# fire sprinkler main flush



## cda (Dec 30, 2009)

10.10.2.1.3  The minimum rate of flow shall be not less than one of the following:

(1) 	Hydraulically calculated water demand flow rate of the system, including any hose requirements

(2) 	Flow necessary to provide a velocity of 10 ft/sec (3.1 m/sec) in accordance with  Table 10.10.2.1.3

(3) 	Maximum flow rate available to the system under fire conditions

do you require a certain diameter flush such as full diameter flush, or one 2 1/2 inch hose, or half the diameter or etc.

when a flush is done???

or does it depend on the size of the pipe?????


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## Insurance Engineer (Dec 30, 2009)

Re: fire sprinkler main flush



			
				cda said:
			
		

> 10.10.2.1.3  The minimum rate of flow shall be not less than one of the following: (1) 	Hydraulically calculated water demand flow rate of the system, including any hose requirements
> 
> (2) 	Flow necessary to provide a velocity of 10 ft/sec (3.1 m/sec) in accordance with  Table 10.10.2.1.3
> 
> ...


Never less then the sprinkler demand including 1 inside hose IF it has one. I use option 2 as long as it is more then #3. Rocks in a fire pump impeller and or worse a sprinkler orifice are Not good!


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## FM William Burns (Dec 30, 2009)

Re: fire sprinkler main flush

#2 or #3  but in Michigan now the water purveyor rules control it but they now typically use #2.  After those rules went into effect we had a major market mercantile's contractor call us for the requirement during construction.  We advised them to call the Water Dept. due to (our paper cut).  During the pump acceptance a large rock tore the impeller up and I just stood back and silently    at the pump rep.  They now know why we required flushing in accordance with 13 and their local rules reflect that and they document flushing now.


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## cda (Dec 30, 2009)

Re: fire sprinkler main flush

question is more to if you have a ten inch sprinkler main coming into the building do you require an opne butt ten inch flush or would you allow them to flush through say a 2 1/2 inch hose as long as they hit the flow requried???


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## TJacobs (Dec 30, 2009)

Re: fire sprinkler main flush



			
				cda said:
			
		

> question is more to if you have a ten inch sprinkler main coming into the building do you require an opne butt ten inch flush or would you allow them to flush through say a 2 1/2 inch hose as long as they hit the flow requried???


The FPD here uses a full-bore flush.  If you have a 10" main, I doubt you would get 10 fps with a 2 1/2" opening.

We had a major retail center call for a full bore flush of a 10" lead-in.  It was noticeably low in volume.  Had PW check 3 times on the water map and on the ground trying to find a closed valve.  They finally found a valve that was undocumented out in the weeds somewhere, which when opened changed the flush dramatically.  Had it not been a full bore, it would have been missed.

We also require a 10 psi safety factor on our hydraulic calcs, so if we used method #1 the demand would include that 10 psi and the hose.


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## FyrBldgGuy (Dec 30, 2009)

Re: fire sprinkler main flush

Always use Number 3.  Full bore flush.

Why?  Because to calculate 1 or 2 and then be able to document that you did achieve the required flow means that you used pressure guages and/or flow test equipment. Now if you used pressure gauges and/or flow test equipment then you most likely exposed someone to the perils of debris exiting the pipe orifice.

Full bore flush achieves the result with less exposure to personnel and equipment.  If they use good judgement then the location and direction of the water would not be a problem.


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## Insurance Engineer (Dec 30, 2009)

Re: fire sprinkler main flush



			
				cde said:
			
		

> question is more to if you have a ten inch sprinkler main coming into the building do you require an open butt ten inch flush or would you allow them to flush through say a 2 1/2 inch hose as long as they hit the flow required???


As long as they can meet the gpm I do not care how they do it. BUT it better be more then 1 hose line. I assume they are going to use a hose monster and a pitot to tell me how much they flowed out of each line. Also I would look for a bag over the outlet to see how much stone we are getting. A lot of stone I want more flow as you know NFPA 13/24 is a minimum amount.   

As FM Burns related his story about improper flushing. I too have one.

A fire pump story, I ask the contractor did you flush the water main before the acceptance test on the pump. He says yep not a problem. Start the pump test, 2000 gpm pump, 1st hose line opened I hear 1 ping, I look at the contractor     " you flushed the underground??" Yes no problem. Open the 2nd hose line and it sounds like a machine gun. We stop the pump test. Pump contractor pulls the pump head, filled with rocks, along with the backflow preventer. Needless to says the pump test was not completed that day. 2 weeks later after a new pump and backflow is put into place we do the test again, it passes. I asked the contractor so HOW did you flushing the underground? "I put a 3/4" garden hose on the hydrant, ran it for 3 hours, ran clear."

