ASME A112.14.1

The ASME Standard is a nationally recognized standard that establishes requirements for dimensions, performance requirements, connections, materials and finishes, testing and marking of backwater valves.

There are six basic types of Backwater Valves:

• Horizontal Backwater Valve: A backwater valve designed to be installed in a horizontal drain line incorporating an internal check member and manual gate valve to prevent backflow.
• Combination Horizontal Backwater Valve and Manual Gate Valve: A backwater valve designed to be installed in a horizontal drain line incorporating an internal check member and manual gate valve to prevent backflow.
• Terminal backwater Valve: A backwater valve designed to be installed at the discharge end of a horizontal drain line incorporating a check member to prevent backflow.
• Combination Floor Drain and Backwater Valve: A floor drain incorporating an internal check member to prevent backflow.
• Normally open Backwater Valve: A backwater valve designed in such a manner as not to interfere with the movement of the air in the drainage system.
• Vertical or 90-Deg Backwater Valves: A backwater valve designed to be installed in vertical piping, such as downstream from a P-trap or a holding tank.