Where is a main sprinkler system valve typically installed?

A main sprinkler system valve is typically installed on the main riser, above the water supply control valve. This placement allows for proper control and isolation of the sprinkler system from the water supply, facilitating maintenance and ensuring that the sprinkler system can be operated independently from the water supply valves. By being above the water supply control valve, it ensures that the supply pressure to the sprinklers is maintained even when the water supply control valve is manipulated.

The arrangement also aids in the overall system's accessibility and functionality, enabling firefighters to quickly locate and operate the valve in emergency situations. It helps in preventing any issues that could arise from water flowing into the sprinkler system during maintenance or repairs that may be necessary on the water supply side.

The other placements mentioned are less ideal for practical and operational reasons in the context of fire safety and sprinkler system management.