I only want to point out that velocity requirements are not necessarily an improvement from the minimum requirements. If you want to accomplish that, do as others have suggested and require sch 40 pipe, or additional pressure cushion, etc.
I know of at least two installations in my experience where the velocity requirements made the design impossible to complete: in one, we were balancing the foam system with the sprinklers and got caught in a loop - pipes were sized to meet velocity requirements, which caused overflowing of the system, and reduced the pressure available to the other system.... Same thing happened on a small Navy office building (Thom knows): the configuration of the building combined with the water supply and 3,000 sq. ft. design area resulted in an infinite loop where to meet velocity requirements, we were at 3 in branch lines before we were able to convince the spec. engineer to relax his requirements. Again: velocity limitations do not equal additional safety factor nor do they increase the quality of the system - they usually just add headache. It can be especially bad when you have not provided a complete layout for the contractors to bid on - they're forced to find out the problems with the velocity requirements AFTER they've signed the contract. Mark A. Sornsin, PE Fire Protection Engineer Ulteig Engineers, Inc. Fargo, ND 701.280.8591 [EMAIL PROTECTED] -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Monday, January 15, 2007 6:24 PM To: [email protected] Subject: RE: Beyond code (was max velocity) Well, not to increase the storm clouds further, the following needs to be explained. 1. Most of what I specify is part of the Facilities Standard that we build buildings under. (pipe types, design areas, densities, etc.) 2. I am the AHJ and the owner's representative, just as it allows in the good book. 3. I have to try my darndest to insure that a system will last a minimum of 50 years, not just till the warranty runs out. 4 I am not in any way advocating the government requirements for the private sector. 5. These buildings are not going to change ownership or occupancy ever. 6. My process is to insure that I have pipe that will remain large enough to provide at least some measure of protection after 50 years of everybody and their dog modifying and changing the sprinkler system in that period of time. 7. Walls will change in these buildings and preventing the sprinklers from covering more than 130 square feet with a light hazard density will help compensate for that. I cannot ever guarantee that sprinklers will accompany wall changes. In our buildings it seldom does, leaving areas unprotected. 8. If you are ever on a federal jury, try to think about the fire protection systems in a highly secured building with really bad egress. 9. I seemed to noticed that some readers apparently feel that these systems should be competitively bid against minimum codes as interpreted by what they are familiar with on other projects. We simply cannot work that way. Too much gets by that shouldn't. 10. This is not a bad return on the taxpayer's money. In the private sector, the architectural and every other trade gets more attention than the fire protection systems. It seems that the fire protection systems are the red headed stepchildren to everything else. I am trying to make this trade better, not worse. 11. It also appears that many think that no one deserves more than just the bare minimum with various interpretations. There is nothing wrong with having something better. Does anyone think that they deserve only the cheapest truck or house or other things or is that reserved for the other guy? I do appreciate constructive criticism and comments, but lets don't let it get beyond that. Thank You Rahe Loftin, P.E. _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum
