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Forward flow testing of backflow preventors - Survey
3

Forward flow testing of backflow preventors - Survey

Forward flow testing of backflow preventors - Survey

(OP)
With work the way it's been I've been getting more into inspections and am concerned about due deligence.
 
From NFPA #25 2002

12.6.2 Testing.
12.6.2.1* All backflow preventers installed in fire protection system piping shall be tested annually in accordance with the following:
(1) A forward flow test shall be conducted at the system demand, including hose stream demand, where hydrants or inside hose stations are located downstream of the backflow preventer.
(2) A backflow performance test, as required by the authority having jurisdiction, shall be conducted at the completion of the forward flow test.

This is a big deal especially in those areas of the country where it's never been enforced.

Some states, I'll single out South Carolina, require provisions be made for forward flow testing in new installaitons, but for others forward flow testing is overlooked by both code and fire officials.

Not a problem if there is a fire pump with test header downstream or there's fire hydrants downstream.

If provisions haven't been made, I envision something similar to a test header for fire pumps, annual forward testing can become a big undertaking in itself.  Suppose we could turn FDC check valve around but in some systems this isn't so easy to do.  In some places, a pit for example, this can become difficult to accomplish.

Georgia has adopted NFPA #25 but at the prices given for inspections it's clear few, if any, are actually doing this part of the inspection.  

Question: What is happening in regards to foreward testing in your state and, if it is pushed, what have you been doing as far as connections?

Thanks.

RE: Forward flow testing of backflow preventors - Survey

even though it has been there since 2002

one the ahj has to adopt the 2002

or, the sprinkler company has to design to 2002 or better, if allowed by the ahj


we have been enforcing it for about two years

two ways if they can calc the main drain on a small system and show it will meet the demand we accept it.

I know some people will not accept the main drain

Or, on bigger systems, all they do is tee off the fdc line, after the check valve, with a normally closed valve and four inch open butt to the outside. We do not have high demand systems, so either one works.

Now with a number of ahjs around us, I know it is not being enforced, and also you get into where is the backflow located and which ahj agency is responsible for it????

we require a backflow in the building 99% of the time stacked on the riser, so we get responsibility by default.  

RE: Forward flow testing of backflow preventors - Survey

Here in Kentucky, it is not being enforced.  However, we have installed several new systems with bfp's on military bases where the full flow test connection was required.  Typically consists of a tee in the header/riser after the bfp, before the alarm check with a full sized line piped outside the valve room.  Line has a normally closed valve inside with a flush connection outside similar to a fire pump test header.  We install snoots with male hose threads outside so that hoses with water monsters can be used to meter the flow during a test.
In a somewhat related issue, we recently had an consulting engineer tell us that the metering was not necessary, and that as long as we flowed through an open pipe of the same size as the bfp, that was sufficient.  I questioned the reasoning since NFPA specifically states that demand plus hose allowance must be flowed during the test.  How can one verify you are flowing the demand without metering through a pitot assembly of some sorts?  What if the bfp was only partially opening during the test?  Simply looking at the discharge through an open pipe outside, I personally couldn't tell the difference.  Are others measuring the flow during the test, or are we going too far?

RE: Forward flow testing of backflow preventors - Survey

"""""including hose stream demand,""""

I missed that portion


ryano669

Good points not a hydraulic person and wondered some of your questions.

If you have an open butt four inch can you pitot it?? for gpm flow???

RE: Forward flow testing of backflow preventors - Survey

(OP)
"How can one verify you are flowing the demand without metering through a pitot assembly of some sorts?"

You can't.

Everyone here knows that.

We've all done sprinkler systems with a density of .60/2000 without a fire pump and what I can easily see here is a 6" forward test assembly with five or even six hoses required to achieve the 1,300 gpm or thereabouts required and if hose streams are somehow taken off downstream the backflow assembly we could easily be looking at 1,800 to 2,000 gpm.  

What I am worried most about is liability... if NFPA 25 & 13 2002 is adopted then what?  You do an inspection without a forward flow and the inspection is incomplete is what. What do you do if flowing the inspector's test and the alarms might annoy someone you don't do it? Of course not, you ring the bells because it is required.

If you do an inspection without the forward test, invoice the customer, get paid and just happen to have a fire where $30 million is lost you risk looking awfully stupid in court trying to explain the reason you didn't do the forward test is it was inconvienent or there wasn't any government enforcement action.

