scope:

Preface

This manual is a guide to the selection, installation, field testing, and maintenance of water distribution valves. Although the manual focuses on distribution valves, other valves, primarily used in plant operations, are also discussed. The manual provides a history of valves and a brief overview of the theory and flow characteristics of valves. It is a discussion of recommended practice, not an AWWA standard calling for compliance with certain specifications. It provides guidance on generally available valve alternatives. Questions about specific situations or applicability of specific valves should be directed to the manufacturer or supplier.

Information contained in this manual is useful for operators, technicians, and engineers for all size utilities, but it is particularly useful for small- and mediumsized organizations. The manual deals only with the more commonly used valves, including the following:

• globe

• butterfly

• plug

• ball

• cone

• gate

• check

Special-use valves are also discussed, but the intent here is only to introduce their availability and applications. Over the years, a wide variety of valves have been developed for specialized purposes. Fire hydrants, though technically considered valves, are not covered in this manual. The reader is referred to AWWA Manual M17, Installation, Field Testing, and Maintenance of Fire Hydrants. This manual refers to AWWA standards for various types of valves. Copies of those standards may be purchased from the AWWA Bookstore.

Several manufacturers graciously provided valve illustrations and other documentation. AWWA does not endorse any manufacturer's products, and the names of the manufacturers have been removed from the material provided. Kanwal Oberoi, Charleston Commissioners of Public Works, Charleston, SC, has provided the drawings for Figures 4-2 through 4-6 and 5-1.

Metrication note: Valve sizes are listed in their current US designation, i.e., nominal pipe sizes in inches. To obtain an exact metric equivalent use a conversion factor of 25.4 mm/in.