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Renewed Lamps for Old: The Circular Economy is business as usual for heritage lighting

In May 2023, the SLL held a well-attended CPD at Coco Lighting in Essex, giving members a practical look at how light fittings can be re-engineered to TM66 Circular Economy principles, rather than scrapped. One striking example on the bench was a 2m diameter cylindrical opal diffuser, one of several feature lights from the atrium of a large office. Formerly populated with T5 fluorescent lamps, transformation was underway to replace these with bespoke LED linear modules. It wasn’t straightforward; our hosts explained the positions for the T5 lamps had been carefully defined to ensure a uniform wash around the sides and face of the cylinder. An LED source is very different to a fluorescent tube, posing a particular challenge where an omnidirectional light spread is wanted. The proposed solution had to be engineered to ensure the desired effect was achieved.

As we stood around the bench looking at this huge piece of engineering, it seemed not only obvious it should be refurbished, but perverse that it might not have been. The quality of the original fitting stood out. After many years of use, the diffuser material showed no signs of heat or UV damage. The client had no desire to change the lighting or aesthetics of the entrance. If you were to scrap it, something new would be needed, to fit just the right space on the ceiling, not require new structural support behind, and give a similar light level. The original lighting was just right for the space, and now benefits from a much-reduced energy bill and no need for difficult lamp changes.

Whilst a late 20th Century office is unlikely to be considered a heritage building, it may become one in time if it is good enough. What stands out with historic buildings is often the quality of the original build. And this often includes ironmongery, furniture, and the lighting.

Ely Cathedral dominates the skyline of the Fens, and later this century will celebrate 1000 years existence. It remains serving its purpose as a place of worship, yet just like our T5 lighting diffusers needs updating and repair from time to time, to ensure it best meets the demands of our world today. Gas lighting was installed in the mid-19th Century, lasting through to the 1930s[1]. Little remains of the scheme, other than two huge gasoliers, standing either side of the High Altar. First converted to electric lighting in the 1930s scheme, these fittings have seen several alterations to their light sources in the past. They are now being upgraded from tungsten capsule lamps to miniature LEDs in the workshops of Great British Lighting, as part of the current scheme to re-light the cathedral.

TM66 has a good checklist in Section 9.4 for use when looking at the re-manufacture of light fittings. When considering refitting a historic light fixture, heritage conservation principles then also need to be applied. Or in medical terminology, “first, do no harm”. We have to pose the following further questions:

  1. What is wrong with retaining the status quo?
  2. What is the objective of the renewing the fitting? Is it electrically unsafe, too bright, too dim, hard to maintain?
  3. Is it technically achievable, at an economic cost?
  4. What are the risks of transporting it off site? Could it be worked on in-situ instead?
  5. Is the intention to replicate the current lighting effect, or do something different?
  6. Will the refurbished fitting retain sufficient original character? New technology may offer energy efficiency, but so too would adding double glazing to stained glass windows.
  7. Could new technology introduce new risks to the building, say through the heat from drivers where there previously were none?
  8. If a previous intrusive modification has disrupted the original design, can it be re-used, minimising the need for further such modifications?
  9. What consents will be needed for any modifications?
  10. If the fitting is not re-used, what will happen to it? Few clients will want a relic non-functional light fitting on display.

When considering an old light fixture, what are we trying to replicate? If it once had gas mantles, the light would have been a slightly different colour tone, perhaps at odds with modern expectations. Glass diffusers with GLS lamps in would usually have intensity hot-spots close to the bulbs. Does one replicate this with LEDs or go for a uniform wash? Imperfections can make for charm.

Historic England offers some guidance here[2]. Many early electric light fittings were adaptations of gas fixtures, with pipes used for wiring right back through the building. Lighting designers in the 1930s lacked precedent for how to make use of this new technology. One early innovation was just to invert the arms of chandeliers for better light distribution, since an upward burning flame no longer needed to be accommodated. So a degree of adaptation of the fitting can be justifiable in a historic context, to get the best result from the technology.

Back to the Ely gasoliers. Once the principle of re-use was agreed, the next step was to have them carefully dismantled and transported for refurbishment. Here, detailed record-keeping by the Cathedral Archivist was invaluable, with photos on file of the previous disassembly for transport and refurbishment undertaken for the 1990s scheme. Once stripped down and cleaned, a design could be developed to integrate new light sources. Following the principles of previous adaptations, rather than place lights on the old gas spigots themselves, small LED capsules, using magnetic fixings, will be placed around the circular band beneath, to illuminate glass crystals fixed onto the gas outlets in the past. At present the work is underway and the gasoliers will be ready to return to the Cathedral later this year.