Maybe this has never happened but we can be sure someday, somewhere it will.

Kentucky?  I've worked in many states and I wish every state/jurisdiction would model themselves after Kentucky.

RE: Forward flow testing of backflow preventors - Survey

See this web site for some good photos of test headers, etc.

http://inspector911.com/forward-flow-test/305#more-305

****************************************
Fire Sprinklers Save Firefighters' Lives Too!


 

RE: Forward flow testing of backflow preventors - Survey

(OP)
LCREP,

See this web site for some good photos of test headers, etc.
http://inspector911.com/forward-flow-test/305#more-305

Thanks.

That's easy enough during initial installation and I would imagine you could easily satisfy most Ord Hazard II occupancies with two 2 1/2" hoses.  

What's the coefficient of discharge from a reamed pipe?  0.80 or is it a little less? (I loaned out my fire protection handbook).

Depending on where the riser is rolling out hoses could be a problem in itself but you could get a more accurate reading through a 1 3/4" playpipe as opposed to an open pipe.

The problem lies with existing systems were provisions weren't made and you still have companies giving inspections for $80 to $100.  Yeah, we got em.  No way you could incorporate rolling out hoses into your test without increasing cost.

RE: Forward flow testing of backflow preventors - Survey

How many contractors follow NFPA 25 to the letter?? Based on how many things we find wrong during our inspections, not too many here in NJ. I always ask for a copy of the last 3 years of inspection reports. When I see 3 different companies I know the building owner is looking for the lowest price and can care less about the fire proteciton on site. What is even better is when one company finds a tons of stuff and the next two have nothing listed. I then ask were any of these items listed repaired? Sometimes I hear "Oh no they were just trying to make money by listing all those things". Got to love it, most times the facilities have so many other things wrong we just do not insure them.  

In these economic tough times I fear more of this stuff will happen.  

****************************************
Fire Sprinklers Save Firefighters' Lives Too!


 

RE: Forward flow testing of backflow preventors - Survey

I left out some info about the "open but" connection.  Actually he specified a custom fabricated sheet metal diffuser of some sort, installed over the open pipe, that wouldn't wash away landscape.  Visualize a trough of sorts.  Technically an open pipe with no way of measuring flow.  
CDAFD- I guess you could pitot an open pipe if you knew the coefficient, as SD2 referred to.

 

RE: Forward flow testing of backflow preventors - Survey

Any company who charges $80-$100 to perform the NFPA 25 inspection activites for a water-based fire protection system is simply not doing a thorough job AND they probably have absolutely no idea how much liability they are assuming when they perform the inspection services.

Just my opinion (after 19 years of personal experience).

RE: Forward flow testing of backflow preventors - Survey

(OP)
LCREP,

You are so right which is why we who 1)know what we are doing and 2) want to do it right need the help of enforcement official and insurance officials.

I don't do everything 100% called for, thinking of forward flows especially, because I would end up losing 90% of the inspection contracts I do have.  Nothing good about being noble and broke.

But those same people who shop for price, who threaten if you write something up, will be the first to sue your rear end if something should happen.

It was just five and six years ago anyone, any bum on the street, could perform a sprinkler inspection.  We had people, afraid we still do, who do "drive by" inspections for $50.  I actually ran across one last year that was being done for $40.

Not counting a forward flow a plain Jane wet system with waterflow switch, water motor alarm bell and supervised alarm is going to take a minimum of 90 minutes to do and I've heard of some inspectors that were completing 6 and 8 inspections in a day.  No way can you do your job halfway right and do 8 in a day.

Hey, ran into an interesting one today on a 500 gpm fire pump.  System installed 14 years ago, has a Eagle Eye flow meter but no test header and to make matters worse the darn pump was installed in an interior room with everything going to a floor drain.  To run a test header would be a major headache which I could easily see running $10K or better.  Supposedly this has been tested every year, never a word said about it and along I come to be someone the owner can hate.  To make matters worse it's a government owned building.  



 

RE: Forward flow testing of backflow preventors - Survey

SprinklerDesigner2,

Yea see this a few times a year especially in office buildings, even in a few hospitals. If the building does not have a standpipe system with a stair tower with an outside door, or no roof test header you are pretty much out of luck. Which is better yet when the put the test header in the pump room and then you have to run 500' of fire hose to get it outside. Got to love low bid jobs.

