Healthy Buildings Conference 2023
Write up by Kate de Selincourt
ASBP’s 2023 healthy buildings conference got underway with a wide-ranging talk by biophilic design specialist Oliver Heath. He explored the way that the qualities of nature and natural construction materials can not only benefit the planet, but also benefit everyone using the building.
Most of us are probably aware of entering a space with a lot of timber, or the textures of woven grass or wool, and feeling ‘this is nice’. Oliver Heath described how this effect can be measured in terms of real changes in our bodies. He described how the impact of natural materials can echo the impact of being outdoors in nature – even when we are stuck indoors.
“We have an innate attraction to nature and natural processes and experiencing them has many beneficial effects. While the environments in cities and inside buildings are not like that, Oliver Heath said, we can bring some of the benefits indoors with us, by good design and materials choices.
The kind of unfolding textures seen in nature – for example, in a tree as it divides into branches, then twigs, and then the veins in a leaf are one way to bring that benefit into the built environment. “We understand these sort of patterns. We can recognise them and they reassure us and can reduce stress.”
It is not just the presence of plants that can provide this visual familiarity. These fractal patterns can be echoed in the structure of a roof, for example.
Unprocessed materials – particularly exposed natural wood – also offer a satisfying multilayered richness of texture. “One study found timber walls in a classroom reduced student heart rates,” Oliver Heath said . “It is remarkable how often timber pops up in this research.”
Timber interiors have also been seen to reduce stress hormones, blood pressure, and improve concentration and focus for the better. Given that stress is implicated in as much as 50% of absenteeism & ill-health, this is not only important for quality of life, it is also important for organisations of all kinds.
More and more employers for example are recognising how the environmental qualities in a workplace affect productivity, health and employee retention, and natural materials play a valuable role in this.
Natural materials and healing
Anna Lisa McSweeney of White Arkitekter talked about design that was making the most of the health benefits of natural materials, in a setting where these benefits could not be more important: a building centring around people with cancer.
Velindre cancer centre, being built on the outskirts of Cardiff, will combine cancer treatment, clinical research and education, all under one roof.
The client has asked for a building that has a non-institutional feel, that has low whole life carbon and that makes good use of natural materials, sourced locally in Wales where possible.
Clinical environments are full of busyness and stress of many kinds, for both patients and staff. “A building that contributes to wellbeing can help people get better more quickly,” Anna Lisa McSweeney said. “Wood in particular contributes to this” she added.
The team is using Welsh timber where possible, so needs to work closely with the supply chain “Offsite manufactured components need to be pre-ordered, there is an inherent lead time. We are also working with knowledge about supply to inform our design, for example, eg using ash because ashes being felled due to ash dieback.”
The team has worked very carefully on all the material choices to reduce embodied emissions. So as well as timber, the design will be making extensive use of hempcrete and clay plasters.
As well as fulfilling the brief to be low-carbon and natural, hempcrete (used in block form) has good thermal properties, and is naturally durable, Anna Lisa McSweeney added.
Clay plasters have attractive tactile qualities. But like the hempcrete, they will also perform an essential energy efficiency role, in this case providing the airtightness layer in much of the structure. “Clay plaster also offers radiation protection that might otherwise have to be provided by lead,” Anna Lisa McSweeney explained . “Some cancer treatment involves carefully targeted radiation. It is essential this radiation does not affect staff and patients in neighbouring spaces.”
While the client is keen to employ natural, life-enhancing materials and finishes, the building’s purpose also lead to exacting requirements when it comes to hygiene and maintenance, especially as many cancer treatments leave patients vulnerable to infection.
So the White Arkitekter team undertook very detailed research into the choice of materials , and developed a carefully stepped approach. This ensured materials were robust enough to withstand the level of traffic and other challenges particular to each location, in terms of hygiene, chemicals, cleaning and fire. Some clinical facilities even use UV robots to sanitise them, so an extra challenge was to ensure finishes would not end up discoloured.
VOCs emitted by materials are really important in any building, but again, especially so where people are sick. The sensitivity of some patients means that even the smell of timber, which so many people enjoy, might be unwelcome. The White Arkitekter team went to great lengths to match the materials choices to the users’ needs “we actually asked prospective users to smell some materials to investigate what people felt about different odours.”
Product information must be levelled up!
Designers cannot make the kind of careful specification described by Anna Lisa McSweeney, without detailed, reliable information.
But as Martha Lewis from Henning Larsen in Denmark told the conference, this cannot be achieved without a greatly increased transparency about what is actually in the products that people specify.
There is a vast and ever-increasing variety and quantity of synthetic chemical entities coming into the environment, including via the construction industry, Martha Lewis said.
“Production of synthetic chemicals has ballooned since 1950 – up 50 times, and expected to triple again by 2050. Construction is the number one end market for chemicals – bigger than the next two, electronics and food & drink, combined”
“While this poses a daunting challenge, the scale also means that if the construction industry grasps the challenge, there is massive potential for change.”
Chemical entities tend to be concentrated in the ancillary components rather than the main structural elements, Martha Lewis said – for example, adhesives and coatings.
She also warned that many bio-based materials also included synthetic chemicals, for example as binders, biocides, and fire treatment “It’s important to look for hard information and not be seduced by greenwash about a ‘natural’ product.”
Just a few countries like the US and Sweden require construction product declarations that give a comprehensive disclosure of the composition. But it is extraordinarily important that everyone has access to this information, everywhere. We can’t minimise the impact until we have that information.
Martha Lewis noted that for example that the BREEAM standard sets a requirement for detailed material declaration in Sweden, yet the same demand for transparency is absent from BREEAM requirements elsewhere – including in BREEAM’s home, the UK.
Some of the most persistent chemicals believed to cause health harms, the so-called ‘forever chemicals’, are also some of the most ubiquitous. PFAS (per- and polyfluoroalkyl substances) is such a category. PFAS have been investigated by the US Green Science Policy Institute, who found that PFAS are used pretty much everywhere. In construction they appear in coatings, flooring, roofing, glass, fabrics sealants, adhesives cabling, tapes, timber products, solar panels, artificial grass and anti-vibration components. And because PFAS are so slow to break down, they linger in the environment, causing widespread contamination, including of drinking water.
Burning plastic is bad news
Another pernicious class of synthetic chemical found widely in construction products is flame retardants. Flame retardants are used in flammable materials such as insulation foam, and are also ubiquitous in furniture, thanks to particularly stringent UK requirements.
Yet as Richard Hull from the University of Central Lancashire warned, flame retardants may not make people any safer in a fire. While they slow the spread of flame, they can actually increase the amount and toxicity of smoke, meaning that people may be rendered unconscious – and even suffer fatal asphyxiation – even though the fire is less ferocious than otherwise might have been.
One test by the University of Central Lancashire of the impact of burning identical sofas treated with a range of fire retardant chemicals, found that after 15 or so minutes, some of the treated furniture had given off enough toxic smoke to incapacitate someone breathing it, while the untreated sofa had not.
International comparisons show that the rate of fire deaths in the UK is indeed low – but it is equally low in other countries (for example, the Netherlands, Italy) where flame retardants are not required on anything like the same scale.
Having fire-retardant impregnated materials in our buildings creates potential toxic hazards in three ways, Richard Hull warned.
- Fire retardants – many of which which are toxic in their own right, even when not burned – may seep out of the impregnated material in day to day use.
- Toxic fire retardants and their breakdown products may be given off by treated materials during a fire.
- Fire retardants change the chemistry of smoke, for example increasing the concentration of deadly neurotoxins hydrogen cyanide and carbon monoxide, both of which can incapacitate or kill when they are inhaled.
Richard Hull explained that the fire regulations in the UK are built not around the safety of people inside – or fighting fire in – a burning building. They simply focus on keeping the structure standing for what is deemed long enough to permit escape. “Smoke toxicity is the biggest cause of death and injury in fires – and yet it is unregulated,” he said.
“I used to think fire retardants would stop fires and save lives. But the best intentions have not always led to the best results.” Richard Hull added.
Fire retardants were introduced after the 1960s saw the growth of plastic materials in homes, with a rise in fires and fire deaths as a result. But not all synthetic materials are equally flammable, he explained. “Fire retardants are added to allow cheaper plastics to be used in high risk situations.”
When synthetic building materials and contents, including any fire retardants they contain, are destroyed in a fire, they create a mess of toxic products of combustion. This is a particular issue for firefighters, who are repeatedly exposed to these chemical cocktails. The surroundings, the soil and watercourses are also at risk, and this means that people in the vicinity may also be exposed.
Work by Richard Hull’s colleague Anna Stec has revealed the stark cost to firefighting crews. The work was carried out on behalf of the Fire Brigades Union. Her research found that cancer rates among firefighters in their 30s are around four times higher than in the general population of the same age. Firefighters who had noticed soot in their nose or throat, or who remained for longer in PPE after an incident without changing and showering, were at highest risk.
Use timber with care
As many speakers showed us, timber is excellent for environmental sustainability and for human wellbeing. But it does burn.
