Could the era of glass skyscrapers be over?

Good for Ken! See Mr Shuttleworth’s contribution under the title of Glass Ceiling on the BBC.

So is the tide turning with people beginning to see beyond the brash salesman portrayal of all-glass buildings as sexy. After all they have no more technical foundation than most passing fashions. For too long soft pseudo ‘facts’ have been used as ‘Emperor’s New Clothes’ to support the unsupportable. Hard facts are needed to illustrate how draft it now is – yet inconvenient real facts for a real evidence base is plainly not sexy enough.

Do not get me wrong, daylight is good for you – but too much of a good thing almost always becomes not so good. Take food vs obesity as an example. The occasional glass of red wine is another one. Daylight is just the same. Deprive yourself of daylight and your health suffers. But too much and the sunshades and sunhat have to come out and ability of the brain to concentrate evaporates. Fine for the right time and place. But it is interesting insight that our eyes’ optimum daylight for concentration seem to reflect an evolutionary history as cave dwellers and foraging under heavy tree cover!

So some hard facts:    

Our eyes recognise a room as well lit with daylight levels of typically between 2% and 5% of the outdoor illumination levels under an overcast cloudy day (ref: British Standard 8206-2). Direct sunlight is typically 10 fold more intense than this overcast sky!

Key to good daylight design is understanding Glare and how the eye adapts to differing light intensities
Key to good daylight design is understanding Glare and how the eye adapts to differing light intensities

Good daylight is far more than ‘Quantity’ of daylight. Glare is also a key determinant of visual comfort / avoidance of visual disability. Too much contrast glare between bright and shade and the eye cannot cope. If indoors’ is at 2-5% of outdoor lighting levels then by definition the contrast between them is some 50 and 20 times. Viewing through a window illustrates the challenge the eye has to cope with. To put this into perspective the ideal maximum contrast should be no more than about x4 for more exacting tasks like comfortable reading.

For our eyes, contrast glare greatly increasing as the light source comes closer to horizontal line of sight. If greater daylight is pushed deeper into a room using larger windows, more light is travelling almost horizontal and hence increases the glare contrast between the window and what then appears relatively gloomy room surfaces. Interestingly the room surfaces may not in fact be gloomy, but because the eye tries to adapt to the main window glare source by closes its iris, it means less of the room surface illumination can enter the eye.

Energy savings are claimed for large windows. That might have been the case in the past, when artificial lighting energy use was 12, 25 or 40W/m2 (the latter being the office norm some 40 years ago and still so in some retail!). But now with high efficient LED lamp sources (eg 100 lumens/W) and task-lighting fast becoming the norm, lighting energy use is heading for 5W/m2. Hence the energy to be saved is a fraction of what historically it was when big windows started to become in vogue.

Glare blinds are advocated to block this glare from large windows. But blinds also block the daylight – is this not self-evidently self-defeating? Besides, as glare varies with type, position and direction at each point in the room there is no single all-inclusive definition of when glare will be a problem. It is one of those ‘too difficult to solve’ challenges. Veiled glare, for example, may occur when a brightly lit object is seen as a reflection on say a computer screen – almost irrespective of window direction. Manual glare blinds seek to address this inability of automatic blinds to predict all glare types. However, while the human being may well have an instinct to alleviate discomfort and hence lower the blinds, it does not have a similar instinct to reset the blind after the glare source has moved on. The result is blinds down and lights left on.

Large window advocates continue to point to measured artificial lighting energy use consistently being higher than predicted. What they do not explain is that their daylight factor calculation predictions assume a nice empty room for daylight penetration. The in-use practice is very different with cluttered desktops and screens blocking most of the daylight. So bang goes those theoretical energy savings.

In reality all the indicators are fundamentally moving away from full height glazing. In a modern ‘Smart Office’ it is not only the artificial lighting energy use that is going down. Tablet computers (eg USB peak 4W charge rates) with flat screens are now using less than 5 W/m2 of energy instead of convention numbers of 15 – 25 W/m2. The diagram below illustrates the ever increasing impact the window size has on your choice of air-conditioning system. Your window cooling load is now easily 75% of your room cooling capacity. And typically your glazed wall corner office will have even greater cooling needs than those shown. It is this peak capacity that defines the air-conditioning capacity and systems type – which is then rolled out cross all you building. Immediately your plant costs are significantly higher than they need to be, as is the consequential annual energy use.