I had a hospital with a 2500 gpm fire pump with no test header and only a flow meter. They removed the test header 12 years ago when they added the last addition to the hospital, and forgot to relocate the test header. 12 years of a only flow meter testing, that is all they had, pump  pasted with flying colors, fire department was OK with it too. I get our underwriters to back me, you put in a test header or we are off the account. They install 250' of 10" pipe for a new test header. We test the pump only can get 750 gpm before it goes to 10 psi. Call the water department, they check the valves and find it partially closed, they open the valve, we get 3750 gpm at 30 psi. They went from calling me a pain in the butt to saving their butt if they had a fire!

****************************************
Fire Sprinklers Save Firefighters' Lives Too!


 

RE: Forward flow testing of backflow preventors - Survey

I have the on-line 25 so it's 2008 but I'm sure the 2002 still does the following:  
13.6.2 Testing.
13.6.2.1*  All backflow preventers installed in fire protection system piping shall be tested annually in accordance with the following:   Etc, Etc and then down a bit:  13.6.2.2 Where connections do not permit a full flow test, tests shall be conducted at the maximum flow rate possible........ and thumbing thru 13 I don't see where it's called for in any reference to a backflow preventer that a means for a forward flow test shall be installed. It seems that 25 get's quite excited about doing the forward flow test 'just so' .... and then goes but-if-you-can't-oh-well. It seems to me to almost be a catch 22 for an inspector: Would you rather go into a down-town building with an 8" supply and DCVA and only find a 2" main drain and write it up as such or would you rather try and figure out what to do with 8" worth of system demand? I'm saying this given 13.6.2.2. I'm more than interested in this because I did exactly this yesterday, did an inspection on a system with an 8" Watts 774 that tied into a 6" header with only a 2" main drain available.



Regards
Dave  

RE: Forward flow testing of backflow preventors - Survey

... not actually THUMBING through 13 ....I don't think I even HAVE a paper copy anymore ...

Dave

RE: Forward flow testing of backflow preventors - Survey

lightecho

would the verbage be there because of older systems that do not have the means to flow the demand, and not require it tobe retrofit???



and thumbing thru 13 I don't see where it's called for in any reference to a backflow preventer that a means for a forward flow test shall be installed

13 has 2007 flavor

8.17.4.6* Backflow Devices.
8.17.4.6.1* Backflow Prevention Valves. Means shall be provided downstream of all backflow prevention valves for flow tests at system demand.

RE: Forward flow testing of backflow preventors - Survey

The maximum flow rate possible could be multiple yard hydrants flowing simultaneously, all of the 2 in. drain valves flowing simultaneously or at the very least you can flow the 2 in. drains, auxiliary drains and ITC's simultaneously if you only have one sprinkler system at the facility. It does not say maximum flow rate possible through one single device. Using multiple hydrants or multiple 2 in. drains will usually be the best common sense approach. 13.6.2.2 makes this approach acceptable; however, there is really now way to determine whether or not the flow rate exceeds the highest demand including hose streams........this allows for the conclusion that there is actually no requirement to confirm the forward flow test is at or above the highest demand including hose streams.

At some facilities it is not a huge problem to reverse the FDC check valve, but in my personal opinion, this action would justify a work order (separate from a typical inspection activity) due to the additional time/effort/liability associated with the process. The additional charge would be justified because a suitable test header was not installed to accommodate the forward flow test.    

RE: Forward flow testing of backflow preventors - Survey

cdfad           

Geeesh    right in front of me

Thx

 

RE: Forward flow testing of backflow preventors - Survey

(1) A forward flow test shall be conducted at the system demand, including hose stream demand

Means shall be provided downstream of all backflow prevention valves for flow tests at system demand.

so are these two the same thing as far as demand???? or is one with out the hose fiqured in???

why cant these committees talk to each other????????????

RE: Forward flow testing of backflow preventors - Survey

(OP)
From NFPA 13 2002 Edition in Chapter 16 Systems Acceptance

16.2.5 Backflow Prevention Assemblies.
16.2.5.1  The backflow prevention assembly shall be forward flow tested to ensure proper operation.
16.2.5.2  The minimum flow rate shall be the system demand, including hose stream demand where applicable.

