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CPVC pipes sizing for Fireprotection. 2

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ME.EnGR

Mechanical
Jan 10, 2017
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Just a quick question, how can i size up cpvc pipes for sprinklers? is it same as sizing using B.I. pipes? thanks for your help. My situation is, there is already an existing fire pump for a building complex, im going to design sprinkler system for the 10 additional rooms i just need to tap my pipes in the existing fireprotection pipes. im just worried since i only have experience designing using B.I pipes, hope someone could help me figure out how to size up piping in fire protection using cpvc pipes.
 
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its an academic building, i have no knowledge on what considerations the original designer did. i just need to have additional sprinklers of the 10 new classrooms connected to the existing building.
 
Plus with all the concern about introducing bad stuff into cpvc pipe and causing environmental stress cracking (I think that's the term Lubrizol uses. Maybe not.) due to contaminants, I would be very hesitant to connect cpvc piping to an existing steel system that may or may not be full of said bad stuff.
 
thank you sir for all your replies, the existing fire protection system that the building has is using cpvc pipes. im only asking for the sizing of pipes if cpvc is going to be use, is there a table for Light hazard pipe schedules using cpvc pipes? just like table 8-5.2.2 in NFPA 13.
 
Does that match the existing calculated "schedule?"

Do you know how to perform hydraulic calculations for fire sprinkler systems? I don't mean that to sound rude. In many parts of the world they are still doing pipe schedule and don't have a grasp on hydraulic calculations.

Your four sprinklers supplied by 1" pipe would be very concerning to me.

Instead of doing this on your own with limited experience, it may be prudent for you to hire a competent fire sprinkler consultant to assist you in your project.

Travis Mack
MFP Design, LLC
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I believe what Travis is saying is that provided your existing fire sprinkler system is the same material as the extension, and the occupancy of the areas is the same, and the existing system was properly calculated originally, then using "equivalency" you may be able to size the new fire sprinkler piping equal to the existing pipe IDs. To try that the new pipe would need to be the same distance from, or closer to, the water source as the existing pipe and supplied by a pipe of the same ID as was originally calculated. All that being said, as a contractor that was personally licensed in 4 states, I recommend consulting with an engineer or contractor in your area that may assist you. I own three calculation software programs, any of them would be capable of calculating that work, and one of them only costs a few hundred dollars online and I have compared its output to my $1K calc software and not found a difference in any output. I am not aware that the pipe schedule system referenced in NFPA 13 may not be used for CPVC pipe, the schedule system is a compilation of pipe IDs and the number of open outlets an ID is capable of supplying, so unless the standard states steel pipe only then it is based upon pipe ID and not product. In fact, when I took my first course in hydraulics the instructors informed us that to establish the densities in NFPA 13, that pipe schedule systems were calculated, and the average density that the schedule system provided became the basis of the fire sprinkler design curves.
 
there is an existing fire protection system in the building with pumps and controls that serves the phase 1, phase 2 & phase 3 of the construction project using CPVC pipes. i believe that the designer of the fire protection system (which is not me) have calculated for for all the areas of the building. my only problem is i dont have the whole fire protection layout for the building to check if the fire pump system is enough, i can do hydraulic calculation as well but i have limited information about the system as a whole thats why im asking if pipe schedule can do it and if there is a pipe schedule table for cpvc pipes and its my first time to encounter using CPVC pipe for fire protection. im also worried for what is happening right now for this project but i have to make decisions fast. Thank you for your intelligent replies at your time also.
 
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