The language in NFPA 13 section 16.7 is an attempt to provide a method to vent some of the trapped air out of the system. At this point, the technical committee did not adapt language to require multiple air vents. In fact, a single 1/2" manual vent is acceptable. The air vent is required to be near a high point and according to the language in the annex, the manual valve should be at an accessible point and preferably not over 7 ft above the floor. Remember, the annex language is a good explanation of the language and shows the intent of the technical committee but it is not a requirement.
*The above is my opinion and has not been processed as a formal interpretation in accordance with the NFPA Regulations Governing Committee Projects. This is provided with the understanding that the AFSA assumes no liability for this opinion or actions taken on it and they are not to be considered the official position of the AFSA or NFPA, or NFPA's technical committees. AFSA cannot provide design or consulting engineering services, and this opinion should therefore not be considered, nor relied upon, as such.* Thanks, John John August Denhardt, PE *Vice President, Engineering and Technical Services* *American Fire Sprinkler Association* m: p: 301-343-1457 214-349-5965 ext 121 w: firesprinkler.org <https://www.facebook.com/firesprinkler.org/> <https://twitter.com/afsa/status/1039528345367732224> <https://www.linkedin.com/company/american-fire-sprinkler-association-afsa-/> <https://www.instagram.com/firesprinklerorg/> *Our members are at the heart of everything we do* *Be a Member, Get a Member* We’re introducing many new programs to help meet your team’s business needs. AFSA is offering a six-month trial membership for contractors and a 12-month trial membership for municipal AHJs. Let’s help potential members see what they’re missing! Current members who recruit a new contractor member will receive a $100 gift card and the new member gets a free webinar. Let’s grow stronger together! Join AFSA <http://www.firesprinkler.org/join>. On Thu, Feb 18, 2021 at 3:44 PM Kevin Hall via Sprinklerforum < [email protected]> wrote: > Yes - that is the intent as explained in the annex. > > "A.16.7 A manual or automatic air venting valve can be a reasonable > approach on wet pipe sprinkler systems to reduce corrosion activity. The > purpose of the air venting valve is to exhaust as much trapped air as > possible from a single location every time the system is filled. The > objective of venting is to reduce the amount of oxygen trapped in the > system that will fuel corrosion and microbial activity. It is neither the > intent nor practical to exhaust all trapped air from a single location on a > wet pipe sprinkler system; however, more than one vent can be used on a > system at the designer's discretion. Interconnection of branch line piping > for venting purposes is not necessary. An inspector's test valve can serve > this purpose. > > 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. The > vent connection to the system should be located off the top of horizontal > piping at a high point in the system; however, the vent connection can also > be effectively located off the side of a riser or riser nipple at a high > point in the system. > > Manual air venting valves should be accessible. The manual air venting > valve should be located at an accessible point and preferably not over 7 ft > (2.1 m) above the floor. Automatic air valves are not required to comply > with the accessibility requirement of manual air venting valves; however, > it is recommended the designer locate automatic air vents over areas > without ceilings, above a lay-in ceiling, or above an access panel. > > Each wet pipe sprinkler system should be vented every time the system is > filled." > > The above is my opinion and has not been processed as a formal > interpretation in accordance with the NFPA Regulations Governing Committee > Projects. This is provided with the understanding that the AFSA assumes no > liability for this opinion or actions taken on it and they are not to be > considered the official position of the NFPA or its technical committees. > AFSA cannot provide design or consulting engineering services, and this > opinion should therefore not be considered, nor relied upon, as such. > > > Kevin Hall, M. Eng, P.E., CWBSP, MSFPE > > Coordinator, Engineering and Technical Services > > American Fire Sprinkler Association > > [email protected] > > 214-349-5971 > > > On Thu, Feb 18, 2021 at 3:33 PM Kyle.Montgomery via Sprinklerforum < > [email protected]> wrote: > > > It was my understanding that the committee's approach to requiring air > > vents was "one is better than none", without wanting to add a ton of > extra > > complexity or expense to the systems. I would assume that the migration > > away from remote inspector's test valves to the on-riser test-n-drain > style > > helped drive the need to at least add something at the far end. > > > > -Kyle M > > > > -----Original Message----- > > From: Sprinklerforum <[email protected]> On > > Behalf Of Kenneth Berman via Sprinklerforum > > Sent: Thursday, February 18, 2021 6:39 AM > > To: [email protected] > > Cc: Kenneth Berman <[email protected]> > > Subject: [EXTERNAL] Re: Air Venting (2021) > > > > care in engineering and design is required to eliminate these air > pockets. > > Gang drains have been used for years to drain low points on dry system > > lines. The same is needed for air evacuation, just at the top of the > > system. A small line joining the peaks of lines may be needed. As for the > > antifreeze piping, you're spot on about the trapped air and pressure > > fluctuations diluting the mix. I like to pump the antifreeze in at the > > control valve and exhaust air out at the heads. Left loose, they'll allow > > air to escape. Tighten them once the mix gets there. Pump it up to ten > > pounds more than static pressure and you're set. Good field workers are > > necessary to get good installations. > > > > > > On Thu, Feb 18, 2021 at 5:10 AM Tom Duross via Sprinklerforum < > > [email protected]> wrote: > > > > > I think it all depends on placement and location, to remove as much as > > > possible. > > > > > > I've been meaning to write a similar post about anti-freeze systems > > > and air vents. These are almost always dead-end systems and I'm > > > finding dilution at the source even after a single year. Granted 13 > > > requires a physical end of line which could be used to vent but I > > > hardly ever see one with existing systems. My only guess for dilution > > > would be air mitigation over time allowing water to pass the BFP or > > > CHV into the AF portion of the system. I would think an AAV would > > > solve this but I wonder with all these secret new listed formulas of > > > AF out there, would they effect the inner parts of these devices? > > > Apologies for the digression from topic but saw this as an opportunity > > > to query the group. Too bad GLC isn't here, he'd have $0.02 to add. > > > TD > > > > > > Cc: Jerry Van Kolken <[email protected]> > > > Subject: Air Venting (2021) > > > > > > I was reading the Air Venting discussion from early 2020 and this > > > really didn't come up. > > > > > > The code only requires a single vent, but I can think of several > > > situations where I there would every branchline would be trapped. Say > > > a tree system with BL on riser nipples, any system in an peaked roof > > > where the branchline travel up the pitch then back down. I don't under > > > stand how the single air vent relives the air from more than that > > > single branchline it would be installed on. > > > > > > I'm I think of this too much like trapped water for drainage? > > > > > > Jerry Van Kolken > > > Millennium Fire Protection Corp. > > > 2950 San Luis Rey Rd. > > > Oceanside, CA 92058 > > > (760) 722-2722 FX 722-2730 > > > > > > > > > _______________________________________________ > > > Sprinklerforum mailing list > > > [email protected] > > > > > > https://urldefense.proofpoint.com/v2/url?u=http-3A__lists.firesprinkle > > > r.org_listinfo.cgi_sprinklerforum-2Dfiresprinkler.org&d=DwICAg&c=wn3mZ > > > QLIuInh2ClcJ0_DIA&r=Z_2A85VL7AQzoqudh6uOyS3bn8etxB7nLN8OBJwQd9A&m=VbPf > > > LWCTAMUexJwVqsi76Nbq4a_wnS8qyLn9iUVi9uY&s=JxsEzZ9PEgu88glIInd633f2XKCH > > > Kz0-h8KAvFwml4k&e= > > > > > _______________________________________________ > > Sprinklerforum mailing list > > [email protected] > > > > > https://urldefense.proofpoint.com/v2/url?u=http-3A__lists.firesprinkler.org_listinfo.cgi_sprinklerforum-2Dfiresprinkler.org&d=DwICAg&c=wn3mZQLIuInh2ClcJ0_DIA&r=Z_2A85VL7AQzoqudh6uOyS3bn8etxB7nLN8OBJwQd9A&m=VbPfLWCTAMUexJwVqsi76Nbq4a_wnS8qyLn9iUVi9uY&s=JxsEzZ9PEgu88glIInd633f2XKCHKz0-h8KAvFwml4k&e= > > _______________________________________________ > > Sprinklerforum mailing list > > [email protected] > > > > > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org > > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org > _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
