Master Stream Operations: Blitz and Bomb Attack
When we talk about big water, we often think of the master stream on the tower or the deck gun on the Engine. These devices can provide up to and over 1000 gpm in a short amount of time but is often viewed as a defensive strategy. We need to start thinking beyond offense and defense as a hard line drawn in the sand. Just because we use a specific tool shouldn’t dictate our strategy. Our goal is to win at all cost and we must use the tactics which will result in that outcome. When faced with a large amount of fire, we often revert to defensive operations due to the initial size-up or impressions. Once we are the strategy of tactics, we rarely move away from that. If conditions allow, we need to be able to advance into the structure if it’s safe to do so. This will ensure complete extinguishment. How many times have you arrived with heavy fire showing, but once the bulk was knocked, the structure was able to be occupied? This can result from heavy fire on the exterior of the alpha side, fire through the attic, or out a window. These are all potential situations that we can still make a positive impact with victim rescue and property conservation. In addition, when we are able to make entry to ensure extinguishment, this could be reducing a possible conflagration if a building rekindles or further extends inside or outside the original compartment. Occupying space ensure success on the fireground whether getting hose line in the structure or searching for victims.
BLITZ ATTACK
Today, we are going to discuss utilizing the master stream in conventional and unconventional ways. First, I want to discuss the Blitz Attack and the Detroit Blitz. The Blitz Attack is performed by utilizing the master stream/ deck gun on the apparatus to apply water from the exterior onto the large body of fire, which is accessible by the reach of the master stream. Once the fire is knocked, the engine crew will follow up by making entry into the structure or final extinguishment.
Similar to the Blitz Attack, the Detroit Blitz or Drive By Blitz is a strategy used to extinguish heavy fire with the master stream but instead of stretching to the hydrant, the engine will go to the hydrant. To accomplish this tactic, the first arriving Engine will stop in front of the house and empty the tank via the deck gun. To make it the drive by, the engine then drives towards the hydrant, doing a reverse lay. The first arriving engine now supplies the next engine which is now the fire attack engine. This allows the second engine to deploy their handling and make quick entry with their tank water until the relay can be established. The only difference between the Blitz and Detroit or Drive By is hydrant location and water supply strategy. video above is Detroit Blitz.
When faced with a large amount of fire, we want to punch the fire in its face with the biggest weapon we have and that is the mater stream, producing a stream of 500-1000 gpm. This amount of water should be able to check a large fire to buy time for the crews to stretch and advance for final extinguishment. Without hitting a large, well involved fire quickly with superior fire suppression weapon, we are facing an uphill battle. With a quick check, it allows for a reset so crews can make entry or have time to get the line stretched to the interior. I am not a huge fan of "‘transitional’ attack because of the negative consequences experienced on the inside, but in circumstances where a large body of fire is present, a blitz can be very effective strategy.
If using a stack smoothbore tip, the stack should consist of 1 3/8”, 1 1/2”, 1 3/4”, 2”. If we want to estimate, we can use the rules of 8s and determine that the flow based of tip size at 80 psi is: 500, 600, 800, 1000 gpm. Now to expand on that, the 80 psi master stream pressure is an outdated pressure standard. We can safely pump these devices upward of 100-150 psi. This will stay within a safe operating procedure while maximizing your flow. So if we take a conservative number of 125 psi we have the following flows: 630, 750, 1000, and 1300 gpm. Now that is the capacity that your master stream smoothbore can flow . We always need to remember that our flow is limited on the weakest part of the system. For many, it will be the tank to pump plumbing size or the size of the size of the pipe to the deck gun.
BOMB ATTACK
The Bomb Attack, as referenced in historical publication by Chicago FD, this strategy is similar to the others but utilizes a portable master stream for when the fire is not accessible via the apparatus mounted master stream. In recent years, this operation as become much easier with new lightweight, portable master stream that have hit the market. This will entail a 2.5” or 3” stretch to supply the portable master stream at a remote part of the building. One advantage of this is the ability to also stretch an attack line off the device, either 1.75” or 2.5”.