Now I ask HOW did you flush the underground water main?? If I hear garden hose we do not even start the pump! :roll:  :roll:  :roll:


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## Frank (Dec 31, 2009)

Re: fire sprinkler main flush

I made up a chart of pipe size, minimum flow required and acceptable number and length of hoses for 2-1/2 to 8 inch hoses.

Chart was based on fire hose friction tables and a typically available water supply curve in the county.

Chart has been given to each inspector and copies passed out freely to contractors.

Is not an exact measurement but puts flows in the right ballpark.

For a 10 inch run in with 100 ft of hose eight 2-1/2 inch hoses would be needed to get about the 2440 gpm.


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## TJacobs (Dec 31, 2009)

Re: fire sprinkler main flush



			
				Insurance Engineer said:
			
		

> cde said:
> 
> 
> 
> > question is more to if you have a ten inch sprinkler main coming into the building do you require an open butt ten inch flush or would you allow them to flush through say a 2 1/2 inch hose as long as they hit the flow required???


As long as they can meet the gpm I do not care how they do it. BUT it better be more then 1 hose line. I assume they are going to use a hose monster and a pitot to tell me how much they flowed out of each line. Also I would look for a bag over the outlet to see how much stone we are getting. A lot of stone I want more flow as you know NFPA 13/24 is a minimum amount.   

As FM Burns related his story about improper flushing. I too have one.

A fire pump story, I ask the contractor did you flush the water main before the acceptance test on the pump. He says yep not a problem. Start the pump test, 2000 gpm pump, 1st hose line opened I hear 1 ping, I look at the contractor     " you flushed the underground??" Yes no problem. Open the 2nd hose line and it sounds like a machine gun. We stop the pump test. Pump contractor pulls the pump head, filled with rocks, along with the backflow preventer. Needless to says the pump test was not completed that day. 2 weeks later after a new pump and backflow is put into place we do the test again, it passes. I asked the contractor so HOW did you flushing the underground? "I put a 3/4" garden hose on the hydrant, ran it for 3 hours, ran clear."

Now I ask HOW did you flush the underground water main?? If I hear garden hose we do not even start the pump! :roll:  :roll:  :roll:

We require the fire district to witness the flushing, and the flushing request is scheduled through me so #1 I can document it in the computer and #2 I can notify PW and #3 we have multiple fire districts covering our town so it keeps everything equal.


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## TJacobs (Dec 31, 2009)

Re: fire sprinkler main flush



			
				Frank said:
			
		

> I made up a chart of pipe size, minimum flow required and acceptable number and length of hoses for 2-1/2 to 8 inch hoses.Chart was based on fire hose friction tables and a typically available water supply curve in the county.
> 
> Chart has been given to each inspector and copies passed out freely to contractors.
> 
> ...


Any chance of scanning it and posting it here?   :?:


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## Frank (Dec 31, 2009)

Re: fire sprinkler main flush

I got our IT person to scan into .pdf and then found after she left I cannot post that here.

Will try again monday.


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## T_Puente (Jul 30, 2020)

Frank said:


> Re: fire sprinkler main flush
> 
> I got our IT person to scan into .pdf and then found after she left I cannot post that here.
> 
> Will try again monday.



Hi Frank, is it possible to email this pdf to me and the calculations they used to figure this out?


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## T_Puente (Jul 30, 2020)

T_Puente said:


> Hi Frank, is it possible to email this pdf to me and the calculations they used to figure this out?


I have a UG Loop of about 700 feet and they were trying to use two 2-1/2" hoses to get the 10fts velocity. I told them there was no way but we could see what's in the line just for the heck of it. We ran the flow test for 20 minutes and pipe shavings came out so they didn't pass. How long would I need to flow the 10" loop line at each of the 6 hydrants using four 4-1/2" hoses? Would that give me the 2,440 gpm needed for flushing? Can you provide the math logic you used to create that chart?


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## cda (Jul 30, 2020)

T_Puente said:


> Hi Frank, is it possible to email this pdf to me and the calculations they used to figure this out?




If you look at the NFPA for fire hydrant flow testing

there is a chart


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## cda (Jul 30, 2020)

T_Puente said:


> I have a UG Loop of about 700 feet and they were trying to use two 2-1/2" hoses to get the 10fts velocity. I told them there was no way but we could see what's in the line just for the heck of it. We ran the flow test for 20 minutes and pipe shavings came out so they didn't pass. How long would I need to flow the 10" loop line at each of the 6 hydrants using four 4-1/2" hoses? Would that give me the 2,440 gpm needed for flushing? Can you provide the math logic you used to create that chart?




Why not flow the big opening ??


