More and more water jurisdictions are not allowing the use of a below-grade vault for the location of the backflow preventer. This growing trend among water jurisdictions is driven by two things:
- The increased use of a reduced pressure zone backflow preventer which cannot be installed below grade
- More and more jurisdictions are recognizing the inherent risks of the vault to employees and the public
Another trend developing is moving the meter out of the vault and into the enclosure with the backflow preventer. Let’s look at some of the reasons for this growing trend.
Meter Vaults are Dangerous
Entering a meter vault is a confined-space entry. Two people minimum are required when the meter needs maintenance. Sometimes fall protection is required depending on how deep the vault is and sometimes a sump pump is needed to remove standing water before the meter vault can be entered.
A Smaller Footprint
By installing the meter inside the backflow cover, the total footprint of required land can be smaller, especially when the latest water meter technology is utilized. Water meters are now available with little to no straight pipe runs before and after the meter. On a project where there is little land available, saving a few square feet of real estate could be helpful.
Save Some Money
Construction projects are always in need of ways to lower the total cost. Often, when a project is over budget, a value engineering process begins. Contractors indicate the value engineering process offers little engineering and no value to the project.
To save the project owner some money, move the meter into the enclosure during design and this often saves several thousand dollars. The cost of the meter in a vault and the backflow inside the enclosure is more expensive than the meter being installed inside the enclosure. Most are unaware of this savings opportunity.
Consider Location and Aesthetics
The placement on the property of the meter and backflow preventer enclosure should be taken into consideration. Enclosures are often located in front of the building at the primary entrance, which is not a well-received location by the building owner. Electrical transformers are typically in out-of-the-way locations. Think about garbage dumpsters: they are surrounded by some type of fencing, landscaping or both. When planning the project, consider locations along property lines or in the rear of the property.
The use of color is also a consideration for the meter and backflow preventer cover. More and more enclosures are being installed in tan and green which helps them blend in with the landscaping of the property. The use of wraps is also becoming more popular to improve the aesthetics of the backflow enclosure. Check out this aesthetics guide for several ways to improve the view.
Show Some Examples
Check out this information from Middlesex Water Company. Notice the reference to above-grade meter enclosures and also check out their input regarding the risk of installing the RPZ inside the building. They point out the possibility of potential flood risk.
Middlesex also has a comprehensive set of standard details for enclosures where the meter is installed inside the enclosure along with the backflow preventer. Check out the drawings starting on Page 16. Much thought has been invested in this set of standard details. New Jersey American Water and Suez also have comparable standard details in place for the water meter to be installed inside the enclosure.
What Can You Do?
As a design engineer, look for the best practices for meter and backflow preventer design. Change is not easy and requires a commitment to pursue what is best. Contact us if you want to talk about your next project. For water jurisdictions, we’ve worked with several water jurisdictions across the county and would be willing to provide our support as you make these changes in your jurisdiction. Reach out to us and we’ll be glad to help you make these important changes.