What Are the Benefits of Welded Outlets?

What would you have if you mixed a mathematician, an electrical engineer, a welding engineer, a plasma torch, a robot, welding wire, and a stack of ductile iron pipe of various sizes? The recipe for an unusually successful pipe product called "Welded Outlets." AMERICAN has a long history of weld fabrication of iron pipe. Products such as "welded-on-boss," "welded-on-collar," "retaining rings," and other fabricated items have been made by AMERICAN and successfully used by our customers for more than 30 years. The development of new welding techniques has allowed us to join large sections of ductile iron pipe while maintaining a Charpy impact value in the weld equal to that of the pipe barrel. Utilizing a robotic plasma torch to cut the intersecting shapes of two or more pipe sections and welding the sections together with a nickel-base weld wire offers many possibilities. One of the simplest is the intersection of a small pipe with a larger pipe at 90° resulting in a reducing-on-the-branch tee. If a design requires it, multiple-lateral, angled, or tangential outlets can be produced on a single length of pipe. Multiple outlets of such complexity would be difficult or impossible to reproduce using standard castings in the same laying length. Development of the design rules, constraints, and pressure rating for this new product required considerable analysis and testing. Finite Element Analysis, experimental stress analysis, mechanical testing, hydrostatic testing of several hundred outlets, and hydrostatic testing of many outlets to failure have been used to establish rules for the design of outlet pipe. Due to the unlimited number of possibilities with this manufacturing process, each new design is verified through the design rules to make certain fundamental requirements are met. Most welded outlets are rated at 250 psi with the exception of the 36-inch, which is rated at 200 psi. Most of the restrictions or constraints with this product are a result of the physical placement of outlets on the parent pipe or the use of outlets in applications subject to beam loading. The physical restrictions of outlet placement are easily checked against the design rules, which state how close the outlets can be to the bell or spigot ends or how close outlets can be to each other. Beam loads or bending moments can occur due to settlement of direct-buried, underground piping or when rigid joints such as those used in a piping gallery are not quite aligned and are forced to fit. In either case, the potential for beam loads can be removed by selection of flexible piping joints. As indicated in American Society of Civil Engineers (ASCE) and American Water Works (AWWA) publications, it is recommended for direct burial service that one or more flexible branch piping joints be located close to an outlet pipe branch weld. AMERICAN offers a number of welded outlet joints, both push-on and restrained, that provide the needed flexibility. These joints are Fastite®, Fast-Grip®, Flex-Ring®, Field Flex-Ring®, or unrestrained Mechanical Joints. Flanged, restrained Mechanical Joint and other rigid joints are not recommended on outlets unless special considerations are taken to remove the potential for beam loads. AMERICAN has furnished several thousand welded-on outlets since they were first introduced in 1990. This is a good example of a new process leading to value-added engineering possibilities, a tradition at AMERICAN.

Gene Oliver, Technical Director, American Cast Iron Pipe Company

Oliver Assumes Technical Director Role

It might be rocket science to find an able successor for AMERICAN's recently retired Ben Helton, an employee for 43 years and technical director since 1992. If that's the case, Gene Oliver, shown above among AMERICAN welded-on outlets, is the man for the job. During his four years of military service, Oliver served on a Titan II ICBM launch crew for the U.S. Air Force Strategic Air Command. In addition to rockets, Oliver knows something about metals, too.

An Applied Physics graduate of Auburn University, Class of 1971, Oliver also holds undergraduate, graduate and doctoral degrees in Materials Engineering from the University of Alabama at Birmingham. He was an adjunct faculty member at UAB in the Engineering School's Materials Science Department for 10 years, teaching casting metallurgy, melting metallurgy, corrosion, extractive metallurgy, ceramics, electrical and magnetic properties of materials, and other undergraduate courses.

During his 22 years with AMERICAN, Oliver has served as a research engineer, manager of Research and Development and now, as the company's Technical Director. A native of Brewton, Alabama, he is an avid sailor and enjoys black and white photography with a 4 x 5 camera.