The windows are the biggest influence on oversized air-conditioning
The windows are the biggest influence on oversized air-conditioning

So what of the alternative? Well first of all I should start by saying that if someone really wants an all glass building then they are fully at liberty to completely cover their building in it. My main focus though, is on making that part of the façade that is transparent (or partly) more appropriate based on hard fact real needs.

With Smart Office low artificial lighting energy needs means the daylight/cooling/heating optimum window area reduces to perhaps 25-35% of the façade area instead of 75%-95%. The low energy Smart IT also mean that the façade thermal insulation is needed as the buildings are no longer ‘self-heating’ using inefficient lighting/IT. More modest windows help here too because wall insulation is still about 5-10 times better than best glass.

As an interesting aside it means more convergence with residential envelope energy design – which is probably a good thing given our planning system now allows building use changes between offices and residential!

So the window design now focuses on ‘Quality’ of daylight and not delivering just ‘Quantity’ as if it were a simple opening in a wall. The window shape, orientation, reveals should be chosen with an emphasis on making the room feeling welcoming with well-lit surfaces while not forcing the eye to adjust to overbearingly large window glare sources. It is interesting that emerging research is showing occupants tend to judge whether to switch on their task lights based on general room surface illumination perception and not the amount of illumination on the desk top!

With regard to the view, I recall research back in the 1980’s that found that the brain fills in the view beyond a series of discrete window openings. The key issue was then to provide an element of foreground and sky to complement the distant mid-level view so the brain had sufficient data for this wider view perception. Perhaps after all the Victorians, with their vertical orientated windows, were on to something!

What is also interesting is the way these smaller loads (solar, lighting and Smart IT) allow more passive systems to meet the peak cooling needs. Without needing the galvanised tin boxes and dropped ceiling, permits less storey height and reduced cladding costs – as well as less useful floor area lost to mechanical and electrical equipment rooms. It almost goes without saying that less extravagant windows also avoid the costs of external blinds or shading. Indications are of overall capital costs reductions for the right windows of as much as 20% less compared with the all glass alternative!

As an aside this also opens up a lot of pre-1980’s buildings as being far more compatible with today’s low energy needs than is normally appreciated, and hence ripe and appropriate for refurbishment!

Surely a return to hard facts based evidence and common sense over the all-glass fashion eco-trip is well overdue.



EcoBuild – is this the right direction?

I found this year’s tenth anniversary Ecobuild exhibition / conference interesting and enlightening. In part this was because of a good range of seminars, briefings and networking opportunities. But also for me was the before and after comparison as I’ve been away in China and Australia for the last four years.

Ecobuild: Ed Davy Sec of State for DECC puts on a brave face!
Ecobuild: Ed Davy Sec of State for DECC puts on a brave face!

At one level the signs of success are clear. Everyone now wants to be sustainable. Everyone wants to be motherhood and apple-pie Green! Wow, and how things have changed over the last ten years. Here is a successful Ecobuild with increasing attendance. But wait…..what are these emerging dichotomies?

  • Ultimately Ecobuild is financially founded on enabling companies to sell more ’stuff’. But is selling ever larger volumes of stuff the basis for a tenable future? Where does ever more consumption of raw materials take us? Surely can need to be exporting success measured in terms of selling less?
  • A dominant theme seems to be: What level of BREEAM / LEED assessment would you like? Then tick the box. Our building is now sustainable. Need do no more. Sustainability is solved!  So is that it?
  • It seems that Part L code compliance no longer has anything to do with actual building energy use. But hang about, does not our ever more demanding consumer expect a label to describe its contents.
  • Game Boy has taken over SBEM code compliance modelling. Engineering judgement and intuition is redundant. Instead gaming rules apply – so add ever more kit and gaming features to inflate the carbon emissions reference target for the best chance of getting your desired low carbon rating!
  • Plenty of politician and austerity bashing. But surely our politicians reflect the public. And our politicians appear to be getting fed up with our industry not delivering. Should we not be on charm offensive to bring the mass public on side?
  • Of the elephants in the room…. where is discussion and pathfinding for 2019 Zero Carbon non-domestic new-build? It seems that more half our 2050 non-domestic buildings have yet to be built!