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## cda (Jul 30, 2020)

Did not read this


http://hgi-fire.com/blog/underground-flushing-how-much-is-enough-part-2/


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## cda (Jul 30, 2020)

Check page 9 and 12


https://www.elkhartbrass.com/files/aa/downloads/catalog/catalog-f6-T.pdf


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## T_Puente (Jul 31, 2020)

cda said:


> Check page 9 and 12
> 
> 
> https://www.elkhartbrass.com/files/aa/downloads/catalog/catalog-f6-T.pdf



HI CDA,
I have read the hgi-fire article. I also looked at NFPA 24 handbook. Those charts are great if you have a guage or pitot tube available.
I was asking Frank for his chart, because some how he has a chart that shows how many hoses would be needed to get a flow of 2440 gpm  at a velocity of 10 ft/s for a 10"  line without using a pitot tube or guage.

The line is 700' loop with 6 hydrants and the contractors want to use 4 4" hoses now in order to get to the required flow. I am thinking they might need 6, am I correct? Anyone know how to calculate this without any type of pitot tube?


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## cda (Jul 31, 2020)

Not sure how you can figure flow without gages

I could lay out 25 hoses and still not get a required flow


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## cda (Jul 31, 2020)

T_Puente said:


> HI CDA,
> I have read the hgi-fire article. I also looked at NFPA 24 handbook. Those charts are great if you have a guage or pitot tube available.
> I was asking Frank for his chart, because some how he has a chart that shows how many hoses would be needed to get a flow of 2440 gpm  at a velocity of 10 ft/s for a 10"  line without using a pitot tube or guage.
> 
> The line is 700' loop with 6 hydrants and the contractors want to use 4 4" hoses now in order to get to the required flow. I am thinking they might need 6, am I correct? Anyone know how to calculate this without any type of pitot tube?




Wait a minute you are the AHJ

Tell them to provide needed flow testing equipment


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## cda (Jul 31, 2020)

T_Puente said:


> HI CDA,
> I have read the hgi-fire article. I also looked at NFPA 24 handbook. Those charts are great if you have a guage or pitot tube available.
> I was asking Frank for his chart, because some how he has a chart that shows how many hoses would be needed to get a flow of 2440 gpm  at a velocity of 10 ft/s for a 10"  line without using a pitot tube or guage.
> 
> The line is 700' loop with 6 hydrants and the contractors want to use 4 4" hoses now in order to get to the required flow. I am thinking they might need 6, am I correct? Anyone know how to calculate this without any type of pitot tube?




Frank has not signed on in four years


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## Paul Sweet (Jul 31, 2020)

Frank has retired.


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## cda (Jul 31, 2020)

Maybe we need a retirement thread category, 

That way they can log on every so often and just put a laugh track in, at the one still Codeing.


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## cda (Jul 31, 2020)

T_Puente said:


> HI CDA,
> I have read the hgi-fire article. I also looked at NFPA 24 handbook. Those charts are great if you have a guage or pitot tube available.
> I was asking Frank for his chart, because some how he has a chart that shows how many hoses would be needed to get a flow of 2440 gpm  at a velocity of 10 ft/s for a 10"  line without using a pitot tube or guage.
> 
> The line is 700' loop with 6 hydrants and the contractors want to use 4 4" hoses now in order to get to the required flow. I am thinking they might need 6, am I correct? Anyone know how to calculate this without any type of pitot tube?




To me you would need to know what the particular fire hydrant flows.


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## cda (Jul 31, 2020)

T_Puente said:


> I have a UG Loop of about 700 feet and they were trying to use two 2-1/2" hoses to get the 10fts velocity. I told them there was no way but we could see what's in the line just for the heck of it. We ran the flow test for 20 minutes and pipe shavings came out so they didn't pass. How long would I need to flow the 10" loop line at each of the 6 hydrants using four 4-1/2" hoses? Would that give me the 2,440 gpm needed for flushing? Can you provide the math logic you used to create that chart?




Just open say three of the steamer connections, let them flow till you are happy, and than do the same to the other three.

Not sure why you are getting debris, after all that water has flowed?


I would say no matter what the flow rated is, I would want to see no debris at the end of the time.


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## T_Puente (Jul 31, 2020)

Thanks CDA


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## FM William Burns (Aug 2, 2020)

A chart could only be used as a hydraulic guide. Without physical or electronic measurement I could not accept. Since this discussion, I have traveled to many presentations that I gave on fire protection systems maintenance and testing with my box. 

The box holds physical aids for the presentations since I had to learn the actual definitions for pebble, stone, rock and boulder in testimony preparation. The prep was necessary after a national chain 1.8 million s.f. distribution center replaced (2) fire pumps during a commissioning test due to foreign object damage I warned could occur. I collected evidence and used it. It was a Perry Mason moment I grin at every time I have to give the reference in a presentation.


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## Insurance Engineer (Aug 3, 2020)

Us retired folks still stop by.......this one is a trip down memory lane.....from what I remember....you know old folks and memory....lol


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