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QuietAir The quietest bathroom fans* Air Flow Solutions

Glossary of Terms

A guide to words and phrases commonly used Air A gas comprising the following constituents (when dry):

Coanda effect The tendency for an airstream under some circumstances to attach itself to and follow the shape of a surface. This can occur even for extremely convex curvatures. CPD Continuing Professional Development. The on-going learning process whereby professionals maintain, update and increase the knowledge and skills in their chosen career. Competent Person An individual who has completed a nationally recognised training scheme allowing them to “self certify” that their work complies with the Building Regulations. Damper A device used to control the volume of air passing through a confined cross section by varying the cross-sectional area. Diffuser An outlet device discharging supply air in a direction radially to the axis of entry. dMEV Decentralised Mechanical extract Ventilation. A method of continuous ventilation of a dwelling using extractor fans in wet rooms. An allowable solution under system 3 of Approved Document F. Dynamic loss The energy lost when an airstream travelling at a known velocity is forced to make a sudden change in direction or velocity. EC Motor An electronically commutated motor running on DC voltage from an AC input. Avoiding the use of a transformer the motor incorporates voltage change resulting in a less bulky and more energy efficient performance. Energy Potential energy The energy of a fluid or body due to its position (or height). Kinetic energy This energy which a fluid or body possesses by virtue of its motion. A rotating propeller type device where the air is moved in the same direction as the inlet and outlet of the fan. Providing high air flow in a slim profile they are ideal for through the wall installation. Suitable for short lengths of ducting only. Mixed Flow A hybrid combination of an axial and centrifugal fan impeller where the air is moved in the same direction as the inlet and outlet of the fan. Provides higher pressure development than an axial fan so suitable for short to medium lengths of ducting. Centrifugal Quiet and powerful and suitable for wall, ceiling and ducted installations. Similar in design to a hamster wheel they work efficiently against system resistance making them perfect for longer duct runs. Fan Curve The fundamental performance of a fan or blower with the X axis expressed in pressure and the Y axis expressed in volume flow. Fan Axial

78.09% nitrogen 20.95% oxygen 0.93% argon 0.03% carbon dioxide Air density The ratio of the mass of a given amount of air to the volume which this amount occupies (ie lb/ft 3 or kg/m 3 ). Secondary air Room air entrained and set in motion by air discharge from a grille Air Changes A method of calculating the number of times air can be exchanged in a room or space by calculating its volume and dividing this value by the air volumetric performance of the fan in order to establish its suitability for the application. In commercial premises CIBSE guidelines should be followed to determine air change rates. Anemometer An instrument used for the measurement of air velocity and air volume. Hot wire anemometer This has a probe consisting of a very fine short length of wire (or small thermistor bead) attached to the end of a supporting tube. The wire is heated electrically, and measurements are made of the heat dissipated by the wire. The rate of heat dissipation is directly related to the velocity of the air passing the wire. Rotating vane anemometer This consists of a disc of angled vanes attached to a rotating spindle and is usually mounted within a protective ring and supporting bracket. The speed at which the vane assembly rotates is a measure of the air velocity acting upon it. This speed may be sensed electronically or by a counter mechanism. Attenuators Devices for reducing the amplitude of a source of energy. Often used in a noise control device to reduce unwanted sounds. BCO A Building Control Officer or Building Inspector who ensures that Building Regulations are followed during construction and signs off the project. Bernoulli’s theorem This says that the total energy per unit mass along any one stream line in a moving fluid is constant, and that the states in which that energy exists (pressure, kinetic or potential) are related and convertible. BIM Building Information Modelling. By 2016 all U.K Government buildings will have to be designed with BIM 3D software as the core design tool. The software enables complete data sets to be attached to components and structures. By- Pass A device within a Mechanical Ventilation with Heat Recovery (MVHR) unit to by pass the heat exchanger during the Summer months enabling the recirculation of ambient air. A 100% by-pass is most efficient. BRE Building Research Establishment. A private research establishment that carries out testing and consultancy for the build environment. The organisation responsible for operating SAP Appendix Q testing.

● 100mm, 120mm and 150mm high performance fans for toilet, bathroom, utility and kitchen ventilation ● Eco Start (delay start) ● Whisper quiet ● Ultra low energy ● Ball bearing motor ● Room refresh, programmable routine ventilation ● Two speed with a choice of controls ● Suitable for long duct runs ● IP45 ● Complies Building Regulations and domestic compliance guide

For further information see pages 46 - 51 * On both speeds, the QuietAir 100 meets the installed performance requirements when ducted as per the Domestic Ventilation Compliance Guide of the current Building Regulations Approved Document F. Sound level of 25 dB(A) on low speed.

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