Uses of Fiberglass Pipes and Large Diameter Fiberglass Pipes

The application and use of underground large diameter composite pipe has continued to grow since the mid to late 80's. Technological advances in fiber winding processes, corrosion resistance, education and promotion, and strong market forces have contributed to the popularity of fiberglass pipe. The definition of large diameter pipe varies, but in general they range from 12" to 14' in diameter. 

Composite or fiberglass pipe has been widely used in industries such as power generation, petrochemical and desalination. Fiberglass pipe is corrosion resistant, with a life cycle typically exceeding 30 years, and is becoming increasingly popular as an alternative to steel, other metal alloys, ductile iron and concrete. According to a 2008 article titled "Large Diameter Pipes: A Lasting Feature in a Growing World," there are more than 60,000 kilometers (37,280 miles) of composite large diameter pipes in operation worldwide. 

Although once considered a specialty product, fiberglass is now the standard material, if not the standard for major market segments, for a variety of reasons due to its ability to withstand sulfuric acid.  For example, fiberglass has been used in potable water projects, agricultural irrigation systems, water supply lines and pressure piping for hydroelectric plants, power plant cooling water systems, gravity and pressure sanitary sewer systems, and "sliding liners" for pipe rehabilitation. Over the past 20 years, fiberglass has begun to move beyond its early stereotype as a one-trick pony (e.g., corrosion resistance) and has proven its value as a cost-effective material that offers substantial benefits to the end user.

The main reasons for the increased use and popularity of fiberglass are key benefits such as high strength-to-weight ratio, dimensional stability, good mechanical properties, ease of installation, reduced installation costs, lower maintenance costs, and overall durability in extreme conditions. Likewise, another advantage of fiberglass tubing over traditional construction materials is its smoother inner surface. This characteristic, with its smooth inner bore, resists scale deposits and can produce greater service fluid flow throughout the life of the project.

There are many factors to consider when designing underground large diameter piping systems; local soil conditions, water table depth, buried loads, live loads, deflection due to buried stresses and operating temperatures - just to name a few. Similarly, the American Water Works Association manual, Fiberglass Piping Manual (also known as M45), provides equations that consider fluid velocity and fluid pressure, turbulence-induced head loss, water hammer, buckling pressure, and surge pressure, among other factors. Designing a suitable underground piping system is a complex process involving extensive calculations - product design should always be performed by a qualified engineer.