# backflow prevention for dental chairs



## dchin (Aug 8, 2010)

I am working on a dental office and would like to know if anyone has experience with the issue of backflow prevention for dental offices.  The office is located in a large medical office building. A main water line enters the suite. There are 3 operatory chairs (general dentistry, no surgery) and a water line will come off the main line and serve two of the chairs and a second line will feed the third chair.  An RPZ Backflow Preventer will be installed at the main line. We are planning to use the Watts 909 Series RPZ. but I am also interested in recommendations.

Does the IPC specifically state that backflow preventers are also required at each individual dental chair?  Section 608.3 and 608.16.9 seem to suggest they are but seem a little vague.

The manufacturer of the chairs has written “ that while they (the company) has found a way to build a backflow preventer into its unit, its approval is precluded by regulation standards which control valve location and size of test fittings.

I appreciate any input

Thanks - Donald


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## peach (Aug 8, 2010)

Use the manufacturer's recommendations (105.4.1).  The RPZ at the water line should be sufficient to protect the public water system.  The water supply to the spit bowl generally comes in high enough above the drain to provide an air gap.


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## pyrguy (Aug 8, 2010)

Newer dental offices don't have spit bowls. The chair has an air/water squirter and two vacuum tubes to take all the 'stuff' away. The drill handles also have water jets.

The protection is not only  for the "public' water supply but to protect the potable water inside the suite for other users.


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## skipharper (Aug 9, 2010)

Donald, see IPC 608.1 and 608.2-if no air gap is present you must protect each fixture individually-the backflow preventer coming into the building is only to protect the potable source from the building. If you have 20 chairs, you have 20 backflow devices if the sinks are not air gapped.


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## dchin (Aug 23, 2010)

Thanks everyone for your input.

Donald


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