THE selection of a sustainable façade system from architectural aluminium specialist TECHNAL has helped deliver a sustainable and energy efficient building for the University of Bath’s Institute for Advanced Automotive Propulsion Systems (IAAPS) – a new, world-class automotive propulsion research facility in Bristol, constructed to achieve BREEAM Very Good standard.

The 11,464 sqm, two-storey building was designed by architect Stride Treglown which partnered with DKA Architects to realise this ambitious project. Main contractor Rydon constructed it as a single-stage design and build contract.

The impressive front elevation façade features TECHNAL curtain wall, which is manufactured using Hydro CIRCAL® 75R recycled aluminium - a prime-quality alloy made with at least 75% recycled post consumer scrap aluminium - the highest share of recycled aluminium on the market. Says Stride Treglown Project Architect, Victor Martos: “Originally, we had specified another system but switched to TECHNAL as it uses CIRCAL recycled aluminium and REDUXA low-carbon aluminium, which makes the system very attractive for buildings such as IAAPS that target a high level of environmental performance.”

Fabricated and installed by Bristol-based Architectural Aluminium and Glass (AAAG) to a planned eight-week delivery programme, the curtain walling combines a linear and an arc section on plan to create a striking faceted façade that runs 43m and is 10m high. The double-height curtain wall joins the rectangular arched entrance at a sliced angle.

Martos adds: “Aesthetically, it was important for us to highlight the vertical joints over the horizontal joints so as to emphasise the height of the glazing and maintain the architectural proportions with the main entrance arch alongside. The TECHNAL curtain walling system allowed us to achieve this. It is very flexible in terms of the design options for mullions and transoms.”

Vertically, the curtain wall mullions have an additional capping piece or “fin” finished in an Anthracite Grey powder coating (RAL 7016). This extends 200mm beyond and goes all the way from the base to the head of the curtain wall, creating a vertical trame design. On the horizontal, SSG silicone sealant transom joints offer a seamless look. “The fact that the external fins could be self-supported without the need of additional structure or ties was fundamental to achieving the desired verticality,” he says.

AAAG Bristol Estimating Manager Richard Flicker explains how the façade was constructed: “Each vertical height section is split into four panels, which alternate between vision glass and lookalike, opaque spandrel panels to conceal the M&E services behind.”

The glass specification is continuous to maintain the same level of reflection and uniformity across the entire curtain wall. It also had to meet thermal requirements, as Flicker explains: “Thermally, the façade had to achieve low heat gains through the façade, which meant careful glass specification.“ Following numerous calculations and close discussion between myself and the construction team, Saint Gobain COOLLITESKN 154 solar control glass was selected. This offers a low G Factor (0.28) and helps control the amount of heat that penetrates into the building by reflecting it back to the outside.”

The open plan office space behind the floor to ceiling glass panes also contributes to BREEAM Very Good. Says Martos: “Ensuring an even distribution of light entering from the north, it reduces the need to use artificial light during the daytime and reduces overall building energy consumption. And engaging early with specialist suppliers to maintain momentum and quality throughout, meant we could also optimise BREEAM credit opportunities.” www.technal.com/en/uk www.stridetreglown.com www.dka.co.uk www.aaag.co.uk