Natural ventilation contributes to award winning sustainable development

A flagship £100m housing scheme, which has already won major housing awards, is taking sustainability to advanced levels, helped by a natural approach to ventilation.

CDS Housing is constructing over 300 new build homes for both rent and shared ownership as part of a five-year regeneration programme at Castlefields in Runcorn, Cheshire.

Using Modern Methods of Construction, CDS Housing aims to create homes that will last at least 30 years with minimal maintenance and optimum sustainability, including a SAP rating typically above 100, timber frame panel construction, timber from sustainable sources, and reduced CO2 emissions. The scheme has won the Chartered Institute of Housing’ s excellence in delivering regeneration at the UK Housing Awards 2006.

All the homes for sale and rent, which range from two storey houses to three- storey apartments, include ventilation systems from Passivent. Each house incorporates Passivent Passive Stack Ventilation in the kitchens and bathrooms, with the apartments using Passivent Assisted Ventilation. All homes additionally feature Passivent Fresh through-wall ventilators and, in the timber windows, Overglass Vent Bars with Frame V ents and Canopy Grilles to provide background trickle ventilation.

Passivent Passive Stack Ventilation (PSV) functions purely using natural air movement, 24/7. A humidity sensitive extract in the ceiling is linked via ducting to a terminal on the roof, which at Castlefields has been colour-matched to the roof covering to enhance aesthetics. The extract operates automatically opening and closing in response to changes in relative humidity allowing moist air to rise up the stack by natural buoyancy, enhanced by wind blowing across the roof thereby providing effective condensation control and helping maintain a dry, fresh environment within. The system has no mechanical parts to go wrong or need replacing, operates silently, does not need any electricity, and is not dependant on occupier input switching it on or off for operation.

Within the apartments, a fresh, healthy environment is being achieved through the use of Passivent Assisted ventilation Systems. A continuously running, remotely located central extract fan linked via ducting to a number of extract points and terminating through a single roof terminal provides efficient mechanical ventilation. Humidity responsive extracts, similar to those within the Passivent PSV system, located in the kitchen and bathroom automatically provide ventilation in response to demand.

On the facades facing the roads, Passivent Fresh 80dB acoustic through-wall ventilators provide attenuated background ventilation . Each unit can be adjusted to provide a small level of trickle ventilation even when closed, and can be easily opened through a pull cord to increase ventilation.

On the opposite facades, Passivent Overglass V ent Bars with Frame V ents and Canopy Grilles provide similar levels of background ventilation whilst preventing under- or over- ventilation. The Overglass Vent Bars are thermally broken. The Frame Vents have a choice of settings and still yield a degree of trickle ventilation even when closed; when open, they direct the flow of fresh air upwards reducing draughts. The Canopy Grille gives appropriate external weather and insect protection.

Observed Project Manager Louise Davies, “We aim to build housing to a high standard, yet take into account the needs and wishes of the people who will be living in them. Passivent l ventilation systems ensure that the homes maintain a dry, draught and condensation free living environment, with minimal maintenance.”

Passivent are highly experienced in the field of offering tailored ventilation solutions to Housing Associations. Key issues associated with low energy and sustainability are always at the forefront of design considerations, whilst also ensuring that system performance and indoor air quality are not compromised.

Passivent offer the following services to assist Housing Associations to ensure adequate ventilation solutions are specified:

• Free on-site technical consultation
• Free CPD seminars
• Online SAP calculations
• Predicted Energy Assessments
• Free estimate and design service

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