Archive for April, 2012

Backflow Prevention 201: What Device is Right for Your Building?

We’ve all been hearing about backflow prevention for our buildings, and to the layman it sounds mysterious and confusing. Here are a few definitions that will make your proposals easier to understand and your decision-making simpler:

     The New York State Department of Environmental Conservation (DEC) has determined that backflow from buildings might cause a serious health hazard to our drinking water supply. As a result the DEC’s clean water campaign, approximately 128,000 buildings in NYC need to install backflow preventers. The City agency that is overseeing this project is the Cross Connection Unit of the NYC Department of Environmental Protection (DEP).

A cross connection is the actual or potential connection between a non-potable substance or source and a potable source.

     Various types of backflow preventers exist for different wastewater applications and health hazard conditions. You must use a licensed plumber to install these devices, and a licensed backflow tester to test them. The plumber should know the city and state codes that specify the correct backflow device to use in each situation, and an engineer must do a preliminary survey to confirm this. Following are descriptions of the different devices:

     Reduced Pressure Backflow Preventer—RPZ: The Reduced Pressure Principle Assembly (RP) is the best mechanical means of preventing backflow pressure and back siphonage. These assemblies are the most expensive backflow prevention devices but are the best way to protect against cross connections.

     Double Check Valve Backflow Preventers—Model DCV: The Double Check Valves are used in non-health hazard (pollutant) conditions only and are designed to protect against backflow pressure and back siphonage. These devices have TWO check valves in line designed to prevent backflow.

     Dual Check Valve: The Dual Check Valve or double backflow prevention valve is basically a stripped down Double Check Valve without shut-off valves and test cocks. They are non-testable and are typically used by water companies and installed after a water meter to prevent the meter from running backwards. This piece of equipment is the center of controversy with many backflow authorities and should never be confused with Double Check Valves. Check with local authorities for required installation, as most do not recognize these as backflow prevention devices.

     Atmospheric Vacuum Breaker—AVB: The atmospheric vacuum breaker is one of the least expensive backflow prevention assemblies. The AVB is a non-testable unit and is good for back siphonage. They must be installed downstream from any shut-off valves and cannot be under pressure for more than 12 hours. These units will NOT prevent backflow pressure and can only protect against back siphonage.

     Pressure Vacuum Breaker—PVB: A pressure vacuum breaker is similar to an Atmospheric Vacuum Breaker but can be installed before the shut-off valves. Check with local authorities as some do not allow the use of a PVB at all. A PVB backflow preventer may spill or spit water out from under the cap, so it should always be installed in a location where water spillage is OK. These units will NOT prevent backflow pressure and only protect against back siphonage.

As you can see, you must be careful to hire a professional licensed plumber who knows the difference between all of these backflow devices and which ones can be used in which applications.

If you have any questions about any of these devices, or are having a hard time getting a straight answer, please call me directly at 1-877-VARSITY (827-7489), and I will help you figure out how to proceed—at no obligation, of course.

caption: Varsity Plumbing and Heating, Inc. is a family-owned and operated business, now celebrating its 50th Anniversary. Below, far right, is founder Bob Bellini with his sons, from left, Rick (Vice President), Tom (Vice President) and Bobby (President), and sons-in-law Robert McConnell (Field Supervisor) and Mike Lyons (Chief Financial Officer).


Bobby Bellini, President of Varsity Plumbing and Heating, Inc.

50th anniversary