Richard Hull was clear that the highly flammable synthetic materials such as the polythene used in the cladding on the Grenfell Tower, are generally far more dangerous in a fire than timber: “Timber is much safer than thermoplastics like polythene, polypropylene and polyurethanes, because timber has the ability to char,” he said. While char is still combustible, it burns much less readily, so does offer protection.
Nonetheless, timber is ultimately combustible, and so must be used with care.
Timber is particularly unsafe when it presents a high surface area to the air compared to its mass, and also (as with other combustible materials) when it is used as a cladding with a void behind that can act as a chimney.
Professor Hull also warned that treatments to increase the longevity of timber are not the same as treatments that reduce fire risk. And most of the latter significantly alter the appearance of timber.
An added risk, pointed out by Martha Lewis, is that fire protection treatment in timber may not itself be very robust – research suggests that fire retardant compounds may leach out of treated timber – rendering the protection ineffective after just a few years, and at the same time, potentially polluting the surrounding environment.
Intelligent design cuts fire risk
There are numerous factors that contribute to the safe design and use of buildings, and “we should be paying more attention to them” Richard Hull warned.
“The cost of a fire occurring has been underestimated. Our efforts need to be focused not just on meeting Part B, that is a bare minimum. If we do a proper job, fire is less likely to happen and less destructive if it does, meaning a building can be restored after a fire and may not need demolition. This is better for everyone and of course better for the environment too.
Paying attention to these factors is first and foremost important in its own right. But they also pave the way to securing building insurance, as Philip Callow of Rosetta Risk Management explained. Philip is a consultant focusing on the insurability of mass timber buildings. He explained that fire risk is not a simple ‘yes/no’ ‘risky/not risky’ calculation. “No building is ever completely safe, and the materials used are only one part of the overall risks of a harmful fire occurring.”
To secure a viable offer of insurance, you need to demonstrate to the insurer that the risk is low enough to insure at a premium that you prepared to pay. So long as you can find that common ground, then the building is not ‘uninsurable’.
As Philip Callow said, there is no question that insurers are wary about fire insurance for buildings with any combustible components. “The cladding crisis exposed the fact that understanding and regulation of fire risks in construction was not fit to be relied upon,” he said.
Philip Callow echoed Richard Hull’s argument that a major shortfall in the fire regulations is that they consider such narrow metrics. Beyond the obvious question of whether the regs actually achieve what they set out to, Philip Callow reiterated that they are only concerned with occupant escape, and not building protection.
There is nothing in regulations about structural integrity beyond what is needed in terms of rescue time. “Yet structural integrity is also going to be of concern to insurers, because the extent of damage will affect the extent of loss.”
“A building that can be renewed and reinstated after a fire represents far less of a loss, on many metrics, compared to one that collapses or has to be demolished because it is beyond repair.” So insurers will want to know what is being done to address this by the project team as an entirely separate consideration to Part B compliance.
Demonstrating the control of risk in your project
An individual project owner can demonstrate to insurers the way risk is being addressed and mitigated, via transparent and well-thought-out processes. If the insurer can be satisfied that these are in force, and well-controlled throughout the design and construction process and on into the buildings use, then they have a lot more of the information they need to assess the risk they are insuring.
Good quality information is being transformed by the availability of digital track records, the concept of digital twins, insurers have not had this real world information before, Philip Callow added.
The Mass Timber Insurance Playbook published by the ASBP is a guide on how to implement these processes through the RIBA stages. It goes a long way beyond regulatory compliance. Good practice establishes voluntary objectives that are set early in the project, and tracked throughout.
The Mass Timber Insurance Playbook contains numerous examples of how risk can be addressed. These not only apply to the physical structure, but also to the way a building is run: How will compartmentation be established and maintained? How will building services be monitored? How easily can firefighters operate if they are needed? How is the building resilient to attempted arson? How readily could any damaged portions be repaired?
Communication with insurers is an essential part of the process. Early in the project, showing insurers what you are doing is very valuable. “There is nothing to beat a face to face meeting on site, showing how you are mitigating risk and making your building resilient.”
Timber treading lightly
One of the many compelling reasons to use timber is of course its low embodied impact. Compared to the manufacture of steel or concrete the growing of timber uses very little high-carbon fuel – as we know, the “manufacturing” energy comes from the sun..
However timber is heavy, timber trees are dispersed over large areas, and a raw log is not much use on most construction projects. So timber for construction must be transported, processed – and then transported some more. And these stages mean energy use. While low compared to the footprints for say steel or concrete, the carbon footprint of timber components are certainly not nothing.
The UK timber industry is mindful of this, and has come together to agree a net zero target, and develop a roadmap to get there.
Timber Development UK signed up to the SME Climate Hub Commitment in 2021 and have agreed to support members in halving greenhouse gas emissions by 2030 and achieving net-zero before 2050, with a further commitment to report on progress on a yearly basis.
