Where piping systems interact with load sensitive equipment it is likely that the allowed interface reactions will govern the pipe system design. Unrealistically low allowable reactions may increase piping system cost while excessively high reactions may increase equipment maintenance costs. The cooperative best efforts of pump and piping designers are needed to arrive at the most cost effective pump piping system on a life cycle basis.Excessive piping reactions at pumps cause high vibration, coupling failures, and pump shaft misalignment. In severe cases there are flanged joint leaks and the occasional occurrence of impeller rub or casing distortion. Excessive shaft misalignment in turn leads to premature seal and bearing failures. These difficulties are a costly maintenance item that can also result in plant shutdowns, and in severe cases, fires and extensive damage. This guide presents industry practices intended to minimize these difficulties while keeping capital and life cycle costs in perspective.A survey prompted by industry inquiries was conducted to establish an experience base about the effect of pipe reactions on centrifugal pumps, the nature of the problems experienced, the standards and criteria used to design and install pump piping systems, and industry attitudes on the issue. The survey concentrated on the experience and needs of piping and pump system designers, specifiers, manufacturers, and operators. It was designed to help the PVRC determine, among other things, its research priorities in these areas.