I doubt if vents will have any noticeable impact. Besides, vents if anything will increase the water velocity. The first time I was standing next to a 6 inch pipe downstream of the deluge valve, the amount of pipe movement amazed me (sounds better than I nearly crapped my pants). It’s not a new phenomena that when water filling pipe hits and elbow, things move. Since it has been that way forever and has not been revisited in the 23 yrs that I’ve been on 13, I cant say what the TC original said about it. Not aware of any engineering studies on it (since it is allowed and things are NOT blowing apart). I have to assume that the movement reduces the potential for failure though to what degree I cant say.
Just because the standard is silent on it, by no means translates to its an unknown issue and that we need to be concerned about it. Tell the engineers to spend time worrying actually problems. Oh and NOT to stand next to big mains when they trip to system. Roland Roland Huggins, PE - Senior VP Engineering American Fire Sprinkler Assn. Dallas, TX http://www.firesprinkler.org <http://www.firesprinkler.org/> Fire Sprinklers Saves Lives > On Mar 12, 2019, at 7:19 AM, Matt Grise <[email protected]> wrote: > > I don’t know if “trying it out” is the ideal option, but if the vents can be > adjusted, it might be possible to get the system set up where the water > filled the system at a rate that was fast enough, but also had a tolerable > water hammer. Or maybe some commercial water hammer arresters could be added? > > I don’t know of any non-theoretical calc methods for designing it though. > > Matt > > > From: Sprinklerforum <[email protected] > <mailto:[email protected]>> On Behalf Of Prahl, > Craig/GVL > Sent: Tuesday, March 12, 2019 9:13 AM > To: [email protected] > <mailto:[email protected]> > Subject: RE: Water hammer in Dry or deluge systems > > Yes, there will be air vents on the system. The FD had concerns on how fast > water would get to the valves due to trapped air in the system. > > Craig Prahl | Jacobs | Group Lead – Fire Protection | 864.676.5252 | > [email protected] <mailto:[email protected]> | www.jacobs.com > <http://www.jacobs.com/> > > From: Sprinklerforum <[email protected] > <mailto:[email protected]>> On Behalf Of Matt > Grise > Sent: Tuesday, March 12, 2019 10:11 AM > To: [email protected] > <mailto:[email protected]> > Subject: [EXTERNAL] RE: Water hammer in Dry or deluge systems > > Is the system vented? I imagine that the ability of the air to escape the > system would also affect how fast the water gets moving. > > Matt > > > From: Sprinklerforum <[email protected] > <mailto:[email protected]>> On Behalf Of Prahl, > Craig/GVL > Sent: Tuesday, March 12, 2019 9:00 AM > To: [email protected] > <mailto:[email protected]> > Subject: Water hammer in Dry or deluge systems > > So, I’ve got an FPE and ME questioning about water hammer in a deluge system. > > We have a unique installation where we have two levels of hose connections > (one array at 12 ft AFF and one at 60 ft AFF) for manual firefighting in an > unconditioned assembly building which is 145 ft high. > > Due to the non-heated condition, one proposed concept for a semi-automatic > system is to use an electric release deluge valve to charge the system from > manual pull stations. > > Flow rate will be 1,000 gpm at somewhere near 150ish psi though 600-800 ft of > pipe inside the bldg. > > The FPE and ME are concerned with water hammer in the piping when the deluge > valve opens based on how fast the valve opens. > > Has anyone dealt with or had to provide calcs for this? NFPA 13, 14, etc. > are fairly silent on the issue. Is it even an issue? I’ve never had this > brought up before on an interior system. > > Anyone have any data on how fast a solenoid operated deluge valve opens? > > Craig Prahl | Jacobs | Group Lead – Fire Protection | 864.676.5252 | > [email protected] <mailto:[email protected]> | www.jacobs.com > <http://www.jacobs.com/> > > > > NOTICE - This communication may contain confidential and privileged > information that is for the sole use of the intended recipient. Any viewing, > copying or distribution of, or reliance on this message by unintended > recipients is strictly prohibited. If you have received this message in > error, please notify us immediately by replying to the message and deleting > it from your computer. > > > NOTICE - This communication may contain confidential and privileged > information that is for the sole use of the intended recipient. Any viewing, > copying or distribution of, or reliance on this message by unintended > recipients is strictly prohibited. If you have received this message in > error, please notify us immediately by replying to the message and deleting > it from your computer. > _______________________________________________ > Sprinklerforum mailing list > [email protected] > <mailto:[email protected]> > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org > <http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org>
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