RE: Fire Pump relief valve discharge
The practice of connecting the relief valve discharge to the pump suction has been accepted for many years.It was removed from NFPA #20 in the nineties but has since been reinstated.I have done this many times for many reasons without any problems.Because it is a closed loop,I have not increased the discharge pipe size. Hope this helps. A.P.Silva silva...@shaw.ca wrote: The building owner wants to connect the discharge piping from the pump relief valve to the pump suction pipe, just upstream of the suction valve. The water supply to the pump is a water storage tank. Anyone seen this arrangement? Is it acceptable? NFPA 20, 2007 section 5.18.7 mentions Discharge to Source of Supply. Is this to the tank or can it be also to the suction pipe? Both 5.18.7 and A5.18.7, seems to have a concern regarding the size of the relief valve and discharge piping, but does not provide much guidance (in my opinion). Anyone care to expand on this concern? The fire pump is rated 1000 gpm @ 105 psi. The source as mentioned previously, are gravity tanks. The relief valve is 4 and discharge pipe is 8 corresponding to Table 5.25. The discharge piping from the relief valve to connection at pump suction pipe has one elbow. At the connection to the pump suction there is a tee. Is the tee to be counted and the sizing be increased as per 5.18.6.2 ? Any pump experts? Tony ___ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: techsupp...@firesprinkler.org To Unsubscribe, send an email to:sprinklerforum-requ...@firesprinkler.org (Put the word unsubscribe in the subject field) ___ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: techsupp...@firesprinkler.org To Unsubscribe, send an email to:sprinklerforum-requ...@firesprinkler.org (Put the word unsubscribe in the subject field)
RE: Fire Pump relief valve discharge
Any problem dumping the relief discharge back into the tank? Thank You Rahe Loftin, P.E. Region 7 - GSA Office - 817-978-7299 Fax - 817-978-8644 Cell - 817-371-3102 ___ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: techsupp...@firesprinkler.org To Unsubscribe, send an email to:sprinklerforum-requ...@firesprinkler.org (Put the word unsubscribe in the subject field)
RE: Fire Pump relief valve discharge
If the relief valve is installed before the pump check, it's going to effect your numbers a little when you test. IMHO, the BEST way to pipe it is as Rahe suggests that way you have a break and tank circulation (which is a good thing for weekly's). I assume no bypass but will you have a flowmeter as well? Maybe you can twin them back? Tom TGIF Any problem dumping the relief discharge back into the tank? Thank You Rahe Loftin, P.E. ___ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: techsupp...@firesprinkler.org To Unsubscribe, send an email to:sprinklerforum-requ...@firesprinkler.org (Put the word unsubscribe in the subject field)
RE: Fire Pump relief valve discharge
No. Follow the same rules as you would for discharging a flow meter back into a tank. At 09:16 AM 3/20/2009, you wrote: Any problem dumping the relief discharge back into the tank? Thank You Rahe Loftin, P.E. Region 7 - GSA Office - 817-978-7299 Fax - 817-978-8644 Cell - 817-371-3102 ___ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: techsupp...@firesprinkler.org To Unsubscribe, send an email to:sprinklerforum-requ...@firesprinkler.org (Put the word unsubscribe in the subject field) Todd G. Williams, PE Fire Protection Design/Consulting Stonington, Connecticut www.fpdc.com 860.535.2080 ___ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: techsupp...@firesprinkler.org To Unsubscribe, send an email to:sprinklerforum-requ...@firesprinkler.org (Put the word unsubscribe in the subject field)
RE: Fire Pump relief valve discharge
Other than the turbulence, which was deemed acceptable for the condition where the relief is piped back to suction under #20, the pipe running from the tank to the suction side of the pump is the same chamber as the tank- unless there's a OSY right on the suction nozzle of the tank- and if you're running the pump, one would expect that to be open unless you're attempting high temperature test for air bubble growth- and you'd be better off piping relief to suction, since if the tank valve was closed, the relief to suction would be all you've got going into the pump! the relief valve would, of course, be open sincethe temp elevating would increase pressure on the air caused by turbulence, assuring a reliable supply of air and water to the suction side. glc -Original Message- From: sprinklerforum-boun...@firesprinkler.org [mailto:sprinklerforum-boun...@firesprinkler.org] On Behalf Of rahe.lof...@gsa.gov Sent: Friday, March 20, 2009 9:16 AM To: sprinklerforum@firesprinkler.org Subject: RE: Fire Pump relief valve discharge Any problem dumping the relief discharge back into the tank? Thank You Rahe Loftin, P.E. Region 7 - GSA Office - 817-978-7299 Fax - 817-978-8644 Cell - 817-371-3102 ___ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: techsupp...@firesprinkler.org To Unsubscribe, send an email to:sprinklerforum-requ...@firesprinkler.org (Put the word unsubscribe in the subject field) ___ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: techsupp...@firesprinkler.org To Unsubscribe, send an email to:sprinklerforum-requ...@firesprinkler.org (Put the word unsubscribe in the subject field)
RE: Fire Pump relief valve discharge
Yes. This building is in an area up north where the temperature drops to -40 to -50 deg.C in the winter. The suction pipe from gravity tanks to pumphouse is heat traced and isulated. Running relief discharge to tank will be a big cost. The flow meter runs back to the tank,bu it is too small to connect the relief discharge. Originally they had it dump to a splash pad outside pumphouse, and for obvious reasons didn't like it when it started to dump water during pump tests. Tony -Original Message- From: sprinklerforum-boun...@firesprinkler.org [mailto:sprinklerforum-boun...@firesprinkler.org] On Behalf Of rahe.lof...@gsa.gov Sent: March 20, 2009 6:16 AM To: sprinklerforum@firesprinkler.org Subject: RE: Fire Pump relief valve discharge Any problem dumping the relief discharge back into the tank? Thank You Rahe Loftin, P.E. Region 7 - GSA Office - 817-978-7299 Fax - 817-978-8644 Cell - 817-371-3102 ___ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: techsupp...@firesprinkler.org To Unsubscribe, send an email to:sprinklerforum-requ...@firesprinkler.org (Put the word unsubscribe in the subject field) ___ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: techsupp...@firesprinkler.org To Unsubscribe, send an email to:sprinklerforum-requ...@firesprinkler.org (Put the word unsubscribe in the subject field)
Re: Fire Pump relief valve discharge
How about a more basic question. Why do you even have a relief valve? With a rating of only 105 psi exceeding 175 psi with a tank feed requires a tall tank. Roland On Mar 19, 2009, at 11:23 PM, A.P.Silva wrote: The building owner wants to connect the discharge piping from the pump relief valve to the pump suction pipe, just upstream of the suction valve. The water supply to the pump is a water storage tank. Anyone seen this arrangement? Is it acceptable? NFPA 20, 2007 section 5.18.7 mentions Discharge to Source of Supply. Is this to the tank or can it be also to the suction pipe? Both 5.18.7 and A5.18.7, seems to have a concern regarding the size of the relief valve and discharge piping, but does not provide much guidance (in my opinion). Anyone care to expand on this concern? The fire pump is rated 1000 gpm @ 105 psi. The source as mentioned previously, are gravity tanks. The relief valve is 4 and discharge pipe is 8 corresponding to Table 5.25. The discharge piping from the relief valve to connection at pump suction pipe has one elbow. At the connection to the pump suction there is a tee. Is the tee to be counted and the sizing be increased as per 5.18.6.2 ? Any pump experts? Tony ___ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: techsupp...@firesprinkler.org To Unsubscribe, send an email to:sprinklerforum-requ...@firesprinkler.org (Put the word unsubscribe in the subject field) ___ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: techsupp...@firesprinkler.org To Unsubscribe, send an email to:sprinklerforum-requ...@firesprinkler.org (Put the word unsubscribe in the subject field)
Re: Fire Pump relief valve discharge
Tony made reference to a 4 in. diameter PRV, so I assume he is dealing with a diesel driven fire pump. The PRV is required for all diesel driven fire pumps. If the diesel driver rpm increases higher than the set idle position, the system pressure could easily exceed 175 psi without a suitable PRV. Smaller diameter circulation relief valves are required for electric driven fire pumps to ensure water circulates through the fire pump during churn periods. Note to Tony: Make sure you include a site glass (site glasses which have built in paddle wheels are the best) to allow water flow verification during inspections and acceptance tests. Rodney K. Hamm, P.E. President/Owner Falcon Fire Protection Office (478) 953-1677 Cell (478) 396-6988 Date: Fri, 20 Mar 2009 09:48:20 -0700 From: Roland Huggins rhugg...@firesprinkler.org Subject: Re: Fire Pump relief valve discharge To: sprinklerforum@firesprinkler.org Message-ID: f20352bd-a4e8-4ca2-b964-6fffc133d...