What new products and systems on the market will help you specify green in 2015? Katie Puckett rounds up nominations from sustainability experts.
1. Carbon Buster blocks by Lignacite
Lignacite has been making masonry blocks from recycled aggregates and other waste materials for more than 60 years. In 2013, it launched the Carbon Buster, billed as “the world’s first carbon negative building block”, developed in partnership with Carbon8 Aggregates.
Each block is made from more than 50% recycled aggregates, combined with carbonated aggregates derived from the by-products of waste-to-energy plants. This means that each block captures 14kg of carbon dioxide, more than is released during its manufacture and transport (up to 100 miles from the plant).
So far, its biggest client has been Hopkins Homes, which has used the blocks in around 600 homes across 30 developments in East Anglia.
Contractor BAM will also be adding the Carbon Buster to its standard specification: “People have been talking about whole-life carbon impacts for a while but we’re now seeing a big upsurge in client interest,” says senior sustainability manager Jesse Putzel. “There is now often a requirement for the structure of a building to have a minimum recycled content.”
2. T-Barrier by ARC Building Solutions
This cleverly shaped insulation product is designed to slot into the cavity between party walls in new-build housing, sealing the junction and enabling it to achieve a U-value of zero.
Although T-Barrier has been available for several years, its moment came with the 2013 update to Part L of the Building Regulations. This prioritises fabric performance, and proposes a notional dwelling in which the party wall has a U-value of 0.0W/m2K. The closer designers get to this, the more freedom they will have elsewhere.
T-Barrier is made of rock fibre mineral wool and there are versions for masonry, timber frame and steel constructions, which also provide up to four hours fire integrity and reduce sound transmission.
It has already been specified by a couple of the major housebuilders, and ARC – which has a patent on the T-shape – is now in negotiations with others about a major roll-out during 2015. The company is also developing a system to provide a full fire and thermal seal between dwellings at roof level.
3. Recoh-vert heat exchanger by Hei-Tech
Wastewater heat recovery (WWHR) systems use the warm water that drains away as you shower to heat the cold mains water coming in, either to the water heating system or the shower itself. “It’s really hot water we need to save,” says Cath Hassell at Ech2o Consultants. “We still need to reduce our use of water full stop, but it’s recognised now that the priority is to reduce our use of hot water.”
Hassell is a fan of the Recoh-vert heat exchanger, a double-walled copper pipe fitted vertically below the shower for use with first-floor bathrooms. Warm waste water runs down the walls of the inner pipe, heating incoming mains water in the outer tube with an efficiency of up to 65%, depending on the length of the pipe.
Such systems are more suitable for domestic use than greywater recycling, adds Hassell, as the latter is vulnerable to bacteria build-up and requires far greater maintenance.
WWHR systems are difficult to retrofit, as there must be space below the shower and the minimum length of the pipe is 1.27m. But they are increasingly popular with volume house builders as a cost-effective “fit-and-forget” way to score SAP points – for example, Recoh-vert costs around £47 per SAP percentage point compared with £160 for solar thermal systems.
4. Propelair toilet
This British invention uses just 1.5 litres of water for each flush. The cistern is divided into two – one half for water, the other containing a patented air pump. The lid must be closed before flushing to create a seal. Then a small amount of water enters the pan to clean it, followed by a high-pressure jet of air that pushes out the contents, before the remaining water refills the trap.
Its environmental performance is impressive, its looks are less so – so it’s more likely to be installed in commercial and institutional settings than domestic bathrooms.
Released in 2013, the toilet has so far been trialled by 25 public and private-sector clients including the London School of Economics, McDonald’s, several local councils and the Peacock Theatre in London, and its inventors have just raised £2.6m of equity funding to promote it.
5. Eco Building Boards
This drywall system is made from unfired clay reinforced with coconut fibres, and offers a natural, breathable alternative to gypsum plasterboard. Clay already has a high thermal mass, but the boards are available with embedded phase-change materials (PCM), boosting their thermal performance still further. At temperatures of 21-24°C, a 16mm-thick board absorbs 60% more heat than 30mm of concrete.
“Clay is good for buffering moisture and also volatile organic compounds, and the PCM gives you a lightweight structure that behaves like a heavyweight building,” says Chris Brookman, who runs specialist product supplier Back to Earth. “Clay boards are still a bit green and hairy for most people, but they’ve been used in some high-profile projects.”
The boards have been available since 2010, but interest has been driven in the past year or so by an increasing awareness of overheating problems. At London’s Somerset House East Wing, 1000m2 of 14mm-thick PCM boards weighing 17kg/m3 have been installed. They deliver the same thermal mass as 50mm-thick concrete panels weighing more than 100kg/m3. Meanwhile, 1,800m2 were fitted at One Church Square, a social housing project in Westminster, completed in 2013.
6. Refurbify by VRM Technology
This is a cloud-based software tool that aims to bring the data-rich rigour of BIM to domestic refurbishment, and so provide greater certainty and transparency for social landlords. Trades use a tablet computer onsite to input survey data and capture photos and videos, and this is then used to manage the retrofitting process and to produce BIM models, plans and compliance reports. The developer is now adding 3D scanning capability, which will greatly speed up the process.
“On a basic retrofit, you’re not going to be able to afford to produce a BIM model, so we’ve taken elements of BIM that sit behind the model, such as the products that are going to be used, how they’re supposed to be used, who is required to install them, the cost and the time it should take, and we end up producing a model that can be imported into BIM products,” says VRM chief executive Neill Ryan.
Released mid-2014, the software is already being used by contractor Lakehouse, the Northern Ireland Housing Executive, a number of housing associations and Haringey council’s RetrofitWorks project.