It's as plain as day in 13 but few designers make provisions.

On most light hazard systems a single, maybe two if water supply is really low, 2 1/2" hose valve right on the riser. Doesn't sound like much but with hose valves, the welded thread-o-lets, caps and labor I betcha we are looking at a minumum of $300 to $500 on your average system.  2 1/2" hose valves and caps are not all that cheap. Add to this the cost of dragging hoses and playpipes around for every annual test.  Sucks.

Georgia has been on 2002 for a number of years now and I have yet to encounter a single system anywhere in the state where provisions have been made much less a full forward test conducted during acceptance.

It's getting real tight out there and $400 added to a small $20,000 job can certainly cost you the job in the current economic climate.

Ok, what about this.  On a typical system come off the riser witha  4" outlet having a 4" butterfly valve, pipe it down similar to what we would have on a wall mounted FDC, then take it through the wall to a 4"x3" reducing assembly similar to a welded swaged nipple http://www.canvil.com/pages/catalogs/snb-p1.htm .  Welded swaged nipple shown for left with an overall lenght of 9". Now all we would need is the is the coefficent of discharge for the 3" outlet or maybe we could safely assume a coefficent of discharge of at least 0.80?  At 10 psi pitot )3.068 ID having C=0.80) we'd get 710 gpm which would do it for a large majority of the systems we install.

Then for larger systems we could use a 6" butterfly with a 5"x5" swaged nipple whch would offer close to 2,000 gpm @ 10 psi pitot.

Then another way would be simply to discharge the water opening the butterfly valve to the point where the residual pressure was less than system demand.

FPE input would be appreciated.


 

RE: Forward flow testing of backflow preventors - Survey

(OP)
How about instead of a 1 1/4 or 2" main drain we just make it s 2 1/2" main drain on 2 1/2 and 3" systems, a 3" main drain on 4" systems and a 4" main drain on 6" and 8" systems utilizing nothing more than a butterfly valve and a couple grooved fittings?

I couldn't imagine a 4" system where you couldn't achieve an adequate forward flow on a 3" main drain or a 4" main drain in the case of a 6" or 8" riser.

Lots of pluses here.  A 3" main drain test on a 4" riser would have to mean a lot more than a 2" drain through an angle valve.

Also fast draining.  If having to drain a system no longer would a couple of $60 an hour fitters have to wait around for the system to drain for an hour.

For a 2" main drain:
2" angle valve $47.79
2" weld thread o let $3.12
2"x 6' sch. 40 pipe $15.00 (guessed at this price)
2" 90 Deg Elbow $3.97
2"x4" nipple $4.53
2" 45 Deg Galvanized Elbow $8.16
2 2" Galvanized wall plates @ $4.72=$9.44
Total price of material: $92.01

Vs a 4" main drain
4" Butterfly Valve less tamper $200.00 (Guessed... the only price I had was with tamper so I took $40 off)
4" Grooved mechanical tee $27.88
4"x6' grooved sch. 10 pipe $15.00 (guessed at this price)
4" grooved 90 deg. elbow $10.63
4" grooved 45 degree elbow $10.38
6 4" grooved couplings @ $6.33 = $50.64
2 4" Galvanized wall plates @ $8.23
Total price for material: $330.99

A 4" main drain will run approximately $238.98 more in material than a 2" main drain and the problem for everything should be solved even for a 6" or 8" riser system. In my mind it beats adding 3 or 4 2 1/2" hose valves then having to drag hoses around to forward test for acceptance and every year thereafter.

$239 is a lot of money to us personally but on a 6" system covering 40,000 square feet it really is nothing to fred over. Matter of fact you would probably save close to that in labor it would take to lay out hoses for the acceptance test.

Labor to install might even cost less not having to drag a 300 machine out of the shop.  In any event I really can't see it costing much more in labor.

Oh, and to the inspectors who seem to overly tighten 2" main drains with a wrench or channel locks this would save that little problem of teeth marks on the shaft.

Seems easy enough but am I missing something?

 

RE: Forward flow testing of backflow preventors - Survey

You have to include only inside hose stream, i believe it says when applicable or something along those lines.

