodied carbon. The system was also designed to be demountable and easily repaired, and components were specified that could be repurposed or recycled.

Backed by Innovate UK funding, the system has attracted positive user feedback that highlights enhanced air quality, significant energy savings, and ease of installation, making it a scalable and accessible solution.

The judges were impressed by how the product’s design integrates with existing systems to enhance efficiency and sustainability without requiring a full replacement. It addresses thermal and humidity aspects, delivering comfort in a less energy-intensive, low-maintenance solution. l

See page 22 for details of all the Building Performance Award winners

Shortlist

l Highly commended: Passive cooling double-skin roof – Universidad de Sevilla

l AR75 – Artus Air

l Heat3D - rapid in-situ measurement of U-values – Build Test Solutions

l In-ground retrofit underfloor heating – JK Floorheating

l iHP X integrated heat pump

cylinder – Mixergy

l S735 exhaust air heat pump – NIBE

l ComfoAir Q600 with ComfoClime – Zehnder Group UK

l Read more at www.cibse.org/bpa

Optimum air conditioning system – EcoTechX

24 – 25 April 2025

UCL Bentham House

London

co-organised by CIBSE and IBPSA-England

Fit for 2050

Achieving net-zero through intelligent, resilient and sustainable design in the built environment.

Learn from 60+ approved speakers sharing peer-reviewed papers and case studies

Join 30+ sessions focusing on the transition to net-zero carbon, design strategies for climate resilience in the built environment, applications of AI, machine learning and parametric design, and learnings from post-occupancy evaluations

Network with built environment professionals including, practitioners, researchers, high-level decision makers, students and, many more.

#CIBSEsymposium

cibse.org/symposium

Delivering suitably ventilated built environments in tropical climates

This module explores considerations that inform the design of buildings and services in tropical environments

Tropical climates, characterised by high temperatures and humidity, have a significant impact on building services design. The goal is to achieve thermal comfort while protecting the building fabric, reducing energy consumption and minimising environmental impact. This CPD will explore considerations for designing buildings and systems that effectively support the creation and maintenance of a suitable internal environment.

Tropical climates exhibit significant regional variations. Figure 1 illustrates examples of the Köppen-Geiger climate classification that divides the world into zones based on temperature, precipitation and seasonality. The tropical zones are generally located within 5°-10° latitude of the equator, although in some eastern coastal areas they may extend to as much as 25° north or south. However, tropical climates are not uniform, being affected by elevation, ground cover, larger-scale physiographic features, and the heat island effect.

Delivering and maintaining effective buildings and systems in tropical climates is a significant challenge. When inadequately addressed by systems designers, it can lead to issues such as condensation, mould growth, excessive cooling loads and barely habitable environments. In many areas, designers must consider the possibility of strong winds, heavy rainstorms and flash floods. As highlighted in guidance1 from the Western Australian Government (WAG), a primary cause of failure is often a lack of understanding of regional conditions by designers, builders and operators who lack experience in tropical environments. There are many regional and tropical-focused codes that are designed to promote the creation of effective buildings for tropical climates. Directly applying more generic building codes developed for temperate

climates to tropical regions can present challenges because of the unique environmental conditions, building practices, infrastructure, and availability of local materials and expertise. People adapted to tropical climates, such as indigenous groups and long-term residents, perceive comfort – especially humidity –differently2 from those who work and live remotely in temperate regions.

Design choices that seem intuitive to a remote designer from a temperate climate may not be suitable for tropical environments. Poorly designed environmental systems reach beyond inadequate thermal performance, encompassing potential building failures, health issues and increased operational costs. Humidity is a key concern, and resulting condensation can lead to mould growth and significant building material damage, such as timber rot, corrosion and reduced insulation effectiveness.

Building design in tropical climates historically3 has been based on passive design principles to maximise natural ventilation, moderate solar gain and exploit natural cooling as a route to delivering occupant comfort. Successful designs account for the specific microclimate of the building’s location, including factors such as the surrounding shading, wind patterns and any local heat island effect. These were traditionally exploited, as in the example of the Malay house illustrated in Figure 2 (on next page). Passive solar techniques, such as orientating buildings towards the sun and selecting materials with favourable thermal mass or light-dispersing properties, can significantly impact the building’s thermal performance. Singleglazed façades can be more energy efficient than double- or triple-glazed systems, if appropriately specified. Shading can make a significant impact, with horizontal shading more effective than vertical shading

Continuing professional development (CPD) is the regular maintenance, improvement and broadening of your knowledge and skills to maintain professional competence. It is a requirement of CIBSE and other professional bodies. This Journal CPD programme can be used to meet your CPD requirements. Study the module and answer the questions on the final page. Each successfully completed module is equivalent to 1.5 hours of CPD. Modules are also available at cibsejournal.com/cpd

Figure 1: Köppen-Geiger climate classification for tropical regions Peel, MC, Finlayson, BL, and McMahon, TA, (University of Melbourne) CC BY-SA 3.0

because of the high solar altitude. Roofs will benefit from high solar reflectivity to minimise heat gains.

The wind climate can usefully influence the building’s form and orientation, since prevailing winds can assist in ventilating internal and external spaces, as well as increasing heat transfer from the building’s external surfaces. This will guide the choice of building characteristics, such as wide openings in the external envelope, high and low ventilation openings, high ceilings, and wind-catching devices. The concept of ‘layout permeability’4 relates to the building layout’s impact on the flow of air (as opposed to the building envelope’s ‘fabric permeability’), and this will determine the opportunity for effective wind-driven cross-flow and stackinduced natural ventilation. Openings in the building envelope designed for ventilative purposes need to be well considered so that they can also be suitably protected against encroaching fauna, as well as providing appropriate security and privacy. Where stack ventilation is employed, it is unlikely to be useful when internal conditions are cooler than the outside, as warm, humid outdoor air will be drawn down into the space – some form of opening control will be required to overcome this. Unfortunately, many tropical locations are not immune to the challenges of poor external air quality, which may limit the application of natural ventilation solutions.

Successful passive design will use climatic conditions to reduce the need for air conditioning – maximising thermal exchange with the environment through natural air movements. Ventilative air movement can be used to aid the removal of internal heat gain, while also improving comfort and personal cooling by increasing evaporation from the body. Because of this, people in tropical areas tend to prefer slightly elevated air speeds compared with those in temperate zones.

A slightly elevated design room temperature with greater air movement is desirable to minimise cooling loads.

Carefully considered selection of building materials and form can minimise heat gains and maximise heat losses. Insulation can provide significant benefits, particularly when installed appropriately in roof structures in both passive and actively controlled buildings. However – as with any material that offers a significant thermal resistance – when used in buildings that are mechanically cooled, exceptional care needs to be taken to ensure that there is no air leakage, nor vapour transfer through (or alongside) the insulation. Otherwise, there will be a very high risk – and practical certainty – of condensation that, unless able to reevaporate quickly, is likely to adversely affect the building fabric.

Inappropriately located insulation may also reduce the building’s ability to reject heat at night. In areas with minimal diurnal temperature swings, the application of thermal mass may not be desirable if it absorbs and retains too much solar radiation – lightweight buildings that cool quickly in the evening may be preferable.

Dehumidification is a key aspect of the cooling load. Traditional design practice in temperate climates tends to assume a constant relationship between sensible and latent heat loads, which is often inaccurate for tropical applications. As highlighted in the useful guidance1 produced by WAG, air conditioning systems in humid areas must be primarily designed to manage humidity, as well as control temperature. The dew point of outdoor (ambient) air is frequently above the setpoint temperature of air conditioned spaces, meaning condensation can occur anywhere outdoor air contacts a cooled surface. WAG notes that setting air conditioning dry-bulb temperatures at, or close to, 27°C can still provide comfort in

conjunction with increased air movement from ceiling fans, potentially providing an effective temperature (ET) of 24°C. (Unlike the CIBSE operative temperature, ET additionally incorporates humidity.) A higher dry-bulb temperature may also reduce running costs, as well as the risk of condensation and mould. Thermal buffer zones, controlled at intermediate temperatures, can help reduce thermal shock when moving between indoor and outdoor spaces.