VRM Technology has received grants from EU’s Horizon 2020 fund and Innovate UK to develop the software further, and is working with Huddersfield University and Leeds Beckett University on the BRE’s S-IMPLER retrofitting project. “It should bring us closer to getting the building we want and better understanding building processes,” says Chris Gorse of Leeds Beckett University. “If we can see how buildings have been built, we know they will perform as expected.”
Read more about VRM at bim.construction-manager.co.uk
7. Porotherm bricks by Wienerberger
These hollow clay bricks have been used for decades in Europe, but they’ve only been promoted in the UK market in the last few years. They have many small pores and a honeycomb structure, which makes them breathable and thermally efficient. They are also strong, light, use less water to make and have a low embodied energy.
A growing number of developers are building with Porotherm, including McCarthy & Stone, BAM and Barratt, which intends to use the bricks for 10% of its buildings in 2015.
Architect Gale & Snowden is considering using the bricks on several developments: “In the right circumstances you don’t need insulation in the walls when using these bricks because the air pockets provide enough, as long as the rest of the building is compact, well-insulated and airtight,” says director David Gale. “It is possible to build a Passivhaus block of flats with just clay brick walls – rendered each side and that’s it. We need to move away from cavity wall construction.”
8. Passive ventilation with heat recovery by Ventive
This passive ventilation with heat recovery system was developed in response to the problem of poor air quality in retrofitted properties, but can be installed in new homes. Increasing air-tightness reduces heating but leads to higher levels of toxic chemicals, CO2 and moisture in the air.
Ventive fits either within a chimney stack or duct, and uses the buoyancy of warm air to create a continuous flow. With Ventive S, the chimney pot is replaced with a cowl and cassette containing a heat exchanger. With Ventive S+, the same unit is installed between the rafters and sealed through the roof. Stale warm air rises up through the system, passing through the heat exchanger and warming the fresh air as it enters the house. This air is drawn down and dispersed through the room.
“Ventilation and energy efficiency is a very difficult balancing act,” says Tom Lipinski, Ventive’s technical director. “You can’t just put a hole in a wall because the insulation won’t work, but the fan in a mechanical ventilation and heat recovery unit can use as much energy as three fridges running 24/7. We were trying to design an effective ventilation solution for insulated homes and we realised we couldn’t defeat air buoyancy and gravity. Then we thought if that if these forces are so strong that they won’t let us force air around the house, why don’t we use them to drive air through the heat exchanger? We did feel like the early flight pioneers realising that gravity always gets the better of you…”
It took several years to develop the product and test it, including designing a completely new heat exchanger to fit within the space along with the omnidirectional cowl, which works with wind blowing in any direction. The first prototype was released 18 months ago and Ventive is now installed in around 200 homes, half of which are social housing. A whole-house version of the system is due to be launched at Ecobuild in March, with a larger heat exchanger that can serve many ducts.
LED lighting isn’t new, but it is continually evolving. The latest products have seen such improvements in efficiency that the economics are almost comparable with conventional fittings, says Jesse Putzel, senior sustainability manager at BAM. “Developers have been specifying LEDs for a long time, but not for the entirety of a building. They might use it for downlighting or high circulation areas, but not for linear lighting in an office. It’s now reaching the point where the efficiency has improved so much that it makes sense from a cost perspective.”
BAM has just specified LEDs throughout one of its own speculative commercial developments in Glasgow: “This is a step change for us,” says Putzel. “Energy efficiency and sustainability have always been a priority but up to a certain point. Cost can still be a barrier but with major innovations coming in controls technologies, I think LEDs will be specified as standard in the near future.”
Okay, so wood isn’t a new material. But there are several technological advances that are enabling it to be specified for a greater range of uses.
Cross-laminated timber (CLT), is an engineered panel made from layers of spruce arranged crosswise and glued. It has high strength, dimensional stability and offers the speed and cost benefits of offsite construction. It even performs well when exposed to fire – the charring on the outer layer acts as an intumescent coating. In the UK, CLT has so far been used for a small but steadily rising number of projects, including the nine-storey Stadthaus apartment block in Hackney, briefly the tallest such structure in the world. Lend Lease is also using CLT to build half the 3,000 homes planned for the Elephant & Castle.
Sussex House uses CLT from KLH
There are a growing number of acetylated products available in the UK, where wood is chemically treated with acetic acid to reduce its ability to absorb water, making it more dimensionally stable and less susceptible to decay. Thermal modified wood, meanwhile, is heated to around 200°C in the absence of oxygen, which changes its chemical structure and increases its durability.
Most timber used in the UK is imported – the UK is the world’s third largest net importer behind China and Japan – which increases its embodied carbon. This is what the Grown in Britain campaign, established in 2013, is hoping to change. Britain has the same species as mainland Europe, but trees grow faster here so the timber is not as strong in its untreated state. However, with thermal modification, hardwoods such as ash and sycamore can become suitable for a wider variety of uses, potentially creating a new market for the trees cut down due to ash dieback.
A study by Napier University also found that C16 Scottish Sitka spruce manufactured into 130mm CLT panels performed as well as 120mm panels made from C24 Austrian spruce. British CLT was also trialled in the podiums for the Commonwealth Games in Glasgow, and is the subject of considerable interest. “This year is likely to be the year when we see a whole project built out of British CLT,” says Steve Cook, principal sustainable development manager at Willmott Dixon and co-chair of the campaign. “At the moment, all CLT is imported from mainland Europe, but if the concept can be proven it could pave the way for investment in a British manufacturing plant.”