Timber Development UK has been joined by the other UK timber trade bodies and the ASBP, and together have drawn up a decarbonisation road map for the industry, as Timber Development UK sustainability director Charlie Law explained. “Everyone wanted to be involved.”
After commissioning an analysis of the carbon footprints of timber growing, processing, supplying and end-use, an emissions reduction roadmap was developed. A timber industry carbon calculator has been made freely available, to enable anyone in the industry to benchmark, declare, and reduce their own emissions .
The two main areas highlighted for reductions were transport (within the UK) and the emissions (transport, processing etc) associated with imported timber products.
Opportunities for major reduction in transport emissions are expected in the medium term, as electric trucks start to enter the haulage industry over the next decade. It might also be possible to power forestry plant with low-carbon hydrogen – remoter sites make electrical power harder to deploy here.
In the meantime diesel-powered transport can also become more efficient. Interestingly one of the areas identified for saving was “driver style”. The aerodynamics of vehicles, and the maintenance and choice of tyres was also significant. Altogether, deploying these optimisations could cut 30% of the current transport footprint, the analysis found.
Another major source of emissions is use of gas for heat in timber processing. And though some might look to waste wood as a “low carbon” alternative, even by the most generous of calculations it is fast being overtaken in the race to zero by our electricity supply, with its increasing proportion of wind and solar power. Direct electricity use is expected to pass biomass in the race in just four years’ time.
Going home grown
It is a lot harder to tackle emissions that happen upstream in the growing and processing of imported timber – unless we replace imports with local timber. Increasing domestic timber production is a shared goal of many in both the timber industry and the design and construction sectors.
Architect Kat Scott and her colleagues at DRMM are so invested in this goal that they have secured a contract from the government’s Timber in Construction Innovation Fund, to investigate potential for more timber production specifically for use in construction
DRMM are collaborating with NMITE (The New Model Institute for Technology and Engineering, home of the Centre for Advanced Timber Technology, CATT) and others involved in the timber supply chain, including Edinburgh Napier University, and timber producers and processors from Scotland, Wales and the Welsh borders.
Kat Scott described how the project ‘Building from England’s Woodlands’ is assessing routes to develop home grown timber products – including what species to prioritise. “We have done lot of voluntary work on this, so being able to go into it a lot more thoroughly and collaborate with the industry is really exciting,” she said.
This project is just one example of how DRMM is taking the principles of ‘regenerative design’ into the heart of the practice. Their holistic approach means considering the impacts of the practice’s output – but also, the impact of the firm’s own operations, environmentally and socially.
“We know that as architects and built environment professionals we have a hugely significant impact through what we do day to day in our working lives. We control not only the energy and emissions, but also the embodied carbon in our projects,” Kat Scott said.
“The good news is that we have significant potential to reduce it with technology and materials that already exist. In that sense ours is one of the sectors that is more straightforward than others to tackle – if you compare construction to aviation or industry for instance.
Evaluating, reporting, and honest self reflection are all key to genuine progress towards sustainable and, ultimately regenerative design. Some of the more quantitative aspects, carbon in particular, are relatively straightforward to measure. There is almost too much guidance out there: “It’s impossible to keep across it all, but we do a lot of training,” Kat Scott said.
“We find the LETI guidance and Architects Declare practice guide particularly useful; I look at the LETI climate emergency design guide and embodied carbon primers most days! The LETI guidance has numerous useful benchmarks, and also a rating system for embodied impact – both up front and over the full life-cycle – that we use a lot.”
DRMM understands the importance of closing the feedback loop so post-occupancy evaluation is also an important part of the practice.
Healing the planet
Quantifying beyond carbon is much more difficult, but that is not a reason not to try: “We aggregate all the data we can, to try to build a full picture,” Kat Scott said.
The practice is looking beyond net zero biodiversity impact, resource impact, climate impact and on towards regenerative design – where a project not only gives back as much as it takes in terms of resources, energy, biodiversity – but contributes towards the regeneration and healing of the planet.
“We are in a situation of crisis both climate emergency and biodiversity. As a society, we are still more degenerative than regenerative.
“We know we are consuming far too much for our planet, and even when resources are sustainable and renewable, the rate we are consuming them is unsustainable. It is shocking that if we carry on like this, by 2050 there will be more plastic than fish in the ocean, that 20% of the world’s population will be at at risk of flooding. And it is shocking that we are still only reusing 1% of materials and construction elements, across Europe.
While statutory targets are lagging, “voluntary guidance and targets are being taken up at scale in UK, which is great.”
“We have huge scope to make changes for the better.”