CIBSE Guide L: Sustainability. A review

Do you remember the first site meeting you attended? The voice in your head whinging: “I’ve come all this way . . . I want to talk about ME! I’m IMPORTANT”
Welcome to the project team, comrade.

Building design is a joint effort

Sometimes we have to remind ourselves of that fact as we stare out of the world from our lighting bubble (can you actually see out of a bubble??)

After yesterday’s fine webinar with Recolight: ‘Lighting and the Circular Economy’ I spent the afternoon with the latest edition of CIBSE Guide L: Sustainability. Its been twelve years since this Guide was first published and although much of the content has changed, the underlying situation remains the same. We knew things were bad in 2007, but we now know far more about how parlous our immediate  future is on this planet than we did back then.


CIBSE decides to lay down some responsibility right from the off:

“Let us not forget that it was our engineering forbearers who set us on this path. The progression of the industrial revolution bought wealth and prosperity across the world. Little did we consider that the change in the way we live would have such a devastating impact on our planet’s ecosystem. It is now down to our generation of engineers, particularly those who have recently embarked on an engineering profession, to find the right solutions. It is to them that this foreword is specifically addressed.

Matthew Boulton, James Watt, William Murdoch – The Golden Boys.

It is incumbent on each and every one of us to fully understand that our Royal Charter commits us to strive to provide the best possible solutions for our built environment for the public good.“

Admirable stuff.

Spoiler Alert: by the way, this is a CIBSE document; it’s not from SLL.
There is non-lighting content here.

The Guide is an excellent text book for all those (and that really should mean all of us) who want to understand and appreciate how we can engage with sustainable practices in building design. I eventually came to realise that the whole point of sitting through a day-long site meeting was exactly so that I could learn to appreciate the skills and demands of the other trades and professions around the table. The Guide makes it clear that we all have a role to play in developing and delivering sustainable buildings:

The challenge is to develop buildings that use much fewer resources to provide functional, healthy and comfortable conditions for their users. This forces us to:

  • better understand client drivers in order to advocate for shifts in approaches
  • re-examine what is human comfort and amenity
  • rethink our traditional linear use of resources towards a leaner, circular economy approach
  • assure our supply chain to ensure safe, legal and socially responsible sourcing
  • better harness passive means, thus allowing the active interventions to be smaller and simpler
  • apply whole-system thinking and seek strategies that offer multiple benefits, for example green infrastructure solutions

As key members of the project team, building services engineers* are in a position to raise other sustainability issues and should seek to demonstrate leadership. This does not mean they should operate on their own nor that topics should be considered in isolation; a holistic approach should be adopted, with the use of whole system and whole life approaches wherever possible.

*It’s necessary, as a lighter reading this Guide, to remember that ‘building service engineers’ includes US.

The Guide is divided into a comprehensive description of the process:

  • Defining sustainable buildings
  • The age of limits (planetary limits, that is)
  • The role of engineers in sustainability
  • Sustainability from a client’s perspective
  • Engineering sustainability
  • Making buildings work
  • Practical principles and guidance on specific sustainability topics

I’m not going to delve into the machinery of this Guide – the best thing you can do is to read it for yourself. If you belong to SLL/CIBSE, it’s a free download – so what’s stopping you?

Instead, I’ve picked out a few of the tastier passages for you to chew over (any bold emphasis is mine):

The Foundations of Sustainable Design:

Rather like historical levels of energy efficiency, what might be regarded as ‘sustainable’ today will almost certainly be regarded as insufficient tomorrow.

Efficient use of resources and limiting negative impacts is no longer enough and we need to start incorporating improvements to restore decades of degradation, for example in biodiversity.

We also need to do so in a responsible manner towards people throughout our supply chains and affected communities, in contrast with an often dangerous and exploitative use of resources.

To support a widespread, more sustainable, approach ultimately necessitates a different economic metric to that of GDP or to use it alongside other parameters. GDP predominately accounts for market transactions and has shortcomings as overall metric of our economies: notably, it does not consider the social or environmental costs of our activities such as impacts on health, wellbeing, or income inequality. A differentiation is required between the terms growth and development, with an economic approach adopting instead the principles of ‘sufficiency’ and ‘remaining within planetary limits’ at its core.

