FRP Fan Stack Material

The fan stack is an essential part of the cooling tower. It’s located within the propeller fan and prevents reverse running of the fan caused by high input air speed. Because the fan stack is integral to your cooling system, it’s important that it’s made out of durable materials that will keep it functioning properly for longer.

What is FRP Fan Stack Material?

Fan stacks for cooling towers can be made from laminated polyester or fiber-reinforced plastic, better known as FRP. FRP fan stack material tends to be the most common choice due to its protection against corrosion, high strength to weight ratio, durability, and cost efficiency. Because FRP is so adaptable and has good dimensional stability, it has become the ideal material for the typical double-coat design of fan stacks. The inside surface allows for the fast removal of air, while the outer surface provides resistance against climatic conditions and noise reduction.

Summary of CTI’s FRP Fan Stack Material Paper

This specification covers the material of construction, workmanship, physical properties and methods of testing fiberglass reinforced plastic panels used in the construction of cooling tower fan stacks.


The resins used in the panels shall be of a thermosetting styrenated and/or acrylated light-stabilized resin composed of polymeric esters in which the recurring ester groups are an integral part of the main polymer chain, or vinyl ester. The resin shall be reinforced with glass fibers.

Filler materials may be used by the stack manufacturer in shaping the profiles. In selecting the material used for the filler, care must be taken to use materials that will not be detrimental to the overall performance of the stack. Products that absorb excess moisture and swell should be avoided.


The panels will conform to the specific dimensions of the profile being produced and shall be fully cured. Panels shall not contain major visual cracks, pinholes, foreign inclusions, or surface wrinkles that would impair the proper resting of the panels, alter the specific dimensions of the panels or otherwise affect their serviceability.

Physical Requirements

Size of individual panels shall be such that when the stack assembly is complete it shall provide a closed sealed round vessel that at the throat will allow free and unobstructed passage of the fan blade.

How Can CTI Assist With Your Cooling Tower Needs?

Cooling Technology Institute has published a plethora of papers about various cooling topics. CTI is also an advocate in promoting the use of environmentally responsible Evaporative Heat Transfer Systems (EHTS), cooling towers, and cooling technology for the benefit of the public. Additionally, CTI is an independent, third-party thermal performance testing to help participating manufacturers and owners/operators achieve the best performance from their cooling towers.

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