There are several types of backflow prevention assemblies used in Indiana. The type you have determines which tests are performed and what certification your tester needs.
Reduced Pressure Zone (RPZ) Assembly
The most common high-hazard device in commercial and industrial applications. Uses two check valves and a relief valve to prevent backflow. Required testing is more involved than simpler devices. Common on fire lines, irrigation with chemical injection, and high-hazard commercial connections.
Double Check Valve Assembly (DCVA)
Two independently acting check valves. Used for low-to-moderate hazard connections including irrigation systems, apartment buildings, and commercial water services without high-hazard chemicals.
Pressure Vacuum Breaker (PVB)
A spring-loaded check valve with an air inlet that opens when pressure drops. Commonly used on residential and commercial irrigation systems. Must be installed above the highest outlet on the system.
Atmospheric Vacuum Breaker (AVB)
The simplest device, used for individual hose bibs and low-hazard applications. Not testable under pressure — does not require an annual test in most jurisdictions, but must be inspected for proper operation.