Fire departments all across the country have the responsibility for protecting their communities from the ravages of fire both big and small. It would be ideal if all fire stayed in the small range requiring only one or two hand lines to extinguish. There are some communities that pretty much fall into this category but even they have the potential for a large fire. It is the small fires that we tend to have the most experience in either by working a lot of them or from simply just training or both. Think about it, when it comes to water delivery on a small fire it’s very basic. Fire attack is started from the onboard booster tank from the first-in engine and if a sustained water supply is needed a supply line is laid from the hydrant. If I had to put a number on it I would say just about all small fires can be handled with 500 GPM or less.
So what happens when we do get the large fires? When it comes to water delivery this is where a lot of fire departments tend to struggle to develop the required flow. The problem isn’t coming up with the required streams in regards to deploying the actual lines and appliances. Actually it’s pretty basic. On large flowing fires it’s the master streams and large hand lines that usually get put into play. Whether its smoothbore tips or combination nozzles being used, the goal is to put the big ones into service. This is half the battle but now we have to get the required flow delivered from the water supplies to support the big streams.
The introduction of large diameter hose many years ago seems to most like this would be the solution to the water supply problem. In fact fire departments did see a dramatic increase in water delivery when they switched to large diameter hose. So why is it when we get fires that require large flow water delivery and we use large diameter hose for our supply lines that we still run out of water? For those of us that were around before large diameter hose, especially the pump operators, you know that they really had to work to deliver the required flow on large fires. Relay pump operations were the norm supplying multiple 2 ½ and 3 inch supply lines to the fire. Fire departments knew what they had to do to move water through their small supply lines. Then came large diameter hose and all the fancy pump operations fell to the wayside. The true fact is that we still need special pump operations even with large diameter hose to move the water from the water supply to the fire ground.
The real problem when you analyze water delivery operations from fire hydrants isn’t usually a lack of water at the source. The water in a stored capacity in the water mains is almost always available. It is the hydrant system pressure, or should I say residual pressure, that is usually lacking to move the required flow for the required distance. In order to get the job done it may take using multiple hydrants as well as hydrants on other grids further away in conjunction with specific pump operations. But for the most part as long as the manpower, equipment, and the will to get the job done are all available the required flow can usually be produced.
As I’m sure you know the overall fire ground operation consists of several companies working in a coordinated effort under the direction of an overall supervisor to execute a fire attack as safely and efficiently as possible. All phases of the operation need to be conducted at the proper time, again to make the final outcome of the operation successful. This is where obtaining and successfully delivering the required flow from a water supply becomes crucial.
Oftentimes the request for more water is put out when the existing water supply becomes depleted. Keep in mind that on a large scale fire there’s a good possibility that multiple supply lines from the closest hydrants are already in place. Bringing in additional supply lines from new water sources will more than likely require long hose evolution’s preferably set up in the relay pump operation to get maximum flow. From the time the request comes in for additional water until the time the operation is set up and ready to deliver can easily take 10 to 15 minutes. If the current water supply is already depleted and frantic requests are coming in for more water, 10 to 15 minutes is too long to wait.
Multiple large streams usually can’t be supplied from the initial hydrant. A secondary supply line needs to be brought in.
Getting a relay operation ready for service takes longer than you can afford to wait when you are out of water. You have to be proactive
The best way to implement the request for additional water is to be proactive. Don’t wait until the operation needs more water, have it ready for them before the request is made. Setting up additional water supplies during the initial phases of a large flow operation will allow the overall water supply situation a better chance for success in fulfilling the required demands for the fire streams without interruption.
Here are two suggestions on how to proactively deliver additional water to the fire ground. When command is established on a fire that has the potential to become a large flow operation, if possible one engine company from the first alarm assignment should be given the task to establish a supplemental water supply. The engine should start its evolution from the fire ground at a strategic location where the additional water may be needed. If the line is not ready to be connected to an engine simply have a firefighter anchor the line. The engine should try to lay to a hydrant that is on a grid separate from the current hydrants already being used. The engine should also set up at the hydrant for relay pump operation. After making the hookups to the hydrant the operator should charge the lines however unless the water supply is already needed at the fire do not charge the supply line itself. The reason for doing this is that if the line turns out not to be needed it will be a lot easier to pick up dry versus having to drain a charged line. The trade-off for this is very minor. Charging a supply line should only take a couple of minutes.
Another thing to consider in proactively seeking additional water is to make special requests in the dispatch assignment for units that will be totally dedicated to bringing in additional water through supply line evolutions. Let’s say for example a particular fire requires a three alarm assignment to meet the challenge of the fire attack. Consider making a call for a fourth alarm with the additional alarm being assigned to water supply. I understand that not all agencies have these kind of resources. However having some type of plan for additional water will make for a better chance for a successful outcome on the fire ground.
The following two illustrations show a first alarm and section alarm assignment. Note that the first alarm shows an engine that laid a proactive supply line set up for a relay. The receiving end of the line is not connected to an engine basically because at the time it was deployed there was no need for the extra water. The second alarm shows the proactive relay connected to an engine to supplement the depleted water supply. There is also an additional relay set up with the second alarm assignment.
FIRST ALARM ASSIGNMENT
SECOND ALARM ASSIGNMENT
The following illustration shows how just three engines can deliver 5000 GPM.
Timing is crucial when implementing the various assignments involved with maintaining a positive water supply on a large flow operation. It can be intense, time-consuming, and resource consuming. Taking a proactive approach in dealing with the water supply is extremely important simply because the fire itself does not wait for the required water supplied to be delivered. Just a few minutes can make a huge difference on the outcome of a large flow fire.