Fiberglass Duct / FRP Duct: Fiberglass (or FRP) duct is thin walled pipe generally used for corrosive fume exhaust from process areas or equipment, but also used for fresh air supply or light-weight conveying of liquids or solids. Fiberglass duct can be used above or below ground, with proper attention to mechanical design requirements. Fiberglass FRP Duct is available in a wide variety of corrosion resistant materials, shapes and thickness. All thermoset resins and most reinforcements can be used to fabricate duct, although flame retardant corrosion grade polyesters and vinyl esters using E-glass reinforcement predominate. Special applications may call for furan, phenolic, epoxy, or other so called "space age" thermosets for specific corrosion resistance, strength, flame or smoke development performance. Furans and phenolic resin based FRP duct systems generally offer enhanced solvent resistance performance compared with polyesters and vinyl esters, while epoxy can offer improved strength in particularly demanding applications such as aerospace. Duct is usually supplied with a round cross section, but oval, square and rectangular duct is also available. Various industry guidelines exist for specifying proper duct construction, including SMACNA, the U.S. Bureau of Commerce Voluntary Guidelines PS-15-69, and others. A typical specification for fiberglass duct is available on this web site. Duct is easily tailored for custom applications requiring higher or lower pressure handling capability than what is shown in the specifications. Please contact Composites USA for questions or guidance in this area. Composites USA works with all the foregoing resins, and also manufactures a line of Factory Mutual Approved and U.L. Listed Dual Guard fiberglass duct and fittings. This FRP duct incorporates a proprietary copolymer thermoset resin, a Halar surfacing veil, and fiberglass reinforcement to meet stringent (IMC, BOCA, SBCA) building code requirements for low flame propagation (ASTM E-84 =5) and low smoke generation (ASTM E-84 = 10) in corrosive fume exhaust applications. Fiberglass duct is usually supplied with a round cross section, but oval, square and rectangular FRP duct is also available. Fittings are available in almost any configuration imaginable. Many of our most popular fitting styles may be viewed at the Fitting Style Sheets link, but specialty fittings not shown can be supplied as well. Various industry guidelines exist for specifying proper duct construction, including SMACNA, the U.S. Bureau of Commerce Voluntary Guidelines PS-15-69, and others. A typical specification for fiberglass duct is available on this web site. Duct is easily tailored for custom applications requiring higher or lower pressure handling capability than what is shown in the specifications. Please contact Composites USA for questions or guidance in this area. The design of FRP duct systems must take into account many different factors. Corrosion, operating pressure, vacuum, temperature, abrasion, flammability, electrical conductivity are just a few of the characteristics of the desired system that must be considered and addressed with proper choice of materials of construction. Mechanical design evaluates the strength of the duct, the requirements for supports, thermal expansion compensation, burial loads, wind, snow and seismic considerations. Laminate analysis, and when required, finite element analysis is a part of the overall design solution.