The Principle Operation of a Dual Check Valve with Intermediate Atmospheric Vent – Backflow Prevention Device – Installation Considerations
The DCVwIV shall be installed as close as possible to the fixture or appliance where the cross-connection exists and in a location where the DCVwIV can be easily accessed for maintenance purposes. The intermediate atmospheric vent is designed to remain closed regardless of the rate of flow. However, during certain conditions water may discharge from the intermediate atmospheric vent therefore, the DCVwIV shall be installed in a location where it can be frequently observed. The DCVwIV shall be installed with the appropriate drainage requirements as specified by the manufacture or plumbing codes. The DCVwIV shall be installed so that no part of the DCVwIV is or can be submerged such as in a pit or a location subject to standing water. The DCVwIV can be installed horizontally or vertically. The installation of the DCVwIV shall comply with local or state plumbing codes and installed in accordance with the manufactures specifications and recommendations. The DCVwIV shall be installed to meet minimum and maximum working pressures, and temperatures. The DCVwIV shall only be installed on low hazard cross-connection. The DCVwIV shall be used on piping not greater than ¾ inch unless otherwise specified. The DCVwIV shall not be installed were the inlet pressure is below 25 psi or where the maximum inlet or outlet pressure is 175 psi.