
FRP design standards keep getting better — what about predicting FRP reliability after it’s in service?
Fiber-reinforced polymer (FRP) composites have come a long way since they were first used for vessels and piping in the chemical processing industry in the mid-20th century.
Design approaches in the early days adapted — not always successfully — standards and methods used for metal equipment: they did not take into account the unique characteristics of FRP.
This resulted in many early failures that tarnished the reputation of FRP as a reliable alternative to steels for corrosion-resistant service.
Fortunately, the situation began to improve in the 1970s as industry developed new design and construction methods that better suited the properties and behaviours of FRP.
Standards for new FRP equipment
Since that time, the ongoing efforts of groups like the American Society of Mechanical Engineers (ASME) have resolved the early design flaws and resulted in excellent design and construction standards for FRP equipment.
Examples include the ASME RTP-1 standard for FRP pressure vessels and ASME NM.2 for FRP piping systems.
ASME RTP-1 and ASME NM.2 prescribe requirements for the design, materials, manufacturing, installation, inspection and testing of new FRP vessels and piping. These are comprehensive, dynamic documents that undergo systematic review and updates.
Design standards do not apply to in-service FRP
However, these standards do not apply to equipment after it goes into service.
In fact, while there are over 200 different consensus standards and codes related to design and construction of FRP equipment, ZERO offer any guidance on what’s required for inspection or Fitness For Service assessment of in-service FRP.
Until recently, this left plant engineers and inspectors with nowhere to turn for help understanding the damage that can be expected once FRP equipment is in operational service.
WRC Bulletin 601 a major step forward for FRP reliability
In August 2024, the Welding Research Council (WRC) published the third edition of WRC Bulletin 601, “Assessment of Existing Fiber Reinforced Polymer Equipment for Structural Damage,” authored by UTComp founder and Chief Technical Officer Geoff Clarkson.
WRC-601 provides technical guidance for including new FRP assessment methods, including attenuation-based ultrasound (UAX) techniques that form the basis of UTComp’s UltraAnalytix® NDT system, into the API and ASME consensus codes that are otherwise focused primarily on inspecting metal pressure vessels and piping.
It’s a major step forward in addressing the gap in inspection needs for in-service FRP assets.
It also provides further validation for the UltraAnalytix methodology developed over 20 years of assessing FRP and other polymeric materials used in pressure vessels, piping and other assets in a wide range of industries.