Thanks Rechard, you are great! As a NFPA member I have asked this question from NFPA-20, I think they will answer in couple of days, I will attach their answer here. I agree with you over item 3-3 which is not reasonable, so you mean if I am even less than 1% unsure about reliability of power source, I am not allowed to use electric pumps (as main without reserved diesel) and should use diesel pumps, right? From your experience, would you please let me know in what kind of industries (May be powerplants,...) or situations we can be sure of 100% reliability of power source to use only electric driven pumps as main? Thanks in advance, Reza
Richard Malek <[EMAIL PROTECTED]> wrote: -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Reza Esmaeili Sent: Tuesday, September 04, 2007 3:28 AM To: [email protected] Subject: RE: Fire Pump Selection - REVISED Richard, Many thanks for your great explanation. I think my previous question about selecting of fire pumps was a bit confusing, so I revised it as below. - Actually this is for a big deluge system, not sprinkler system, I mistyped sprinkler system in my previous email. Let me ask my question in another way. I want to asume 3 scenarios for selecting fire pumps for a water demand of 3900 GPM at 90 Psi. 1- Want to be economical and and I don't afford to buy reserve pumps: (is it allowed as per NFPA not to have reserve pumps)? If you are referring to basic NFPA 13, 15, 20, etc. requirements, a reserve pump isn't required although if you have an electric drive without a reliable power source, maybe in that case you could say you need a reserve (i.e. diesel drive) although I wouldn't look at that way. One supply (water supply + pump in this case) is required and satisfy with diesel or electric. I'm not sure if there is an occupancy type NFPA standard that requires a reserve pump (I would doubt it, but I'm not familiar with every NFPA occupancy type standard) 1-1: I have a very reliable power source: I will buy only an electric driven main fire pump 3500GPM at 102 psi working at about 112% of rated capasity ( I won't buy diesel, because I have a reliable power source and also I want to be economical) 1-2:I doN't have a reliable power source: I will buy only a diesel fire pump 3500GPM at 102 psi to work as my main fire pump. 1-1/1-2 sound OK 2- have too much money, I will buy reserve pumps: 2-1: I will buy a main electric pump 3500GPM at 102 psi and a diesel pump 3500GPM at 102 psi and my eletric fire pump would be main pump and diesel pump would be reserve pump which will work at power failure conditions. 2-2: is above arrangement as per NFPA? or I should arrange diesel pump as main? Either is OK per NFPA from my perspective. If you're only concerned about power failure, the diesel drive addresses that and the electric would be unnecessary (diesel is your main AND reserve). If you are looking at reliability more broadly, an electric paired with a diesel probably provides some increase in reliability (diesel addesses power availability and electric addresses the some of the inherent complexity in the diesel drive) 3- Want to be very very economical: I don't want to buy expensive pumps like Pattreson, Peerless, ... who are producing big pumps, I want to be very economical and buy the cheap pumps from my supplier who can't make a 3500 GPM pump, so I have to split the pumps and buy two sets of 1500 GPM at 129 psi working at about 130% or rated capacity. 3-1: I have a very reliable power source: I will buy 2 electric pumps each 1500 GPM at 129 psi working as main pumps. Sounds OK, nothing stops you from using 2 50% pumps in my opinion. 3-2: I doN't have a reliable power source: I will buy 2 diesel pumps each 1500 GPM at 129 psi working as main pumps. Sound OK, 3-3: I am not 100% sure about reliability of power source: I will buy one electric pumps and one diesel pump at the same capacity of 1500 GPM at 129 psi, electric pump will start first and when water demand exceeds than 1500 GPM, then diesel pump will start, this arrangement is because in case of power failure, I can supply at least 50% of water demand to control half of fire. I know this is not logical, but imagine that power failure possibility is less than 1%. Wouldn't agree with your logic here. 50% supply for a deluge system isn't of much use. Particularly with the deluge systems, have to meet or exceed the demand or the protection isn't there. Regarding the 2 pumps, if you're demand is down to 3900 gpm, you could likely make that work with a single 3000 gpm. That's nothing that extraordinary. I would be looking at my estimates for installed cost and life cycle costs as well for a single vs. 2 pumps. I thnk typically the owner would be better off with a single 100% pump vs. 2-50%. Good luck. Would you kindly please analyze these three scenarios and let me know if any of them is aganist NFPA? If you have to choose one economical choice (among item 1) and one non economical choice (among item 2), and one very economical choice (among item 3), which ones you will choose? Many thanks for your kind help in advance. Thank, Reza --------------------------------- Sick sense of humor? Visit Yahoo! 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