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Dave
03-02-2009, 06:34 PM
This is an article I wrote for my February newsletter about the importance of backflow prevention and how it plays into detailing. Using proper saftey measures will help to avoid health issues and also detailing business inspections, shop or mobile.

Backflow Prevention And Detailing

You might be asking yourself, why should I worry about backflow prevention?

Well, the short answer is because every time you use detailing chemicals and a garden hose you are creating "The Perfect Storm" for contamination.

Backflow prevention devices vary for different applications and are installed in different locations but I'll keep it simple and focus on our newest product, the Atmospheric Vacuum Breaker (AVB) and it's importance in detailing.

Imagine pouring yourself a nice glass of water after spending an hour washing your car, only to spit it out because your water tastes like the car wash you just used. Yes, this can and has happened before! Every time you submerge your hose into your wash bucket you are putting your self at risk for potential contamination by simply not using the proper saftey devices. The same applies when using a foam gun or any other attachment on your garden hose!


Picture shows common contamination risk's. Cross Connections

http://i177.photobucket.com/albums/w240/rdavex7/backflow-prev-diagram.jpg


An Atmospheric Vacuum Breaker (AVB) on your outside faucet or laundry faucet with hose threads is a simple device that prevents the reverse flow of water and self drains through small holes when your hose is detached.

What Is Backflow?

Backflow is the reversal of the flow of water or mixtures of water and other unwanted substances from any source (such as used water, industrial fluids, gasses, etc.) into the distribution water mains or pipes of the water system.

Water distribution systems are designed to flow in one direction from the street main to your house. When the direction of flow is reversed due to pressure differences, (such as fire fighting efforts, a water main break, or consumer high side pressure (pumped)) , backflow can allow contaminants to enter the potable drinking water system through cross-connections. When this happens, any substance that may be in contact with the water supply main or line could be siphoned into the public water system.

A single backflow incident can potentially affect hundreds or even thousands of people. Preventing the backflow of contaminants and pollutants in the water system is absolutely essential if health and property are to be protected.

What Is A Cross Connection?

A Cross connection is the physical link that allow backflow incidents; permanent or temporary piping arrangement which can allow your drinking water to be contaminated if a backflow condition occurs.

A potentially hazardous cross-connection occurs every time someone uses a garden hose sprayer to apply insecticides or herbicides to their lawn or by placing the hose in a bucket of car wash solution while washing their car. Another cross-connection occurs when someone uses their garden hose to clear a stoppage in their sewer line.

How Can Backflow Be Prevented?

Different types of backflow prevention assemblies are required depending on the degree of hazard. A high hazard exists when there is danger that backflow could create a health threat.

Examples of this classification include: lawn irrigation systems with chemical injection, hospitals, and manufacturing plants where dyes or chemicals are mixed. Moderate hazards occur when there is not a health threat, but backflow could cause discolored, smelly, or objectionable water. Retail stores and offices are examples of this classification meaning mobile detailers should use an AVB when using a customer supplied water connection.

Backflows due to cross-connections are serious plumbing problems; however, they can be avoided by using the proper protection devices. Be involved in keeping your water safe from contamination. Without proper protection devices, something as useful as your garden hose has the potential to poison your home's water supply. In fact, over half of the nation's cross-connections involve unprotected garden hoses. Without a backflow prevention assembly between your hose and hose-bibb (spigot or outside faucet), the contents of the hose and anything it is connected to can backflow into the piping system and contaminate your drinking water. This hazardous situation sometimes can affect more than a single home. Each spigot at your home should have a hose-bibb vacuum breaker (AVB) installed.




Self-draining Hose Connection Vacuum Breaker

There are many versions at a cheaper price, this is a good inexpensive AVB.


http://i177.photobucket.com/albums/w240/rdavex7/vb222.jpg


http://i177.photobucket.com/albums/w240/rdavex7/vb222_typical_instalation.jpg



Thanks for reading!

Dave

bunky
03-03-2009, 03:57 PM
In our area, backflow devices are required by code on new homes.

Bob
03-03-2009, 06:01 PM
I think they are required everywhere now that we have a universal national code.
I'll admit though, sometimes I have taken them off to get better flow. I'm not sure if the screw head is designed to break off but mine always break and they are a pain in the rear to get off after that screw head breaks. I'm not sure if this is done on purpose though.

Dave
03-03-2009, 07:28 PM
The set screw is supposed to break so it can't be removed, I just take it off so I can use it everywhere.

Home owners with double check valves on their irrigation systems are required to have them tested and the test results be submited to the city. They sent thousands of letters to home owners a few years back about this.

Some new homes here have double check valves on the incoming water after the meter now which creates a closed system and requires an expansion tank on the water heater to compensate for the expansion and contraction of the water.

Russecu
03-04-2009, 04:45 AM
My house came with them on the external hookups. I think its a good idea and everyone should have one.

bunky
03-04-2009, 08:41 AM
The set screw is supposed to break so it can't be removed, I just take it off so I can use it everywhere.

Home owners with double check valves on their irrigation systems are required to have them tested and the test results be submited to the city. They sent thousands of letters to home owners a few years back about this.

Some new homes here have double check valves on the incoming water after the meter now which creates a closed system and requires an expansion tank on the water heater to compensate for the expansion and contraction of the water.

The installed backflow on my house are not very good and when I had a new hot water tank they installed the expansion tank plus had to replumb the drain to pass code. I had paid to get it done so they pulled a permit.