Passive solar design means the building will benefit from natural daylighting and aided by north-facing rooflights pitched at a 15-degree angle. A brise soleil will protect the south-facing elevation from solar gain during the warmer months.
FEATURE QUOTE “Use of the AECB is normally client or architect driven – where they see it as being a sustainable solution for reducing their carbon emissions, as well as measuring and verifying the building will perform over a period of time. It is essentially a self-certification while, unlike BREEAM, it is achieved through the building itself.” Rob Humphrey, Roan Building Solutions.
MMC Magazine hears from Rob Humphrey of Roan Building Solutions regarding the application of modular construction to meeting the AECB standards in constructing sustainable buildings.
Offsite approach to sustainability
Some of the most sustainable structures to have been completed so far in this country have been built for commercial and retail clients – companies who not merely wish to be ‘Seen to be Green’, but who understand the long term benefits of owning and occupying properties that offer low energy and other running costs.
This is one of the reasons that more clients are opting to procure new projects under the guidance of the Association for Environmental Conscious Building, or AECB. Founded way back in 1989 it numbers many building professionals amongst its membership as well as local councils, housing associations and other environmentally conscious stakeholders.
Additionally there are a growing number of offsite manufacturers ready and able to assist in delivering designs which meet the AECB’s requirements. Companies such as Roan Building Solutions from which Rob Humphrey shared his insight into compliance.
Speaking to MMC Magazine Rob Humphrey explained: “Use of the AECB is normally client or architect driven – where they see it as being a sustainable solution for reducing their carbon emissions, as well as measuring and verifying the building will perform over a period of time. It is essentially a self-certification while, unlike BREEAM, it is achieved through the building itself.
“We’re currently building an office designed to AECB silver standard from its CarbonLite programme, which is due for delivery in early August (2015). The new office in Somerset for John Wainwright and Co Ltd has been designed and specified by a local architect who is AECB-registered. We have taken this specification and tailored the modular solution to meet the required standards and are on track to erect it on site in a six-week time frame with the handover due to take place early August.
“Modular methods of construction tend to be more nimble than traditional build to changes in construction standards. Offsite construction provides manufactured buildings in a more controlled environment allowing more regular quality and performance checks throughout the construction process.”
For those not familiar with AECB it offers three levels or standard: Silver, PassivHaus and Gold – all designed to deliver new-build, energy-efficient properties which significantly reduce carbon dioxide emissions.
Standards are expressed in terms of energy use and CO2 emissions per square metre; while AECB buildings are designed to provide a constant, comfortable temperature in both winter and summer months, with low running costs.
The 240 square metre facility in Radstock for the quarrying business will comprise three offices, a meeting room, kitchen, WCs and an additional open-plan office area.
As with most of its projects, for the John Wainwright contract Roan has relied on a cold rolled steel frame to provide the structural strength for each of the 10 modules. The infill then features a timber frame make up with 150 mm deep studs, fully filled using mineral wool insulation, then a rigid foam board across the entire outside. With the joints all taped, this helps achieve an airtightness figure of less than 1.5 m3/m2/hr and a U-value of 0.25 W/m2K. The floor meanwhile offers a U-value of 0.2 and the Velfac fenestration – including both V200 system windows and curtain walling – achieve 1.2 W/m2K as well as providing ample natural daylight.
Rob Humphrey added: “The emphasis with AECB standards is on precise design ensuring a building’s predicted energy performance is actually delivered. A critical success factor in achieving high energy performance is air tightness. That requires meticulous detail of workmanship to ensure all joint apertures are sealed correctly and with suitable materials.
“Airtightness makes maintaining a comfortable environment – both in ambient temperature and air quality – acute so we’re using a highly efficient MVHR system. From a modular view, Wainwright’s AECB blueprint presented few challenges in translating it into a six-week build which should be delivered in full, on time and budget. That’s a powerful combination which we believe will encourage even more clients to take the sustainable route for all the right reasons.”
Roan Building Solutions provides a wide range of sustainable, offsite constructed buildings across a variety of sectors including commercial, education, rail and healthcare. It has delivered green, economical buildings with many achieving BREEAM ‘Excellent’ standard across the sectors.