American Fire Sprinkler Association 12750 Merit Dr., Suite 350 * Dallas TX 75251 Ph: (214) 349-5965 Fax: (214) 276-0908
------------------- TECHNICAL UPDATE JUNE 10, 2009 ------------------- Is a waterflow pressure switch required on a dry system if the dry system is being fed by a wet system that has a waterflow switch? We have reviewed NFPA 13, 2007 Edition that you indicated as the applicable standard. Our informal interpretation is that a waterflow device is required. Section 6.9.2.2.1 indicates that the alarm apparatus for a dry pipe system shall consist of listed alarm attachments to the dry pipe valve. The purpose of the waterflow switch is to indicate that the dry pipe system has tripped due to a lower air pressure and water was introduced into the system. Even though the wet pipe system waterflow switch will likely activate, the gauges could be overlooked on the dry pipe system or the gauge readings could be meaningless to an untrained person during the waterflow alarm investigation. The standard does acknowledge that the dry pipe system can be downstream of the wet pipe system’s alarm valve in Section 6.9.2.2.2. This section allows the waterflow alarm from the dry pipe system can be connected into the wet pipe system alarm sounding or annunciating device. However, the standard also indicates that if the dry pipe system has 20 or less sprinklers, Section 8.17.1 indicates a local waterflow alarm is not needed. Applying the same size restriction to the need of a waterflow device is appropriate. ----------------- Technical Update is prepared by the Technical Services Dept. of the AFSA: Vice President of Engineering and Technical Services Roland Huggins, a PE registered in fire protection engineering; Phill Brown, a NICET IV certified automatic sprinkler technician and NFPA Certified Fire Protection Specialist (CFPS) and Tom Wellen, a degreed fire protection engineering technologist. 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. Copyright © 2009, American Fire Sprinkler Association. All Rights Reserved -------------------------- If you’d rather not receive future faxes from AFSA, fax your removal request to Amy Sweeney at Efax (214) 242-3155 or call toll free (888) 839-4830 or send e-mail request @ [email protected]. Please include your company name and the specific fax numbers(s) at which you do not wish to receive faxes from us. Our failure to comply with your request may be unlawful. _______________________________________________ Sprinklernotes mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklernotes
