There’s a right way and a wrong way to do everything — even backflow preventer installations. For years, backflow preventers were installed in vaults and basements because engineers thought that that would be the best way to protect the equipment. We’re getting smarter about where and how to go about backflow preventer installations and Doa Meade is leading the charge.
Doa Meade is the director of infrastructure management for the Las Vegas Valley Water District. She is a big proponent of above-ground installations of all valves, backflow preventers and meters. Not only do outdoor, above-ground installations save time and money, but it is the safest place to put your equipment.
We recently spoke to Doa about this topic and the detailed cost analysis she recently did that may surprise engineers everywhere.
What We’ve Learned About Backflow Preventer Installation
One of the things Meade and her team learned over the years is that you can put a backflow preventer and a meter in the same enclosure, above ground, in essentially the same footprint as a vault. “We also learned that we didn’t need to have dual backflows when you brought the whole thing above ground because they’re more than looped throughout the site. And we didn’t need any extra space for pipe length. We realized that we can reduce the size,” Meade says.
Utility Vaults Are Expensive To Build and Maintain
Underground utility vaults are dangerous. According to data collected by the U.S. Department of Labor (USDOL), Bureau of Labor Statistics (BLS) Census of Fatal Occupational Injuries (CFOI) program, nearly 100 fatal injuries occur in confined spaces each year and almost five million confined space incidents are reported annually.
Vaults also flood, which increases the risk for cross-connection. And they cost a lot of money to build and maintain.
“It costs about $50,000 per vault to construct and you need two of them because they’re looped,” Meade says. “And it’s at least a month’s worth of building a vault before it can take water,” she points out.
“It costs $20,000 to $30,000 to go above ground. If you go above ground, you’re just bringing your piping up out of the ground and all you’re doing is pouring a concrete pad,” Meade says. “You can get that whole assembly constructed, tested, and passed in one week. So, what we have now is a very efficient, above-ground installation.”
Above-Ground Backflow Preventer Installations Save Money
For a developer — time is money. She recently did a detailed cost analysis of the above-ground installation versus vault installation and found significant savings. Developers are saving about $60,000 in labor, per project, installing backflows and meters in the same above-ground enclosure.
Developers who like to rehab their vaults are also saving money. Meade says a typical vault rehab costs about $15,000 compared to the $20,000 it costs to move a backflow preventer installation and meter above the ground, but the additional $5,000 is made up in the first year on maintenance alone.
That’s because when annual testing is performed, only one technician is needed. No longer do you need fall protection equipment or a sniffer for gas. You don’t have to do sumps, it’s no longer a two-person job.
And developers are getting the message. “We’ve had one project in the last three years that actually requested a vault. Everybody else is going above ground now, simply because it saves them a lot of money,” Meade says. Above-ground enclosures that are designed and manufactured to meet the requirements of ASSE 1060 are not only popular in Las Vegas. They’re growing in popularity across the United States. If they’re not as common in your part of the country — make the switch. Our “Engineer’s Guide to Industrial Enclosure Design” can get you started.