I agree with SprinklerDesigner2, we've been doing this for years, you can either upsize the main drain to 2" for 3" & Smaller risers or we will leave a tee & valve on larger systems and our inspectors have some manifolds that have several 2.5" weld-o-lets on them so we can hook up hoses for the forward flow.  If the room where the riser is is not easily acceptable we will pipe out a 6" galvanized grooved pipe out of the wall to connect to during testing.

If you look at that added $239.00 you can almost make that up on the first forward flow test if it saves you two hours of screwing around.

RE: Forward flow testing of backflow preventors - Survey

(OP)
chevy4x4trucks,

Lots of if's.

Forward flows shouldn't be a problem on systems with a fire pump, as long as the backflow device is upstream the fire pump, or in systems with a pit with backflow serving hydrants at the back of the building etc.

The "problem" is with smaller systems with single risers.  Something we would expect to find in a 30,000 sf grocery store.  Typically these have a 4" riser and I haven't thought of a scenario yet where a 3" main drain wouldn't deliver 350 gpm.

One of the problems with hose valves, fire hoses and playpipes is what happens when you got one of those "I barely made it" systems where the water supply is 41 static, 30 residual at 600 gpm when the system requires 340 gpm @ 33 psi.  If all you got is 29 psi downstream the backflow device I can see problems getting the required flow through two hoses.  Might take three.

I've been a designer for 33 years but seriously began inspections just a short time ago which I am allowed to do in Georgia as a NICET IV tech. I can honestly say I have learned a lot and there is a lot more to doing an inspection properly than I thought.  Dragging around hoses is physically harder than I thought too (old body you know) and with my newly found respect for the inspection peeps I am going to keep them in mind when I lay out systems in the future.

I have learned I don't want no fool around with stinking fire hoses.  If you've never done it try it sometimes.

13 and 25 doesn't say you have to measure the flow directly but you must forward flow at system demand plus hose demand if hose is taken off downstream the backflow preventor.  How else you going to do it unless you measure it somehow? All due respect to a previous poster but how much do you have flowing, how can you tell it is enough, even if opening multiple main drains and inspectors tests?

Turning the FDC check around.  Easy for us to say sitting on our cushy chairs in our air conditioned office but I've tried this and it ain't near as easy as people like me make it sound while we tell someone else to do it.

Most calculation programs give the amount of water required at the discharge side of the backflow preventor (344 gpm @ 55 psi for example) and also what is required at the source (344 gpm @ 60 psi).  If we were to open the 4" main drain to where the residual pressure on the riser (assuming it isn't checked) to where the residual pressure is what is required (this would be a lower pressure than what is available) an inspector would be assured of getting more than 344 gpm in forward flow.  A forward flow of a backflow preventor would take all of three minutes. Sure beats dragging hose around like an idiot.

Also what a wonderful thing to tell if a valve is partially closed or the water supply has deteriorated.  For a couple hundred bucks we could solve so many problems while giving the world far more reliable systems.

The only question I have left is what do I do to minimize tearing the heck out of the landscape?

I am going to start doing this as standard practice on my next design project unless I can be shown a reason it wouldn't work.

RE: Forward flow testing of backflow preventors - Survey

I just read my previous post and I would like to clarify one item. I see where I was really not very clear regarding my intended point of view. I completely agree that all future water-based fire protection systems should be provided with a suitable connection to allow full flow testing AND the arrangement should make it as easy as possible to measure the flow using a hand held pitot tube.

I was referring to the following NFPA verbiage:

12.6.2.1.3 Where connections do not permit a full flow test, tests shall be completed at the maximum flow rate possible.

12.6.2.2.1 Where connections do not permit a full flow test, tests shall be conducted at the maximum flow rate possible.

A.12.6.2.1 The full flow test of the backflow prevention valve can be performed with a test header or other connections downstream of the valve. A bypass around the check valve in the fire department connection line with a control valve in the normally closed position can be an acceptable arrangement. When flow to a visible drain cannot be accomplished, closed loop flow can be acceptable if a flowmeter OR SIGHT GLASS is incorporated into the system to ensure flow.

All I was attempting to convey is that the NFPA committee finally included a little common sense in the standard to account for the systems which do not have a suitable flow test connection.

