Why fiberglass?
Fiberglass is used by many manufacturers of open and closed circuit cooling towers. It is used to manufacture various types of components, and even structural profiles as in the case of field-erected cooling towers.
what would be the reasons for such a choice? This composite material is much more expensive than sheet metal. Moreover, the manufacture of the “body parts” of the cooling tower and the special pultrusion profiles involves a considerable investment in terms of manufacturing equipment.
On the other hand, a construction that is made with preformed and perforated sheet metal panels, for example, is certainly easier to standardize and simpler than one that involves preparing a set of moulds to manufacture specific fibreglass components. These also generally require an aesthetic finish similar to that of car body or furniture components, which entails higher costs. So… what is the reason for choosing fibreglass?
Polyester reinforced with fiberglass gives strength and structural lightness
Advantages
The answer is simple in essence, but this conclusion has been reached thanks to a series of prior technical considerations and evaluations that require a thorough knowledge of manufacturing technologies. When in constant contact with water, fibreglass does not rust, does not alter over time, is not affected by the weather and therefore does not need maintenance. It is also lighter than steel and if accidentally damaged, can be easily repaired to “like new” condition.
The structural strength of the moulded components is obtained by superimposing layers of glass fabric called “mat”, which is then impregnated with resin. Once catalyzed, the resin and the various layers of mats are melted into a single body. 
result is a structurally robust piece with a uniform and continuous surface.
External protection is achieved by applying a UV-resistant gelcoat directly to the mould, while the interior is waterproofed by applying a gelcoat with a paraffin additive that totally prevents diffusion to the outside.
In the case of the most complex and fragile parts, special attention is paid to the orientation of the glass fibres, so that they can better support and distribute the static and dynamic loads to which the parts are subjected.
Fiberglass and pultruded profiles
Pultruded structural profiles, on the other hand, are produced using a specific die according to the design of the profile itself. In this case, the catalyzed resin is mixed with the fiberglass before the casting process. A special feature of pultrusion profiles is the use of continuous filament fibreglass to ensure that the profile has the mechanical and structural strength generally required for this type of product.
Pultruded profiles can also be protected against UV radiation and the risk of water permeability.
Why build fiberglass cooling towers?
So why do some manufacturers prefer this technology to cheaper ones?
Although the answer seems obvious, the reason is not one of convenience in itself: it is linked to the decision to add value with a superior quality product. The aim is not to reduce but to completely eradicate the corrosion problems and the resulting maintenance that the end user would have to face.
The use of fibreglass components offers greater “flexibility” even in the presence of chemically aggressive water, while the standard design ensures that the price remains competitive.