Paper: A New Joining System For FRP Oilfield Piping

Fiberglass reinforced pipe (FRP) was originally developed and marketed in the oil field as a highly corrosion-resistant alternative to steel in relatively small-diameter, low-pressure gathering and flow lines. As the acceptance of FRP grew, so did the demand for larger diameters, and higher operating pressures. This acceptance of FRP in the oil field as an almost commodity item inevitably led to widespread stocks of fiberglass at both the distributor and the end-user level, until now probably 70% of the pipe sold is installed without the specific knowledge of the manufacturer.Aside from the educational aspects which are necessary with all new materials, the major reason for this kind of attention was the need to insure that the crews were trained in the proper installation of the adhesive bonded joint. It can be proven that a properly made adhesive joint, under the right conditions, is as strong as the pipe itself and, in fact, these requirements are written just that way in some standards and specifications. Unfortunately, this is more easily specified than it is attained. Most thermosetting adhesives are sensitive to both humidity and temperature conditions. Adhesives, by definition, rely on intimate surface contact in order to perform efficiently, hence the need for nearly perfectly clean and dry bonding surfaces. As anyone who has tried to lay adhesive joint pipe in a West Texas dust storm or a Louisiana "Sun Shower" can tell you, these conditions are not always easily attainable. In addition to all this, because adhesives undergo a chemical reaction, temperature plays a critical role in the working time in the container and in the curing time of the joint. Recognizing these limitations, FRP manufacturers have spent a great deal of time and money working to minimize these difficulties and increase the overall reliability of the joint. For example, nearly all FRP is supplied with end protectors to keep the bonding surfaces clean and dry. Many suppliers offer heat assist methods for curing the joints in cold weather. Installation instructions are supplied with each adhesive kit. At least two of the major manufacturers are offering adhesive joints with a built-in mechanical assist to hold the joint straight and immobile while the adhesive cures - all of this in an effort to improve the reliability and acceptance of FRP throughout the industry.