Sections 12.6.2.1.3 & 12.6.2.2.1 clearly imply that there is no need to measure the flow rate as long as you are flowing the maximum flow rate possible given the available system connections. The "or sight glass" portion of Section A.12.6.2.1 provides further evidence; there is absolutely no way possible to determine the volume of flow through a closed loop when simply looking through a site glass.

I make my living primarily through inspection services (along with FPE consulting and some small scale repairs/renovations) so I completed a little research a few years back and I have thought this subject through to some degree. During our annual inspection routine, we typically flow the maximum volume of water possible at locations which do not have fire pumps or yard hydrants downstream of the backflow preventer. I hope this a more concise post.

My customers tell me on a very regular basis that we perform more functions and are more detailed than any other fire protection contractor they have ever had at their facility. I am aware of most of the pertinent standards and I am definitely aware of the liability. I wonder how many people and/or sprinkler contractors out there actually understand the liability they are assuming when they perform these inspection services.

My point about reversing the FDC check valve is that it involves a significant amount of time/effort/liability and that we do not include this service as part of our standard inspection routine. If a customer likes the idea we will complete this service at an additional cost (work order). I have been told that I am a little bit of a rare breed since I am a FPE who actually gets dirty (and sometimes tired) performing these types of activities (inspections, repairs, minor installations, reversing FDC check valves, laying out hoses for fire pump tests, etc.). I enjoy it more than sitting behind a desk (been there done that for a few years and still do for some clients) and I am building a brand new company (early stages of new company means the owner pretty much does everything!!).

Well, I am a little tired and obviously rambling from subject to subject........I think I will stop typing and hit the sack!

RE: Forward flow testing of backflow preventors - Survey

(OP)
FFP1,

Thank you, clarifies a lot.  

Like many we are ramping up our inspection activities and it is liability that concerns me most.  In no uncertain terms I've attempted to make it clear to everyone involved if we end up in a lawsuit it will most likely involve the inspection department. If you contemplate a bit all other possible liabilities pale in comparison to the possible liabilities brought on by inspections.

That job I mentioned where we had a fire pump sans test header given the job by a closed loop flow meter.  That pump has never been tested properly and it is easy to visualize a nearly closed gate or stuck check valve that has been there from day one.  We're the last to touch the system and should something happen we are involved even if we are innocent.

We have an about to be newly minted NICET III inspector who worked hard coming up through the fitter ranks and not a day goes by I don't try to impress upon him the importance of his job, the importance of being as thorough as possible, is to the company.  A huge responsibility to the customer and the company.

I don't care so much what other people do but to be on the safer side I think I will just go with oversizing the main drains as I mentioned or going with a bypass around the fire department connection.  Not bad really, a couple 4" grooved tees, a wafer valve, grooved 90 degree elbow and 7 extra grooved couplings.  On most systems you could just let the water run and use hose where water might be a problem. Excellent matter of fact.
 

RE: Forward flow testing of backflow preventors - Survey

Question: as mentionned in the upper link :

"A bypass may be installed around the check valve installed in the piping between the system and Fire Department Connection (FDC).  The bypass would include a supervised valve in the normally closed position.  During testing the contractor would flow out the outlet of the fire department connection through the appropriate hose and nozzle configuration"

Aren't there clappers in the siamese's body that keep the water from flowing out ? Are these clappers easy to remove and then put them back ?

RE: Forward flow testing of backflow preventors - Survey

The clapper in a siamese body is designed to prevent water from flowing out of one of the 2 1/2" outlets if only one of the two is being used to supplement the sprinkler or standpipe system. With the clapper in place, water flowing back out for the purposes described above will only flow through one of the outlets. The clapper cannot be removed from the body (in any siamese I have worked with) through the 2 1/2" outlets.

Regards
Dave

RE: Forward flow testing of backflow preventors - Survey

Regarding the requirement for testing the BFP or RPZ annually, we tried enforcing it in 03 in our jurisdiction until we received a "paper cut" from the water authority and city hall.  The water guys also got mad at our presence for underground testing and took that over.  Present day, we have been getting contractor documentations that they are being done and we have had to follow up on around 10% due to excessive loss from acceptance.  The water guys are now sending staff to training and have inquired about installing test headers.  Our reply was great and be sure to hire a licensed sprinkler firm for the installation.  

SD2, you are absolutely correct in that this is one of those issues being overlooked or not enforced due to political control issues in many areas of the country.  

