Essential Guide to Backflow Freeze Protection for Your Irrigation System

Pressure vacuum breakers feature a smaller footprint and are commonly used for residential irrigation, including lawn sprinkler systems, large gardens and greenhouses. These devices typically aren't as rugged as double-check or reduced pressure zone valves. 
PVBs are susceptible to failure due to:

• Installation height: PVBs must be installed the highest point above the tallest sprinkler head or they will not function properly.
• Highly freeze-prone: Their brass components can easily crack if water remains in the line and the pipe is exposed to freezing temperatures. Even if properly winterized, the bonnet or breaker assembly can become damaged by freeze.

Double-Check Valve (DCV) 

Double-check valves are commonly used in commercial settings and for fire suppression systems. Introduced in the 1950s primarily for use in the fire industry, they contain two independently acting spring-loaded check valves in series, offering redundancy in the case of failure.

As the DCV grew in use, its flaws became more apparent: there was no way to examine the valves for failure because the DC is a closed system. And there was no way to tell if those valves had failed without a professional inspection and a backflow test kit.

The DC valve remains a prominent option today, though in most cases it's recommended for use only in low-hazard situations. Made of metal and often installed below-grade, DCVs can crack or malfunction if water is left inside the assembly during a freeze.

Reduced Pressure Zone (RPZ) Assemblies

RPZs include two check valves and a relief valve between them that discharges water if a malfunction is detected, making RPZs inherently safer in contamination scenarios.

While the RPZ solved for the DC valve's flaws, it created another problem: If the first check valve fails, the relief valve will continue to dump water until the line is shut off. Because of this, RPZs should exclusively be installed outside where excess water can flow away from a building.

What you need to know about RPZs:

• Used for high-hazard protection: Required in applications where there's a significant risk to health, such as with chemical fertilizers or reclaimed water.
• Offer visual failure indication: If the check valves fail, the relief valve opens, dumping water — a clear sign that service is needed.
• Should only be installed above-grade: Indoor and below-grade installations are not advised due to the potential for flooding.
• Are vulnerable to freezing: If the metal is exposed, the relief valve can freeze open and continuously discharge water, wasting hundreds of gallons per minute.

The bottom line: RPZs should be properly winterized and protected from the elements in an enclosure that allows for inspection, servicing and proper drainage.

A frozen backflow preventer can seize and fail, allowing cross-connection and backflow into the water supply. Freezing can also damage, crack or destroy a backflow preventer's checks, valves, gaskets and housing.

Even when drained, backflow preventers exposed to freezing air can suffer component damage. Manual winterization also requires time and coordination each fall and spring, introducing risk if it’s done late or improperly.

The Solution: Cover Your Backflow Preventer in Winter

The best long-term solution to combat freezing conditions is with a permanent, above-ground ASSE 1060-certified enclosure that protects your backflow device year-round, no matter the climate. We recommend installing a Safe-T-Cover enclosure for peace of mind.

Unfamiliar with the ASSE 1060? The ASSE 1060 is a standard of guidelines for “fluid conveying components” and their strength, drainage capability and ability to withstand cold conditions. This was established in 1996 by the American Society of Sanitary Engineering (ASSE).

Note that not all enclosures on the market meet ASSE standards. When purchasing an enclosure it's important that it meets the intended ASSE requirements, like Safe-T-Cover does.

Safe-T-Cover’s modular aluminum enclosures are engineered for extreme durability and ease of use. Each enclosure offers:

• Custom sizes and configurations to fit your site and equipment
• ASSE 1060 Class I certification for freeze protection
• Optional slab heaters, louvers, and ventilation for year-round climate control
• Lockable access panels for security and compliance
• Finish options to blend with the surroundings available at no added cost

Above-ground enclosures eliminate the need for seasonal removal, prevent freeze damage, and improve access for testing and maintenance. That's a win-win for your equipment and the water supply! 

Contact us today and we'll design your cover.