@firesprinkler.org Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes How about a more basic question. Why do you even have a relief valve? With a rating of only 105 psi exceeding 175 psi with a tank feed requires a tall tank. Roland On Mar 19, 2009, at 11:23 PM, A.P.Silva wrote: The building owner wants to connect the discharge piping from the pump relief valve to the pump suction pipe, just upstream of the suction valve. The water supply to the pump is a water storage tank. Anyone seen this arrangement? Is it acceptable? NFPA 20, 2007 section 5.18.7 mentions Discharge to Source of Supply. Is this to the tank or can it be also to the suction pipe? Both 5.18.7 and A5.18.7, seems to have a concern regarding the size of the relief valve and discharge piping, but does not provide much guidance (in my opinion). Anyone care to expand on this concern? The fire pump is rated 1000 gpm @ 105 psi. The source as mentioned previously, are gravity tanks. The relief valve is 4 and discharge pipe is 8 corresponding to Table 5.25. The discharge piping from the relief valve to connection at pump suction pipe has one elbow. At the connection to the pump suction there is a tee. Is the tee to be counted and the sizing be increased as per 5.18.6.2 ? Any pump experts? Tony ___ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: techsupp...@firesprinkler.org To Unsubscribe, send an email to:sprinklerforum-requ...@firesprinkler.org (Put the word unsubscribe in the subject field)
RE: Fire Pump relief valve discharge
True. Good point. I should've mentioned the pump is diesel. The tank is 40' high. To conform to NFPA 20, 2007 section 5.18.1.1, 121% of churn gives (105 x 120% x 121%) + (40 x .433) = 170 psi (approx), assuming churn pressure is 120% of rated pressure. Someone would have thought it was not too far from 175 psi. I wasn't involved with the original design. Anyway the discharge from the relief valve can't be much to maintain 175 psi system pressure. But NFPA 20, 2007 section A.5.18.7 (appendix) requires ...back pressure capabilities and limitations of the valve to be used to be determined. I might be wrong, but I'm assuming the reference to back pressure means friction loss. If it is, I can't see friction loss being a critical factor. Unless, as piping the relief discharge causes a closed loop, is there a concern that the pressure would keep on increasing at every cycle? Tony -Original Message- From: sprinklerforum-boun...@firesprinkler.org [mailto:sprinklerforum-boun...@firesprinkler.org] On Behalf Of Roland Huggins Sent: March 20, 2009 9:48 AM To: sprinklerforum@firesprinkler.org Subject: Re: Fire Pump relief valve discharge How about a more basic question. Why do you even have a relief valve? With a rating of only 105 psi exceeding 175 psi with a tank feed requires a tall tank. Roland On Mar 19, 2009, at 11:23 PM, A.P.Silva wrote: The building owner wants to connect the discharge piping from the pump relief valve to the pump suction pipe, just upstream of the suction valve. The water supply to the pump is a water storage tank. Anyone seen this arrangement? Is it acceptable? NFPA 20, 2007 section 5.18.7 mentions Discharge to Source of Supply. Is this to the tank or can it be also to the suction pipe? Both 5.18.7 and A5.18.7, seems to have a concern regarding the size of the relief valve and discharge piping, but does not provide much guidance (in my opinion). Anyone care to expand on this concern? The fire pump is rated 1000 gpm @ 105 psi. The source as mentioned previously, are gravity tanks. The relief valve is 4 and discharge pipe is 8 corresponding to Table 5.25. The discharge piping from the relief valve to connection at pump suction pipe has one elbow. At the connection to the pump suction there is a tee. Is the tee to be counted and the sizing be increased as per 5.18.6.2 ? Any pump experts? Tony ___ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: techsupp...@firesprinkler.org To Unsubscribe, send an email to:sprinklerforum-requ...@firesprinkler.org (Put the word unsubscribe in the subject field) ___ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: techsupp...@firesprinkler.org To Unsubscribe, send an email to:sprinklerforum-requ...@firesprinkler.org (Put the word unsubscribe in the subject field) ___ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: techsupp...@firesprinkler.org To Unsubscribe, send an email to:sprinklerforum-requ...@firesprinkler.org (Put the word unsubscribe in the subject field)
RE: Fire Pump relief valve discharge
