Different design challenges

Technal has adapted its FY65 aluminium window specification to meet the narrower than normal opening vent dimensions at a £52 million student village in Coventry, balancing the requirements for daylighting, ventilation, student safety and aesthetics.

A total of 3,500m² of Technal FY65 aluminium windows, together with the company’s MX52 curtain wall and STII high traffic entrance doors, were fitted at the 893-home development.

Designed by FBM Architects, Paradise Street is inspired architecturally by the original medieval city of Coventry. The scheme’s homes are arranged in a ‘wall’ and three towers to address the busy ring road, with a gatehouse opening into a 2,000m² piazza.

To enhance student wellbeing by maximising free air ventilation and minimising the use of artificial light, every single window in the development is floor-to-ceiling with each student’s desk located across the window so they can take full advantage of the views of the city.

Balancing the ventilation and necessary daylighting requirements led to the introduction of a fixed and opening vent to each room. This however, presented a different design challenge when it came to the window detailing.

“One of the key challenges we faced with the design specification was how narrow the opening vents had to be to maximise the size of the adjacent fixed light within the aperture,” Daniel Holden, managing director at Leeds-based facade contractor Casu Consulto said.

“Technal was tasked with ensuring we could achieve an opening vent that was some 53mm narrower than the minimum recommended size, while still achieving PAS 24 compliance.”

Initially, Technal and Casu worked together to produce a comprehensive document to demonstrate that the proposed solution met thermal, air and weather tightness. It also confirmed the Technal system’s performance.

Once approved, the team engineered and fabricated a prototype window that proved locking points, gearing, hinges and handles all worked without clashes. ‘Pull-out’ tests were also undertaken to validate the system’s capability.

Another design priority was the creation of an uninterrupted facade.

FBM Architects associate director John Senior said: “At street level, the first three storeys are constructed using a red, handmade facing brick. This represents the social and human element to the city of Coventry and fits in with the traditional aesthetic of the local terraces.

“In contrast, the 12 to 14-storey aluminium clad towers mirror the city’s industrial and engineering heritage, especially with the development located on the former Merlin Engineering factory where the legendary spitfire aeroplane engines were manufactured.

“To optimise student safety while creating a facade without visually apparent service penetrations, we specified an opaque or non-vision veil over the opening window, providing a safe and secure barrier. The window prototype was used to conduct ‘pull-out’ tests to ensure the veils offered a suitable barrier.”

The windows, which in the tower situations are 1.2m wide x 2.1m high, had to meet a high thermal performance with a U-value of 1.4W/m²K. Because of the smaller window size, alongside a specially coated double-glazed unit that achieved a centre pane U-value of 1.0W/m²K, Casu and Technal specified thermal foam inserts for the profiles, ensuring compliance with the thermal requirements.

Other Technal systems installed include 500m² of MX52 Visible Grid Curtain Wall. This has been installed into an angled brickwork detail, creating an interesting wedge shape design to the common room spaces.