Regarding recordkeeping mentioned by LCRep; we require a "red" binder book with the most recent five years at the riser and when we review them annually upon inspection, we find similar discrepancies with items needing service from previous contractor maintenance inspection.  Thankfully, we try to be diligent in follow-up on repair needs after we read them.  The owners don't like the binder book but we got tired of hunting records down and owners saying they would have to look for them.  It's has been an ordinance since 1994 and initiated after I arrived.

Regarding the increased Main drain piping and or installation of a means for forward flow testing; to be honest I really never gave it much thought after that "paper cut" mentioned above.  I believe I will begin tomorrow requiring it in my plan reviews until I get another paper cut.

I'm glad I joined this bulletin board since this type of situation has bugged me for years and something as simple as requiring test means based on adopted 13 never occurred to me.  Thanks SD2 for bringing the topic up.
 

"Fire suppression is a failure in prevention"

RE: Forward flow testing of backflow preventors - Survey

just a novice question

But what is actualy being tested with the forward flow test???


is it to see if the backflow will allow the required system gpm required??

or is it something else???

RE: Forward flow testing of backflow preventors - Survey

(OP)
"But what is actually being tested with the forward flow test???

Is it to see if the backflow will allow the required system gpm required??"

I'm pretty darn sure that is exactly it.

 

RE: Forward flow testing of backflow preventors - Survey

Measure the pressure loss at the sprinkler/standpipe system demand including hose streams gpm and see how close it is to the mfg cut sheet on the devise. Install calibrated gauges on the device ports before and after the backflow devise,flow the required gpm flow, see what the loss is between teh 2 gauges.  Example the required flow is 1000 gpm. Mfg cut sheet indicates @ 1000 gpm the pressure loss should be 8 psi. Flow 1000 gpm, loss is 8 psi OK, flow 1000 gpm loss is 15 psi, u have a problem.

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Fire Sprinklers Save Firefighters' Lives Too!


 

RE: Forward flow testing of backflow preventors - Survey

I would like to pose this for the designers:  If you have an existing system like most of us do without existing suitable means for forward flow testing, it would be a political nightmare for us AHJ's to retro enforce the means being added with a possible exception to a modification to the "main drain" possibly.  

With this being said; is there a close coefficient that can be used for the typical 2" main drain orifice like .7, .8 or .9 in the formula 29.83 x d2 x √P x C so we can get reasonable close to verifying in the field upon inspections?
 

"Fire suppression is a failure in prevention"

RE: Forward flow testing of backflow preventors - Survey

(OP)
"With this being said; is there a close coefficient that can be used for the typical 2" main drain orifice like .7, .8 or .9 in the formula 29.83 x d2 x √P x C so we can get reasonable close to verifying in the field upon inspections?"

I wouldn't use anything higher than a .7 and then only if I installed a short pipe nipple discharge from the 45 deg. elbow.

Problem with a main drain is the angle valve which has a pretty small orifice (I just now measured one) of just 1 3/8" on a 2" angle valve.

Economic conditions being what they are, I have a sense it is falling apart and gaining speed around here just over the last month or two, uprading to compliance won't happen.  No fire department in their right mind, assuming the jurisdiction has an elected government, will be successful in forcing anything retroactive and they shouldn't.

Doing it for free unless absolutely forced to?  Are you nuts?  I never thought I would see it again but not far from me a 150,000 sq. ft. school went for $0.99 per square foot.  I haven't seen $0.99 per square foot since the 1980's and at those prices you *might* break even if everything goes perfectly and the guys don't take breaks.  Quality suffers in times like these.

Thousands of small businesses are strugging to stay alive and the $500 to $1,000 could mean all the difference in the world.

 

RE: Forward flow testing of backflow preventors - Survey

SD2,

I couldn't agree with you more. I have seen an apartment complex (13R) go for $0.92 per sqare foot and an 85,000 square foot school go for $0.87 yes I said $0.87 per sqare foot.
I don't have a problem with pricing and installing the proper devices to meet the forward flow requirments but until the local AHJ's start enforcing it at the plan review stage and/or the building department in their plan review it's just not going to happen.

Chad Johnson
Flow Fire Protection

RE: Forward flow testing of backflow preventors - Survey

Thanks SD2 that's helpful!

"Fire suppression is a failure in prevention"

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