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fire sprinkler backflow preventors

C

cda

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For those that have to deal with backflows have you started requireing a forward flow test on top of just testing the back flow???

13.6.2.1* All backflow preventers installed in fire protection system piping shall be tested annually by conducting a forward flow test of the system at the designed flow rate, including hose stream demand, where hydrants or inside hose stations are located downstream of the backflow preventer.

nfpa 25 2011 edition it was also on the 2008
 
We have included it in our specifications for several years. You can actually use the FDC by removing the check valve for testing and puting outlets on the FDC inlets. We typically specify two 2-1/2 fire hose valves on the riser. We also specify MIC monitoring stations with a sacrificial coupon monitored through the fire alarm system to meet those requirements.
 
Dad,

Nice BUT I would be concerned that with high flow system such as ESFR and specific application sprinkler design two 2.5 valves may not be enough to reach the required flow. Also for a light hazard it is over kill. I would say the number of hose connections should be based on the hydraulic design of the sprinkler system and have the sprinkler designer prove they can get the flow required.
 
Our State FMs have just started to require forward flow testing in health care facilities and ALFs. Sometime in the next month, my lead sprinkler guy and I will start inspecting our clients facilities, making a material list and deciding how to best implement the retro-fit. Most will require piping changes. I started yesterday and now have a list of 75 + facilities that need to be retrofitted.

But, many of the systems we service have no readable hydraulic nameplates. How do we determine the required flow rates? How do we determine the actual flow rate of the sprinkler systems? A pitot gauge and pressure gauge? What formula?
 
Only required if system has a backflow

Most systems I see just tee a four inch open butt to outside, with Normaly closed valve
 
Last edited by a moderator:
Fireguy,

Yes this is a problem, this is what I would do, look at NFPA 13 for the occupancy, light and ordinary hazard, most likely. Light hazard sprinkler .10/1500 say 150 gpm plus 100 gpm for hose = 250 gpm, ordinary sprinkler .20/1500 say 300 gpm plus 250 hose= 550 gpm. That would be a good start point regarding flow. Now if you have a warehouse or an extra hazard occupancy, that gets much more complicated.
 
flow, flow, flow... we require the fire line be flowed before the backflow preventer is connected, after, and then flow the fire pump with the commissioner.
 
Yup, good stuff..very important also...case in point, this is usually done after all other u/g flushes, so it is a good thing I required a forward flow test prior to the opening of a brand new large, underground city parking structure, when low and behold....no water (gauges initially showed good static)..so....water department ended up finding out that another contractor installing a nearby hydrant, failed to re-open a nearby gate valve......so......you never know....this could have gone a good year or so before anyone was ever the wiser....
 
Just checking here - "coffee break training indeed!

I'm getting some resistance to backflow testing from the 'contractors' nearing completion of two pretty big systems. "We never have to do

that test anywhere else!"

Which I am sure no one on the board has ever heard.
 
We have had new out if the box fail the test

Or even though ug was flushed still got debris in the backflow

So guess they argue about doing hydrostatics also!!!!
 
Mac said:
Just checking here - "coffee break training indeed! I'm getting some resistance to backflow testing from the 'contractors' nearing completion of two pretty big systems. "We never have to do

that test anywhere else!"

Which I am sure no one on the board has ever heard.[/quote(]

Gee let me see, ask them did you ever hear of NFPA 13 and 25????? If so just tell them to read it! Amazing what you pick up reading the code......LOL
Click to expand...
 
I sent the requirement up the food chain - It came back down, and we will be testing & reporting Friday.

The project will probably be turned over to the owner on Monday 12/10.

Sometimes you gotta bust some heads!
 
Mac said:
I sent the requirement up the food chain - It came back down, and we will be testing & reporting Friday. The project will probably be turned over to the owner on Monday 12/10.

Sometimes you gotta bust some heads!
Click to expand...
:agree way to go!
 
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