Defining Backflow Prevention Devices & Various Types

When water is supplied into a home or any establishment, there is a possibility that the main potable water line can get contaminated without the use of a backflow prevention device. Water supply systems normally keep pressure at certain levels to make sure that water flows from the main line to each and every home’s tap, shower, and other fixtures. The reduction of pressure can sometimes result in unwanted circumstances which involves the backflow of water.

In simple terms, backflow is the reverse flow of water, suspended solids, and gas into potable water lines. This is why backflow prevention device were developed. The problem normally happens at cross connections. Basically, cross connections are where potable water systems get connected with non-potable water systems. There are plenty of cross connections within a property which adds more reason to have backflow prevention. Here are a number of possible causes of backflow:

Back-Siphonage – this normally happens with fluids of higher pressure go into areas with low pressure fluids. The sudden drop of pressure, possibly due to the excessive use of water, is among the reasons why this happens.

Back-Pressure – this occurs when natural gas is forced into a container that could make its way into pipelines and out the kitchen tap. This occurrence is caused by heat exchanging equipment, boilers, and power washing equipment.

Types of preventive devices:

1. Air Gap – the most reliable method and the simplest to prevent backflows is to use an air gap. Basically, the air gap is an open vertical space. This stabilizes the pressure and works without any moving parts. Because of its simple concept, air gap device are found in almost all homes.

2. Reduced Pressure Zone Device – also known by its abbreviation RPZD, these devices provide a very effective means of preventing backflow. Unlike other types of preventive devices, RPZDs are made to prevent high-risk situations where a large number of people could be harmed by backflow.

3. Double Check Valve – more commonly found in sprinkler systems, double check valves have two gate valves on either end to isolate water. Water can flow in either direction, making it easy to use.

4. Hydrostatic Loop – this method involved the vertical positioning of pipes at least 33 feet high. The hydrostatic loop’s design effectively discourages siphoning and backflow.

5.Chemigation Valve – although you won’t see this in your neighborhood, it’s still important to note the type of preventive device that is being used in other areas. A chemigation valve is normally used in agricultural areas. It is used to keep the water in a specific area free from any chemicals such as fertilizers, pesticides, and other chemicals that are used in agricultural purposes. This valve has a number of components that make up the entire system.

6. Atmospheric Vacuum Breaker – this type of backflow prevention device is more commonly seen in household applications. In this setup, an elbow-shaped device at a 90 degree angle is used. On the outside of the device, there is a valve which is responsible for preventing the backflow. The only downside to this device is that it is not testable, which means manufacturers need to ensure that each one passes quality checks.