For larger spaces, air conditioning requirements should ideally be considered in zones; such zones may not be immediately apparent and may require parametric computer modelling to establish zones of environmental control within the building. Air conditioning installations, whether centralised or decentralised, should be designed to meet the needs of every zone, and the control regimes related to the use of each zone. Mechanically cooled buildings should be slightly pressurised by ensuring that the supply air volume flowrate exceeds that of the total exhaust flow, preventing the uncontrolled ingress of warm, humid air. However, as WAG1 notes, effective pressurisation is only achievable in buildings with a fully encapsulating insulated vapour barrier.

Tropical regions are likely to experience consistently high temperatures, intense solar radiation and high humidity levels throughout the year, which places a significant load on cooling systems – the design must, therefore, account for these. Systems primarily focused on sensible cooling may not adequately remove moisture from the air. This can happen when oversized systems quickly reach the set temperature and shut down before dehumidification is complete – keen sizing of cooling equipment may be an advantage in terms of moisture control. To mitigate this, certain system configurations can be employed. For example, the WAG guidance1 recommends using multi-circuit cooling coils instead of a single continuous coil. This approach maximises the coil surface area below the air dew point, even during periods of reduced sensible loads, improving dehumidification.

Centralised systems may offer advantages in terms of diversity and backup capacity, while decentralised systems can be more flexible. In centralised air conditioning systems and dedicated outdoor air systems (DOAS), incoming air must be conditioned before it enters the space. Air quality in tropical cities may be poor as a result of emissions and low wind speeds, so, in such locations, ventilation systems must address the requirement for outdoor air while also filtering out pollutants.

The dehumidification of fresh air accounts for a large portion of a tropical building’s

Figure 2: A traditional Malay house (after ‘The Malay House’, Lim Jee Yuan, 1987)

cooling load, and handling latent and sensible loads separately can provide a more resource-efficient solution. Water vapour may be removed with a variety of techniques, including: rotary dehumidifiers (employing adsorbent such as silica gel); liquid desiccant dehumidifiers (employing liquid absorbents such as lithium chloride); heat pipes; chilled water or direct expansion (DX) coils; and membrane dehumidification (see boxout). These can be arranged to focus primarily on moisture removal without sensibly overcooling the space. Where absorbent and adsorbent processes are used, there may be opportunities to use waste heat or solar thermal sources for the regeneration process. Heat recovery systems, such as thermal wheels, can be used to transfer heat between air streams, but may be less viable in tropical climates.

Environmental systems should be designed for controlled part-load conditions, as they often operate below their maximum capacity. Variable-speed drives and other modulating technologies can enhance system performance and save energy. However, part-load operation can be troublesome with variable-speed cooling systems, as they need to be carefully selected and controlled to ensure they still remove moisture when humidity is high while sensible cooling loads are low. Rather than a single large unit, it may be advantageous to select multiple staged units that can each work nearer peak capacity.

Conditioned air should be supplied to the space through diffusers that induce room air into the primary air supply, so reducing the risk of condensation by ensuring the cooler supply air is mixed with room air before contacting any building surface. Displacement ventilation – with relatively large volumes of air supplied at low velocity near the floor with relatively high temperatures – may provide an alternative means of supplying air while reducing the risk of condensation. Suitably regulated demand control ventilation (DCV), using CO2 sensors, can adjust the mechanical (or, potentially, natural) fresh air intake based

on occupancy levels, which can reduce the space dehumidification load.