Heritage projects come in all sizes and budgets. Retaining elements of lighting can be a cost-effective way to keep character. The Norris Museum in St Ives, Cambridgeshire, was one such example. Totally inadequate for the museum, rows of small glass shade pendant lights hung above dark wooden display cases bathed also in uncontrolled daylight. Nevertheless, it had a quaint charm. Following a successful Heritage Lottery Bid, a full refurbishment was carried out, with new and far superior lighting installed. But we found a home for a few of the salvaged glass pendants, lighting the replica study of the museum’s founder Herbert Norris.

We picture working with traditional materials such as wood and metal when thinking of worthy historic light fixtures. But what if the building is from the mid-20th Century and the material palette includes concrete and asbestos? This was the challenge presented at Grade II* Listed Guildford Cathedral, an interwar design completed in 1965. Light fittings, along with most of the interior surfaces were finished with an asbestos coating but integral to the appearance of the space. So following careful consideration, the wall sconces, pendants and external bulkheads were removed from site by appropriate licensed contractors and stripped of asbestos. Only then could they be properly examined and disassembled, and their refurbishment planned.

In looking back at these examples, we can see that re-engineering of light fittings is nothing new, and that quality design of a product generally leaves us with something worth saving. TM66 provides a poignant new emphasis on this, with a focus on the embodied carbon and other climate costs associated with constantly manufacturing from fresh raw materials. By some estimates World copper reserves could run out within the next 30 years[3]. As for the medieval villagers pulling down redundant castles to use the stones for their houses, it will soon simply be too extravagant to use new metal where existing is readily to hand.

But is it enough? As TM66 recognises, daylight is our most efficient light source. For the first 800 years of its existence, beyond its glorious windows Ely Cathedral had just a few candles or pitch-torches, and these would have only been for task lighting. Even the 1930s electric scheme sought only to light specific areas, emphasising the lighting of people and not the building. Yet as slimmer profile light fittings and other technology have become available, there is a temptation to light every last niche and archway, far beyond what could have been imagined for the original build. For meaningful energy savings, we must not slash the consumption of converted halogen fixtures only to treble the amount of new lighting in the building. Just as the extensive outdoor lighting schemes of the past decades are being critically re-appraised now for their effect on the night sky and ecology, so too indoor schemes must be carefully considered in terms of what we are lighting, and why. We should recognise there can be beauty in darkness and what we choose not to light too.

[1] A brief history of artificial lighting at Ely Cathedral (

[2] Internal Lighting in Historic Buildings | Historic England

[3] TM66 Section 9.3


To view the full published article online, please visit SLL Light Lines Magazine

Greening our Heritage Properties: a holistic approach to energy efficiency

Author: Chris Hughes, Principal Engineer & Engineers Without Borders UK Change Maker

England has one of the oldest building stocks in Europe. Around 20% of our housing was built more than 100 years ago. In addition, we have many other valued period properties, from palaces and stately homes to the halls of power in Westminster and Whitehall. The need to regenerate these structures to be more energy efficient is unavoidable – and it is vital that engineers take a sympathetic look at the solutions available.

In its sixth Carbon Budget, the Committee for Climate Change stated that buildings, including homes, are the 3rd largest carbon emissions producers in the UK – accounting for 13% of all the UK’s carbon emissions. We can’t drastically modify these heritage structures, and for more modern buildings it is neither feasible nor environmentally desirable to conduct a mass demolition and rebuilding programme, so we need to find practical ways to decarbonise our existing and historic building stock. The National Trust has already assessed its carbon outputs and has set ambitious targets to decarbonise by 2030 – but how can engineers balance issues of sustainability and energy efficiency against the need to preserve original structural features and fabrics?

It cannot be assumed that modern or ‘standard’ engineering and technologies will solve all these problems. Adapting heritage sites to meet modern usage and environmental demands requires an appreciation and understanding of the building’s structure, the environment in which it sits, and the solutions that sustained it in the past. For example, visitors to heritage attractions expect modern facilities which need to be incorporated sensitively. The historic building itself may have been designed as a family home originally, but now it will have back offices for staff, storage requiring precise humidity conditions for precious artifacts, and sometimes private accommodation for the incumbent owners. This means multiple requirements regarding heat, light and ventilation that need to be met sustainably and efficiently.

