Are my FRP and composite assets able to continue in service?
In-service evaluation of fiber-reinforced plastic (FRP) and other composite equipment and components must detect and evaluate damage mechanisms that are created by the service conditions. In most applications, FRP is a structural material that must support loads while exposed to corrosive conditions. When FRP is able to continue in service, it is considered to be “Fit for Service”.
Inspection of in-service FRP must detect and quantify damage that will affect the ability of the FRP to perform. A further requirement is that detection must allow enough lead time to plan repairs or replacement.
All damage mechanisms that affect FRP involve combinations of resin, glass and the bond of resin to glass. These damage mechanisms can be detected as:
- changes in stiffness of the FRP;
- reduction in thickness; and
- depth of damage to the corrosion barrier.
The charts below show how these have been observed to change with time in service. Tracking these to identify the earliest time that action is required is the goal of in-service inspection. Almost nothing covered in inspection of new FRP can be used to provide this information.