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 life-cycle 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

About the authors

Louise Mansfield is legal director at Bevan Brittan; Andrew Rolf is healthcare technical advisory lead at Mott MacDonald; and Helen Sturdy MCIBSE is 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
² Construction Leadership Council: Delivering the Golden Thread: Guidance for dutyholders and accountable persons (August 2024)

Further reading

These and other resources, including a webinar, are available on the Estates and Facilities Collaboration Hub, under the ‘fire section’. 

The post A safer future for NHS estates appeared first on CIBSE Journal.

The workshops were funded by the British Embassy in Beijing and the SuDBE Programme of Chongqing University, and aimed to bring experts together to address some of the most pressing challenges in the field of decarbonisation and climate resilience.

This collaborative initiative brought together UK and Chinese industry experts, policymakers, government officials and academics – first in London and then in Chongqing – to present and discuss current policies within the sectors of buildings and infrastructure.

The result is a report to both governments on various approaches to decarbonisation policy frameworks, as well as a roadmap outlining urgent research needed to support these frameworks.

The CIBSE technical team participated in both workshops. Head of net zero policy Julie Godefroy, research manager Zoe De Grussa, and I covered a range of policies, standards and guidance.

These included national policies such as Part O, and the role of the recently launched Net Zero Carbon Buildings Standard (NZCBS) in driving industry decarbonisation efforts. We also discussed CIBSE TM59 and future weather files, and how they were being used to future-proof buildings and services for higher temperatures.

CIBSE representatives worked with Chinese and UK academics and government officials to exchange knowledge, expertise and insights on policies to drive decarbonisation and adaptation in the built environment. The workshops offered a unique opportunity to understand different policy approaches and start a collaboration between both countries on climate resilience and decarbonisation.

The built environment is one of the greatest emitters of carbon and other greenhouse gases in the UK and China, and yet policy on the decarbonisation and resilience of the sector is underdeveloped in both countries. As a result, current efforts are uncoordinated and ineffective to meet any national or global carbon-reduction targets.

In China, the Green Buildings policy framework sets national standards that address: safety and durability; health and wellbeing; occupant satisfaction; resource efficiency; and environmental sustainability. The policy is then adapted at regional level to address local climate, financial and social characteristics, and resource availability and requirements.

China’s officials highlighted that the country’s future focus is on financial incentives (developing green finance schemes to promote energy reduction and renewable energy generation), more national and regional regulation development, and data gathering through monitoring strategies.

Although China’s construction sector has focused mainly on new buildings and developments, they see future decarbonisation efforts focusing on the refurbishment of existing stock and the need to learn large-scale retrofit strategies from the UK.

China’s top-down approach, unlike the UK bottom-up style, provides a clear roadmap for achieving national targets. The UK government provides national policy such as Part L and Part O of the Building Regulations, but there is no consistent framework on decarbonisation and resilience.

Rather, the industry is developing standards such as the UKNZCBS, to meet government targets such as net zero by 2050. The voluntary nature of standards and lack of regulatory and financial incentives means there is no clear road to decarbonisation.

However, carbon emissions in the UK have already peaked, and are currently on a downward trajectory. In China, government policy is still working towards reaching peak carbon emissions by 2030 and carbon neutrality by 2060.

Furthermore, in the UK, the building industry is already quantifying the embodied carbon of buildings (and lobbying for government to regulate it – Part Z), while in China there is little consideration of embodied carbon; instead, the main focus is on reducing operational carbon.

Ultimately, each approach has its positives and negatives, with challenges in implementation, innovation, regional adaptation and incentivisation. But a common goal connecting both countries is the decarbonisation of the sector while securing building assets’ longevity and long-term resilience to climate risks.

CIBSE’s ongoing involvement in shaping policy for a sustainable, net zero future is a key part of the Institution’s global mission to lead and support the built environment in responding to the climate crisis.

The post International rescue: China’s route to decarbonisation appeared first on CIBSE Journal.

According to analysis from Hays, marking the 2025 Salary Survey, economic optimism among professionals has dropped significantly, with only 21% expressing a positive outlook, compared with 46% last year.

Pay rises are also down, with building services salaries rising by only 1.3%, lower than the previous year’s 2.5% increase. This modest growth in pay contributes to dissatisfaction and retention challenges among employees.

Despite the pessimism, the sector continues to demonstrate resilience in the short term, with 83% of employers planning to hire within the next 12 months, a modest rise from 81% last year. And 37% of employers are hopeful about job creation prospects over the next two to five years.

Employers have their own challenges. Key concerns include talent retention (52%), skills shortages (51%) and managing change (40%), all of which threaten to disrupt progress over the coming year.

The annual industry survey conducted by Hays for CIBSE Journal paints a clear picture of the challenges facing engineers. Issues such as reduced career progression opportunities, dissatisfaction with pay, and the looming impact of AI adoption are reshaping the landscape of building services engineering (see ‘AI: friend or foe’). These hurdles, however, also present opportunities for innovation and growth if tackled strategically.

Hays has coined the phrase ‘The Great Dissatisfaction’ to describe the bubbling frustration among building services engineers regarding career progression. Opportunities for advancement appear to have dwindled, with only 62% of engineers perceiving room for growth, down from 78% last year. Positivity about career prospects has also declined, dropping from 68% to 60%.

Phil Jackson, Hays

‘Building services engineers are currently feeling dissatisfied and unable to progress in their roles for several reasons – however, it’s not due to a lack of opportunity within the market,’ says Phil Jackson, director at Hays.

‘Numerous professionals have reported a lack of transparency regarding career progression and opportunities, which needs to be addressed by firms. This lack of clarity can lead to frustration and a feeling of stagnation among employees.’

Mike McNicholas, managing director at AtkinsRéalis, agrees, emphasising the importance of creating accessible career pathways. ‘One of the key things is giving visibility to everybody on what progression is available. We need to provide a roadmap that allows people to upskill themselves in the language, the process and the key features of one domain compared to another. We call it talent resilience, encouraging engineers to expand into different ways of working.

McNicholas says AtkinsRéalis works hard to ensure formal pathways for lateral fluidity, as well as vertical progression, whether it’s practising a craft across multiple areas, stepping up to project management, or expanding into other disciplines. He says this is essential in ‘developing the skills in our employees to be able to step up and take on different roles’.

Mike McNicholas, AtkinsRéalis

The skills shortage remains one of the most pressing issues for the industry, with 96% of firms reporting difficulties over the past year, up from 93% in 2023. Root causes include fewer entrants to the industry (56%), competition (49%) and salary concerns (31%).

‘There’s not a general shortage of capability; we’ve got lots of talent,’ McNicholas explained. ‘But when we hone it into specific areas, the shortage becomes very acute. Key areas like net zero sustainability, AI, and digital skills are particularly challenging.’

Addressing these gaps requires a multifaceted approach. Danny Madden, director at S I Sealy, highlighted the importance of structured training and mentorship. ‘Introducing employees to structured pathways, particularly CIBSE chartership programmes, will create stronger, more experienced engineers for the future,’ he says.

Madden also raised the importance of practical experience. S I Sealy has a reputation for training and developing young engineers. ‘We work on multiple project sizes, so it exposes an engineer to lots of different things,’ he says.

‘No-one is stuck designing ventilation for five years. They work on the whole project from cradle to grave, which helps engineers learn skills across all RIBA design stages.’

Danny Madden, S I Sealy

Madden says: ‘I’ve spoken to young engineers who left their companies because they were stuck on feasibility stages for years and never saw their designs implemented. I think this can really limit development.’

ChapmanBDSP’s apprenticeship programme typifies one potential solution. Kathryn Cox, HR director at ChapmanBDSP, says one of its apprentices from the first cohort of the CIBSE apprenticeship levy has just passed his endpoint assessment.

‘After six years and four months at the company, he is now a senior mechanical engineer. These success stories highlight the value of recruiting and training talent within the organisation,’ says Cox.

Apprenticeships are ‘crucial cogs’ when it comes to closing skills gaps. ‘There are firms who are doing excellent work in this area. Overall, there’s an opening up of pathways into building services that is important for versatility and helping to improve workforce diversity,’ says Jackson.

Over the past year, building services salaries rose by only 1.3%, lower than the previous year’s 2.5% increase. Jackson explained that ‘post-pandemic, there was an influx in demand across building services, which added pressure to firms to increase pay quite rapidly to attract staff. That market has now calmed, and salaries are levelling out – a stabilisation that needs to happen from time to time’.

Kathryn Cox, ChapmanBDSP

Retention challenges are exacerbated by dissatisfaction with career progression and pay. Around 43% of building services engineers say they intend to look for a new job in the coming 12 months, less than the 57% who wanted to move last year.

Of those who intend to look for a new job, 65% say they could be tempted to stay at their organisation if they were to offer better pay and benefits.

Jackson highlighted alternative strategies to compensate for limited salary growth. ‘Firms are being creative in what they can offer outside of salary,’ he says. Top benefits revealed in the survey include life insurance, pension provision and flexible working.

Cox agreed, saying that ‘companies are having to do a lot more to keep staff. Better employee benefits and a deeper understanding of what employees want all play a significant role in retention. People are looking at things much more holistically’.

Building services engineers value purpose and sustainability in their roles. While 56% feel their organisation’s employee value proposition aligns with their experience, 44% disagree. With 85% prioritising purpose and 82% valuing sustainability, Cox says that younger generations, in particular, are increasingly seeking social and environmental value, often prioritising it over salary.

‘Employers must provide clear career pathways and invest in continuous learning to drive their employees’ growth,’ Jackson explained.

McNicholas also highlighted the importance of mentorship and advocacy. ‘We’ve implemented a sponsorship programme for underrepresented groups. It’s aimed at accelerating their careers and creating advocacy for their talent. This approach has been instrumental in unlocking potential and driving retention. We often find our ambition for an individual is more than it is for themselves. We can see where they can take their careers.’

Madden highlighted that S I Sealy has never brought in an external director. ‘This really helps with retention, because it shows the people who want to progress that the opportunity is there,’ he says. ‘It’s so important to be inclusive, making sure people feel part of a team and creating that positive culture at your company.’

Cox remains optimistic. ‘Yes, there are challenges,’ she says. ‘Post-Budget, companies face greater expenses, but there are so many great opportunities on the horizon for the industry. It’s an exciting time.

The post Bubbling to the surface: 2025 Hays Salary Survey appeared first on CIBSE Journal.

The study evaluates the ‘heat pump readiness’ of existing UK housing, with a conclusion that flies in the face of many an established assumption that widespread radiator upgrades and building fabric improvements are essential for heat pump adoption.

Upgrading radiators is common when replacing a boiler with a heat pump in the UK, and is often more cost-effective, but can still be expensive. The paper notes that replacing an entire home’s radiator network can cost £6,000–£7,500. Add in the heat pump and this exceeds the £7,500 grant from the UK’s Boiler Upgrade Scheme. It also adds installation time and disruption to the process. Analysis from this research suggests that the transition to heat pumps may be less disruptive and costly than previously thought.

The research and paper were developed and written by Laurence Childs (UCL), George Bennett, (Department for Energy Security and Net Zero – DESNZ), Stephen Watson (Loughborough University) and Grant Wilson (University of Birmingham). They present a novel approach to evaluating the heat pump readiness of existing UK homes by using diagnostic data from approximately 4,600 domestic heating systems. The aim of the work was to determine the proportion of homes that could switch to heat pumps without needing costly upgrades to their radiators or building fabric. This is a crucial question, because the UK plans to replace gas boilers with heat pumps to achieve net zero carbon emissions by 2050.

Previous survey-based assessments have indicated that 90% or more of UK dwellings would require new radiators to deliver sufficient heat at the lower flow temperatures delivered by heat pumps, particularly low temperature heat pumps (LTHPs) that typically operate effectively with flow temperatures below 55°C.

The study highlights the limitations of survey-based methods for assessing heat pump readiness, because surveys often overestimate heat loss and underestimate radiator output. Measured data captures the real-world performance of heating systems and the heat demand set by occupants.

The study emphasises the need to employ lower flow temperatures when using heat pumps. Gas boilers typically operate at 60-70°C, while heat pumps are more efficient at flow temperatures below 45°C. The analysis revealed that many homes already operate at flow temperatures compatible with heat pumps.

The study used diagnostic data from internet-connected combi boilers, which included gas power input, flow temperature of water going to the radiators, and control information on whether the boiler was providing space heating or domestic hot water (DHW).

The data was used to analyse the relationship between heat demand, flow temperature, and the potential for using heat pumps without upgrades. The study developed a method to estimate the underlying heat demand of a dwelling by using the power profiles of boiler operation, accounting for the heating system’s thermal mass and the rate of heat transfer to the dwelling.

The annual heat demand of boilers in this study closely aligns with the distribution modelled by the National Housing Model, as shown in Figure 1. This suggested that the sample was representative of UK boiler-heated homes.

Figure 1: Comparison of annual gas power input of boilers in this study and annual space heating demand for gas-heated dwellings as represented in the National Heating Model

A theoretical relationship between radiator power output and flow temperature was used to determine the required flow temperature to meet the estimated heat demand. The results were categorised based on maximum flow temperature and peak heat demand, to assess if homes could operate without upgrades when employing LTHPs or high-temperature heat pumps (HTHPs, which typically can operate efficiently with flow temperatures of 65°C). Different time averaging intervals (six, three and one hour) were used to determine the impact of heat scheduling on flow temperature requirements. A longer averaging interval better represents the continuous heating profiles typically used by heat pumps.

The findings suggest that the costs and disruption of heat pump installation could be substantially lower than previously predicted. The use of real heating system performance data can supplement survey-based assessments to identify more accurately where upgrades are needed, thereby facilitating a more rapid heat pump deployment at a national scale.

The study underscores the potential of data-driven testing procedures for designing future heating systems that could lead to more accurate specification of heating systems and enable increasingly cost-effective designs of low carbon heating.

The results also suggest the potential benefits of hybrid heating systems, where supplementary electric heaters or boilers are used to meet peak heat demand, reducing the need for extensive upgrades. The study demonstrated that spreading out the heat load through longer heating periods can reduce the required flow temperatures.

The study analysed a single year of data from boilers in England and lacked detailed information about the associated buildings or heating systems, relying solely on what could be inferred from the boiler type. The absence of return temperature data for most boilers necessitated estimating heating system temperatures. The study highlights that milder winters driven by climate change could further reduce flow temperature requirements.

While the estimated thermal mass of heating systems fell within a plausible range, it was probably overestimated; however, sensitivity analysis confirmed that this had minimal impact on the findings.

Radiator cooling rates were modelled using a simplified interpolation method, which may not fully capture the exponential nature of radiator cooling. A straightforward filter was applied to exclude DHW events, assuming minimal space heating demand during these occurrences.

The study acknowledges that the operational conditions during the data collection period may not reflect typical averages. Gathered after the energy crisis, the data might also reflect occupants underheating their homes. Furthermore, its focus on whole-system data limits the ability to distinguish whether a few critically undersized radiators require replacement or if an entire system upgrade is needed – scenarios that have significantly different cost implications.

Figure 2: A set of cumulative distributions showing the predicted proportion of UK dwellings that could meet heat demand at low temperatures for the three different averaging models, and that applied by the original BEIS survey model

Additionally, the study does not consider other factors affecting heat pump readiness, such as space constraints, noise concerns, or electricity grid limitations.

The paper suggests that there will be varying requirements for fabric and radiator upgrades across dwellings when installing heat pumps, but the extent of upgrades appears lower than previous survey-based estimates.

As illustrated in Figure 1, averaging heat demand over six hours, the model found 31% of dwellings could operate at 55°C or lower without radiator upgrades, compared with 10% in Department for Business, Energy and Industrial Strategy (BEIS)¹ surveys. Similarly, 66% of dwellings could operate at 65°C or lower without upgrades, compared with 46% in BEIS surveys. This indicates that up to two-thirds of UK homes may be suitable for HTHPs, with around one-third also ready for LTHPs, provided heating controls allow heat load spreading.

This is a considerably higher figure than previous survey-based analyses, which suggested almost all homes would need radiator upgrades when switching from gas boilers, and indicates a larger potential for heat pump adoption in the UK using existing infrastructure.

The full paper, with references, is available for free from BSER&T at journals.sagepub.com/home/BSE

Notes
BEIS existed until 2023, when it was split to form the Department for Business and Trade and DESNZ.

The post How ready are UK buildings for heat pumps? appeared first on CIBSE Journal.

Tall, slender columns punctuate the internal valley. These burgeon into a canopy-like covering of leaf-shaped panels inspired by China’s native ginkgo trees. The columns support a flat, slender roof that overhangs the 150m x 150m square building. A series of skylights punctuates the roof, flooding the interior with daylight filtered through the ginkgo-leaf canopy.

A 16m-high glazed façade wraps around the giant building to ensure its spectacular interior is on display to passers-by. The glazing is self-supporting, without so much as a steel strut or glazed fin to mar its transparency. The façade’s designers, Eckersley O’Callaghan (EOC), say this is the largest self-supporting glass façade in China and the tallest of its type ever completed.

It was an achievement recognised by the judges of the Society of Façade Engineering Façade 2024 Design and Engineering Awards, when the scheme won the International New Build category. The judges described it as: ‘A beautiful, sculptural yet highly technical and complex design – superbly detailed.’

EOC’s involvement with the project started in 2018, when it was appointed as façade consultant to the scheme’s architect, Snøhetta, after it won the international design competition with its scheme to ‘reinstate the library’s relevance in the 21st century’.

The firm’s role was to develop the façade concept to ensure it would perform as intended, while rationalising the detailing so the scheme could be built by local teams. ‘We helped steer the design direction and, by liaising with contractors and fabricators, were able to understand the costs and buildability of the various façade proposals,’ says Minxi Bao, associate at EOC.

The architect’s initial concept was based on a glazed façade formed from a series of vertical, 3.2m-wide, curved glass panels – like giant, semi-circular sections of transparent channel stood on their ends. The glass was positioned so that it curved in opposite directions on adjacent panels, to give the walls a rippling, corrugated appearance.

The benefit of this solution, from a structural perspective, was that the curve helped the panels to resist loading, says Bao: ‘We liked the idea, because it gave the façade significant geometrical  stiffness, but we understood it would be a challenge to fabricate curved units at this scale.’

EOC went to the world’s leading glass suppliers to find a potential manufacturer for the curved panels. The engineer asked for feedback on the manufacturing feasibility of the panels at two heights: 16m and 20m. This showed that, while it was possible to realise the concept at both heights, the cost of doing so would have been ‘prohibitively expensive’, according to Bao.

Developing an economical solution

EOC set about developing a more economical façade solution that would not compromise the architectural concept. It changed the glazing from curved to a more pragmatic flat panel, which it arranged in a zig-zag fashion. ‘We came up with a pleated solution using flat panels that would be cheaper to manufacture and easier to build,’ explains Bao.

Working with the architect, the engineers also opted for the lower roof height of 16m, to ensure a buildable design that would keep the scheme within cost and buildability constraints.

In-depth structural analysis was carried out on the folded plate proposal to establish the depth and modulation of the plate, the relative stiffness of joints and the required thickness of glass. Specific areas of the façade – such as the building’s corners and its interaction with the portal frames spanning the entrances – also required detailed investigation to ensure the solution’s viability.

To accommodate the vertical movements of the roof, the top connection to the main structure features a slotted hole, allowing the roof to deflect downward by 50mm and upward by 30mm, without loading the glass

The flat, insulating glass units that make up the zig-zag walls are 15.8m high and approximately 2.5m wide. They are assembled from a laminated outer glazed unit comprising five panes of glass bonded together by SentryGlass interlayers. This is backed by a slimmer, two-ply inner unit. The interlayer allows the separate glass plies to act as one. The gas cavity is created by a spacer bar and sealant around the perimeter of the glass panes.

Mechanical connections were investigated for the glass-to-glass connections between adjacent panels, potentially involving cast-in inserts within the glass.

Ultimately, for visual clarity, a simple structural silicone-bonded joint was adopted to attach the vertical edge of one unit to that of its neighbour. ‘The units don’t have any intermediate support along their vertical edges, so all the load needs to be resisted by the glass,’ says Bao.

The panel’s zig-zag arrangement is highly beneficial, enabling the giant glazed panels to work together to efficiently resist wind loading on the façade. Bao explains: ‘If we’d designed a completely flat façade, the glass would have had to be really thick, because we’d end up having to use a significant number of layers [to give it sufficient stiffness]; by adopting a pleated solution, we are able to use the in-plane stiffness of the adjacent glazed units.’

Accommodating roof movements

The glass façade’s design and detailing was engineered to accommodate both vertical and horizontal movements of the main structure, caused by dead loads, wind loads and seismic loads. EOC’s relatively simple solution was to accommodate roof movement in the steel retaining channels at the top and bottom of the glazed units.

Each integrated glazing unit (IGU) has a stainless-steel profile, factory bonded to its top and bottom edges. The profiles slot into steel channels at the top and bottom of the units. These are attached to the building’s structural steel frame. Polytetrafluoroethylene (PTFE) bearings line the sides of the steel profiles to enable the IGUs to slide smoothly up and down, left and right (for the in-plane horizontal) within this channel restraints.

It was not wind loading, but seismic movement that provided EOC with one of its biggest challenges – and, in particular, the interaction of the glass wall with the roof.

‘Beijing is at the junction of three seismic zones, the capital city does have a really high safety factor for earthquake action in the Building Codes,’ says Bao.

Under the worst-case seismic scenario, the building’s sizeable roof, which is held aloft on the grid of slender vertical columns, was predicted to sway by up to 120mm horizontally.

To accommodate this in-plane lateral displacement, steel hemispherical rockers positioned at the centre point of the bottom of a glazed panel allow the IGUs to rock left and right.

Vertical deflections of the main structure are either caused by dead loads, or wind loads. To accommodate the vertical movements of the roof, the top connection features a slotted hole, allowing the roof to deflect downward by 50mm and upward by 30mm, without loading the glass.(see diagram) .

EOC worked closely with the structural engineer in developing the supporting solution to ensure the building’s structure wasn’t over designed and that the architect’s vision was maintained.

To comply with Chinese code requirements, EOC used Finite Element Analysis to model the facade in detail and quantify its performance and capability to accommodate the main structure’s movements.

Controlling solar gains

The architectural requirement for the façade to be self-supporting and free from framing precluded the use of openable vents to allow passive ventilation of the giant reading room.

To keep the interior comfortable in Beijing’s hot summers and cold winters, the glazed panels have a U-value of 1.6W/m²K. Solar gain is controlled primarily by overhanging the roof, shading the façades. In addition, a bespoke high performance low-E coating applied to the glazing gives it a g-value of 0.24, to further limit the amount of heat transmitted through the glass. ‘The glass fabricator customised a specific coating for this project to ensure performance parameters would be met,’ says Bao.

On the east and west elevations, the façade varies in height from 15.8m to 8m, where it rises over a plinth of terracotta blocks, which provide a decorative facade. The 30mm-thick blocks, which are 450mm high and 2,100mm wide, appear to be bonded to the glass, but are actually attached to a subframe hidden behind.

In addition to extensive digital modelling, visual mock-ups of the façade were made to assess the quality of light transmitted to the reading room, which Bao says, ‘is quite subjective’.

The engineers were fortunate that there was no requirement for fire-rated glazing or for fire compartmentation within the glass façade. There was, however, a requirement for 120-minute separation at the glazing interface with the terracotta. This was provided using a steel plate and fire-stop detail.

From an acoustic perspective, the mass of the giant laminated glass units meant the façade’s acoustic requirement of 30dB Rw+Ctr (where Rw is the weighted sound-reduction index in decibels and Ctr is an adjustment factor to account for low-frequency noise) was satisfied for the reading room without additional acoustic treatment.

The façade developed by EOC, also helped to reduce both embodied and operational carbon.

The pleated facade provides the glass with additional stiffness, reducing the amount of material required, which cuts embodied carbon. Furthermore, additional heat energy is required to curve a glass panel, and so, moving from a curved panel arrangement to a flat panel arrangement, meant that the embodied carbon could be further reduced.

With regards to operational carbon, the use of a curved panel would have limited the number of available coatings that could have been applied compared to a standard flat panel. Hence, making use of flat panels meant that the glass could have a better thermal and solar performance, allowing the building to use less energy to heat and cool the library.

The façade also contributed to the building achieving three stars, the highest level, under China’s Green Building Evaluation Label.

The spectacular library opened its doors to the reading public in December 2023, reaffirming the library’s relevance in the 21st century. No wonder the SFE Awards judges were impressed.

The post A new chapter in façade design: Beijing’s unique new library appeared first on CIBSE Journal.

India’s rapid urbanisation and growing housing demand present unique obstacles to achieving net zero construction. These include diverse weather patterns, pollution in cities, overheating risks because of global warming in coastal and southern areas, language barriers, and economic constraints. A lack of widespread awareness of sustainability complicates these efforts, and regional differences in building materials and practices make it challenging to standardise low carbon solutions.

To address this gap, a study was conducted to develop an interim carbon assessment framework tailored to the unique challenges faced by the Indian construction industry.

The research paper ‘Paving the way to net zero carbon standards: A guide to designing net zero carbon buildings in a region that lacks carbon assessment frameworks’ offers a critical pathway for designing net zero carbon buildings in regions without standards. It shows how global best practices can be integrated with India’s distinct environmental, cultural and economic contexts.

Shweta Salvankar’s paper ‘Paving the way to net zero carbon standards’ was named the Most Significant Contribution to the Art and Science of Building Services Engineering at the 2024 CIBSE Technical Symposium

Steps to net zero: the framework pathway can act as a guide until carbon standards are developed

The paper also presents a structured methodology for carbon assessment, combining embodied and operational carbon evaluation in India. It incorporates sensitivity analysis, dynamic simulation and thermal modelling techniques to evaluate the lifetime carbon emissions of buildings, highlighting the benefits of integrating renewable energy systems. This approach aligns with India’s international commitments to sustainable development and offers a structured roadmap for emerging carbon assessors.

The assessment of embodied carbon is crucial in identifying the carbon footprint of specific materials. The methodology includes a detailed life-cycle assessment (LCA) of materials, focusing on their recyclability and environmental impact. The framework applies tools such as One Click LCA to evaluate material impacts across key metrics, including global warming potential and biogenic carbon storage.

The operational carbon assessment focuses on evaluating the building’s energy performance and its impact on carbon emissions. This involves dynamic thermal modelling to assess the interplay between passive and active strategies for energy efficiency. Sensitivity analysis identifies critical variables that significantly affect modelled building performance, such as building orientation, window-to-wall ratio, and shading devices. These are then optimised through iterative analysis to enhance the building’s thermal performance.

A key aspect of the operational carbon assessment is the integration of renewable energy systems, particularly photovoltaics (PVs). Exploring the potential of PVs to reduce reliance on Grid-supplied electricity demonstrates how renewable energy can significantly lower operational carbon emissions. This complemented a secondary simulation to select the most efficient active cooling systems.

The framework’s success is evidenced by substantial carbon reductions observed across multiple projects. By leveraging global best practices and adapting them to local conditions, the framework ensures relevance and practicality. It emphasises the importance of early-stage design decisions in achieving net zero carbon goals. By incorporating carbon assessment into the initial stages of the design process, architects and engineers can make informed choices that significantly impact the building’s overall carbon footprint.

The study also highlights the need for training and more awareness around standards and legislation. By providing practical and actionable strategies, the framework empowers designers and developers to implement sustainable practices.

• The CIBSE IBPSA-England Technical Symposium 2025 will take place on 24-25 April at UCL, London. Early-bird discount is available until 16 February. www.cibse.org/technicalsymposium

Aboyt the author:
Shweta Salvankar is a senior building performance and sustainability engineer at Harley Haddow

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The judges praised this year’s entries for their ability to meet core objectives with efficiency, reflecting the industry’s commitment to healthier and more sustainable indoor environments. These shortlisted innovations represent the cutting edge of air quality management, offering impactful solutions that align with the growing emphasis on occupant wellbeing and environmental responsibility.

Kaiterra: Sensedge Mini Indoor Air Quality Monitor

The Sensedge Mini is an advanced indoor air quality monitor designed for seamless integration into both new and retrofit projects. It measures six key IAQ parameters: PM, CO₂, VOCs, ozone, temperature and humidity – allowing proactive air quality management in a sleek, discreet design. With BMS integration and cloud-based analytics, it supports automated ventilation control and provides detailed insights for healthier, energy-efficient indoor environments.

Its modular design makes sensor replacement simple, reducing downtime and extending lifespan, while various power and data transmission options ensure flexible installations. Certified by Reset and Well, the Sensedge Mini supports sustainability and future-proofs buildings against regulatory changes.

Monodraught: Acuity Central Connectivity System

Monodraught’s Acuity system is equipped with advanced sensors, and measures key parameters such as temperature, CO₂, VOCs, pollutants and humidity, offering a comprehensive view of indoor climate. Data is securely transmitted to the cloud via 4G/5G, enabling real-time analysis and proactive issue detection. Weekly reports provide actionable insights, optimising system efficiency, energy use and air quality.

The Acuity system eliminates manual data collection using IoT and cloud technologies for remote monitoring and software-over-the-air updates, reducing onsite visits and carbon emissions. Its integration with Monodraught’s HVR Zero hybrid ventilation system minimises energy use by balancing natural and mechanical ventilation, while seasonal adaptability ensures year-round comfort and efficiency.

With an intuitive interface for real-time monitoring and diagnostics, Acuity aids quick issue resolution. Its modular design supports bespoke control setups for various projects, with continuous development to ensure high performance.

Pluvo: the Pluvo Column (pictured at top)

The Pluvo Column is a compact, energy-efficient air filtration totem designed to improve air quality in urban hotspots, such as transport hubs. It processes 1m³ of air per second, creating clean air zones with a 20-60m radius, reducing exposure to pollutants such as NOx, SOx and PM10, and viruses. Its three-stage filtration system, including an electrostatic precipitator, gas filtration media and F8 post-filters, captures up to 99.5% of targeted pollutants and operates with low power consumption (<700 watts).

The Pluvo Column’s modular stainless steel structure features polycarbonate panels with integrated LED or digital displays for advertising and wayfinding, making it self-funding. IoT technology enables remote monitoring and optimisation, while Pluvo manages maintenance, including pollutant collection and consumable replacement. Its compact 0.5m² footprint and straightforward installation make it suitable for diverse locations.

Constructed from recyclable materials and minimal adhesives, the Pluvo Column emphasises sustainability and circularity.

Savills: Data Led Air Handling Control

This demand-driven air supply system leverages machine learning and wireless IAQ sensors to enhance building ventilation efficiency. By integrating IAQ sensors and people counters into building management systems (BMS), it delivers fresh air precisely where needed, reducing energy waste and optimising occupant wellbeing. Granular visibility of air quality and occupancy levels allows the system to adapt dynamically to buildings with variable occupancy patterns.

Using Well-certified sensors, it monitors temperature, humidity, CO₂ and particulate levels, paired with optical people counters for 99.8% accurate occupancy detection. This data informs air handling units (AHUs), dynamically adjusting air volume based on real-time demand.

Implemented at 52 Lime Street, pictured left, the system reduced HVAC energy consumption by 40% and improved IAQ without compromising comfort. It integrates seamlessly with existing BMS infrastructure, ensures fail-safe operations, and provides dashboards for IAQ and energy performance monitoring.

Vent-Axia Lo-Carbon Sentinel Econiq

With the Future Homes Standard approaching, which aims to cut carbon emissions in new homes by up to 75-80% compared with current regulations, Vent-Axia’s Lo-Carbon Sentinel Econiq is designed for low carbon heat recovery ventilation in airtight, thermally efficient homes.

Offering up to 93% heat recovery and specific fan powers (SFPs) as low as 0.39w/ls, the unit operates with noise levels as low as 15.5 dB(A), while delivering excellent indoor air quality through advanced sensors and controls.

The Sentinel Econiq includes advanced filtration options (ISO ePM10 and ePM2.5) to remove allergens and particulates, maintaining system efficiency. Designed for sustainability, it uses low-embodied carbon materials and facilitates end-of-life recycling.

To book a place at the BPAs on 27 Feb visit www.cibse.org/bpa

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Two key standards provide guidance in this area: BS7074:1989 Application, selection and installation of expansion vessels and ancillary equipment for sealed water systems – Code of practice for domestic heating and hot water supply, and BS EN 12828:2012+A1:2014 Heating systems in buildings – Design for water-based heating systems. While both aim to achieve stable system operation, they adopt different methodologies, leading to varying outcomes when applied to the same system.

Both begin by requiring the calculation of the system’s water volume and the amount of thermal expansion resulting from temperature changes between filling and operation. But then the guidelines diverge in their treatment of reserve volume, vessel sizing methodology, and fill pressure.

Under BS7074, 10% is added to the calculated expansion volume to account for system variability. However, this standard provides no guidance on fill pressures, leaving its interpretation open. BS EN 12828 requires the addition of 0.5% of the total system volume to the expansion calculation as a reserve. This ensures the expansion vessel always contains water, which is critical for maintaining stable pressure and preventing air ingress during cooling or other operational changes.

The approach to sizing expansion vessels differs significantly. BS7074 suggests multiplying the calculated expansion volume by three and rounding up to the nearest standard vessel size. This approach can become problematic for larger systems or those with significant height differences. Iterative recalculations may be needed to achieve the desired working pressure.

BS EN 12828 determines vessel size by first calculating the minimum and maximum working pressures. From this, the standard calculates the maximum permissible percentage of vessel usage and derives the minimum required vessel size in a single step. This method is more precise and avoids inefficiencies associated with undersized vessels.

System setup is critical for stable performance. Both standards agree on the importance of maintaining positive pressure under cold, static conditions to prevent air ingress. They specify that the minimum system pressure must be at least 0.2 bar above the static height of the system. However, approaches to fill pressure differ substantially.

BS7074 does not provide specific guidance on fill pressure, and the common practice of equating fill pressure with vessel gas pressure often results in empty vessels at startup. This can cause pressure fluctuations and air ingress, particularly in taller systems or chilled water applications. Furthermore, this setup leads to challenges with pump operation. As pumps react to system pressure, they require a stable differential to prevent excessive cycling. Without sufficient water in the vessel, pumps may experience rapid start-stop cycles, increasing wear and energy use.

In contrast, BS EN 12828 specifies that the fill pressure must exceed the vessel’s gas pressure to ensure water enters the vessel. This prevents sudden drops in pressure and reduces the likelihood of air ingress. By maintaining a stable reserve volume within the vessel, this standard supports consistent pump operation. The differential pressure required to prevent pump cycling —typically 0.2 bar — is more reliably maintained, improving energy efficiency and reducing wear on components.

The differences between these standards has practical implications. Systems designed under BS7074 may experience frequent air ingress, which accelerates corrosion, increases chemical consumption and shortens system lifespan. In addition, no guidance on fill pressure and reserve volume can lead to operational inefficiencies, such as excessive pump cycling.

BS EN 12828 offers a more comprehensive framework. Its emphasis on maintaining adequate reserve volume and stable pressure ensures better reliability, reduces maintenance frequency, and extends component life. The standard may require a larger initial investment in vessel capacity, but long-term benefits outweigh costs.

Choosing the appropriate standard depends on the system’s specific requirements and operational goals. While BS7074 offers simplicity, its limitations can lead to long-term inefficiencies and reliability issues. BS EN 12828, with its more precise calculations and detailed guidance, provides a robust solution, particularly for those with complex operational demands.

By understanding the differences between the standards, designers and operators can optimise performance, and reduce life-cycle costs.

About the author

Steve Simmonds is a specification manager at Spirotech

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Often, the changes that need to be made for even small energy efficiency gains require a full Capex-intensive refurb and renew project. But there are quick wins to be made, especially when it comes to the performance of motor-driven systems such as HVAC, water pumps, compressors, fans, and other production equipment. 

The first place to look is the energy efficiency rating of your motors. Since July 2023, all new electric induction motors installed with a rated output of between 0.75kW and 1MW must meet IE3 efficiency level, and 2-6 pole safe area motors between 75kW and 200kW must meet the requirements of the Super Premium Efficiency class IE4 (or better) in the EU and UK.

However, electric motors can last many years. We often find customers with motors rated as low as IE2 (old Eff1) or even IE1 (old Eff2). Even though they might not need replacing in terms of functionality, swapping them for the latest, high-efficiency motors can deliver payback in months rather than years.

Ideally, all motor-driven systems that require the motor speed to vary, such as HVAC equipment, should come with a variable speed drive (VSD). If your motor-driven unit doesn’t have a VSD, that’s another quick win, with typical energy savings in the region of 25%. If it does have a VSD, there still may be opportunities for fine-tuning. The relationship between a motor and a VSD is crucial for energy efficiency. Performance can vary between brands and can change over time.

It’s also easy for these components to be over- or underspecified, and paired or installed sub-optimally – in these instances, you wouldn’t necessarily notice that they were underperforming. If you haven’t had any diagnostics done on your motor-drive systems, it’s well worth engaging with engineers to see if fine-tuning can be done.

A survey will also help determine if your motors or drives might be nearing the end of their service life, in which case an upgrade or refurbishment will help maintain reliability. Critically, digital diagnostics tools can ensure you catch any opportunities for efficiency gains on an ongoing, real-time basis.

This was a real benefit to a recent customer that used various types of machinery to manufacture products and distribute them to a network of customers and suppliers across the UK and Europe. It needed to spot energy inefficiencies in a fast and scalable way.

Our diagnostics tools helped the customer identify inefficient and high-consumption motors and replace them without disruption to production. We installed more than 100 network analysers, 50 InSite control units, and more than 600 sensors and accessories, which means the customer can now easily understand where energy is being used the most and act accordingly.

The major benefit to the customer is that it can expect to recoup its investment in the first quarter following installation. Projected energy savings total more than 2.5GWh per year – 40% of the site’s annual consumption.

Until energy consumption is measured, saving potential cannot be determined (measure to save). An efficient and accurate system of measuring and monitoring electrical data is important to ensure the success of all initiatives.

Firms such as ABB Electrification have high-precision, accurate energy meters and sensors to capture quality data. This can then be analysed by a BMS or energy-management system to identify opportunities to save energy.

Electrification offers real-time optimisation and control and monitoring, and reporting of energy from Grid to socket. Motor and drive efficiency is one of the simplest ways to improve operational reliability, reduce energy cost and improve building sustainability. When you add analytics providing a real-time window into energy use and offering informed insights, these upgrades make efficiency the ongoing priority. By leveraging these tools, building operators can take steps to streamline their systems and reduce costs.

About the author
Richard Gee is UK sales manager, motors & generators, at ABB Motion

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The property company manages a portfolio valued at £13bn – of which it owns £8.9bn – and is aiming to achieve net zero carbon by 2030. Central to this ambitious goal is the replacement of gas boilers with heat pump systems in its properties.

The transition from fossil fuels started in 2012 with the installation of a hybrid heat pump system at 350 Euston Road, where heat pumps work in tandem with gas boilers to meet peak heat demand. In its latest project, British Land has replaced four gas boilers with heat pump chillers at its York House headquarters in London and says it will be the blueprint for future energy retrofits.

Template for transition: York House retrofit

Screenshot of the dashboard view of the new heat pump

The retrofit of York House involved the replacement of four gas boilers and chillers with two parallel 4-pipe air source Climaveneta heat pumps, which concurrently supply chilled water and heating to the low-temperature heating system. Climaveneta is part of Mitsubishi Electric.