Unitised, decentralised equipment – such as fan coil units (including variable refrigerant flow [VRF] and ‘split’ air conditioners) and radiant cooling – may be used to reduce the load on the mechanically supplied air. Such systems need careful selection and sizing so that they are suitably controllable to meet coincident sensible cooling and to meet any dehumidification requirements, even at part-load conditions. Any radiant cooling that is used to supplement convective cooling must avoid creating surface temperatures below the room air dew point so as not to produce uncontrolled condensation.

Mixed-mode systems can be employed to combine both passive and active cooling methods to enhance comfort and minimise energy use. For example, natural ventilation may be suitable as free cooling during cooler or unoccupied periods, particularly at night.

The WAG guidance warns that any part of mechanical systems with a surface temperature below approximately 25°C is susceptible to condensation and needs fitting with a suitable insulated vapour barrier. Airtightness of ductwork is essential to avoid leaks of cooled air, which can also pull untreated air into building cavities, leading to condensation and mould growth. Ducted fan coil units should always include a separate insulated safety drip tray below the unit. Equipment needs to be acclimatised for tropical conditions, especially if installed outdoors. This involves using materials and components that are resistant to corrosion, ultraviolet radiation, and extreme temperatures. Outdoor equipment needs to be protected from corrosion, and should withstand a temperature range of 13°C to 32°C, along with heavy rainfall. The alternative is illustrated in the example of Figure 3. Refrigeration plants must be designed to withstand high ambient temperatures and humidity levels. Any externally mounted equipment will –depending on location – be exposed to the local flora and fauna, and will require suitable

Membrane dehumidification

Membrane-based dehumidification units operate by selectively separating water vapour from the air using a specialised membrane, and can function as standalone units or as predehumidification components within air conditioning systems.

The dehumidification process is driven by the vapour pressure difference between the incoming humid air and the relatively dry exhaust air from a building. The membrane unit typically features an

air-to-air cross-flow moisture exchanger, similar in design to the heat exchangers used in energy recovery. Humid primary air and dry secondary air pass on opposite sides. The membranes are often hydrophilic and made from polymeric or nanoporous (micro/meso/macro) materials. Common membranes include hydrophilic materials such as polyvinyl alcohol (PVA) and nanoporous metalorganic frameworks (MOFs), microporous zeolites, and mesoporous silica-based

protection and a regular inspection schedule.

Renewable energy sources are particularly pertinent in tropical regions because of the consistent availability of solar radiation and the need to reduce reliance on fossil fuels for cooling and other energy demands. Solar PV is a key renewable energy technology for tropical climates and because of the high proportion of diffuse light, thin-film PV modules may perform better than crystalline silicon-based cells. PV panels can be integrated into various parts of a building, such as façades and roofs, and can act as sunshades.

The reliability and serviceability of the plant are key considerations. Locally sourced materials and equipment are generally beneficial, as they are better understood by local artisans. For building longevity and beneficial impacts on life-cycle carbon and cost, the ease of maintenance and operation by local teams is paramount. It is essential to programme in appropriate testing and commissioning to ensure installed systems operate as designed and achieve the desired safety, comfort and efficiency levels. Properly planned and delivered contextualised education of building users and operators plays an important part in the development process to ensure that they benefit from the building’s best performance. l

materials. Moisture from the incoming air is adsorbed onto the membrane surface, transported through the membrane, and desorbed into the exhaust air stream. While the dehumidification process itself does not require electricity, additional fan power is necessary to move air through the cross-flow exchanger.

Current technologies achieve maximum vapour transfer efficiencies of approximately 50% under tropical conditions.

Figure 3: A condensing unit ravaged by the climate

Module 245

March 2025

1. Which of these countries is most likely to be tropical wet?

A India

B Mauritania

C Papua New Guinea

D Thailand

E Vietnam

2. Which reference is noted as identifying that many failures are due to a lack of understanding by building professionals?

