Advanced glass coating helps deliver BREEAM Excellent for all-glazed building

The newly completed 122 Waterloo Street development in the centre of Glasgow offers its occupants floor-to-ceiling glazing throughout, with almost uninterrupted views thanks to the latest Schüco curtain-walling system designed, manufactured and installed by Edinburgh-based façade specialist Charles Henshaw & Sons Ltd.

But, impressively, the landmark building – which will be the Glasgow headquarters of global financial services firm Morgan Stanley – will also be one of the most energy efficient buildings in Scotland, thanks in part to high-performance glass coatings from Pilkington United Kingdom Limited.

The scheme has been certified BREEAM Excellent, and achieved an ‘A’ rated Energy Performance Certificate (EPC), the latter based on a detailed assessment of the building’s energy performance. The glazing helps to minimise this by reducing energy emitted from the building, as well as the heating effect of the sun, both of which can make maintaining a comfortable interior climate more energy-intensive.

The scale of the building and the large area of glass used means that excessive radiation of heat from the building could lead to rapid heat loss during colder conditions, requiring an increase in heating to keep the interior warm.

To mitigate this effect, the glazing features a Pilkington Optitherm™ S1 Plus low-emissivity coating which reflects radiated heat back into the building.

The second issue that can affect buildings where most of the envelope is glazed is excessive heat build-up when the sun is shining directly into the interior. This can present a challenge for building managers, often requiring high levels of energy-intensive air conditioning.

To combat this, a solar-control coating has been used, reducing the amount of heat energy that is able to enter the building while maintaining high levels of transparency.

Michael Metcalfe, commercial sales manager at Pilkington UK, said: “The Pilkington Suncool™ 70/35 T coating selected by the design team offers high visible light transmittance, reduced solar transmittance and excellent low-emissivity all in one product.

“This means the floor space will be brightly lit by sunlight but won’t suffer from overheating on warmer days.”

The coatings are not the only innovative part of the glazing used in the project, as the glass is held in place by the latest structurally bonded curtain wall system from manufacturer Schüco. Each unit contains a large pane of clear glass and a smaller pane of opaque, coloured spandrel glass, creating horizontal lines across the façade between each floor of the building.

Michael Metcalfe continued: “The metal carrier frames in which the glass sits are extremely low profile, so the edges of the panes of glass are very close to one another. This removes the mullions normally associated with unit-based glazing systems, creating a flush glass surface with almost uninterrupted views.”

The clarity of the glazing was further improved by the use of Pilkington Optiwhite™ true low-iron glazing throughout, which significantly reduces the slight green tint that is inherent in standard float glass.

On the ground floor, Pilkington Optilam™ laminated glazing was used to provide protection against manual attack and increase the security of the building.

Completed in December 2017, the nine-storey building also includes 155,000 sq ft of Grade A office space.