What is Backflow and Why you may need a Backflow Preventer?

Backflow is the reverse flow of water or mixture of water and other liquids flowing into the potable water system. A backflow preventer allows water to go through in one direction but prevents it from going in the opposite direction. The backflow of unwanted liquids and (even solids) can be highly toxic and contaminate your homes potable water system. Here are some of the main reasons why having a Backflow Preventer is important. 

Back Siphonage

The reverse flow in a plumbing system caused by negative pressure in your plumbing pipes. This occurs when there is a stoppage of water supply, when the flow of water gets too low, it induces a flow in the opposite direction. For example, high withdrawal rates from a fire truck pulling water from a public supply line or if a water distribution line breaks.

Back Pressure

Back pressure is the reverse in flow in a system caused by an increase in the downstream pressure above that of the supply pressure. This occurs when the downstream pressure exceeds the water supply pressure which can be from the installation of heating systems, pumps, and pressure producing systems. For example, thermal expansion from either a hot water heater or a boiler heating the water causing it to expand, as well as the increased pressure caused by a pump. 

Cross-Connection

Cross-connection is the potentially harmful connection between a potable water system and a direct/indirect connection to other harmful substances. If cross-connection is not protected, a backflow incident could contaminate your potable drinking water system. A direct cross-connection could could happen if your potable water line is connected directly to a boiler and cause contamination from descaling agents or glycol.

Degree's of Hazard

Types of Backflow Preventers

Air Gap Backflow Prevention

A mechanical backflow prevention device that has a physical gap between the free flowing discharge end of a potable water supply line and an open or non-pressured device vessel.

Atmospheric Vacuum Breakers

Contains a float check, check seat, and air inlet port. For non-continuous pressure application, protection against backsiphonage, provides protection for low and high-hazard situations.
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Dual Check Valves

For low-hazard applications where a backflow preventer is not required. Will protect against both backsiphonage and back pressure of contaminated water in your potable water supply.
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Pressure Vacuum Breakers

A mechanical backflow prevention device that contains an internally loaded check valve with an independently acting loaded air inlet valve. When an instance of back pressure or backsiphonage occurs, both check valves close tight. If the check valve should fail, then the air inlet valve will open and allow the air to satisfy the vacuum. For continuous and non-continuous pressure application, protection against backsiphonage ONLY, provides protection for high-hazard situations.

Double Check Valve Assemblies