Key actions on age of limits (discussing planetary resource limits)

  • Have a broad understanding and awareness of existing and evolving knowledge and science on planetary boundaries and overarching sustainability objectives
  • Apply this understanding to the advice provided to clients on what may be suitable project objectives
  • Apply this understanding to the engineering approach on projects; seek opportunities to stretch best practice and demonstrate leadership in tackling global and local sustainability challenges.

Talking about the Client:

When it comes to sustainability, the client (be it developer, landlord, owner or occupier) may not know what to ask for or what can be achieved.

Although it is often assumed that the client wields the power, in fact projects progress through discussion and negotiation and all consultants have some input.

As an influential and often powerful voice, it is important for the building services engineer to bring sustainable solutions to the table. In the project team, assumptions can be made on which consultants have the greater input or responsibility for sustainability. It is up to the engineer to clarify all the areas in which she/he can contribute.

The typical project team has an imbalance of knowledge, with consultants bringing much more expertise and experience than the client. The facilities management team may have an even greater imbalance, with no immediate recourse to the original design team or expertise to understand the principles.

In order to build the expertise in sustainability that clients deserve, professional education and training is increasingly incorporating expertise on sustainability. Continuous Professional Development (CPD) and other training should be regularly reviewed to ensure that up-to-date knowledge is continuously developed. Requirements for recruitment and promotion should increasingly require experience in sustainable solutions.

And a couple of insights on lighting design:

Lessons learned from (completed) projects

There is typically limited feedback on the operational performance of buildings, which means that design, refurbishment, refit and operational activities are not evolving in the way that they could be. Designers do not often visit buildings that they have been involved in designing, but this provides invaluable feedback that could be used to inform further projects. CIBSE Guide H (CIBSE, 2009a) includes some feedback from occupant surveys on lighting controls, which shows that the following should be borne in mind:

  • People are good at judging whether they need the lights on: therefore, do not switch lights on or increase brightness automatically unless this is essential for safety, or appropriate for managed areas.
  • People are not good at switching lights off: try to provide automatic switch-off, but people do not like being plunged into darkness. Where possible lights should be dimmed, or a warning given. There should be readily accessible local override switches.
  • People dislike automatic systems that distract them or do not do what they want: automatic switching or stepped dimming is best done at fixed times rather than at seemingly random intervals. Occupancy detectors should be positioned to avoid nuisance triggering.
  • Local controls should be accessible and their operation intuitive: switches should be close to the point of decision and their operation clear.
  • Individual requirements differ: given the choice, users select a wide range of illuminance levels. Lower levels are often chosen for work with computer screens; people with less acute eyesight or more exacting work may need additional task lighting.
  • Lighting controls systems are often not adjusted properly during commissioning and during operation. Controls meant to allow energy savings often lead to wasteful energy use in practice due to issues such as changes in the internal layout, lack of fine-tuning and commissioning; users often intervene if controls do not meet their needs e.g. to de-activate automated dimming. In particular, passive infrared (PIR) sensors need to be adjusted for sensitivity and timing.

Training and handover are one of the most important stages in the evolution of a new or refurbishment project. Yet the staff responsible for operating a building may not be present during handover, particularly in new-build scenarios and speculative developments. It is also common that training for building operators is insufficient, or rushed, and staff changes can mean that knowledge is lost.

Useful stuff . . .but then, we already knew that. Didn’t we?

The paragraph on lighting is brief and to the point . . . and wholly focused on health and wellbeing – NOT on energy efficiency. Now THERE’S A QUANTUM SHIFT for you.
If you know the WELL Building Standard, then you can work out what’s in Guide L.
I don’t need to tell you that stuff again.

Oh, but if you don’t know the details of the WELL Building Standard, you might want to do a bit of homework. When the Guide gets to the bit about Materials Selection, we have a job to do:

Building services engineers should work collaboratively with architects, interior designers, facilities teams and building operators to design-out sources of internal pollutants wherever possible and suggest standards that can be applied, such as those contained in the WELL Building Standard and other environmental assessment methods.

Working collaborately brings me back to my opening comment. Sustainable working means working together. We are certainly not in a bubble (however comfortable it might make us feel)

It leaves us with one question to ponder: it’s been 12 years since the first Guide to Sustainability. What will the next 12 years bring, given that we’re told we have to demonstrate our intentions towards mitigating climate change during this decade? This year, if possible, before we end up back in the ‘old normal’.

Answers on a cave wall, with a burnt stick, please?


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