Hot air rises. This simple fact explains the heat blanket effect inside a building and it often results in temperatures increasing to unacceptable levels.Three primary sources of heat negatively affect the comfort levels within a building. The major heat source is the radiant heat absorbed through the roof. The second source of heat is that which enters the building through the walls, through windows and doors. The third source of heat is that generated by processes within the building (cooking, manufacture etc). Added to this is the heat emanating from the people active within the building.Heat entering through the roof forms a ‘heat blanket’ under the roof. As it gets hotter outside, so this ‘blanket’ increases in depth. Heat generated lower down in the building rises to add to this blanket which now increases considerably in depth. The most common way of dealing with this heat blanket is to ventilate the building, allowing the heat to escape through the roof to the outside. This is only partly effective because the volume of heat building up is often too great for the ventilators to deal with.Too reduce the heat blanket within the building one needs to control the heat entering the building, rather than to deal with the fact that the building is hot. The major source of heat – the roof – is easily and inexpensively dealt with. By simply applying a heat barrier coating to the outside of the roof, the heat blanket is dramatically reduced making it possible for the roof-top ventilators to effectively remove the heat generated by the activities inside the building.More often than not a building’s climate can easily be controlled by simply insulating the outside of the roof. However in situations where a large amount of heat is generated by people and machinery etc, the addition of adequate ventilation will ensure a comfortable environment through the long hot summer days.It is important to note that the heat barrier coating applied to the outside of the building will also, to a lesser degree, reduce the amount of heat escaping from the building during colder months. Ventilators will, however, continue to allow heat to escape – heat which is sorely needed to counter the chill of winter. More sophisticated ventilation systems are remotely controlled and can be switched off when not required. Huge amounts of heat enter a building through the roof, even if it is painted white or silver. Only by preventing this primary source of heat from entering the building in summer will an acceptable level of environmental comfort be achieved.Buildings where the heat blanket effect cause major problems include restaurants, factories employing a large workforce , ones with heat-generating processes, shopping centres where hundreds of people produce huge amounts of heat and venues like theatres and halls. As air-conditioning becomes more and more expensive to install and to operate (and less ‘green’) the options described above deserve closer consideration as viable alternatives to dealing with the increasing heat of Africa.
CERATECH Thermal Barrier Roof Coatings provide an inexpensive alternative to expensive airconditioning.
