Penoyre & Prasad’s sound-slashing windows star in this week’s Specifier.

For the £4m Green Wrythe Lane primary care centre in Surrey, completed this summer, architect Penoyre & Prasad wanted to create a naturally ventilated building.

Project architect Adam Cole says the challenge was complying with the Health Technical Memorandum, which sets special standards for components, such as windows, in healthcare buildings. Moreover, the 2,000m2 health centre, in Carshalton, would be next to a busy road where traffic noise was bound to disrupt GP consultations.

The practice worked with acoustic consultant Sharps Redmore, services engineer Whitbybird and manufacturer Architectural Aluminium to develop an acoustically attenuated window unit. Cole says the units, whose outer boxes were constructed from 6mm powder-coated aluminium, provide 23dB sound reduction, and have a 0.4m2 gap for ventilation.

Attenuation is achieved by a removable cassette, made from two 150mm acoustic louvres set back-to-back and an integrated insect mesh, positioned over an opaque aluminium sliding window unit. The unit also incorporates two conventional side-hung units – one for extra ventilation and one to enable cleaning from inside the building. The two side-hung units are composed of high-performance glass and half shaded by horizontal cedar units, set to minimise solar gain while allowing maximum natural light inside the rooms.

Cole says users of the building are impressed and that the architect will certainly consider using this window system for other healthcare projects.