2702 HOYT AVE 2018-01-02 MF Import

March 2, 2007 L NIIQivc13 • Div 101c DRY PIPE SPRINKLER SYSTEM The Viking Corporation, 210 N Industrial Park Drive, Hastings MI 49058 Telephone: 259-945-9501 Technical Services: 877-384-5464 Fax: 269-818-1680 Email: techsvcs@vikingcorp.com 4. OPERATION When a fire occurs, the heat produced will operate a sprinkler causing the air pressure in the piping system to escape. When the pressure trip -point is reached (directly or through the accelerator), the dry -pipe valve opens allowing water to now through the system piping and to the water motor alarm or electric pressure switch to sound an electric alarm. The wafer will continue to flow and the alarm will continue to sound until the system is manually shut off. A dry pipe valve equipped with an accelerator will trip more rapidly and at a higher air -pressure differential Component parts of the dry pipe system operate in the following manner A. DRY VALVE OPERATION When the air pressure in the dry system has dropped (from the fusing of an automatic sprinkler) to the tripping point of the valve, the floating valve member assembly (air plate and water clapper) is raised by the water pressure trapped under the clapper Water then flows into the intermediate chamber, destroying the valve differential As the member assembly rises, the hook pawl engages the operating pin which unlatches the clapper The clapper is spring -loaded and opens to the fully opened and locked position automatically B. ACCELERATOR OPERATION The accelerator operates on the principal of unbalanced pressures. When the accelerator is pressurized, air enters the inlet. goes through the scrren filter into the lower chamber and through the anti -flood assembly into the middle chamber From the middle chamber the air slowly enters the upper chamber through an orifice restriction in the cover diaphragm. In the SET position the system air pressure is the same in all chambers The accelerator outlet is at atmospheric pressure. When a sprinkler or release operates, the pressure in the middle and lower chambers will reduce at the same rate as the system. The orifice restriction in the cover diaphragm restricts the air flow from the upper chamber causing a relatively higher pressure in the upper chamber. The pressure differential forces the cover diaphragm down pushing the actuator rod down This action vents the pressure from the lower chamber to the outlet allowing the inlet pressure to force the clapper diaphragm open. The pressure in the accelerator outlet forces the anti -flood assembly closed preventing water from entering the m!Jdle and upper chambers. On a dry pipe system the art pressure from the accelerator outlet is directed to the dry pipe valve intermediate chamber As the au pressure increases in the intermediate chamber, the dry valve pressure differential is destroyed and the dry valve trips allow- ing water to enter the dry pipe system. On a pneumatic release system, the Outlet pressure ,s vented to atmosphere, speeding the release system operation. PLACING THE SYSTEM IN SERVICE 1 Shut off the supply control valve. Check the entire system to ensure all piping, sprinklers. and piping components are in .,erviceable condition Replace any opened sprinklers with the same type and temperature rating. Dram all low points of the system: then, close all drain valves. (On a drum drip, the upper drain valve remains open and the lower is closed.) For air check system or auxiliary dry systems, drain the dry portion of the system only 2 Set Dry Pipe gyslem a. If an acaeleratu: is used, with no pressure on the system, observe the air gauge on the accelerator. The gauge must read zero (It may be necessary to loosen the air gauge to vent the trapped au pressure in the upper chamber) b. Set Dry Pipe Valve - Open the test drain valve, remove the hand -hole covet . wipe the valve seat , ^an, pull the clapper down into the CLOSED position (hold while inserting wrench handle through hock -pawl assembl; hole), slide wrench handle through hole approximately 1 inch (25 mm). apply upward force on wrench and latch the dry -valve clapper. remove the wrench. fill the dry valve with water to the bottom of hand hole, replace hand -hole cover. c Pressurize dry -pipe system with air pressure as recommended in the Dry Valve Data Section Water Pressure psi Max 50 75 100 125 150 Air Pressure psi Mill 15 20 25 30 35 Max 25 30 35 45 50 of Wail until the accelerator air -pressure gauge wads the same as the dry pipe valve e Open water supply control valves slowly. f Close the dry pipe valve main drain valve slowly. g Make sure the Alarm Test Shut-off Valve is in the ALARM position 3/-721