If only one or two sprinkler heads have been activated, which technique can quickly stop the flow while keeping the rest of the system operational during overhaul?

In situations where only one or two sprinkler heads have been activated, the use of a sprinkler wedge is effective for stopping the flow of water from those specific heads while allowing the rest of the sprinkler system to remain operational. A sprinkler wedge is a device that can be inserted between the sprinkler head and the piping to block the flow of water. This technique minimizes water damage during the overhaul phase of firefighting operations, as it prevents unnecessary flooding of the area while still allowing the system to remain active for undamaged heads, ensuring life safety and property protection.

Other techniques like closing the outside valve or charging the standpipe system would disrupt the entire sprinkler system and potentially compromise safety. Closing the outside valve would stop the flow to all heads, while charging the standpipe system would not address the specific issue of limiting water flow at the activated heads. Reverse-charging the system could create chaotic water flow and does not appropriately isolate the individual heads in question. Thus, using a sprinkler wedge is the favored method in this scenario for targeted control.