Understanding Residual Pressure in Firefighting

In the context of firefighting, residual pressure refers to the pressure that remains in a fire hose or sprinkler system after the water flow has been shut off. This pressure can be dangerous for firefighters and can cause damage to equipment if not properly managed.

When a fire hose is charged with water, the pressure inside the hose increases. As the water flows out of the hose and into the fire, the pressure inside the hose drops. If the water flow is suddenly shut off, the pressure inside the hose does not immediately drop to zero. Instead, there is a residual pressure that remains.

Firefighters must be aware of residual pressure when working with fire hoses and must take steps to safely release the pressure before disconnecting the hose. This can be done by slowly opening the nozzle or by using a device called a “pressure gauge” to measure the pressure and release it in a controlled manner.

Residual pressure can also be an issue in residential sprinkler systems. When a sprinkler is activated, the pressure in the system drops. If the water flow is shut off, there will be residual pressure remaining in the system. This residual pressure can cause damage to the system and can make it difficult to repair.

Properly managing residual pressure is an important aspect of firefighting. Firefighters must be aware of the potential for residual pressure and take steps to safely release it in order to protect both themselves and the equipment they use.