And the good news stories – did we notice? The cost of delivering zero carbon new homes falls by almost 90% over the last 10 years. This is what happens when industry accepts the challenge of taking on very ambitious policy targets, develops solutions with its supply chains, institutes pathfinder projects and collaborates for the common good. We can do it, so why not more of this so we can get our construction industry better positioned for society’s future needs.

Extract from article by Chris Twinn in CIBSE Journal Apr 14 

Is it us at fault: Chancellor cuts green support in return for instant gratification?

This time the Chancellor’s target is the carbon minimum price support and business ROCs obligations following on from his £50 home bills handback – having been bounced into it by the Opposition’s unilateral £200 handback policy.

©Danilo Rizzuti
©Danilo Rizzuti

The case for supporting new green jobs, the inward investment, increased fuel security, greater energy bill savings – year on year, has been lost in favour of one-off bill reduction as the Government lines itself up for short term vote grabbing.

Is our government system so blinkered and lost to the bigger picture? Are our politicians so naïve?

Repeatedly the enormous opportunity to creating green jobs in energy efficiency and reducing energy use has been put to them. In principle using less energy means less of our hard earned income disappears overseas and into a Russian bank account. Instead it goes to creating employment and green businesses in the UK.

The idea that a £1 /week bill handback is a big deal is solely a media spin. This arbitrary £50 is out of an average bill of £1364/year. Surely the more logical way forward would be tackle the larger costs in this bill related to the number of kWhs people have to pay for? This could be so much more than £50/year saving. And the saving could be expanded year on year as energy efficiency mass rollout becomes cheaper.

The amount of cash the UK will well need to future proof our antiquated energy infrastructure is eye watering £330 billion. Has the Government got that cash? No, it is dependent on investment by the energy industry. Yet these short term headlines are the very things that are frightening off those same investors. They have cash to invest now, are largely foreign owned and will use it in other countries where they can predict government policy and investment returns. And will that cash be around later? No, we will have lost early-to-market advantage and every other country will be after that same investment.

Whether we like it or not future energy costs will continue to rise faster than inflation. There are 5 billion people in Developing Countries who want our standards of living but are currently using less than a fifth of the energy we currently use. And as China is showing, their growth in buying power outstrips ours. World costs for energy will continue to climb on the back of supply and demand. Our politicians are simply play King Canute all over again.

But my question is why all this is not the compelling case for green investment it appears to be? Why is it all this logic and much more is just ignored by our politicians? I suggest this is because we as an industry and we as a significant component of wider society are not putting together a coherent and joined up proposal.

I suggest this is all our fault. As an industry we are not good at presenting integrated arguments. We are fragmented and easily divided by single issue counter arguments. Our big corporates put only their narrow view silver bullets and accept politicians’ willingness to listen to big corporates in isolation. Our SMEs despair at making any meaningful contribution. We miss the point of joining up with the social and national finances aspects. We duck the issue of how this all weaves together for the common good. We talk in jargon and not plain English. We are not good at engaging and becoming part of the mass media. We are so selective in what we present such that real outcomes are never what we suggested. We as an industry have gained a reputation for failing on delivery (eg: Green Deal, reduced actual energy use, predicted vs actual energy use, greater new house numbers, homes that are affordable, etc…). Boy do we still have some lessons to learn.

Is it surprising the politicians do not listen to us?


SBEM for Game Boy!

Achieving Part L energy code compliance no longer has anything to do with building energy use. Your new building energy rating is not expected to tell you what your energy use might be.

What is going on….All-Sports-Commentary

SBEM – the computer tool behind part L – has been taken over by Game Boy.  It’s now about gaming the system to achieve code compliance. It is counter intuitive and with it engineering judgement has become redundant. Innovation is stifled as it does not conform to predefined gaming rules. And the more the Part L targets are tweaked, the more the gaming features divide win from lose. The aim is solely to second guess a black box reference model to win!

