TP26-05 Impact of ASCE 74-23 Standard for FRP Cooling Tower Design

Cooling towers rely on a robust open-frame structure to support various internal systems and withstand a harsh operating environment. The use of pultruded fiberglass profiles has been prevalent for over 40 years as an improvement over wooden structure. As with any material of choice, proper application comes from specific understanding of the mechanical properties, in combination with service conditions and life expectancy. The Cooling Technology Institute (CTI) has developed a set of Standards (STD-137 and ESG-152) to establish good design practice for cooling towers in the absence of any application-specific National or International Code. These Standards have served the cooling tower industry well for many years, as demonstrated empirically by a lack of failures of both older structures and those that have been subject to extreme conditions such as high wind events, seismic events, and aggressive circulating water conditions. The intent is to highlight the effectiveness of the CTI Standard as a sound basis for cooling tower structures and the lack of need for a broader, yet more stringent standard, such as the recent release of ASCE 74-23 Standard for “Load and Resistance Factor Design (LRFD) for Pultruded Fiber Reinforced Polymer (FRP) Structures”. Comparisons will be made between the two design standards, as well as specific installed structures that serve to demonstrate the adequacy of the existing CTI Standard(s). Existence of industry-specific standards should give cooling tower owners a high comfort level, knowing that they have been developed with the unique purpose of providing a long and trouble-free service life.