These conflicting demands do not just apply to stately homes, of course: many public buildings including hospitals, town halls, theatres and schools face similar challenges. In addition, large swathes of our basic housing stock comprise Victorian terraces, 1930s suburbs, post-war ‘homes for heroes’ and garden cities. As engineers, we need to find solutions that will not just deliver short-term energy bill savings, but that transform these aging buildings into sustainable living spaces.

Indigenous or vernacular design, which uses readily available material resources, hints at some solutions, as well as ‘lost’ building practices. Shutters can help keep heat in at night, natural flooring materials can retain heat but remain permeable, and reinstating ‘cold’ roofs allow the removal of humidity and reduces thermal losses from insulating at ceiling level. We can draw inspiration not only from the UK, but internationally. In Ghana, locally available wood and stone are variously used to combat atmospheric conditions ranging from dry heat to extreme humidity.  In north Africa and the Gulf peninsula wind towers provide a means of passive cooling using the prevailing wind direction. Malay houses are perfectly adapted to the high humidity with natural materials promoting ventilation and providing solar shading with overhanging roofs.

In the UK, we are relearning the benefits of some older materials. Concrete render applied in the mid-20th century to reduce heat loss is now causing damp problems in properties originally constructed of porous materials that easily exchange moisture with the air. These concrete skins are now being replaced with traditional lime renders, which will work sympathetically with the building’s original structure. Sustainable, natural wool insulation is being reintroduced. Sash windows are common in heritage structures, and need regular maintenance due to their timber frames, but keeping on top of this can reduce cold draughts.. Repairing external walls can also reduce uncontrolled infiltration.

The potential to improve energy efficiency and decarbonise our housing stock is significant. Thousands of houses were built in the same period using similar construction techniques and materials, which means they are likely to face the same issues. But this also means that appropriate, sustainable solutions can be applied on a grand scale (if the industry can respond to demand).

It further offers the opportunity for householders to come together collaboratively and collectively. For example, it could give them better buying power to reduce the cost of investment, or the ability to pool their own skills to help each other achieve the necessary improvements. And in the end, being invested in the process is what will make the difference in achieving our carbon reduction targets, reversing climate change, and securing the long-term future of the planet.

Clearly, what is required is a holistic approach that considers the existing building fabric and design, the needs of the occupants over time and the longer-term impacts of any energy efficiency measures. It is simply ineffective and inefficient to disregard solutions that have been deployed in the past – especially if they were designed into the structure and use of the building. In taking this approach to regeneration, we can preserve our past whilst protecting our future. This is precisely the philosophy that underpins Engineers Without Borders UK and the principles of global responsibility that it promotes.

Become part of our global movement today at

Article published in E&T IET magazine and accessible online:

Pride Month – Behind the flag

In June 1969 a gay bar in Manhattan, called the Stonewall Inn, was raided by police. Riots followed for days in protest of discrimination and police brutality, sparking the gay rights movement in the US. This movement spread across the world, adopting the term Pride, and is celebrated across the month of June as the anniversary of the riots.


The pride flag was created by Gilbert Baker in 1978 to represent the LGBTQ+ community and refused to trademark it. There have been many iterations, including removal of colours and addition of new patterns to represent the unique struggle of BAME, transgender, non-binary and intersex people. Originally it was seen as controversial for use by companies and public bodies, now it is common place across the month of June.


Despite the legal strides, most significantly the Gender Recognition Act 2004 and the Equalities Act 2010, there are still cultural barriers to inclusion.

Here at CBG we want to support breaking down barriers and champion inclusivity.

International Women in Engineering Day 2023!

Happy International Women in Engineering Day from all at CBG Consultants.

International Women in Engineering Day (#INWED) now in its tenth year and was launched to celebrate women in engineering around the world. #INWED is an international awareness campaign which raises the profile of women in engineering and plays a vital role in encouraging more young women and girls to take up engineering careers.

To celebrate #INWED2023 we wanted to highlight some of our engineers and share their advice for those wishing to pursue a career in engineering…


Jemma Clerkin – Electrical Engineer

I wanted to be in a sector where sustainability had an important part to play in modern society. I first started my engineering journey with a renewable energy course but then moved onto building services. Engineering plays an important role for sustainability & our choices can make a positive impact on energy saving. As an electrical engineer one of my roles is to choose & specify equipment that not just works but also contributes to energy savings, for example lighting controls. Using daylight sensors & motion detectors to name a couple, this will control when the light goes on & off & can overall save energy, thus in the long having a positive effect on our environment.

