Master stream mayday: Pa. video shows danger of working around high-velocity water

Situational awareness and communication are critical factors when master streams are applied with firefighter working interior


Master streams are an effective tool used to fight and suppress fire, especially in defensive situations or when distance must be maintained while pumping large volumes of water.

Master streams, like those mounted on a truck or aerial device, are capable of delivering water anywhere from 500 to 2,500 gpms at 100 psi. With a 100-psi nozzle, the velocity of the water is travelling approximately at 120 feet per second, which equates to 80 mph.

We have seen the effects of a master stream being used to knock over/push in objects, like chimneys or walls, when trying to suppress fire or remove any hazards like the chimney. The force of the water can be devastating.

Imagine it hitting a person.

Master stream strike

In our corresponding video, we have a situation where a master stream has hit a firefighter, causing a mayday situation. It is unclear how or why the master stream struck the member, only that it is never a good thing when this happens.

In the video, we see a few master streams being used to knock down fire in different parts of the building. At some point, one of the master streams hits the firefighter, causing a mayday emergency. We can see the RIT team being activated as they ascend the ground ladders into the second-story window to deal with the mayday situation.

Typically, when master streams are being used to direct water in from the exterior, firefighters are no longer inside the structure. They have likely exited the structure due to the growth of the fire – hence the need for bringing in a master stream. However, there may be times when firefighters are still needed inside to help direct the streams of water or to simultaneously perform overhaul. Regardless of the reasons why firefighters would be inside, it’s always essential to avoid being struck by a master stream.

Every firefighter must be aware of their surroundings. In the absence of situational awareness, tunnel vision sets in. Tunnel vision is easy to allow, as our focus becomes fixated on our most critical task in that moment. Although the situation takes place during winter with snow falling, regardless of the time of year or weather occurring, situational awareness needs to take place with due regard for what is happening in our environment – as in the case of master stream application.

Communication is going to be key with avoiding situations like this. Interior crews must know what is coming their way. This is where the operations chief or officer can be instrumental – they can communicate with the aerial ladder crew as well as the interior crew to coordinate the operation. If there is no operations section officer, then the officer assigned to the crew working inside needs to be communicated to by the aerial ladder crew or by command. Even the incident safety officer (ISO) can be involved with the communication between the interior and the exterior crews.

Training time

After watching this video with your company, take time to do the following:

  • Discuss the possible failures that could lead to a firefighter being hit by a master stream; and
  • Review your department’s operational procedures related to master stream use.
  • Ensure that the aerial operator directing the master stream communicates with the interior crews about water coming
  • Ensure the ISO informs or checks on the interior crews prior to master stream application into a building. The ISO can make sure the interior crews are out prior to application.

Editor’s note: Have you ever been struck by a master stream? What was the experience like? Share in the comments below.

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