A ASHRAE guidance

B Building and Environment paper

C CIBSE guidance

D UN-Habit guidance

E Western Australian Government guidance

3. Why is it recommended that buildings are slightly pressurised?

A To ensure that air leaking through the insulation is suitably cold

B To increase the velocity of air in the space to enhance comfort

C To maintain the entrainment of room air at the supply diffuser

D To prevent the ingress of warm humid air from outdoors

E To reduce the need for extract fan power and so reduce energy consumption

4. Which one of these is not noted as a common membrane material for dehumidification?

A Metal-organic frameworks

B Polyethylene

C Polyvinyl alcohol

D Silica-based materials

E Zeolites

Product of the month

Ideal Heating Commercial introduces 10-year warranty on Evomax 2 boiler

Ideal Heating Commercial has announced a 10-year warranty for its bestselling commercial wall-mounted boiler, the Evomax 2. Recognised as the UK’s top-selling commercial boiler, the Evomax 2 is designed specifically for the UK market and manufactured in Hull, where the company has made significant investments in its production facilities.

Andy Forrest, national sales manager at Ideal Heating Commercial, said the new warranty reflects the company’s confidence in its market-leading boiler and its commitment to British manufacturing. ‘Ideal Heating Commercial is one of the few true British manufacturers left in the heating industry,’ he stated.

The enhanced warranty covers 10 years of parts and labour when the Evomax 2 is installed with an Ideal Heating pipework header kit,

UK first for Panasonic M Series heat pump

A bungalow in Thurso, Scotland, has become the UK’s first home to have the Panasonic Aquarea 9kW M Series heat pump installed. Homeowner and installer Ryan Pollard, of RDI Renewables, replaced his gas boiler to improve energy efficiency and meet his family’s high hot-water demand.

The compact and stylish system, featuring Panasonic’s Smart Cloud controls and R290 refrigerant, delivers outstanding performance, with a seasonal coefficient of performance average of 4.85.

l Visit www.aircon.panasonic.eu

featuring a plate heat exchanger, and commissioned by Ideal Heating Commercial. The company offers commissioning as a free service, ensuring the boiler is operating correctly from the outset. Installers also save time and money with this service.

As part of the 10-year warranty terms, an enhanced appliance and primary system check is required, at a charge of £250 per boiler.

Jung Pumpen expert advice available in the UK

Jump Pumpen has announced that Matthew Camille, contract manager at Pump Technology, is the key contact for enquiries about its wastewater and sewage pumping solutions.

Berkshire-based Pump Technology is the UK’s largest authorised supplier of Jung Pumpen equipment.

Camille will be available by phone or email to offer expert advice or answer technical questions, or if you wish to request a detailed pump selection for any project specification.

l Call 0118 9821 555 or email Matt@pumptechnology.co.uk

This new offer does not replace the five-year warranty, which remains available with free commissioning.

The Evomax 2’s popularity is attributed to its reliability, efficiency and ease of installation. It delivers up to 99.6% full-load efficiency and up to 110% part-load efficiency, with a high turndown ratio of 5:1.

The boiler meets low-emission standards, with NOx levels of less than 40mg/kWh (Class 6). Available in outputs from 30-150kW, it can scale up to 900kW when used in cascade formation. To further simplify cascade installations, Ideal Heating Commercial offers lowheight and standard frame and header kits, as well as an online configurator tool. A three-boiler cascade can be assembled in less than 90 minutes, as demonstrated in the company’s video.

l For more information, visit idealcommercialheating.com

Hot-water solution delivered for Big Motoring World

ACV UK’s WaterMaster Evo 35 has been installed at Big Motoring World’s headquarters in Gillingham, Kent, to provide a reliable, energy-efficient hot-water system for its new gym.

The unit’s stainless steel heat exchanger and tank-in-tank technology ensure a comfortable and continuous supply of hot water for showers and washbasins.