Digging deeper….

By choosing the right gaming software vendor can improve your chances by 20% or more. Did you know that the A-G scale is not carbon emissions – it is a reference model comparison? Hence a key gaming feature is adjusting the reference model baseline to enhance your chances. The more you raise the reference model energy use, the easier it is to get under that target allowance. Remember that you get extra savings opportunities by adding complexity features.

 So where is this getting us….

We are now getting energy intensive heavily air conditioned buildings with better ‘energy labels’ than energy frugal passive buildings. Needless over provision of fitout systems capacity is the norm because this lifts the target allowance. It also perversely reduces the significance of longer term building fabric performance. Fitout partitions are positioned in the game to maximise perimeter room cooling gains as this also raises the target allowance. Air conditioned all-glass escape stairs and the like are provided as this lifts that target allowance. Glare, blinds down and AC continuously running are the result because the claimed daylight factor credits do not in reality make comfortable rooms. Code compliance is so divorced from reality – and the gamers know it – such that the reality of their assumptions cannot be double checked in the completed building. The complexity of code compliance means very few understand what is going on – yet real building energy use is a function of a whole string of other currently disenfranchised stakeholders.

Having spent much of the last four years working abroad I have found it fascinating coming back with new eyes and experiences to see how the UK’s leadership in this field has been side-tracked.

 So what should be done to put us back on the right track…

  • Far more transparency in Part L and SBEM – to promote continual improvement, engineering intuition, lower energy innovation and wider stakeholder engagement.
  • A single clear absolute kWh/m2.yr value as the target allowance to beat by whatever systems the designers decide – not the gaming encouraged by the comparison of similar solutions.
  • Code compliance should include predicting alternative in-use scenarios – analogous to your car consumption figures.
  • Removal of excessive fitout/unregulated energy profiles to ensure the building fabric / base systems have due priority / influence.
  • Mandate our universities to research real life feedback, identify the ‘Performance Gaps’, critique and propose continual evolution of modelling tools and real life implementation.
  • A simpler alternative code compliance route for the many simpler buildings – ie ‘Elemental’ component performance compliance for ‘deemed to satisfy, without needing project modelling.

As professionals our role is to develop solutions for the common good – not to support the propagation of system distortions. We also must be crucially aware of our liability as our end-user consumers becoming increasingly expectant that a label describes what is in the tin.


Zero carbon for zero extra cost: preparing for 2019 UK new buildings

Chris Twinn of TwinnSustainabilityInnovation

With China and Brazil striving for the West’s living standards and looking to our best green building standards – worldwide carbon emissions are set to rise dramatically! From their current low energy use per person, it doesn’t take much back-of-envelope calcs to show more than 4ºC of climate change. Taking 30% off our energy use does not cut it when you are already emitting three planet worth.

They are looking for West leadership. Instead we hide behind sustainability as cost-plus little steps with historic institutional barriers. But we could unlock all this if we are prepared to take on Smart Design:

  1. Smart IT – Designing for tablet computers instead of PCs slashes both IT and its cooling energy.
  2. LED task lighting – More than halves light energy use and its cooling energy.
  3. Daylight – Designed for quality rather than quantity brings new light to window design.
  4. Adaptive comfort – Improved productivity & energy by giving people control of their room conditions.
  5. Simple facades – Reverse the trend towards complex and expensive facades.
  6. Passive cooling – Reduced IT and solar allows thermal mass to provide most of the cooling.
  7. Small M&E – Greatly less demands means smaller, simpler and economical.
  8. Less material – Less M&E allows more net-lettable, no dropped ceilings, less storey height & cladding.
  9. On-site or local renewables – Greatly less energy needs so easier for FIT/RHI to meet needs.
  10. Integrated design – Essential – instead of using a pick-and-mix of green add-on’s.

The future for sustainability is using less materials to deliver the built amenity needed to deliver prosperity. Less materials should mean less cost. Are we up for this?

Blog thoughts

cropped-imagesCAZE3USS.jpgOur world faces many challenges.
Please feel free to read and respond to my thoughts on some of these issues.  My contact details are on the Contacts web-page.