Debunking Myths about Composites in Industrial Applications
Suppliers of composite pipes and tanks agree that the past year has been comparatively slow when it comes to new projects. Few of the major industrial manufacturers who so often demand composite-lined tanks or pipes seem to be undertaking new construction, and in some market segments replacements are slow as well. One of the reasons for the state of this market is end users’ lack of awareness and understanding of composites. Some commonly held misconceptions include:
You can’t put composites in alkaline solutions
It is known that alkaline solutions, in some cases, can cause degradation to the main constituents of FRP composites. This is particularly the case with bare glass fibers, where a reaction with an alkaline solution forms expansive silica gels. However, it is the performance of the composite system as a whole that should be the primary consideration when operating in this type of environment. When this is done, composites have been shown to exhibit superior performance and durability characteristics than more conventional materials.
Composites can’t handle extreme temperatures
The greatest concern with temperature effects on composite structures is that freeze-thaw conditions can potentially result in debonding of laminates, either from concrete or other composite elements, particularly if there are gaps at the adhesive bond line. However, consideration of the operating conditions at the design stage, along with careful selection of fiber and resin will ensure that performance and service life are not affected.
Composites present an inherent fire hazard
While the fiberglass reinforcements used in corrosion resistant laminates will not burn, most thermoset resins used as the matrix for composite laminates will support combustion. Even the “fire retardant” resins will burn vigorously when fire is supported by an outside source. The rate of flame spread is somewhat lower for these fire-retardant resins. Fire retardant thermoset resins typically contain halogens or bromine molecules. When combustion occurs, these additives suppress or smother the flame and the laminate becomes self-extinguishing.