The system’s quick recovery time reduces costs and emissions, while ACV UK’s outstanding technical support was key to the decision. The installation took just two weeks.

l Visit www. acv.com/gb

Q&A

WiBSE North West (NW) was relaunched in June to coincide with Women in Engineering Day. It has quickly become a cornerstone of support and empowerment for women and gender-diverse professionals in Manchester’s building services industry. Its monthly Supper Club was created to provide a welcoming space where attendees can share experiences, foster connections and inspire one another. In just over six months, the club has evolved into a vibrant network, proving the importance of community in a traditionally male-dominated field.

AWhy is WiBSE North West important?

Many women in the industry experience the feeling of being the odd one out when walking into a maledominated space. WiBSE NW was founded to address this issue by giving women and gender-diverse individuals a platform to feel seen, heard and supported. Through events such as the Supper Club, the group fosters inclusivity, encouraging members to build relationships that help them navigate their careers confidently.

Q What kind of events do you host?

AOver the past six months, WiBSE NW has hosted impactful events that highlight the importance of connection. The Supper Club is rooted in face-to-face engagement, allowing participants to build authentic relationships and draw strength from shared experiences. Other events have included the WiBSE Winter Warmer at the Manchester Christmas Markets. These activities go beyond socialising; they emphasise the belief that informal, welcoming spaces can strengthen professional ties and foster long-term support networks.

As we celebrate International Women’s Day this March, WiBSE North West representative Rachael Gilbert explains how starting a monthly Supper Club in Manchester has built a stronger, more inclusive industry

AHow is WiBSE expanding its reach?

The success of WiBSE NW has attracted interest from other regions and associations looking to set up their own networks. I will support this growth by offering advice and insights into launching a group. Whether it is guidance on organising events or sharing experiences that make a difference, WiBSE is a resource to champion inclusivity and strengthen local industry networks. This year, the group is expanding its reach regionally, hosting a mixed quiz night, the first event to invite men. Seeing men warmly embrace the WiBSE space with respect and enthusiasm made the evening even more meaningful, highlighting the power of inclusivity and allyship. Over the rest of the year, WiBSE NW will continue with its Supper Club and

“Informal, welcoming spaces can foster long-term support networks”

hopes to run CPD events on confidence and leadership. The commitment to fostering spaces where everyone feels valued will continue to guide its growth.

The Supper Club concept has been replicated in the south, with WiBSE committee member Harriet Morphew hosting WiBSE Southern’s first dinning event on 7 March, in Brighton.

Q What top tips would you give to someone looking to launch a WiBSE network in their region?

A Be brave – you’re already ahead just by considering this step! Connect with your local region, because support from groups such as CIBSE NW can help spread the word. Encourage colleagues, as a small industry thrives on committed connections. Set a date – momentum starts with one event, such as WiBSE NW’s monthly ‘WiBSE Wednesday’. Keep it small; around 12 people for manageable conversations and organic growth. Choose a comfortable venue for face-to-face networking. Promote it online via Eventbrite, LinkedIn or CIBSE emails, and stay connected.

Q What are the benefits of joining WiBSE nationally?

A Joining WiBSE at a national level offers the opportunity to work alongside the main WiBSE committee. Working at this level means contributing to national awareness initiatives, amplifying the group’s voice, and advocating for gender diversity and representation. Involvement in the broader WiBSE network is a powerful way to make an impact and champion change, ensuring that everyone in the industry has the opportunity to thrive. l

Email WiBSE chair Jessica Glynn at jessica.glynn@atelierten.com

Rachael Gilbert

Get ready for InstallerSHOW

InstallerSHOW - 24-26 June 2025, NEC Birmingham - is leading the charge towards sustainable building and retroﬁtting with the launch of InstallerBUILD in 2025, and you’re invited!

InstallerBUILD will tackle the key issues of building sustainably and retroﬁtting our buildings, encouraging collaboration between trades and speciﬁers as we head towards Net Zero and a more sustainable built environment.

The

24-26 June 25 NEC Birmingham

HAUS, a full scale two-storey house build, will serve as the heartbeat of InstallerBUILD, surrounded by manufacturers and suppliers who share the vision to showcase sustainability and shine a light on innovation.