The range of modern kitchen extracts is very wide and is pleasing to the eye variety of forms and materials. However in pursuit on external beauty you should not forget that the main task of this device is to get rid of fat, evaporations, soot, ashes and unpleasant smells which inevitably arise in the course of cooking. Calculation of power of extract, i.e. volume of air which it can miss in unit of time will help to cope with this task.
Instruction
1. By means of tape measure measure length and width of your kitchen and also room height. Transfer the received results to meters and multiply. You receive the volume of kitchen in cubic meters. If room geometry difficult, use plans of BTI – the floor area of your apartment in square meters is always indicated them. For example, the area of kitchen – 15 sq.m, room height – 3 m. The volume of kitchen is equal 15 x 3 = 45 m3.
2. Calculate necessary air exchange which the extract has to provide. For this purpose increase the volume of kitchen by ventilation rate – the size which defines how many times within hour indoor air are completely updated. According to Construction Norms and Regulations, the system of mechanical ventilation in kitchen has to provide the ventilation rate equal 10 – 12. In our example the power of extract will be 45 x 12 = 540 m3/h.
3. Be defined in what mode your extract will work. There are two options: removal of air and recirculation.
4. Removal of air outside is considered more effective, however consider some subtleties. Use calculations of air exchange and buy the powerful device (600 – 1200 m3/h), only if the air duct is brought to the street through external wall or in the building is ventkanat for extracts. Most often only natural ventilation is provided in our multi-storey residential buildings. Flow capacity of such ventkanal (provided that they are not littered and are not blocked by enterprising neighbors who have wanted to increase the area of the kitchen) is usually 150 – 180 m3/h (if very much carries, then 300 – 400 m3/h). The extract of bigger power will not pull stronger, but will create air "skids" in system and will break normal ventilation in all strut.
5. In the recirculation mode air is not taken away outside, and passed through dense charcoal filter and comes back to the room. This mode is used in case the air vent is inaccessible, ventkanat is littered or blocked. The overall performance of extract considerably decreases due to the need to overcome filter resistance. Therefore increase rated power by 30 – 40%. In our example the extract with power not less than 540 x 1.4 = 756 m3/h will be required.