Selecting a Backflow Control Device

There are a variety of devices and techniques focused on preventing backflow into potable water systems. Below is a basic overview of devices, characteristics and considerations when evaluating your water system and backflow control choices. If you have questions, or would like to discuss a backflow application, please contact us to learn more.

What type of backflow preventer should be used?

Backflow prevention devices and assemblies generally include: atmospheric vacuum breakers, dual check valves, pressure vacuum breakers, double check valve assemblies and reduced pressure principle backflow assemblies.

In general, there are four elements to consider when designing your backflow prevention program:

– System characteristics
– Degree of hazard
– Type of application
– Type of installation

The proper selection of backflow preventers is crucial to ensure the devices work properly and are providing adequate protection for the specific application. It must be stressed that these devices are not all equally acceptable as protection against all types of hazards and other factors must be considered with each application.

Testable Backflow Prevention Assemblies vs. Non-Testable Devices

Testable backflow prevention assemblies are required for use at a service connection. These “testable” assemblies are used for containment of the entire potable system away from the public water system. Since their proper function is imperative in order to prevent contamination of the public potable water supply, a method of testing is necessary.

Non-testable backflow devices are usually used for internal protection, within the potable water system, whereby they are isolating an internal cross- connection from the remainder of the consumer’s potable system. If these types of valves fail, protection of the public potable pupply is still facilitated by the “testable” assembly at the service connection.