The Turbo Ventilators must be installed on the roof of a building where there is access to the wind from all directions to be most effective. It can withstand intermittent winds of hurricane strength. When installing a turbine be sure to keep it away from parapet walls, the walls of adjacent buildings and the like. From this, it is obvious that the types of applications are only as limited as your imagination.
The turbine is ideally suited to installation on steel roofs such as IBR and corrugated iron (they allow solar radiation through into the building very easily), having said that the Turbo Ventilators can, and have been, installed on slate, tiles (low amplitude), fibreglass sheeting, asbestos, thatch, chimneys, vehicles, and poly-carbonate skylights.
Fumes are another reason for ventilating a building. Fumes should be dealt with wherever possible at the source. The use of Turbo Ventilators to extract fumes should only be used for the excess or spillover fumes. Be very careful when offering the turbine as a solution to the removal of fumes as the vent rate is very low compared to mechanical ventilation, and if the fumes are dangerous to health of the people and/or environment the turbine cannot be used because the air is vented outside. e.g. Asbestos plants.
Where odours and dust are objectionable, the turbine can be used to increase the air changes in the building to dilute the effect of the fumes. Attached is a list of recommended air changes suggested for various types of industries and activities.
To calculate the number of Turbo Ventilators needed to obtain the required air changes per hour, calculate the volume of the building by multiplying the length by the breadth by the height. Then multiply the number of air changes by the volume then divide by the extraction rate of the turbine into this result to establish the number of Turbo Ventilators.
Removing diesel and petrol fumes requires that you provide a minimum removal rate of 250 m³/hour for every horse power of the motor. The temperature of diesel fumes is very high ± 150°C, therefore it rises very quickly. As long as enough ventilation has been provided, and the fumes are removed quickly before they cool down again extraction can be efficient.
Petrol fumes are emitted at a much lower temperature (32°C) and therefore low level extraction is normally required. However the air change method will provide a vast improvement by allowing the dilution of the fumes.
Moist air is less dense than dry air and consequently has a tendency to rise. Upper corners of rooms which are often colder than lower areas in buildings, are therefore exposed particularly to rising currents of moist air from below.
The problems of condensation are most common in the winter months. This is due to the fact that the outside temperature causes the surface temperature of the roof, walls and glass to be colder than the dew point of the moist air inside the building. This is very noticeable in plants where steam or water of a high temperature are used. The steam or water vapour rises to the level of the roof and the moment it touches the cold ceiling it turns into water droplets, falling like rain onto machinery, people etc., causing damage.
It is always better to treat the emission of the moisture vapour at the source by using mechanical extraction hoods, and not to expect the turbine to do it. Often the air being drawn into the building has to be heated to prevent cold air entering the building and increasing the problem by creating a fog. It has been known for roof sheets to be heated in a factory to prevent the formation of water droplets.
Stack effects are important elements in air movements in buildings and during winter substantial volumes of air will rise. This encourages concentration of moisture and is particularly critical in buildings where most of the moisture input is on the ground floor while the first floor may be less well heated.
It is typical for nearly half the air lost from buildings as ventilation to make its way into the roof space. Condensation can result, particularly where the ceiling is insulated and the temperature in the roof space is low. Much of the air lost by ventilation in houses enters the roof space through cracks and pipe openings.This conveys moisture from the interior into the roof space. In traditional buildings large quantities of fresh air entered the roof space at the eaves and the moisture was dissipated.
If insulation is installed in roofs, they usually have little effect on the penetration of air from the building below but they can, by blocking the eaves, reduce the inflow of fresh air to the roof and allow moisture levels to rise unacceptably.
In addition, the insulation prevents heat from reaching the roof space which thus, in a well insulated building, is very much colder than in the past. There is an increased risk of condensation.
Turbo Ventilators on the roof can be used to increase the level of ventilation and thereby reducing the level of moisture of the air, which reduces the condensation risk.
In summary, use the turbine only for the spillover of moisture, and even then be very careful, if water droplets are being formed on the underside of the roof, it is highly unlikely that increased ventilation by means of the turbine will stop the problem - heating of the roof sheet or additional mechanical extraction is needed.
Air movement to prevent a feeling of stuffiness can be achieved with very low air speeds e.g. 0,1 m/s. The removal of factory heat and the cooling of the body are the most important aspects of ventilation.
It is however, recommended that the minimum quantity of fresh air introduced per hour into a non-air-conditioned factory should not be less than 28.80 m³ per person or 5.40 m³ per m² of floor area.
(These quantities are generally accepted as necessary to remove odours and maintain oxygen and carbon dioxide levels).
The Turbo Ventilators have not been passed as a fire ventilators. Under no circumstances are they to be sold as such as there is strict legislature governing the construction and operation of fire ventilators.