The integrity of the water supply in the plumbing and water system shall be maintained. One of the most essential facets of this includes preventing contamination due to backflow. Two major devices employed to avoid this include vacuum breakers and backflow preventers. While these two devices achieve the same thing, they differ in mechanism and uses. This blog details vacuum breakers vs backflow preventers: what they are, how they work, their differences, and how you can choose the right one for your needs.
What is a Vacuum Breaker?
A vacuum breaker is essential to any plumbing system, preventing contaminated water from flowing backward into the clean water supply. It admits air into a system and breaks the vacuum created by the stoppage of the water’s flow, ensuring that any siphon effect drawing contaminated water backward is broken. In-place vacuum breakers are usually installed at hose bibs, faucets, and other fixtures where the risk for back-siphonage is high.
What is a Backflow Preventer?
As the name explains what it does, the backflow preventer prevents the backflow of water from a possibly contaminated source into clean water. Unlike vacuum breakers, which work under one set of conditions, a backflow preventer can handle both back-siphonage and backpressure situations. Therefore, this device is essential to protect potable water systems, whether residential or commercial/industrial.
Vacuum Breakers vs. Backflow Preventers: What’s The Difference?
How Vacuum Breakers Work
A vacuum breaker functions based on a straightforward principle. These devices are fitted at all points where back siphonage may occur. In the event of a pressure drop and the formation of a vacuum, the vacuum breaker opens to admit air into a system, breaking the vacuum and preventing any polluted water from siphoning into the clean water supply.
For instance, a vacuum breaker device is at the top of any irrigation system. It opens in case of pressure failure in the water, allowing air in, thus preventing contaminated water from your garden from backflowing to the main water supply.
How Backflow Preventers Work
As opposed to the former, backflow preventers are more complex and versatile. They can stop both backpressure and back siphonage. A typical backflow preventer features two check valves and a pressure relief valve, similar to the RPZ assembly.
These backflow preventers ensure that the main water supply is saved from chemicals, sewage, and all hazardous materials that may be present in a plumbing system for any commercial setting.
Mechanism and Functionality
Beginning with the fundamental differences in mechanisms and functionality, a vacuum breaker was created to prevent back-siphonage. Back-siphonage is the sudden drawing of water back into the system when a drop in water pressure creates a vacuum.
The vacuum breaker opens to allow air to enter the system, breaking the vacuum and thus preventing contaminated water from being siphoned back. On the other hand, a backflow preventer is a much more thorough device that prevents both back-siphonage and backpressure.
Backpressure is the pressure exerted downstream that exceeds supply pressure, shoving contaminants into the potable water system.
Backflow stoppers use a combination of check valves, air inlets, and relief valves to ensure water flow in one direction—to ensure safety and purity in the water supply chain.
Installation Requirements
Installation requirements for vacuum breakers and backflow preventers differ since they have different mechanisms and protection capabilities. Generally, the vacuum breaker is easier to install. The vacuum breaker shall, in most cases, be installed at the highest point of the water system to break the vacuum and prevent back-siphonage effectively.
However, the installation of backflow preventers involves a more complicated procedure. They must be installed at a point that will stop back-siphonage and backpressure; this is usually downstream from all possible cross-connections.
In most cases, this requires extensive plumbing modifications, mounting pressure gauges, and other piping to accommodate the device.
Location
Placing vacuum breakers and backflow preventers within a plumbing system is vital to their function. Vacuum breakers are installed at a fixture or on the end of a pipeline; this would place them on hose bibs, irrigation systems, and other discharge locations. Their placement is critical in ensuring they can introduce air into the system at the right point to prevent back-siphonage.
However, backflow preventers are primarily installed at the point of supply of the main water line or at specific points of use where the risk for contamination is at its highest. This could be in an industrial setting, commercial buildings, or even residential homes with irrigation systems. Their placement is meant to offer barrier protection to the whole water system against potential contamination.
