BPAT Flash Card Slides

Full Glossary

Cross-Connection

Any actual or potential physical connection between a potable water supply and any source of contamination, pollution, or non-potable water.

Backflow

The undesirable reversal of flow of water or other substances from any source into the distribution pipes of a potable water supply.

Back-Siphonage

Backflow caused by a reduced or negative pressure (vacuum) in the supply piping. Occurs when supply pressure drops below atmospheric pressure, creating a siphon effect.

Back-Pressure

Backflow caused when downstream pressure exceeds the supply pressure. Common in boiler systems, elevated tanks, or pumped systems connected to the potable supply.

Potable Water

Water that is safe for human consumption — free from harmful contaminants and meeting all applicable drinking water standards set by TCEQ and the EPA.

Reduced Pressure Principal Assembly (RP)

A backflow prevention assembly consisting of two independently acting check valves and a hydraulically operating, mechanically independent pressure differential relief valve, two shutoff valves and four test cocks. Provides the highest level of protection and is required for high-hazard connections subject to backpressure.

Double Check Valve Assembly (DC)

A backflow prevention assembly consisting of two independently acting, spring-loaded check valves, two shutoff valves and 4 test cocks. Used for low, non-health hazard applications. Does NOT protect against high-hazard (health hazard) cross-connections.

Pressure Vacuum Breaker (PVB)

A backflow prevention assembly containing a spring-loaded check valve and spring loaded air inlet valve, two shutoff valves and two test cocks. Protects against back-siphonage only for both health and non-health hazards — NOT approved where back-pressure conditions exist. Must be installed at least 12 inches above the highest downstream outlet.

Atmospheric Vacuum Breaker (AVB)

A non-testable backflow prevention device that protects against back-siphonage only for both health and non-health hazards. Must be installed at least 6 inches above the highest downstream outlet. Cannot be under continuous pressure for more than 12 hours in any 24-hour period.

Spill-Resistant Pressure Vacuum Breaker (SVB)

Similar to a PVB but designed to minimize spillage when the air inlet opens. Protects against back-siphonage only for both health and non-health hazards. Must be installed at least 12 inches above the highest downstream outlet.

Health / High Hazard

A cross-connection that could introduce a substance that may contaminate the potable water supply. Examples include chemical feed lines, irrigation systems with fertilizer injectors, and medical equipment connections.

Non-Health / Low Hazard

A cross-connection that could introduce a substance that is objectionable but not a health hazard (e.g., aesthetic impairment such as taste, odor, or color).

TCEQ

Texas Commission on Environmental Quality — the state agency responsible for protecting Texas' human and natural environment, including regulation of drinking water, backflow prevention licensing, and cross-connection control programs.

BPAT

Backflow Prevention Assembly Tester — a TCEQ-licensed individual authorized to test, inspect, and repair backflow prevention assemblies in Texas. License must be renewed every three years with 24 hours required continuing education.

Differential Pressure

The difference in pressure between two points in a system, measured in pounds per square inch differential (psid). Used during testing to evaluate the performance of check valves and relief valves in backflow prevention assemblies.

Relief Valve Opening Point (RP)

The differential pressure at which the relief valve of an RP assembly opens. The relief valve must open at a minimum of 2.0 psid. A reading below 2.0 psid indicates a failed relief valve.

Check Valve Failure (DC/PVB/SVB/RP)

A check valve in a DC, PVB and SVB fails if the differential pressure falls below 1 psid. The number 1 check of an RP assembly fails when the differential pressure reading falls below 5.0 psid. A reading above the relief valve opening point while testing the number 2 check valve of an RP indicates the check valve is holding and passes the test.

Air Gap

The unobstructed vertical distance through the free atmosphere between the lowest opening from any pipe or faucet supplying water and the flood level rim of the receiving vessel. The most positive form of backflow protection — observable but not a testable assembly.

Flood Level Rim

The edge of a receptacle (such as a sink or tank) over which water would overflow. Used as a reference point for determining required installation heights for vacuum breakers and air gaps.

Continuous Pressure

A condition where a backflow prevention device or assembly is subjected to supply pressure for extended periods. AVBs cannot be under continuous pressure for more than 12 hours in any 24-hour period. PVBs, SVBs, DCs and RPs are designed for continuous pressure service.