Backflow preventers are assemblies with two check valves and two shut-off valves that prevent reverses in process flow. They may also include test cocks for each chamber within the assembly. Backflow preventers have a variety of applications. For example, they are used to prevent boiler water, which may contain anti-freeze, from contaminating water supplies. Backflow preventers use several types of check valves. Swing check valves have a closure element that is pushed aside by the flow, but that...
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Q & A on Backflow Preventers

We asked our users for their input on Backflow Preventers. Here are the results of 63 users familiar with Backflow Preventers.

Who Took Our Poll? | Design Trends | Applications and Use | Features | Buying Advice

Who Took Our Poll?Top

Design TrendsTop

Q:
What new technologies are influencing back flow preventer design?
8 answers
Answers:
For smaller type RPZ and Dbl Check devices, I see the recent change to partial plastic bodies that will lower the cost to consumers to be helpful. The lower cost of a new installation will allow consumers to be more understanding of the requirement and need. On all devices large and small, I'd say it has to be "Cartridge Design" which enables quick and successful repairs.
~Frederick S, Master Plumber Certified Tester and Repair Tech, Pompano Beach, FL
Where chemical injection via the customer's private plumbing system is concerned; also nuclear plants whether use of potable water and questionable source waters/fluids may come in contact via cross connections. Solar heating units that may use potable water systems.
~Derrick B, CrossConnection Control Specialist/BFP Inspector, Conyers, GA
Anything dealing with public drinking water systems.
~David G., Purchaser, Edna, TX
Improved manufacturing capabilities.
~Manufacturing, Burlington, Canada
Development in materials
~Maarten Nouwens, Marketing/Sales, Oude Tonge, Netherlands
Flow rate increase
~Engineering, Design, Woodland, WA
Line pressure
~Dan R, Consultant, Edmonton, Alberta
Cost
~David S, Project Manager, Pineville, NC

Q:
From your perspective, which companies are creating the most innovative back flow preventers?
10 answers
Answers:
Any backflow device that has been approved by the University Of Southern Cal. They have been involved with them since Day One.
~David G., Purchaser, Edna, TX
I would say all of the companies are trying equally hard to come up with innovative ideas. With the National and World Wide requirements accelerating quickly, I am sure we will see many innovative changes in design, materials and clever new ideas.
~Frederick S, Master Plumber Certified Tester and Repair Tech, Pompano Beach, FL
Danfloss, Watts, ApolloValve/Conbraco and perhaps Wilkens by Zurn.
~Derrick B, CrossConnection Control Specialist/BFP Inspector, Conyers, GA
So far the best BFPs for our application have been from China.
~Other, Sidney, BC Canada, Canada
Crane Stockham in Belfast
~Maarten Nouwens, Marketing/Sales, Oude Tonge, Netherlands
Watts febco willkins
~David M, General constuction, Ruston, LA
Watts.
~Byron B., Engineer, Lincoln, NE
Watts
~Manufacturing, Burlington, Canada
Ames
~Corina Vijeu, Design Engineer, Philadelphia, PA
DIG
~Engineering, Design, Woodland, WA

Applications and UseTop

Q:
What are some of the applications you have used a back flow preventer for?
14 answers
Answers:
Primarily, I inspect/survey for plumbing cross connection's and have commercial customers comply with local code/ordinance, state and federal regulation regarding the SDWA. Depending on the level of hazard to the local distribution system, I have the entity install the appropriate BFP on the domestic or fire line taps for containment. This responsibility and authority also extends for isolation applications. Is the device chosen to be used for non-health or health hazards?
~Derrick B, CrossConnection Control Specialist/BFP Inspector, Conyers, GA
Almost every application you can think of: 1. Hospital equipment. 2. typical office bldg's 3. Wave pools. 4. Flume rides. 5.Restaurant equipment. 6.Motion Picture developing systems. 7. Irrigation systems. 8. Dental Clinics 9. Candy factory's 10. The TV show "Top Chef" 11. Large decorative fountain projects 12. Car Wash buildings. 13. Public Schools. 14. Baptismal Fonts 15. Scenes from the movie "Caddy Shack"
~Frederick S, Master Plumber Certified Tester and Repair Tech, Pompano Beach, FL
To protect the storm drain protectors which we manufacture and sell to prevent contaminants passing into storm drains with exiting waste water. The back flow preventer stops any sewage from coming back into our drain device and causing contamination of the system.
~Other, Sidney, BC Canada, Canada
Protection of water supply from contamination within a building's plumbing system. Gas Stations, Restaurant, Dentists & Doctors Offices, Retail, Factories, Office Buildings, Multi Familiy Residences.
~Architect/Builder/Contractor, Pleasantville, NY
Pipe lines in chemical industry, oil & gas industry and (drink and waste) water.
~Maarten Nouwens, Marketing/Sales, Oude Tonge, Netherlands
To stop high hazard materials from getting back into the public water system.
~David G., Purchaser, Edna, TX
Water line installation, drinking water, fire line, sprinkler line
~Architect/Builder/Contractor, Mountain View, CA
Backflow preventers for sprinkler systems and for private wells.
~Byron B., Engineer, Lincoln, NE
Protecting the domestic water supply from any contamination.
~Manufacturing, Burlington, Canada
Potable water on industrial sites, hospitals, schools.
~Dan R, Consultant, Edmonton, Alberta
Irrigation golf course and residential use
~David M, General constuction, Ruston, LA
Water Treatment Plants we have bid on.
~David S, Project Manager, Pineville, NC
Fresh water supply system.
~Engineering, Process/Production, Yokosuka, Japan
Fire Protection
~Corina Vijeu, Design Engineer, Philadelphia, PA

