Fire Inspector's Guide: How to Install Auto Sprinklers

Hire a licensed contractor or registered engineer to design the sprinkler system in accordance with NFPA and local fire codes. Regulations usually require the system designer to stamp and sign the plans. Outline in the plans drawings and specifications for items, such as the main control valves, types of pipe, supply lines and pipe diameters. Include in the plan the alarm bell, connections for fire department equipment and the technique to prevent freeze in the system.

Compute the hydraulic requirements for the fire sprinkler system. This component calculates the pipe and valve sizes to ensure that each sprinkler head has the proper water pressure and flow. In addition, the computations must allow the correct amount of water to the sprinkler heads and the loss of pressure, which occurs in various parts of the system. Submit the plans to the local Fire Marshall or other designated authority to obtain approval for the system.

Follow the NFPA list of approved materials for pipes, which includes alloy, steel or copper piping. Run the pipes along beams, wall studs and floor joists. Install sprinkler heads that require a minimum flow to activate the unit. Slope horizontal pipes, one-inch for every 40-feet of the pipe run, back toward the drain located on the riser. Connect the fittings for the fire sprinkler heads. Install bracing to limit lateral and vertical movement of the pipes.

Attach fire department connections at the appropriate intervals to assure access within 150 of any space in the home. Position the connections 3 to 5 feet from the floor. Install the system's drain, control and test valves. Mark all valves with waterproof identification tags. Run water through the supply pipes to flush out any debris before connecting the sprinkler heads or the riser.

Connect the sprinkler heads to the system. Install the riser -- the vertical supply pipe leading from the water meter, which supplies water to the system. Connect the alarm mechanism and the gate and drain valves on the riser. The alarm activates the system. The gate valve opens and closes the flow of water to the pipes. The drain allows for the removal of water from the system for maintenance and repairs. Test the system at 200 pounds per square inch for two hours or per local fire code requirements. Have the system inspected and approved by the local inspector.