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.

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

The post Air of excitement: air quality award shortlist appeared first on CIBSE Journal.

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

The post Beware double standards: pressurisation design and expansion vessel sizing appeared first on CIBSE Journal.

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

The post Driving for efficiency: analysing HVAC performance appeared first on CIBSE Journal.

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

The post British Land’s heat pump retrofit at York House appeared first on CIBSE Journal.

The move was celebrated in style with the office’s inaugural Christmas party, although with new carpets and upholstery recently fitted, red wine was left off the drinks menu. 

Staff have moved into the top two floors of the building, which has five storeys plus mezzanine on the lower-ground floor. Staff areas have been refurbished to provide agile, functional spaces that reflect the outward-facing, collaborative values that CIBSE is keen to embrace. 

Unlike Balham, where teams were siloed in their own rooms, Saffron Hill’s staff floors are open plan, with an internal balcony and exposed staircase providing a sense of light and space. 

Staff work at traditional desks, railway carriage-style meeting pods, or individual workstations. Common areas, including two kitchens, encourage collaboration and creativity.

The response to the new 17,000ft² office among employees is positive, with one new employee admitting he probably would not have taken the job if CIBSE had still been in Balham. 

The arrival of staff at Saffron Hill completes the first part of the relocation project. The next phase is to open up the ground and lower-ground floors to members and stakeholders by building a vibrant skills hub to foster lifelong learning. This will comprise a training suite, versatile auditorium, and welcoming members’ lounge. 

After completion later this year, CIBSE will monitor the building for a year before deciding on the decarbonisation strategy. Decisions made will be shared beyond CIBSE and will form the basis of an ongoing demonstration project.

Following an extensive tendering process, CIBSE appointed multidisciplinary consultant Inhabit to lead the project at the start of the process so the firm’s MEP expertise could be used to perform due diligence on the buildings being considered by CIBSE.

The new fit-out includes a variety of vibrant, flexible space

Colin Stuart, founding director at workplace consultant Baker Stuart, helped CIBSE write a brief for the appointment and worked with the CIBSE Premises Advisory Committee (PAC) through workshops to establish the Institution’s vision and values for its new home. 

It became apparent to Stuart that the relocation was a chance for CIBSE to demonstrate best practice. ‘The idea is not to be the best of the best, but to show how a typical company can decarbonise its building on a reasonable budget, and create an office that makes staff feel valued,’ he says.

Saffron Hill was chosen because it most closely aligned with CIBSE’s vision. It met the original brief’s cost and functional needs, but also took account of secondary needs around membership and commercial growth.

‘Although the cost of fit-out and purchase is higher, the value delivered per square foot was the best of the lot. None of the other buildings we saw could provide the training and conference facilities, and members’ area, and the first floor allows for growth of CIBSE Services,’ says Stuart.

CIBSE was keen to appoint an MEP specialist to lead the project, in part because the services constitute the biggest part of the project and because the first phase of the project had to work with the future decarbonisation strategy.

‘We wanted it to be led by a CIBSE Member, which would bring MEP engineering front and centre,’ says Stuart. ‘Functionality and environmental performance were key for us. Inhibit had to design for day one and for five years’ time. It’s a delicate balancing act between making sure it’s a good, serviceable building now, while being mindful of the journey we’re going on.’

The appointment of Inhabit started with a call for expressions of interest in CIBSE Journal. The 36 respondents were sent a prequalification questionnaire and their answers were scored by PAC, with five being selected for tender. The tender document asked participants to devise a decarbonisation strategy for a sample office.

On this basis, the shortlist was whittled down to three and they were invited to interview with PAC. Based on the strategy and interview, Inhabit was selected unanimously. 

‘Inhabit really impressed us in identifying what we wanted to achieve. It wasn’t about using the latest technology, but about doing good, robust engineering,’ says Stuart.

The building dates back to the 1950s and an extension was added in 2008. However, the HVAC condition was poor, says Stuart. ‘We had a robust risk process and we had a contingency for issues such as asbestos and reinforced autoclaved aerated concrete (RAAC) removal. We haven’t had to use the contingency for RAAC, but we’ve had to use some of it for rewiring,’ he says.

Many systems are coming to the end of their lives, including the boilers. There is no BMS and individual fan coil units are working against each other. Fire doors also need repair or replacement.

Stuart says there were no substantial issues with the structure or façade, but some of the windows weren’t opening properly. The façade will be included in Inhabit’s review of the decarbonisation strategy. 

Inhabit is currently working with CIBSE on a monitoring regime. Areas being tracked include air quality, energy use and lighting.

‘We will look at the metrics and then decide what represents value for money for CIBSE as a landlord. What we don’t want to do is gild the lily and do something a typical landlord couldn’t afford to do,’ says Stuart. The process will also consider using accreditation schemes and standards such as NabersUK and the UK Net Zero Carbon Buildings Standard.

Stuart says: ‘The building needs to support CIBSE and its people. It needs to be extrovert – it’s not just about having 100 desks, it’s about what the building does for stakeholders.

The post CIBSE head office: first steps to decarbonisation appeared first on CIBSE Journal.

The integration of flow, temperature and water quality sensors allows facility managers to measure energy costs within hydronic chilled and hot water applications.  The comprehensive range of reliable and robust instrumentation offered by Badger Meter provides dependable solutions that are simple to install and maintain.

Available for all aspects of the HVAC industry, our exceptionally durable and accurate monitors are available in a range metering technologies, materials and sizes and can be tailor-made to suit each individual application.

BlueEdge offers complete flexibility for every stage in a system’s lifespan, whether it be a new build or retrofit, providing accurate measurement and actionable data in the most demanding applications, creating HVAC systems that meet the challenges of the modern world.

With simple installation onto existing HVAC systems and non-intrusive operation, technologies such as the Dynasonics TFX-5000 Ultrasonic Clamp-On Flow Meter offer a cost-effective solution in the drive towards sustainability and net-zero.

Nutating disc technologies from Badger Meter, such as the Recordall® Disc Series Meter, provide a robust, reliable solution for leak detection in closed-loop systems, offering minimal maintenance and high accuracy to protect system assets. Discover how one HVAC and Plumbing System Supplier was able to use this BlueEdge solution to deliver simple and effective leak detection to customers in Michigan and Northern Ohio.

The Role of Water Quality Monitoring in HVAC Applications

What is the importance of water quality monitoring in the drive towards sustainability?

Continuous monitoring of water quality within HVAC systems is crucial in ensuring the long-term health of building networks. Monitoring Dissolved Oxygen, Pressure, pH and Conductivity helps to maintain effective systems, reducing the potential for equipment failure and avoiding costly repairs, replacements and downtime.

Incorporating systems, such as the Badger Meter MetriNet, allows the detection of subtle changes in vital parameters that could be indicative of leaks, chemical imbalance or contamination.

Real-time monitoring of these parameters allows building managers to move away from system spot checks and manual sampling schedules that have proven to be both costly and inaccurate.  Intermittent testing of water parameters only shows what is happening within the system at that particular time. System failures happen very quickly and can be easily missed using this method.

The MetriNet provides a constant stream of data in real-time, allowing for proactive system management, helping to avoid corrosion and scaling within pipework while also controlling microbial growth and reducing biofilm, avoiding potential health issues such as legionella and dramatically reducing routine maintenance requirements. This results in more efficient, cost-effective and sustainable HVAC systems that comply with regulatory guidelines, while also ensuring the health and safety of building occupants.

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When disaster strikes, reliable emergency lighting is crucial for safety and evacuation. Therefore, it’s vital that the correct electrical back-up solution is in place. Hence my question in the title… can you use a UPS (Uninterruptible Power Supply) or a Static Inverter/CBS (Central Battery System) to provide power to the emergency lighting system during a mains failure?

In very simplistic terms, UPS and Static Inverter systems provide backup power in case of a power outage however, their primary functions do differ. A UPS is designed to protect critical electrical equipment, nominally IT, whereas a Static Inverter is specifically designed to maintain emergency lighting for a specified duration. So, whilst technically there is synergy in their conversion technology, the application, and regulatory requirements, dictate that they are very different animals.

Therefore, the simple answer is, no you cannot use a UPS and, yes you must use a Statice Inverter/CBS. But why? Let us explain:

Understanding The Basics

Firstly, although the acronym CBS is often used to cover all emergency lighting systems, there are some variations, for example  a CBS is typically AC Input /DC Output and SI generally stands for Static Inverter which is typically an AC Input/AC Output (single or three phase)

In brief, Emergency lighting is a range of backup lights that will operate fully automatically in the event of an emergency situation, nominally electrical power failure. It provides sufficient illumination to enable all occupants of a building to evacuate the premises safely during a blackout.

The Importance Of Emergency Lighting Standards

Emergency lighting is regulated by standards like the Regulatory Reform (Fire Safety) Order 2005the base guidance document BS5266, BS50172 which specifies the minimum provision and testing regimes of emergency lighting systems, and BS EN 50171 which specifies  the central power systems.

The Regulatory Reform (Fire Safety) Order 2005 (FSO) is the primary legislation governing fire safety in non-domestic properties in the UK. It requires people such as building owners or employers to install suitable emergency lighting based on a building’s risk assessment findings and building regulations.

You can’t just supply a “box and batteries”.

And, importantly, the law does place some responsibilities on the supplier/manufacturer.

Adhering to these standards is not just a case of supplying and installing the correct system, but also incorporates the responsibility of the manufacturer to ensure that the emergency lighting installation meets the required standard.

For example, the size and type of fuse(s) or protective devices installed in the distribution system shall be specified by the manufacturer, and the central inverter shall be capable of tripping any associated protective device installed in final or distribution circuits, without shutting down the device or rupturing its output protective device. Failure in one of multiple output circuits does not lead to a failure of any of the other output circuits.

Staying Up To Date With Regulations:

Delving briefly into BS50171, by the way, the latest amendment BS50171-2021 comes into law at the end of 2024; there are many specific technical aspects that are required in a CBS that a “traditional” UPS does not incorporate.

From the simple rating plate on the EL unit clearly stating load and battery autonomy/battery type etc, to internal wiring that must be permanently marked, subcircuit and phase failure monitoring, recharge characteristics i.e. 80% in 12 hours, through to a battery charger with short-circuit that will not cause damage to the unit itself …and many more!!

And, of course, those batteries have to be sized correctly at End of Life, (EOL), which in itself is a topic for debate, and a pet subject of mine, on how to calculate autonomies correctly!

Note Para 6.6.11 of EN50171 does state:– Where a UPS system is used to feed the essential safety systems, it shall comply with EN 62040-1 (a UPS design standard) AND the additional requirements of this document.

So, while a UPS can be adapted for emergency lighting, a Static Inverter is inherently designed to meet these standards. Now we know that you are required to install a CBS system for an Emergency Lighting application.

And it’s not just a case of buying and installing an emergency lighting system, it must be maintained correctly.

Maintenance, Testing And Commissioning Of Emergency Lighting:

Under the above-mentioned regulatory reform, Para 17 Maintenance –  the responsible person must ensure that there is a suitable system of maintenance in place and that systems are maintained in an efficient state, in efficient working order, and in good repair.

Regular testing and maintenance are crucial for ensuring your emergency lighting system works correctly and as intended. Government guidelines stipulate that all emergency escape lighting systems should be tested regularly.

Traditionally, manual testing is carried out however, emergency lighting devices are now available with self-test facilities.

A typical test uses a key-operated switch, a ‘secret key’ that lets you test the emergency lights whilst preventing the operation of the test switch by non-authorised personnel. It is often found near the main fuse board or relevant light switches.

In addition, it is advised to keep a record of all tests carried out and any relevant findings in the fire safety logbook. Even though this is not compulsory by law, it is useful for demonstrating compliance with fire safety legislation.

Testing Would Usually Include The Following: 

• If it’s a centrally powered system with extra lights, conduct daily visual checks on the central controls.
• A monthly function test should be carried out by operating the test facility long enough to ensure that each emergency lamp illuminates and is working.
• An annual full discharge test to ensure that the lamps stay on for the full discharge period (usually 3 hours) and that the batteries are recharging properly.

Caution needs to be taken following a full discharge test. This is because batteries typically take 24 hours to re-charge. Hence, the premises should not be reoccupied until the emergency lighting system is fully operational unless alternative arrangements have been made.

Not All Emergency Lighting Systems Require The Same Type Of Solution.

There are four main types of emergency lighting:-

• Escape route lighting: the means of escape out of the premises is effectively identified, sufficiently illuminated, and can be safely used by the occupants of the building. This helps reduce panic and identify evacuation routes and obstacles in emergency situations.
• Open area lighting: sometimes referred to as anti-panic lighting and applies to floor areas larger than 60m².
• High-risk task area lighting: provides higher levels of illumination to allow potentially dangerous processes to be shut down or stopped prior to evacuation, for example turning off major machinery equipment.
• Stay put/emergency safety lighting: Occupants will be allowed to stay in the premises until there is less than 1-hour duration left in the emergency lighting. The system then allows them to be directed or escorted to a low-risk location. It must be clear how long occupants can stay and how the end of the ‘stay put’ period will be indicated.

In Conclusion:

Reverting to my original question…..do I, or can you, use a UPS (Uninterruptible Power Supply) or a CBS (Central Battery System) to provide power to the emergency lighting system during a mains failure?

Hopefully, we have clarified the answer to that question, and you will not be a penitent man and use a UPS system where an emergency lighting system should be installed.

ALL occupied buildings, whether new or old, require emergency lighting. With today’s highly populated office blocks, Emergency lighting is a vital aspect of building safety to ensure everyone can evacuate safely in the event of an emergency situation.

Supplying, installing, and maintaining an Emergency Lighting system has statutory legal obligations on the designers, manufacturers, installers and those responsible for maintaining them.

Emergency lighting is essential for protecting occupants during emergencies, making it of utmost importance for building owners. The consequences of not complying with the law can incur costly fines, closure of businesses, or even prison sentences.

Fortunately, BPC Energy offers a range of high-quality Static Inverter systems that meet the highest standards for emergency lighting, and specific, bespoke, requirements are designed in-house and manufactured in our own workshop facilities. Our PowerPro EL range of Static Inverter Systems are designed specifically for emergency lighting applications.

Our expertise and commitment to quality make us your trusted partner in creating and maintaining safe environments. Investing in a reliable emergency lighting system is crucial for protecting lives and property.

By understanding the differences between UPS and Static Inverters, you can make informed decisions to protect your building and its occupants.

Contact BPC Energy today to learn more about our Emergency Lighting solutions.

Thank you for reading! Head to our website to learn more about Emergency Lighting backup systems and be sure to follow us on LinkedIn, X, Instagram, and Facebook for more power protection and related backup solutions.

Author: Mike Elms – BPC Energy’s Sales & Marketing Director

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The topic was the subject of a panel session at the Light2Perform event, held at Build2Perform Live, chaired by Matt Waring, editor at [d]arc media.

Opening the discussion, Dan Lister, Society of Light and Lighting (SLL) president and Arup associate director, highlighted how clients are keen to retrofit their lighting with ‘large-scale LED upgrades’ – but the challenge is not just about deploying LEDs, but also about reducing their environmental impact, he said.

A key milestone has been the development of BS 8887, which focuses on remanufacturing, added Lister, who called it ‘a game changer’ for its ability to offer more consistent metrics for sustainability. 

Simon Fisher, founder and director of F Mark, said he has seen a growing appetite for change over the past 10 years, but costs remain a barrier for many clients. He added that sustainability is becoming a more valid metric with the emergence of TM65.2 and TM66, which focus on embodied carbon calculations and circular economy principles respectively.

The conversation shifted to the practical application of circularity, particularly the reuse and refurbishment of lighting products. Lister shared Arup’s experience of refurbishing light fittings in its own offices, achieving an embodied carbon reduction of more than 80%. ‘It’s not as hard as everyone thinks it is,’ he said, adding that case studies are critical for building confidence among clients. 

‘We’re conditioned to think that new is best,’ Fisher said. ‘We need to demonstrate through case studies that remanufactured products can deliver the same or better results.’ This cultural shift, he argued, is essential for scaling up reuse and repair. 

Kristina Allison, associate at WSP, said circularity must be embedded into the design process: ‘It shouldn’t even be a question. It’s our responsibility as designers to make sustainability a core part of our work.’

The concept of lighting as a service emerged as a key topic. Fisher acknowledged its potential to monitor and report environmental benefits, but admitted: ‘It’s a nightmare to implement.’ He cited the complexity of ownership models, and the disconnect between specifiers, manufacturers and end users, as significant barriers. 

Lister pointed out that design plays a vital role in sustainability, regardless of the delivery model. ‘The biggest impact on embodied and operational carbon is the design,’ he said. ‘It’s about finding the right solution for the space and avoiding over-provisioning.’ He explained that effective lighting solutions require a conscious approach to fitting design, placement, and embodied carbon savings, which are sometimes overlooked in favour of contractual and operational simplicity.

Allison agreed, emphasising the importance of focusing on people. ‘If the lighting isn’t for the people using the space, we don’t need it,’ she said, echoing the sentiment that sustainability must go hand in hand with human-centred design. 

Education and legislation

Allison stressed the need for education, within the industry and among the public. ‘It’s about changing society’s attitudes,’ she said, citing night-light festivals and school engagement programmes as examples of how the industry can inspire the next generation. 

Fisher shared his work on Scotland’s upcoming Circular Economy Bill. ‘On our first call with the Scottish government, the goal was clear: they never want to buy a new light fitting again,’ he said. While this might not be practical, Fisher emphasised the importance of considering reuse and remanufacture in all procurement decisions. 

The panel concluded by discussing the role of organisations such as the SLL in driving forward sustainability. Again, Lister highlighted the importance of technical standards. ‘The rest of the world is looking at us,’ he said. ‘The way to make real change is to get these standards out there and make them more powerful. 

‘Let’s not just drive for low carbon and low energy use and sacrifice the human aspect. More is less; put less light in. We need to make sure we are lighting in the right place at the right time.’

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Eyebrows were raised, therefore, when the College proposed installing photovoltaic (PV) panels on the 509-year old chapel roof, as part of its plan to decarbonise operations by 2038. The proposal met with protests from conservation groups; Historic England stated that the panels would ‘damage the architectural character and interest’ of the building¹, and it was concerned that the reflective quality of the panels would be different in appearance from the existing lead.

Despite such objections, King’s College was keen to press ahead: the 1950s lead roof needed replacing and the chapel offered large potential for renewable energy. Max Fordham and Caroe Architects were given the responsibility for devising a solution that would not harm the significance of the chapel.

There were four aesthetic challenges: hiding the panels from prominent viewpoints; minimising reflections from the sun; overcoming undulations on the roof; and accounting for the impact of thermal expansion. In addition, the system had to be fully demountable.

Through a combination of engineering ingenuity and detailed modelling, Max Fordham came up with a solution that satisfied the planners and allayed conservationists’ concerns. In total, 483 REC Alpha 420 Pure-R panels were installed, producing about 123,000kWh per year that is fed into an onsite electricity supply.

To assess the visibility of the PVs from the ground, Max Fordham’s MEP engineer director, Phil Armitage, walked around Cambridge to ascertain from where the roof could be seen. ‘The pitch of the roof is quite shallow and, from ground level, you hardly ever see the ridge above the beautifully detailed stone parapet. The chapel design emphasises this parapet, not the boring, ordinary lead roof behind it,’ he says.

While largely hidden from the ground, there were sight lines from prominent locations, particularly from King’s Parade, near the Corpus Clock, and the college quadrangle. This meant Max Fordham was limited in how far the PVs could extend up the slope of the roof.

Figure 1: The top-hat bracket positioned over the rail lowered the profi le of the PV system by 100mm

This limitation threatened to reduce the number of panels by a third, because it meant only two rows of panels could be installed on each slope – the third row would have been visible above the ridge from the ground. The answer, says Armitage, was to lower the profile of the PVs so they could be positioned higher up the roof slope, enabling three rows to be installed. A top-hat section, bolted to the supporting rail, enabled the PVs to be lowered by 100mm – the rail supporting the PV is positioned on the L of the top hat (see Figure 1). The lower profile meant the top edge of the array could be 670mm further up the slope, allowing a third row of PVs to be installed, which could not be seen from the Corpus Clock.

Each 1118 x 1730mm panel is clamped to an independent aluminium frame system supported on metal posts that sit on baseplates anchored to timber boards. Lead upstands and caps waterproof the posts. The fixings are designed to ensure the PVs can withstand wind uplift, which is caused by winds flowing across the exposed upper surface faster than across the lower surface, creating a pressure differential and resulting in lift.

To assess the risk of the sun reflecting off panels, a study based on a sun-path diagram looked at where and when the reflection would be visible. The conclusion was that there are only a few times in the year when you would see reflections from Trinity Street and Garret Hostel Lane Bridge, which planners deemed acceptable.

Thermal expansion also had to be accounted for. If the rails supporting the PVs ran the length of the roof without interruption, there would have to be 200mm spacings at 15m intervals between the panels to allow expansion; being visible from the ground, this would not have been acceptable. The solution was to divide the rails into 15m bays, which reduced thermal expansion and meant the gap between bays was only 50mm. ‘It sounds like a tiny detail, but it’s a significant part of the design development,’ says Armitage.

The shallow 25° angle of the roof pitch meant that the north and south slopes were suitable for PVs

The design also had to take into account the undulations in the roof. Photon Energy, the specialist contractor, adjusted the height of the fixings by changing the depth of the packing between the posts and the top-hat section. This ensured a smooth, even surface across the length of the installation. The posts are designed to be removable, leaving no trace but for a lead square welded in to cover the gap. ‘This is about a moment in time in a building that has a very long life’, says Armitage. ‘The appropriateness and relevance of PV will change, so you have to think about what happens if they need to be removed.’

The PVs are supplying electricity to the College site after a new connection was made to the main college’s electricity supply, via an adjacent building, earlier this year. Armitage believes the project’s success shows the potential for solar panels on other historic sites, including York Minster, where PVs are now being installed.

‘Where PVs can be installed in a sensitive way that does not alter the enjoyment of a building, they are an entirely appropriate response to the climate issues faced by society,’ he says.

The view from Great St Mary's church tower: one of the few places from where the PVs are visible

References:

1  Letter to the Diocese of Ely from Historic England, October 2022. bit.ly/CJHEKCC

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