Q:
Please share with us any “non-standard” applications that a back flow preventer has been used for.
6 answers
Answers:
Some I have seen used applied to the hot water line (isolation) of a water tank. Two installed on a singular pipe tap on a domestic use line where only one is necessary. Installation of a DC or RP on a customers collection system tap where gravity prevented flow reversal from being an issue.
~Derrick B, CrossConnection Control Specialist/BFP Inspector, Conyers, GA
That would have to be the Motion Picture processing facility we did in the early 70's. We had tanks of chemicals on several different floors where water was used in the developing and processing of the films. On a light note: How about the "Water Cannons" at a Six Flags Park.
~Frederick S, Master Plumber Certified Tester and Repair Tech, Pompano Beach, FL
In some applications backflow is specified as a backwater valve on drain lines, these are two different applications.
~Manufacturing, Burlington, Canada
Backflow prevention in rural residences, farms mainly.
~Dan R, Consultant, Edmonton, Alberta
Back flow preventers in the wall of a impondment lake.
~Maarten Nouwens, Marketing/Sales, Oude Tonge, Netherlands
Air flow
~Engineering, Design, Woodland, WA

Q:
Do you know of any disastrous mistakes that occurred due to the incorrect usage of a back flow preventer?
6 answers
Answers:
Yes, installing a reduced pressure principle BFP in vaults, below grade. During heavy rains or "out of sight, out of mind" viewpoints, in most cases are NOT maintained, or not plumbed for above grade drainage. They will flood out the RP BFP thus making it ineffective as to its level of hazard use. Also, installing a BFP not designed for vertical flow up or down use.
~Derrick B, CrossConnection Control Specialist/BFP Inspector, Conyers, GA
I think restaurants are and have been falsely protected from the C02 units as well as the chemical connections that are made by non-plumber vendors to the potable drinking water supply within restaurants. I think the risk is great and the protection level is weak or non existing to say the least.
~Frederick S, Master Plumber Certified Tester and Repair Tech, Pompano Beach, FL
Yes, I have seen steel pipe lines which were buried 3 feet under ground laying in pieces on the surface due to water hammer. It was not only the wrong use, it was wrong design as well.
~Maarten Nouwens, Marketing/Sales, Oude Tonge, Netherlands
No, however there are many incidents of disastrous mistakes that have occurred due to the absence of a backflow device.
~Manufacturing, Burlington, Canada
Lack of installation knowledge and maintenance.
~Dan R, Consultant, Edmonton, Alberta
Explosion due to back pressure.
~David G., Purchaser, Edna, TX

FeaturesTop

Q:
What would your design or feature "wish list" be for this product?
8 answers
Answers:
I think the wish list is all about maintenance. Installation is and always has been quite straight forward. I would say the integral parts of a typical device are going the same way faucets went in the mid 70's. And that is "Cartridge" . The quicker the repair with the least amount of brand specific parts is where we are heading.
~Frederick S, Master Plumber Certified Tester and Repair Tech, Pompano Beach, FL
To make the materials used in construction of the devices more durable under freeze/frost conditions in the field.
~Derrick B, CrossConnection Control Specialist/BFP Inspector, Conyers, GA
Easy way to drain them in winter to prevent freeze from water left sitting on number one ball valve.
~David M, General constuction, Ruston, LA
A non-slam check valve with minimum pressure loss and which is maintenance-free
~Maarten Nouwens, Marketing/Sales, Oude Tonge, Netherlands
Small space requirement, low-pressure drop, and price.
~Byron B., Engineer, Lincoln, NE
Longer durations between certification.
~Dan R, Consultant, Edmonton, Alberta
Higher pressure, better materials
~Engineering, Design, Woodland, WA
Ease of installation
~David S, Project Manager, Pineville, NC

Q:
Is there any advice you want to share with users to help them avoid common errors in selection or usage of a back flow preventer?
6 answers
Answers:
Again, COMMUNICATE WITH YOUR LOCAL WATER PURVEYOR and/or HEALTH DEPARTMENT. So many times I have experienced developers, design planners, engineers, general contractors, etc. install the wrong type. Plumbing code may allow for MINIMUM protection; however, local code may require otherwise. This is a local governing authority's prerogative.
~Derrick B, CrossConnection Control Specialist/BFP Inspector, Conyers, GA
Use nozzle check valves (so called Noz-Chek), the ultimate check valve.
~Maarten Nouwens, Marketing/Sales, Oude Tonge, Netherlands
Have a licensed professional do the selection and the installation.
~Frederick S, Master Plumber Certified Tester and Repair Tech, Pompano Beach, FL
Watch for the pressure drop at the flowrate required.
~Byron B., Engineer, Lincoln, NE
Get the proper size for the application.
~Engineering, Design, Woodland, WA
Need to be more aware of pressure drops.
~David G., Purchaser, Edna, TX

Buying AdviceTop

Q:
Do you have any advice for people relative to buying or using back flow preventers?
5 answers
Answers:
Select a well known brand that will allow for future repair parts availability. Don't hesitate to install a backflow device within your own complex. The one at the meter is primarily protecting the source. You can be in danger from within your own facility.
~Frederick S, Master Plumber Certified Tester and Repair Tech, Pompano Beach, FL
Yes. Contact your local water purveyor and/or health department BEFORE you choose a device to have installed. Certain ordinances or codes may determine which type to purchase and why.
~Derrick B, CrossConnection Control Specialist/BFP Inspector, Conyers, GA
Be sure to evaluate the degree of hazard in order to select the right valve.
~Manufacturing, Burlington, Canada
Use nozzle check valves (so called Noz-Chek), the ultimate check valve.
~Maarten Nouwens, Marketing/Sales, Oude Tonge, Netherlands
Buy only CSA approved models.
~Dan R, Consultant, Edmonton, Alberta


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