Wafer design valves verification based on ASME B16.34

Abstract

A flange connection is a very common method of valve attachment to the pipe. The flange is a ring-shaped device designed to be used as an alternative to welding or threading various piping components, including valves. A wafer design is defined as a flangeless design with facing that permits installation between American Society of Mechanical Engineers (ASME) and manufacturer standard (MSS SP) flanges. One advantage of using a wafer design instead of a flanged end design is that smaller face-to-face dimensions save space, and the weight and cost of the valve are lower. This paper compares face-to-face wafer type valves and double flange butterfly valves in class 150 and size ranges between 4″ and 20″ designed according to American Petroleum Institute (API) 609. Using wafer type butterfly valves as per API 609 is very common in the oil and gas industry. However, it is not common to use a wafer type ball valve for saving weight and space. This paper reviews a case study of a wafer ball valve design, including the flange bolt holes inside the body and the closure. The criteria in the ASME B16.34 standard regarding the minimum allowable wall thickness of the valve were used to verify this design. Therefore, this case study can provide a good guideline for verifying the design of wafer type ball valves with the bolt holes inside the body, as per ASME B16.34 criteria.