Parallel Installation

Facilities that provide critical services and require a constant, uninterrupted source of water, such as hospitals, may have parallel backflow preventers installed to allow a continuous water supply even when one backflow preventer is out of service for testing, repair or replacement.

For these types of installations, it is important that the combined and separate flows meet the needs of the facility.

        Figure 1: Parallel Installation - Single Service (Medical Facility, Hospitals, etc.)

Figure 1 Parallel Installation Single Service

A parallel installation is shown in Figure 1. Note that the water supply line leaves the meter, divides and is rejoined past the backflow preventers, creating one supply line again.

Figure 2: Single Meter Dual Service - Backflow Preventers in Service

Figure 2 Single Meter Dual Service - Backflow Preventers in Service

Installations that split the supply line for two different purposes are not parallel installations. An example is the use of potable water for irrigation (Figure 2). In those situations, a reduced pressure backflow preventer is required to protect the water supply

Figure 3: Not Approved "T" Installation - Double Service

Figure 3 Not Approved T Installation Double Service