We have had a question come up about main drain testing per NFPA 25: In the NFPA 25 2011 handbook it states:
13.2.4 Before opening a test or drain valve, it shall be verified that adequate provisions have been made for drainage. The commentary for this item includes the phrase: In high-rise buildings with the sprinkler riser in the stairway, a separate drain line is often installed that is one diameter larger than the largest main drain valve connected to the drain line. The drain line should not be considered a main drain connection, but should be viewed as an auxiliary drain for each floor. Unlike the main drain, the auxiliary drain is not intended to be flow tested. The auxiliary drain line can be used to conduct flow tests on pressure regulating valves installed in the fire sprinkler system and in the fire department standpipe system, and also to test the system flow switch. This is followed up with the testing requirements: 13.2.5* Main Drain Test. A main drain test shall be conducted annually at each water based fire protection system riser to determine whether there has been a change in the condition of the water supply piping and control valves. (See also 13.3.3.4.) Additionally this annex material is presented: A.13.2.5 Main drains are installed on system risers for one principal reason: to drain water from the overhead piping after the system is shut off. This allows the contractor or plant maintenance department to perform work on the system or to replace nozzles after a fire or other incident involving system operation. The test for standpipe systems should be done at the low-point drain for each standpipe or the main drain test connection where the supply main enters the building. NFPA 13 2010 Handbook states: 8.16.2.4.5 For those drains serving pressure-reducing valves, the drain, drain connection, and all other downstream drain piping shall be sized to permit a flow of at least the greatest system demand supplied by the pressure-reducing valve. And the handbook expands with: Piping controlled by sectional valves represents a significant segment of the sprinkler system. Sectional or floor control valves serve the same function for that portion of the system as the main drain does for the entire system. The use of express drains in high-rise nuildings is one method of disposing of water from upper floors. Express drains or floor drains used when the drain does not drain directly to the outside must be capable of handling the flow and not restrict it. Is the NFPA 13 material meant only to apply to the full flow testing of pressure reducing valves? We have some concern that these two standards conflict on the idea of "express drains" when it comes to floor control manifolds not installed on combination standpipe risers. With a dedicated sprinkler riser is the intent to use a full flow main drain test at each floor control valve, or only at the lowest level of the building on the lead in? Floor control valves aren't explicitly defined but appear meet all the requirements of a "system riser" which is defined, and is the term used in the actual code material. Mike Morey, SET, CFPS Sprinkler Designer BMW Constructors, Inc. O: 317.651.0596 | C: 317.586.8111 www.bmwc.com -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://fireball.firesprinkler.org/mailman/private/sprinklerforum/attachments/20120209/955cf7e9/attachment.html> _______________________________________________ Sprinklerforum mailing list Sprinklerforum@firesprinkler.org http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum
