Kyle, *disclaimer: I work for a company that sells air vents*
The short answer: The in-line vent doesn’t work in fire sprinkler systems. The long answer: In a closed mechanical system there are generally two stages of air removal: 1) bulk air removal, which requires a simple ball valve (manual) or float valve (automatic) at a remote high point and 2) dissolved air removal, which requires an air scoop/expansion chamber or a vortex style air separator. The removal of dissolved gases (gas molecules entrained in liquid water) is desirable in closed loop flowing systems. Because sprinkler systems are stagnant and the water entering the system contains approximately 10 ppm of dissolved oxygen (0.001% of water volume) the use of an expansion chamber at the beginning of the system provides no value. Less than 1% of all oxygen available for corrosion in a sprinkler system is dissolved in the water when it enters the system. Attempts to “de-oxygenate” sprinkler water, either chemically or mechanically, are insignificant when looking at the bigger picture. Thanks, Lucas Kirn, PE Engineered Corrosion Solutions (314) 415-1387 | http://ecscorrosion.com From: Kyle.Montgomery <[email protected]> Sent: Monday, March 9, 2020 11:02 AM To: [email protected]; [email protected] Cc: Ben Young <[email protected]> Subject: RE: [EXTERNAL] Re: Air Venting How in the world would that work? I mean, the air is in the pipe when it’s installed, it doesn’t enter at a later date. From: Sprinklerforum [mailto:[email protected]] On Behalf Of Ben Young via Sprinklerforum Sent: Friday, March 6, 2020 2:04 PM To: [email protected]<mailto:[email protected]>; [email protected]<mailto:[email protected]> Cc: Ben Young <[email protected]<mailto:[email protected]>> Subject: [EXTERNAL] Re: Air Venting The idea is to get out a majority of the trapped air but not every bit. So in your case you don't need to tie in every sprig and have multiple air vents, you could put it off one of the back sprigs but a remote branch line works too. The other option is to use AGFs in line vent that you can put near the beginning of a system and it supposedly gets the air out before it has a chance to form pockets downstream. Haven't used one yet but they seem cool On Fri, Mar 6, 2020 at 1:33 PM Bob Knight via Sprinklerforum <[email protected]<mailto:[email protected]>> wrote: In this case, the branch lines are all located beneath the trusses. The trusses are shallow open web wood two feet on-center. The elevation is 11’8” everywhere, so the sprigs are actually the highest points. That said, it sounds like the air vent just needs to be at the furthest point that it can be. Thank you, Bob Knight, CET III Fire by Knight, LLC 208-318-3057 From: Sprinklerforum [mailto:[email protected]<mailto:[email protected]>] On Behalf Of Steve Leyton via Sprinklerforum Sent: Friday, March 06, 2020 10:52 AM To: [email protected]<mailto:[email protected]>; [email protected]<mailto:[email protected]> Cc: Steve Leyton Subject: RE: Air Venting I’d put it on a branch along the highest part of the building to which piping is attached, assuming that the piping more or less follows the roof contour. SL From: Sprinklerforum [mailto:[email protected]<mailto:[email protected]>] On Behalf Of Bob Knight via Sprinklerforum Sent: Friday, March 06, 2020 9:21 AM To: [email protected]<mailto:[email protected]> Cc: Bob Knight Subject: RE: Air Venting Thanks Steve. I get the high point part. This system is all one elevation, but sprigs are being used. Do I put the air vent on one of the sprigs, and is the most remote branch line the appropriate location? Thank you, Bob Knight, CET III Fire by Knight, LLC 208-318-3057 From: Sprinklerforum [mailto:[email protected]<mailto:[email protected]>] On Behalf Of Steve Leyton via Sprinklerforum Sent: Friday, March 06, 2020 10:17 AM To: [email protected]<mailto:[email protected]>; [email protected]<mailto:[email protected]> Cc: Steve Leyton Subject: RE: Air Venting Usually - and I mean to say, almost always – that’s going to be the high point of the system. Trapped are generally migrates to the high point eventually. There are exceptions and some piping configuration can trap air in pockets that aren’t at the highest point of the system, but that’s usually where it is. [cid:[email protected]] From: Sprinklerforum [mailto:[email protected]<mailto:[email protected]>] On Behalf Of Bob Knight via Sprinklerforum Sent: Friday, March 06, 2020 9:11 AM To: [email protected]<mailto:[email protected]> Cc: Bob Knight Subject: Air Venting Not being an air venting expert, when NFPA 13 (2016 ed.) says “The air venting valve should be located where it will be most effective. System piping layout will guide the designer in choosing an effective location for venting. In order to effectively accomplish venting, it is necessary to choose a location where the greatest volume of trapped air is vented during the first fill and each subsequent drain and fill event (A.8.16.6).” No other guidance is provided, so would this be at the most remote branch line, or at the end of a dead end main, or somewhere else? Is there a “best practice” that is being used? Thank you, Bob Knight, CET III Fire by Knight, LLC 208-318-3057 [FBK-LOGO-EMAIL] _______________________________________________ Sprinklerforum mailing list [email protected]<mailto:[email protected]> http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org<https://urldefense.proofpoint.com/v2/url?u=http-3A__lists.firesprinkler.org_listinfo.cgi_sprinklerforum-2Dfiresprinkler.org&d=DwMFaQ&c=wn3mZQLIuInh2ClcJ0_DIA&r=Z_2A85VL7AQzoqudh6uOyS3bn8etxB7nLN8OBJwQd9A&m=XBAfr8VvT_tqVmRgf4SS23R-L_XrkNqeFKnmzVeos0o&s=KKnRzmomHZu6jow9hSzsZThLbttz2R2r9rvIf1HsADE&e=> -- Benjamin Young
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