22 01276 408404 | www.greenwood.co.uk 01276 408404 | www.greenwood.co.uk 23 Fresh air Background ventilators Extract air Continuous Extract Ventilation Building Regulations Our continuously running Unity fan complies with System 3 of the Building Regulations as a de-centralised Mechanical Extract Ventilator (dMEV). Installed in each wet room throughout a property, the units run continuously between low and high speeds. High (boost) speeds are usually activated via occupant control (light switch) or automatic sensing (humidity/timer). Continuous ventilation offers an excellent solution for new and existing homes as it does not cost the earth to run – in fact it’s less than a penny a day for 365 days of the year! The Domestic Ventilation Compliance Guide This published document brings together the first specific details of good practice installation. Covering four ventilation systems, the document provides information and guidance on ducting connection, installation and commissioning. To ensure that no nuisance noise is generated, which can have a negative impact on occupants, continuous fans need to comply with the installation requirements set out in the guide. Important guidance DO   Ensure the ducting takes the most economical route out of the building  Ensure that duct is adequately supported  Ensure that bends are sweeping to offer the least amount of resistance  Ensure ducting is fully insulated  Ensure all vertical duct installations incorporate a condensate trap  Ensure condensate drain is insulated if terminated to atmosphere  Follow guidance set out in the Domestic Compliance Guide DON’T  Allow duct route to sag, causing peaks and troughs   Pass duct through an opening that allows a restriction to form causing resistance  Install ducting without proper insulation or condensate requirements The method Positioned in bathrooms, WCs, kitchens and utility rooms, fans run continuously at very low speed to ensure a consistent level of extraction and indoor air quality. Boost operation is commonly activated via the light switch, when short bursts of high extraction are required, or via the automated humidity and timer sensors. For new build, habitable rooms feature background ventilators, usually in the form of a window vent. The continuous extraction eliminates the need for the high background ventilation rates associated with intermittent extraction. This principle also applies for refurbishment where low level continuous ventilation ensures the effective provision of good indoor air quality. Key benefits 1.  A simple and effective form of whole house ventilation. 2.  Low energy consumption. 3.  Complies with System 3 of the current Building Regulations. 4.  Single fan for use in any application. 5.  Extremely low running noise. System 3: Continuous Mechanical Extract Ventilation CONTINUOUS EXTRACT VENTILATION CONTINUOUS EXTRACT VENTILATION 22 01276 408404 | www.greenwood.co.uk The importance of correct ventilation installation – Did you know that the Building Regulations cover installation? Tile Vent termination (min 7500mm2 equivalent area) Tile Vent Condensate drain (to nearest waste water connection) Ceiling loft Room extract grille & discharge grille: Ensure the equivalent area of the opening is a minimum 85% of the equivalent area of the ducting being used Maximum length of flexible ducting Flexible ducting support Minimum radius = the diameter of flexible ducting used Discharge Grille Airflow Airflow Room terminal/extract grille Grille discharge opening Peaks and troughs Restrictions Preferred flexible ducting route Ceiling void External Airblock Ceiling Void Flat ducting support The Building Regulations have seen a new focus on installation practice and on-site performance certification. The Domestic Ventilation Compliance Guide sets out a clear path to classify ventilation as a controlled service.