Forward flow testing of backflow preventors - Survey 3

[SprinklerDesigner2]

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.

 

[chevy4x4trucks]

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.

 

[SprinklerDesigner2]

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.

 

[FFP1]

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!

 

[SprinklerDesigner2]

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.

 

[ludwig80]

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 ?

 

[ContractorDave]

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

 

[Arsnman4]

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"

 

[cdafd]

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???

 

[SprinklerDesigner2]

"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.

 

[LCREP]

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.

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

 

[Arsnman4]

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"

 

[SprinklerDesigner2]

"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.

 

[KGBeast42]

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

 

[Arsnman4]

Thanks SD2 that's helpful!

"Fire suppression is a failure in prevention"