‘The benefits of using 4-pipe heat pump chillers is that there’s a year-long cooling load, and we get to use some of the rejected heat from that process to heat the building,’ says Daniel Valente, head of projects at Nationwide Air Conditioning.

Other improvements to the HVAC system included the introduction of indoor air quality (IAQ) controls for ventilation, a full validation of the fan coil units, and confirmation of water flow rates and temperatures.

The previous gas boilers had 1.3MW of heating capacity, while the new heat pumps have a heating capacity of 600kW, with a duty standby arrangement and a combined cooling capacity of 1.2MW.

The project has resulted in a 57% annual decrease in HVAC energy usage, and electrical energy use has reduced from 982MWh in 2019 to 419MWh for the 12 months up to September 2024, even with heating and cooling moving from gas to electric.

An advanced building model, in line with the Nabers UK standard, was built to identify what the peak loads would be.

‘We came up with a proof of principal that we could actually utilise a 95% peak load design to minimise the equipment size, but also to optimise the project costs. It enables us to start controlling the building on a demand-driven strategy,’ says Draper, of Twenty One Engineering. The design was validated by the operational gas profiles of the building, he adds.

The system maintains a temperature of 17°C when the building is unoccupied, says Draper. This reduces the time needed to heat up the building, which maximises the efficiency of the heat pump.

One challenge was to ensure that a flow temperature could be maintained that was hot enough to heat the building at all times, says Valente. ‘We needed to ensure that we were able to increase the flow temperature at periods of high load, so we installed a second-stage water-to-water heat pump,’ he adds.

The unique aspect was that there was no hydraulic separation in the LTHW system, and a much lower heating capacity. ‘The water-to-water heat pump only injected heat when needed to meet the building heating load required during the winter months,’ Valente says.

The benefits of this were higher operational efficiencies, lower initial capital costs, and a simpler installation.

Key to British Land targeting net zero carbon is the adoption of ISO standards 50001 Energy Management and 14001 Environmental Management, as well as the Nabers UK rating scheme, which provide frameworks for measuring and reducing energy use. ISO 50001 Energy Management is used to monitor and improve the energy performance of its buildings, and ISO 14001 Environmental Management to measure and continually improve other areas of sustainability.

‘ISO frameworks demonstrate that we are operating in line with our commitments, and that we have clear objectives and goals that we are working towards,’ says John Gentry, British Land’s head of technical services and sustainability. 

CIBSE Certification offers UKAS-accredited certification for ISO 9001, 14001, 45001 and 50001 and, last year, took over from the BRE as the scheme administrator for Nabers UK, the operational energy rating scheme. CIBSE Certification certified British Land’s environmental and energy management systems. 

One of two four-pipe heat pump chillers installed at York House. Credit: Mitsubishi Electric

Nabers UK, which has its roots in Australia, has two UK products – Design for Performance (DfP), which drives energy efficiency in new offices, and Nabers Energy for Offices, which measures the energy efficiency of existing offices. British Land is keen to use Nabers Energy for Offices to monitor the performance of existing buildings, including retrofits such as York House. It is using Nabers DfP to accurately predict energy performance of new buildings such as 1 Broadgate. 

The strength of the rating is that energy data has to be validated annually, allowing the continuous monitoring of plant, says Matthew Beales, British Land’s head of technical project delivery. 

British Land has long invested in sub-metering. This has been key for ISO 50001, which requires metered data to be submitted annually. ‘The system gave us the granularity of data to be able to really drill down into the profiles of our buildings and see how they were being operated – and where we were using energy unnecessarily,’ says Gentry. 

British Land’s Credit 360 data management system records, tracks and analyses building data, including energy and water consumption. It can identify anomalies in performance – so, if an occupier’s energy or water use spikes, the system flags it, allowing for investigation and resolution of the underlying issue.

Geoffrey Brophy, British Land technical services manager, is responsible for data quality. ‘I like to know what’s going on in the building that I’m responsible for from an energy point of view,’ he says. ‘I don’t want to sit in front of an occupier and not know what I’m talking about.’

Phil Draper, managing director at Twenty One Engineering, says British Land’s metering and data systems made meeting the ISO requirements relatively straightforward. ‘Most were already within British Land’s culture. It already had internal auditors, for example,’ he says.

Meet the Nabers UK

British Land has a long association with Nabers UK, having been on the working group that established the rating scheme in the UK. 

‘We need to look beyond modelled theoretical certifications, such as EPCs and Breeam, and look at actual operational rating targets, such as Nabers UK,’ says Matt Webster, the property company’s head of environmental sustainability. 

British Land was the first in the UK to receive a Nabers UK DfP target rating certificate for the 1 Broadgate office in London, which is due for completion this year. ‘In projects such as Broadgate, we can see the benefit of Nabers UK in terms of efficiency, the collaboration between the design team and the property management team, and supply chain,’ says Webster.

The refurbished interior at York House

The detailed energy modelling required by Nabers UK means that British Land has the confidence to use more efficient plant and more sophisticated control philosophies in new and existing buildings, he adds.

While British Land is leading the efficiency drive, there is a growing awareness among its customer base about Nabers UK and building performance, Webster continues.

‘At York House, there are some pretty big occupiers that have set their own climate goals and climate strategies to which the building can then respond,’ he says.

Webster is ‘really pleased’ that CIBSE is now running and administering Nabers UK. ‘The technical capabilities of CIBSE Certification as an independent organisation are fundamental to the integrity of standards such as Nabers UK. It ensures the ratings are properly verified and understood,’ he says. l

For more on Management Systems Certification at CIBSE Certification, including ISO 50001, go to: cibsecertification.co.uk/management-systems

For details of Nabers UK, visit:
cibsecertification.co.uk/nabers-uk

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