Jamey, The main drain test conducted on the incoming water supply to the building is performed to insure adequacy of the water supply compared to previous tests. Extreme changes in static or residual pressure will indicate changes in the municipal supply and/or obstructions in the piping including closed or partially closed inline valves.
The tests conducted on the sectional valves are done to insure the valve is still operational (that it will close when required) and the drain test is done to make sure that it is fully open after you closed it for the test. This procedure will indicate any dropped gates or broken valves where the valve appears to be open externally, but it is actually close internally because it is broken. rick matsuda city of dallas -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Jamey Prentice Sent: Wednesday, April 11, 2012 3:21 PM To: [email protected] Subject: RE: main drain test This one has always confused me, If you are not required to perform a residual drain test on each sectional valve assembly why does the manufacturers literature state to do so? Have included Tyco's requirements for reference: The following inspection procedure must be performed as indicated, in addition to any specific requirements of the NFPA, and any impairment must be immediately corrected. Alarm/Flow Test Procedure Step 1. Place the test & drain Valve in the "test" position. Step 2. Fully open the drain valve. Make certain that drainage water will not cause any damage or injury. Step 3. Verify operation of associated alarms. Step 4. Close the drain valve. Step 5. Place the test & drain Valve in the "drain" position. Step 6. Verify that the residual (flowing) pressure indicated by the pressure gauge is no less that originally recorded for the system when it was first installed. Step 7. Close the drain valve. Step 8. Verify that the static (not flowing) pressure indicated by the pressure gauge is no less that originally recorded for the system when it was first installed. Jamey _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum
