Very few water jurisdictions provide standard details for above-ground backflow enclosures. As a result, designers won't spend time searching for these details, nor will they take the risk to design outside of those standard details and consider above ground backflow enclosures. This hinders best practice design.
That's because designers fall back on what they know will be approved. It gets designed again and again—even though it is not the best practice. By not exploring other options, designers fail to realize insulated backflow enclosures (that are outside and above ground) are not only cost-effective, but they also eliminate unnecessary risks.
This blog is the first in a three-part series on the importance of designing compliant backflow enclosures. The design of your backflow enclosure must be well-thought-out. Designers should exude strong attention to detail when it comes to backflow preventer assemblies. So, let's begin by taking a look at why the location of your backflow preventer is such a critical decision for the building owner or water customer.
Outside, Above Ground Backflow Enclosures Are Safer
The first thing you must consider is how much safer it is to house your backflow preventer assembly in an outside, above ground backflow enclosure.
If the backflow preventer assembly is installed in a vault, the water customer now has a confined space on their property. Many of these customers will be completely unaware of the vault on their property, let alone the risks and responsibilities related to the confined space.
As a water jurisdiction, you probably have policies and procedures in place related to entering a confined space and may conduct routine training to prevent accidents. Your water customer probably does not have these safeguards in place.
As we look at vault installations across the country, rarely do we see any signage warning a person to stay away from the vault. Imagine a person innocently opening the lid to a vault and the problems this could create. In the event of an injury or death, many people could face lawsuits, including:
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The building owner
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The designer
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The water jurisdiction
By designing a backflow enclosure, you avoid this unnecessary risk. Ask the water jurisdiction to provide a standard detail for outside and above ground backflow preventer installations. This will allow you to avoid the vault and provide peace of mind.
Backflow Enclosures Eliminate Flood Risk
Not only are outside, above ground backflow enclosures safer, they also eliminate flood risks, too.
In fact, we typically find out during presentations that many mechanical and plumbing engineers are unaware of the significant flood risk that exists if a catastrophic failure occurs. Over the past four years, we’ve found most designers think the floor drain will be enough to handle any water that discharges from the relief valve. This is not the case.
The reduced pressure backflow preventer will release water when it is doing its job, which is to protect drinking water. All it takes is a little debris to start the discharge process, which could be as much as a foot of water every 10 minutes. Why would any building owner want this potential problem inside the building when a better solution is readily available?
We anticipate the day when the insurance industry figures out the reduced pressure zone (RPZ) actually causes floods. Insurance industry-leaders will ask, "Why was it designed and installed inside the building?"
You can avoid them by using backflow enclosures located outside of the building. Ask the water jurisdiction to provide a standard detail for outside and above ground backflow preventer installations.
Decrease Cross-Connection Risk With Backflow Enclosures
The purpose of the backflow preventer is to prevent water from returning to the distribution system in the event of back siphonage or back pressure. When the vault is flooded, and the test cocks of the backflow assembly are underwater, this creates a potential cross-connection. This defeats the original intention of the device! The contaminated water in the vault can be drawn into the water customer’s lines or drawn back into the distribution system. Think about how long a vault will be filled with water after flooding disasters! And we seem to have more and more of these disasters in many locations across the US.
Eliminate this potential cross-connection. Don’t design the backflow preventer in a vault. Ask the water jurisdiction to provide a standard detail for outside and above ground backflow preventer installations.
They'll also be looking to others to pay for the flood-contamination costs. Designing the RPZ inside the building comes with risks. Keep this in mind—vaults are designed for fire protection.
Insulated Backflow Enclosures Are Cost-Effective
Designing a backflow enclosure that's outside and above ground actually saves you money.
Think about it for a minute. Installing a backflow assembly in a vault costs the water customer several thousand dollars. When the vault is filled with water, the assembly will be subjected to standing water, sometimes on an ongoing basis (or for months at a time), which shortens its lifespan. That's because the epoxy coating on the gate valves and on any grooved couplings will quickly deteriorate. The assembly is not designed to be under water.
Gasket life is also shortened, which means the water customer may end up replacing this expensive device prematurely.
If the device is installed above ground, inside an ASSE 1060 insulated backflow enclosure, it will stay dry and the customer will avoid additional expenses.
Backflow Enclosures Protect Your Backflow Assembly
Backflow assemblies play an important role in clean drinking water. Unfortunately, the backflow preventer gets little thought during design on most construction products. Designers are busy and pressed for time to get the drawings completed and often use the same design that has been used over and over for years and years.
Considering the location of your backflow assembly is very important. The best location is outside the building in an above ground ASSE 1060 insulated aluminum enclosure. Contact us to see if we can help you with your design. If you’re a water jurisdiction we'll improve your standard details. We can provide many examples and can work with you to develop a comprehensive set of details for your jurisdiction.
You can also get design ideas by looking through our new "Enclosure Aesthetics Guide." Don't assume backflow enclosures have to be an eyesore. Check out our free guide today!