Thanks. A waste cone and sight glass are included. Tony -Original Message- From: sprinklerforum-boun...@firesprinkler.org [mailto:sprinklerforum-boun...@firesprinkler.org] On Behalf Of Rodney Hamm Sent: March 20, 2009 10:26 AM To: sprinklerforum@firesprinkler.org Subject: Re: Fire Pump relief valve discharge Tony made reference to a 4 in. diameter PRV, so I assume he is dealing with a diesel driven fire pump. The PRV is required for all diesel driven fire pumps. If the diesel driver rpm increases higher than the set idle position, the system pressure could easily exceed 175 psi without a suitable PRV. Smaller diameter circulation relief valves are required for electric driven fire pumps to ensure water circulates through the fire pump during churn periods. Note to Tony: Make sure you include a site glass (site glasses which have built in paddle wheels are the best) to allow water flow verification during inspections and acceptance tests. Rodney K. Hamm, P.E. President/Owner Falcon Fire Protection Office (478) 953-1677 Cell (478) 396-6988 Date: Fri, 20 Mar 2009 09:48:20 -0700 From: Roland Huggins rhugg...@firesprinkler.org Subject: Re: Fire Pump relief valve discharge To: sprinklerforum@firesprinkler.org Message-ID: f20352bd-a4e8-4ca2-b964-6fffc133d...@firesprinkler.org Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes How about a more basic question. Why do you even have a relief valve? With a rating of only 105 psi exceeding 175 psi with a tank feed requires a tall tank. Roland On Mar 19, 2009, at 11:23 PM, A.P.Silva wrote: The building owner wants to connect the discharge piping from the pump relief valve to the pump suction pipe, just upstream of the suction valve. The water supply to the pump is a water storage tank. Anyone seen this arrangement? Is it acceptable? NFPA 20, 2007 section 5.18.7 mentions Discharge to Source of Supply. Is this to the tank or can it be also to the suction pipe? Both 5.18.7 and A5.18.7, seems to have a concern regarding the size of the relief valve and discharge piping, but does not provide much guidance (in my opinion). Anyone care to expand on this concern? The fire pump is rated 1000 gpm @ 105 psi. The source as mentioned previously, are gravity tanks. The relief valve is 4 and discharge pipe is 8 corresponding to Table 5.25. The discharge piping from the relief valve to connection at pump suction pipe has one elbow. At the connection to the pump suction there is a tee. Is the tee to be counted and the sizing be increased as per 5.18.6.2 ? Any pump experts? Tony ___ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: techsupp...@firesprinkler.org To Unsubscribe, send an email to:sprinklerforum-requ...@firesprinkler.org (Put the word unsubscribe in the subject field) ___ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: techsupp...@firesprinkler.org To Unsubscribe, send an email to:sprinklerforum-requ...@firesprinkler.org (Put the word unsubscribe in the subject field)
Re: Fire Pump relief valve discharge
If it is a relatively new pump, it may churn at 140% but I'd be shocked if that were the case. I haven't gone looking but has any one seen a horizontal pump that exceeds the old 120% criteria? The pumps I've played with have been less than 110% and there are a boat load that are at or below 105%. As such, it seems the answer to you discharge problem may be to evaluate the actual system and do away with the relief valve. Keep in mind that the outlet pressure is not limited to 175 psi but to the pressure rating of the components so location (that is impact of elevation differences) is applicable. Roland On Mar 20, 2009, at 10:38 AM, A.P.Silva wrote: True. Good point. I should've mentioned the pump is diesel. The tank is 40' high. To conform to NFPA 20, 2007 section 5.18.1.1, 121% of churn gives (105 x 120% x 121%) + (40 x .433) = 170 psi (approx), assuming churn pressure is 120% of rated pressure. Someone would have thought it was not too far from 175 psi. I wasn't involved with the original design. Tony ___ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: techsupp...@firesprinkler.org To Unsubscribe, send an email to:sprinklerforum-requ...@firesprinkler.org (Put the word unsubscribe in the subject field)
RE: Fire Pump relief valve discharge
The building owner wants to connect the discharge piping from the pump relief valve to the pump suction pipe, just upstream of the suction valve. The water supply to the pump is a water storage tank. Anyone seen this arrangement? Is it acceptable? NFPA 20, 2007 section 5.18.7 mentions Discharge to Source of Supply. Is this to the tank or can it be also to the suction pipe? Both 5.18.7 and A5.18.7, seems to have a concern regarding the size of the relief valve and discharge piping, but does not provide much guidance (in my opinion). Anyone care to expand on this concern? The fire pump is rated 1000 gpm @ 105 psi. The source as mentioned previously, are gravity tanks. The relief valve is 4 and discharge pipe is 8 corresponding to Table 5.25. The discharge piping from the relief valve to connection at pump suction pipe has one elbow. At the connection to the pump suction there is a tee. Is the tee to be counted and the sizing be increased as per 5.18.6.2 ? Any pump experts? Tony ___ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: techsupp...@firesprinkler.org To Unsubscribe, send an email to:sprinklerforum-requ...@firesprinkler.org (Put the word unsubscribe in the subject field)
