NFPA 11 seems to let one bypass NFPA 20?
NFPA 11 seems to let one bypass NFPA 20?
(OP)
We are overseeing a tank farm project where a low expansion foam system is being installed to NFPA 11. There are (4) tanks with (7) 550gpm chambers a piece. The system is calling for 4000 gpm@ approx. 120 psi which will mean in this case (2) 210 hp electric pumps. The design is to be fully manual. So here’s a twist thrown by NFPA 11: In Ch4 under 4.2 Water Supplies; 4.2.2 Water and Foam Concentrate Pumps;
4.2.2.1 When water or foam concentrate pumps are required for automatic foam system operation, they shall be designed and installed in accordance with NFPA 20.
4.2.2.2 Controllers in accordance with NFPA 20 shall not be required for manual systems.
Question A to 4.2.2.1: What if they are NOT automatic?
Question B to 4.2.2.2: I assume the controllers still have to be listed… just not designed or installed as per NFPA 20? What would be the guidelines then?
Sorry about the long winded explanation / question.
4.2.2.1 When water or foam concentrate pumps are required for automatic foam system operation, they shall be designed and installed in accordance with NFPA 20.
4.2.2.2 Controllers in accordance with NFPA 20 shall not be required for manual systems.
Question A to 4.2.2.1: What if they are NOT automatic?
Question B to 4.2.2.2: I assume the controllers still have to be listed… just not designed or installed as per NFPA 20? What would be the guidelines then?
Sorry about the long winded explanation / question.





RE: NFPA 11 seems to let one bypass NFPA 20?
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RE: NFPA 11 seems to let one bypass NFPA 20?
RE: NFPA 11 seems to let one bypass NFPA 20?
Tank fires are very rare, which makes the cost of automation excessive. The standard allows the use on non-NFPA 20 controllers because they are way too complex to meet the simple need of starting and stopping the pump. The pump or foam skid. mfr should be able to recommend an approriate control/switch for the pump. Make sure the money is spent on having all valves/switches clearly identified (numbering, color coding, etc...) and have a good set of instruction permanently installed in the foam house (think bulletin board size, so multiple people can look at them simultaneously).
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RE: NFPA 11 seems to let one bypass NFPA 20?
But I assume one still requires a 'listed' controller, whether or not one needs a controller as per NFPA 20?
RE: NFPA 11 seems to let one bypass NFPA 20?
As a minimum the switch/controller will need to be UL Listed electrical equipment. Also, expect that any old switch is not going to do. It's going to have to be in/on a red box and will probably be required to have a "power OK" light and possibly a "pump running light" (This what you normally see). The pump manufacturer should be able to provide an approved, Non-NFPA 20 controller.
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RE: NFPA 11 seems to let one bypass NFPA 20?
RE: NFPA 11 seems to let one bypass NFPA 20?
I think that NFPA 11 4.2 intention is as follows:
4.2.2 Water and Foam Concentrate Pumps;
4.2.2.1 When water or foam concentrate pumps are required for automatic foam system operation, they shall be designed and installed in accordance with NFPA 20.
i.e. it is refering to both the water supply (it must be NFPA 20) and the Foam pump (must be NFPA 20 also) when the foam feed is required to be automatic.
4.2.2.2 Controllers in accordance with NFPA 20 shall not be required for manual systems.
I think it refers only to foam pump systems (eg. a balanced pressure pump skid electric or diesel), in some cases the AHJ allows that the foam pump skid can be operated manually so a fully NFPA controller is not required.
In the case of a bladder system I think the water supply shall be NFPA 20 and the actuation could be manual with the option of using a hydraulic actuated ball valve to reduce the number of valves to open. Also could be fully automatic for example by using deluge valves actuated by the loss of pressure in the foam discharge device line.
There are bladder systems that keeps the bladder under pressure in stand by mode and others that don´t. I don´t know which is better and when.
www.williamsfire.com manuals include some diagrams to ilustrate.
RE: NFPA 11 seems to let one bypass NFPA 20?
Is it your interpretation then that 4.2 is not relevant to the fire pump itself, but more to ancillary pumps that might be used in proportioner skids?
As for the hydraulically actuated ball valve on the concentrate line, I think that's the way to go also but the owner prefers to make it as unlikely as possible that the system ever be inadvertently operated.
RE: NFPA 11 seems to let one bypass NFPA 20?
An NFPA 20 controller is not required on a manually operated foam systems because there is no need for the monitoring of local or remote signal start signals/sensors, test timers and the redundancies and alarms associted with automatic starting. All of this would simply be a waste of money on a manually operated foam system.
I have been around numerous manual foam systems in 18 years and have never seen an NFPA 20 controller on the water pump of a manual foam system, except in those cases where the pump is a multiservice pump and also supplies automatic systems.
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RE: NFPA 11 seems to let one bypass NFPA 20?
I guess the last question would seem to be does it need to be a fire pump at all?