Yes, we have done many combined Private domestic and private fire water pump stations. When you start to look at such a pump station you need to develop design parameters for all domestic and plant usage along with fire water demand. You need to determine with a great degree of confidence the domestic and plant process usage and specific time line of process water demand and domestic water demands; such as when and where the process water is required and at what flows, what are the operating parameters for the plant workers and what are the shift and break times since at breaks and meal times domestic water usage is much greater than during normal operating times. Does the plant have a dining facility and what type of equipment is being used.
Once you have determined the domestic flows and when and where they occur you then need to sit down with the end user to determine their needs. What type of pressure is required for the process equipment, domestic water devices, flush type or tank type, grass irrigation system, etc., once you sit down with the end user (not the client's engineer but plant operations personal who are operating the facility) you need to determine if multiple smaller domestic service pumps are required in order to have the system operate in an economically and technically sound manner. Having a 2,500 gpm domestic water pump turning itself on and off to provide make up water is not economically sound. It is more reasonable to have 4 or 5 smaller pumps in parallel, with start and stop controlled by a 4x or 5x pump controller which monitors the pressure on the combined system to sequentially start the pumps based on system water pressure. You will also need a device to handle the pressure surges from the pumps starting and stopping, On the systems that I have designed I have used a 500 gallon hydro-pneumatic bladder tank to handle the pressure surge. However the hydro-pneumatic size needs to be determined based on the final system design. The fire pump start pressure is set based on sprinkler system design parameters and the domestic systems design parameters. There is more to this contract and design than meets the eye and the SFMO's blessing does not mean a thing since the SFMO has no liability to the client only you have the liability and it will be for the sprinkler and domestic water pumps since there appears to have been no engineering based on the operational needs of the facility. Just because it meets the code does not mean that it meets the clients operational needs. >From what you have described this project needs to be much better defined as a >whole since the fire protection jockey pump might be the 2,500 gpm domestic >service pump and since it is connected to the private service fire water main >it will fall into the requirements of NFPA 24 "Standard for the Installation >of Private Fire Service Mains and Their Appurtenances" operative word is >"private". Your might have to design the fire pump house and pumping >equipment as a municipal water service pump station meeting both AWWA >requirements and NFPA requirements, example that the paint on the interior of >the fire pump must be AWWA certified for domestic water service use, the >entire pump station might have to have full emergency power back up including >all pumps and all power such as lights, alarms, pumping equipment, controls, >heating and ventilation, etc. I have a sample drawing that I can provide you off line if you want to look at it for conversation. Have a fire safe day. Jim Davidson Davidson Associates Fire Protection * Medical Gas * Code Consulting 302-994-9500 Fax:302-234-1781 -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Ted Hall Sent: Friday, November 18, 2011 11:46 AM To: [email protected] Subject: Fire Pump to multi suppy We are bidding a project where we have been given the design view from 10,000 feet. But the contractor who is awarded the project is to complete the design. The project will have a million gallon storage tank to supply both fire sprinklers an facility water. There is to be one pump house which we would not be involved with that will house a 2500GPM pump at 145psi and another 500GPM pump at about the same PSI. The Fire Pump House will have one electric fire pump at 125 psi and one diesel fire pump same rating and one conversion// spare fire pump at the same rating. All pumps will feed from the storage tank and into a 12" underground loop. The schematic shows a demand of plant water which could be as much as 2500GPM and the fire sprinklers (ESFR system) coming off the same underground loop. The owner has gotten the SFMO's blessing on this arrangement but I am thinking I am going to be replacing fire pumps due them starting and not shutting off. No way a jockey pump can keep up with the demand of the plant water. Has anyone ever been involved with this configuration before. I am thinking it isn't even code. Ted Hall, CET NICET 119535 Water Based {Formerly AutomaticSprinkler} Systems Layout Level III Sentinel Fire Protection 2040 Westland Dr. S.W. Cleveland, Tn. 37311 Office 423 476-7570 Fax 423 476-9014 [email protected] -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://fireball.firesprinkler.org/mailman/private/sprinklerforum/attachments/20111118/a138b5b6/attachment.html> _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum
