In recent years, the material of choice for structural components in most field erected industrial cooling towers has shifted from wood to pultruded fiberglass. Although there are many reasons for this the primary drivers are the lack of premium grades of lumber suitable for use in cooling towers as well as expected reduced maintenance costs associated with the use of pultruded fiberglass. As the demand for pultruded fiberglass has increased, costs for same has come down further increasing the popularity of this material. Today, not only new cooling towers are being designed with pultruded fiberglass structures, but repairs are also being completed with the same material.
When repairs to wooden cooling towers are completed using pultruded fiberglass materials, care must be taken to ensure the new components properly transfer the imposed loads. Since fiberglass parts can be made to virtually any shape, unsophisticated users may select replacement parts only on overall dimensions without regard to the load bearing capacity of the member in question. This is where the need for an engineering analysis comes into play. Also, special care must be taken when transitioning from a fiberglass part to a wooden part such as columns. Structural connections can also be problematic since some components used in wood will not work with the hollow fiberglass shapes used to replace some timber components. Be especially careful with crossflow hot water basin supports (joists) to be sure their connection to wooden columns is effective. Finally, remember in cold weather environments where freezing temperatures are likely, fiberglass materials will react differently than wood.
Each pultruded fiberglass manufacturer publishes a design guide for their materials which should serve as the starting point for designing a wood to fiberglass replacement project. Additionally, the Cooling Technology Institute standard ESG-157 should be followed when undertaking such a project.
Let ATS help you get extended reliability and serviceability from your cooling tower with a wood to fiberglass conversion. We do it right the first time and every time.