My engineering hero is not trying to be bias but Nikola Tesla, in my eyes he was a genius of his time. He helped shape the world of electrical distribution & AC current which is still used to this day. What I admire most about Nikola Tesla, he wanted to make a change.  When he was researching how to produce “free electricity” he wasn’t interested in the profits of making money from electricity, he wanted to make it free & available for everyone. He was an engineer with inventions that helped shaped our world today.

There is so much I enjoy about working as an electrical engineer in the building services sector. There are so many projects that CBG undertakes & I love the variety. One day working on a heritage project, the next is residential. When you pick up a project from the start you get to see it develop over time & transform into the final product. You get to take away the moment of “I was part of that project”.

I would say do your research on what you’re interested in, prepare questions & go to university open days & career days. Always have an open mind because you may start off in thing & it might lead down a different path.  I would also say, don’t give up! There will always be challenges that need to be faced & if engineering is what you want to do, push through it. It will be worth it.


Sibani Bhagotra – Graduate Sustainability Engineer

Greetings, I am Sibani Bhagotra a sustainable Architect/Engineer. I decided to pursue a career in the engineering sector because I wanted to make a positive impact on the built environment by integrating sustainability principles into architectural design. I believe that engineering plays a crucial role in creating energy-efficient buildings, designing sustainable infrastructure, and finding innovative solutions to environmental challenges.

My engineering hero is my family, specifically my grandfather, father, and brother, who are all engineers. They have been a constant source of inspiration and guidance throughout my journey. “I was drawn to architecture because it allowed me to embrace and channel my creativity, but I wanted to engineer this creativity in the ability to transform ideas and concepts into tangible structures that impact people’s lives is incredibly fulfilling to me. Reinstating that engineering is not just a profession but a mindset that can be applied to every aspect of life.

What I enjoy most about my job is the opportunity to merge creativity with technical expertise. As an architect with a background in sustainability engineering, I find great satisfaction in integrating sustainable design strategies, such as passive heating and cooling, renewable energy systems, efficient material selection, and water conservation, into projects. Seeing the positive impact of these sustainable design choices on energy consumption, occupant comfort, and environmental performance is a contribution to the betterment of society.

There is nothing that is beyond anyone’s capabilities. The entire narrative revolves around one’s interest in a particular subject. Once you feel curious and motivated to gain knowledge and expertise in a specific field, that’s when you realize you can delve deeper into the subject and potentially pursue it as a profession. Engineering is a multidisciplinary field, and having a diverse skill set can be advantageous. I think engaging with mentors and peers can provide guidance, support, and potential career opportunities in the field of engineering. Engineering projects often involve collaboration with interdisciplinary teams. Developing strong teamwork and communication skills is crucial for effectively conveying ideas, working collaboratively, and ensuring project success.

Remember, as an engineer or an any multidisciplinary art and science professional, you have a unique perspective and the ability to make a significant impact on sustainable design practices. Embrace your multidisciplinary background and continue pushing the boundaries of innovation in the built environment.


Any women seeking to join CBG Consultants in any Engineering role can expect personalized mentorship from Senior Engineers and a range of company activities and rewards. We actively encourage more women to apply by offering various benefits, and maintaining our IIP Silver status.

Work with us

#INWED2023 #makesafetyseen @INWED1919

An exciting new chapter for CBG Consultants & Light Perceptions!

We are excited to announce that we have established a new lighting consultancy division with the acquisition of Light Perceptions Ltd, providers of specialist lighting design services for more than 20 years. Light Perceptions’ experience covers landmark ecclesiastical and historic sites, private estates, museums and galleries, and other public buildings. Bruce Kirk, Founder of Light Perceptions, has joined the CBG Board.


CBG’s Managing Director Andy Payne said: “Through the CBG Light Perceptions division, we will be able to offer bespoke lighting design and project management services. This is fantastic news for our whole team, for our clients, and for others we collaborate with.”


Director Bruce Kirk added: “With a growing focus on sustainability in all stages of the construction lifecycle, the combination of Light Perceptions’ expertise and CBG’s resources means we can offer in-house, a comprehensive low carbon managed lighting and MEP solution across all projects.”


We look forward to this new era and the opportunities it will bring for our clients, employees, and everyone we work with.


For more information, please contact us.



A fun day out of the office – CBG Activity Days!

A fun day out of the office!


Every year CBG Consultants employees get the chance to take part in Activity Days, where colleagues from our London, Oxford, Cambridge and Manchester offices get the chance to socialise together in team building activities.


