Backflow Preventer Location

[Mech]

2009 IPC

Three proposed buildings on one parcel in PA, which all will be fed from a common street tap.

Is there a code requirement that each building has its own backflow preventer instead of one common bfp for all 3 buildings in the exterior meter pit? I did not find anything in Section 608, except that the potable water system must be protected.

Thanks

 

[VillageInspector]

I would require each building to have its own back flow preventer

 

[Msradell]

I think code would allow you to just have one because the purpose is to protect the water system. In reality I agree with Villageinspector I would definitely prefer having one for each residence.

 

[JBI]

Would you want your water contaminated by your neighbor's?
I also would require one for each building.

 

[mtlogcabin]

Back-flow prevention is not normally required for an entire building . They are required for certain fixtures and systems (fire sprinklers) where cross contamination may occur. That is why you can not find the answer to your question within the codes.

 

[SCBO1]

Mech,

Just a bit curious how that's being done, are the buildings daisy chained or will there be three individual lines exiting one meter pit?

 

[cda]

Mech,

Just a bit curious how that's being done, are the buildings daisy chained or will there be three individual lines exiting one meter pit?

Back flow at entry to property?

Loop for fire hydrants and domestic?

Tap off that loop to run to each building ??

 

[SCBO1]

Is this is looped, is it done in the city utility easement or on private property?

 

[ICE]

residential or commercial?

 

[tmurray]

Back-flow prevention is not normally required for an entire building . They are required for certain fixtures and systems (fire sprinklers) where cross contamination may occur. That is why you can not find the answer to your question within the codes.

I think they are talking about connection to a public utility, which generally would require backflow protection to ensure that a loss of pressure in the main does not siphon contaminated liquid back into the main, resulting in contamination spreading to adjacent buildings/properties. But for private wells, yes you would be correct in that case.

We would require each building to have a backflow preventer. If there is a backflow preventer on the main to the property, this arrangement increases the chances substantially that a loss in pressure in the main will cause cross contamination between the buildings once water pressure is restored.

 

[Mech]

Wow, lots of comments and follow up questions! Thanks.

All buildings are commercial - a parking garage, a medical office building, and an apartment building. The MOB at the moment only has restrooms, a mop sink, and water fountains.

The water is from a public water system.

The civil engineer's plans show one meter pit w/ backflow preventer at the entry to the property and then one common supply line, not looped, that each building taps off of (daisy chained). The buildings do not have their own water line back to the meter pit.

The fire suppression line has its own connection to the public water system, and then all three buildings daisy chain off that one supply line. I believe each building will have its own bfp for fire suppression; I am not concerned with this arrangement as I am not responsible for fire suppression.

I am responsible for only the medical office building. There is at least one, if not two, other plumbing professionals responsible for the other two buildings.

I would prefer each building receive its own bfp.

If the code's intent is to protect the city's system, then the design has done so. If the code's intent is to provide protection between buildings, then this design fails.

 

[mtlogcabin]

I believe each building will have its own bfp for fire suppression; I am not concerned with this arrangement as I am not responsible for fire suppression.

Do not leave the BFP requirements up to the fire guys. The plumbing code up dictates the type of BFP that is required depending on the system. My experience is the fire guys only look to see if one is installed not what type to use for a specific system. Two different ASSE standards

Barometric loop
High or low hazard
Backsiphonage only
(See Section 608.13.4)
Double check backflow prevention
assembly and double check fire
protection backflow prevention assembly
Low hazard
Backpressure or backsiphonage
Sizes 3/8² –16²
ASSE 1015, AWWA C510, CSA B64.5, CSA B64.5.1


Double check detector fire protection
backflow prevention assemblies
Low hazard
Backpressure or backsiphonage
(Fire sprinkler systems)
Sizes 2²–16²
ASSE 1048

 

[cda]

Wow, lots of comments and follow up questions! Thanks.

All buildings are commercial - a parking garage, a medical office building, and an apartment building. The MOB at the moment only has restrooms, a mop sink, and water fountains.

The water is from a public water system.

The civil engineer's plans show one meter pit w/ backflow preventer at the entry to the property and then one common supply line, not looped, that each building taps off of (daisy chained). The buildings do not have their own water line back to the meter pit.

The fire suppression line has its own connection to the public water system, and then all three buildings daisy chain off that one supply line. I believe each building will have its own bfp for fire suppression; I am not concerned with this arrangement as I am not responsible for fire suppression.

I am responsible for only the medical office building. There is at least one, if not two, other plumbing professionals responsible for the other two buildings.

I would prefer each building receive its own bfp.

If the code's intent is to protect the city's system, then the design has done so. If the code's intent is to provide protection between buildings, then this design fails.

Does the city have any local requirements ???

 

[Mr. Inspector]

Not required per the IPC. But may be required by local code or utility company.

 

[north star]

$ * $

Mech,

Check with the State of Pennsylvania, Health Department,
or whomever writes the "water protection" laws for the state.
A bfp may not even be required for your 3 bldgs.

I agree that it is a good idea to protect all 3 from each other,
but is it required by "the powers that be" in PA ?......Some
states have decided that a business occupancy and residences
are considered a "Low Hazard" and therefore, ...no protection
is required.

Also, will your 3 bldgs. have Commercial Lawn Sprinkling
systems installed ?.........These type systems can introduce
chemicals in to the potable water system and cross contamination
is a real concern.......Again, check with the State of PA and the
current laws and regs........They may leave it up to each
jurisdiction to decide, or they may have "across the board"
Laws and regulations that apply to the whole state.


$ * $

 

[fatboy]

Not required per the IPC. But may be required by local code or utility company.

Section 608.1


608.1 General. A potable water supply system shall be


designed, installed and maintained in such a manner so as to

prevent contamination from nonpotable liquids, solids or

gases being introduced into the potable water supply through

cross-connections or any other piping connections to the system.

Backflow preventer applications shall conform to Table

608.1, except as specifically stated in Sections 608.2 through

608.16.10.

 

[steveray]

Set by the water purveyor here....

 

[Mech]

Sprinkler BFP will be per the Sprinkler contractor. I do not get a say in the matter. They have their own tap into the street. Potable water gets its own tap into the street.

Not sure if the locals have their own requirement for BFP or not. I've been putting out fires on other projects and have not had time to contact the municipality.

As stated above by mtlogcabin and Rick18071, a BFP is not required for the building and fatboy listed the code section that only requires the water system to be protected. All the projects I work on, I specify a BFP, so I never get a comment during code review stating a BFP is required.

The company that contracted me did not mention irrigation, so my building will not get lawn sprinklers. If they tell me later they want irrigation, I will be giving them a separate BFP. They may be tapping for irrigation in the outside meter / BFP vault.

There is no drain piping shown discharging from the meter / BFP vault. Once they figure out a vault drain is needed, we might be getting separate BFPs.

 

[Mech]

I spoke to the water authority today. They are OK with one double check valve in the meter pit protecting the three buildings on site. The Medical Office Building I am working on has two unfinished floors. Per the water authority, if an X-ray machine is added, blood is drawn, or sutures are administered, then this building requires an RPZ BFP, which cannot be installed in the meter pit.

 

[cda]

So an x ray machine pollutes the water,,,

Interesting

 

[Mech]

So an x ray machine pollutes the water,,,

Interesting

I have never dealt with x ray machines nor do I know how they operate. I do recall a coworker designing a plumbing system several years ago for a medical office building and one piece of equipment used potable water to cool the machine. It may have been an x-ray machine; I am not sure. Another coworker informed me that the old school x-ray machines used water to develop the film. Nowadays, if it is digital, I would say water and electronics do not mix.