Composite sleeve system

The use of fiber-reinforced composite materials for pipeline repairs was developed during work at Southwest Research Institute and Battelle in the late 1980s (Fawley, 1994 Stephens and Kilinski, 1994). There are two basic types of composite repair systems preformed (composite sleeves) and wet lay-up (composite wraps). The first commercially available system was Clock Spring , which consists of an E-glass/polyester resin-based composite material preformed into a multilayer coil that is installed using an adhesive (Figure 4.4). 

The ease of installation makes the composite sleeve crack arrestor system effective. These units can be installed on the pipeline without the need to cut the pipe or for any... 

A conventional solution to this problem would have encountered serious challenges, such as additional work permits required from various divisions and companies and safety hazards due to the close proximity of process equipment and other product lines this project under traditional scenarios would have been an arduous and expensive task. The Clock Spring Snap Wrap composite sleeve reinforcement system was the logical alternative choice as no hot work, down time, or line reductions were necessary. 

The following references have a wealth of information regarding the Clock Spring composite sleeve repair system ... 

The inhibition of composite propellants is somewhat easier than that of DB propellants. The binders used for composite propellants (with or without fillers) have been reported for inhibition of composite propellants. Such inhibition systems possess stronger bonds with composite propellants and prove to be more compatible coupled with better shelf-life of the inhibited propellants. However, epoxy or novolac epoxy resin with or without inert fillers is generally preferred for the inhibition of composite propellants due to a combination of properties possessed by them. The inhibition is usually done by casting technique and inhibition thickness is usually required on higher side in order to make the missions successful. In India, thread winding technique or inhibitor sleeve technique is preferred where 2.5-3.0mm inhibition thickness is sufficient as against 3.5-4.0 mm in case of inhibition by casting technique . 

Because the acceptance criteria AC 174 do not concern materials from which railing systems are made, whether they be wood, concrete or WPCs, composite materials appeared to be in a difficult situation. Nonstructural (as yet) materials should in fact serve as structural, such as in railing systems. That is why most of manufacturers of composite (or plastic) railing systems use reinforcing components, such as wood posts covered with composite (or plastic) sleeves, and metal (steel or aluminum) inserts in support (top and bottom) rails. 

A combination of composite materials in conjunction with steel was introduced into the pipeline industry in the 1980s, when the application of composites overlaying steel sleeve became a standard for pipeline repairs. One of the most notable applications is that resulting from the collaborative efforts of Emon and the Gas Researeh Institute (GRl) in 1991, which resulted in installation of SSLP in their system. After eight years in service, the SSLP was inspected, and was verified to be in the same condition as in its initial state. Later on, TransCanada Pipelines Inc. also ventured into the use of SSLP pipes in several projects in 1998, 2001 and 2002 (Stephen, 2005). 

Conventionally, most steel pipelines were repaired by removing the corroded section and replacing it with a new pipe or by reinforcing the defected section with an external steel sleeve (Mohitpour et al., 2003). Recently, fibre-reinforced polymer (FRP) composite overwrap repair systems have been introduced and overwhelmingly accepted as an alternative repair system for pipelines. 

---