As an Investors in People (Silver) company, CBG Consultants believes in the importance of social connection between colleagues across the company, both in the office and out. Creating space for teams and managers from different offices to relax and socialise with each other outside of the office is key to overall happiness and wellbeing, and consequently has a positive impact on the company.


In 2022 CBG Consultants held five different Activity Days, one of which was the Crystal Maze Experience in London, a brilliant activity full of 90s nostalgia where thankfully no one got left behind in a lock in! Others included Swingers Golf in London for the competitive crazy golfers; U Drive Cars for the car enthusiasts; Hardwick Park water sports for those wishing to be tied to the back of speed boat by a rubber donut; and for those craving less adrenaline a serene Oxford river cruise picnic.


If you want to get involved and experience more exciting opportunities at CBG Consultants, then visit our careers page for our list of job vacancies!


Day in the life of a Graduate at CBG Consultants


From a young age I’ve always been interested in making things and developed a curiosity for how things work, so a career path as an engineer was a natural progression for me.



There were several of reasons, but the biggest attraction was the vast portfolio of projects CBG are involved with.



Very insightful, I have learned a lot from colleagues. Having the opportunity to be hands on with the work means I’m learning a great deal as I go.



I usually start my day by catching up with lead managers of the projects I have been appointed to. Then depending on the stage of the projects, I’ll be designing mechanical systems from scratch including calculations and sourcing. Some days involve site visits for surveys to get a better understanding of projects or I’ll have on site meetings to attend.



There are some aspects of Uni I have found to be very useful, especially CAD standards and report writing.



The diversity of projects I get to work with, ranging from hospitals, banks, data centres, residential, rail etc. Mentmore Towers was particularly memorable, as it was interesting to see such a historical and iconic building.



Conforming to deadlines and finding solutions to complex mechanical problems.



I’ve completed a 2 day Advanced Revit training, and I’ve had the opportunity to attend weekly CPDs. The mentoring and guidance from superiors and peers is ongoing and everyone has been really supportive.



Great, my co-workers are friendly and everyone works hard. There is a good balance of work Activity Days and team meals.  We will also sometimes attend post work events together, and there has been the opportunity for people to take part in competitions like the annual SLL Ready Steady Light competition



I aspire to reach Chartership status, which CBG will assist me with. As well as giving me access to memberships such as IMechE.



Absorb as much information as possible no matter what discipline and ask as many questions as you can.



CBG Consultants Donate Blood

A+ positive start to the New Year here at CBG Consultants Ltd as we continue to organise office team trips to donate blood!

Did you know one donation can save up to three lives?

135,000 new blood donors are needed each year. Could it be you?

Register here!


Winners of Ready Steady Light 2022!

In October 2022 a team from CBG Consultants braved the elements and took part in the annual SLL Ready Steady Light competition, for the second year running. Held in the grounds of Rose Bruford College, with a helpful team of current students on hand, up to fifteen teams take part. Each team is assigned an area, and an allocation of just six light fittings. They have to come up with a concept for their scheme, then implement it and create a narrative. Light fittings can be exchanged at the swap shop, and a variety of colour gels are available. At around 7pm it’s tools down and a welcome hot meal in the campus café, while judges pace the sites and mutter secretly amongst themselves. Does the concept work? Is that a bit of stray glare they can see? Why has the light spilt over and illuminated an ugly TV dish? Could those cables running on the ground have been concealed better? Teams themselves visit their competitors’ installations, and vote for the peer award. After a tense wait, all is revealed, with awards given for best technical installation, best artistic scheme, and the winning peer award.


After some playing around with light fittings (really the main point of the evening), the CBG team focused on just a couple of interesting features on one tree: a derelict bird box, and a small hollow on a cut trunk. Using some narrow beam spots with colour filters aimed onto these focal points, the stage was set for a dramatic showdown between law enforcement and an errant acorn-stealing squirrel. An eerie red foreground wash amongst the branches completed the sense of an immersive crime scene.


To our delight, the team scooped the artistic prize and was also praised by the technical award judges. As for the squirrel? Well, that’s another story….


CBG Project Parsons North features in Architects’ Journal

CBG Consultants was appointed to provide a full M&E design package RIBA stages 3-7 on the recently completed development at Parsons North, which is featured in today’s Architects’ Journal. This mixed-use development for Westminster City Council provides 60 new homes, as well as restoring and rejuvenating a neighbourhood of streets and gardens to this corner of the Edgware Road.

This project utilised BIM and CBG produced the M&E design package using Revit in line with the BIM Execution Plan.

For more information about the project, please read the article in Architects’ Journal.