What is a Registered air gap?
A registered air gap is a space where water can flow freely from a supply pipe into a tank or receptacle, but backflow is prevented by the unobstructed air gap. These are commonly found on applications such as water trucks, water trailers, water carts and vacuum excavators.
A registered air gap is an approved method of achieving backflow compliance where either back siphonage or backpressure conditions may exist.
Hydrant standpipes and Air Gaps
Air gap testing ensures proper backflow prevention by verifying a sufficient physical separation between the water supply and the tank or vessel being filled. This separation prevents contaminated water from flowing back into the potable water system.
- Backflow certification is required for air gaps with a backflow prevention certificate (Form 9 report on inspection and testing of testable backflow prevention devices) issued by a backflow endorsed plumber.
- This certificate is required in the standpipe registration process.
We can attend, inspect and provide a test report on the same day to assist with your application for use of a standpipe.
Types of Backflow Prevention Devices:
Reduced Pressure Zone (RPZ)
Designed for higher-risk situations. RPZs have two independent acting non-return values to create a lower pressure zone, preventing backflow.
Double Check Valve (DCV)
Commonly used for residential and commercial applications, these devices use two check valves to prevent backflow. Flow-through the device will only occur when there is sufficient pressure to overcome the valve springs.
Single check-valve (testable) (SCVT)
Single check valves act as one-way gates, allowing water to flow in only one direction and are often used in fire system applications and pumps.
Atmospheric Vacuum Breakers (AVB)
Suitable for applications where there exists a potential for back siphonage, AVBs use atmospheric pressure to prevent backflow.
Pressure Vacuum Breakers (PVB)
Similar to AVBs but designed for higher pressures, PVBs are often used in industrial settings.
Registered Air Gap (RAG)
This method involves creating a physical separation between the potable water supply and a potential source of contamination, such as a drain or a tank.