Concept:
Whole house Passive Stack Ventilation systems are based on the 'Stack Effect'. This is the movement of planned air paths through the dwelling as a result of internal and external temperature differences and wind induced pressure differences.
PSV systems ventilate the whole house by siting extracts in 'wet' rooms (e.g. kitchens and bathrooms, including en-suite), and ducting vertically to individual terminals sited on the roof. Wind induced pressure differences cause moist air in these areas to be drawn up the ducts to be replaced by fresh air through inlet vents situated in the walls or window frames of habitable rooms. A free flow of fresh air from 'dry' to 'wet' areas creates whole house ventilation (see illustration).

Authority:
PSV systems are recognised by the BRE, and are included in the revised Building Regulations England and Wales Approved Document F1: 1995 and Scotland Approved Scottish Technical Standard 3 2005 as an effective alternative to mechanical fan ventilation.

Applications:
PSV Systems are suitable for dwellings, commercial buildings and flats, up to 4 storeys high, that require three or less individual stacks. Each 'wet' room must be ventilated by an individual stack.
More complex ventilation requirements can usually be met by a Mechanically Assisted Ventilation System. However, Ubbink will advise on the most effective system to meet all ventilation requirements.

System Design:
Whilst the concept of PSV is simple, the design of an effective, practical system relies on a number of interrelated criteria, including floor plans and room volumes, plus geographical location and site exposure factors.
In order to provide the specifier with a reliable ventilation solution that conforms to all relevant regulations (and, if required, to individual performance specifications), Ubbink offer a complete design and supply service. On receipt of building and site plans, together with location details, Ubbink will design suitable PSV systems, or advise on alternative ventilation solutions, for each individual dwelling. This service specifies duct sizes and routes, roof vent options and extract points to provide a whole house ventilation system that meets all relevant building regulations, including fire and acoustic performance and relieves specifiers from the need to perform complex air volume calculations whilst guaranteeing an effective, trouble-free ventilation system designed to meet the particular requirements of individual buildings.
Ventilation specialists provide complete technical back-up, from initial design through to final installation to ensure optimum trouble-free performance.

Control:
Standard PSV systems have no manual control mechanisms. However, air flow responds to temperature difference, increasing and decreasing when internal and external temperatures vary, making the system self-regulating.
Controlled PSV systems utilise humidity controlled extract valves and air inlets which open and close according to internal humidity conditions. The system is thus regulated closely in line with demand and is even more energy efficient than a standard system.
Controlled PSV extracts and inlets operate naturally with no electrical connection required.

Building Regulations:
The Building Regulations England and Wales Approved Document F1:1995 and Scotland Approved Scottish Technical Standard 3 2005 recognises the benefits of passive stack ventilation systems as an alternative to mechanical fan ventilation and provide guidelines for its use.

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