By Paul Shapiro
Now, it’s my turn: Following are my words of wisdom on moving the big water.
Rule 1. Tradition and pride can be hazardous to your health.
Tradition and pride make the fire service go round. They are fun, they promote camaraderie, and they’re “easy.” What do I mean by “easy?” Look at these statements, and tell me if they sound familiar:
- We’ve always done it this way, and the fires have always gone out.
- This is an aggressive fire department; we go in and attack the fire.
- Fire departments that make exterior attacks are known as “foundation savers”; they’re a bunch of wimps.
- Pump 150
- Smooth bore tip nozzles are the only ones that work.
- Automatic nozzles are the only ones that work.
- This one is my favorite: We don’t get those kinds of fires here (large ones).
The list goes on an on. I’m sure all of you have your favorites. If you analyze each of these statements, you can find one common denominator: It is easy. You don’t have to change anything; there are no studies or evaluations to do, and there is no risk-taking to endure. You just do the same thing over and over again. Well, guess what? The times are changing. Take a look at the history of the fire service. We’ve gone from horse-drawn wagons to motorized apparatus. We traded in our buckets for hose. We have gone from no self-contained breathing apparatus (SCBA) sucking in all the life-destroying particles, to using SCBA. And of course, we’ve gone from 2½-inch supply lines to large-diameter hose (LDH). I would like to have been a fly on the firehouse wall when some of these changes were made or, for that matter, just suggested. Are you starting to get the picture?
My one recommendation is to keep an open mind. Tradition and pride are a very important parts of the fire service, but don’t let it get in the way of making your job easier and, more importantly, safe.
Rule 2. Keep it simple.
Firefighting definitely gets high marks as far as degree of difficulty is concerned, both mentally and physically. Let’s face it. We are dealing with an abnormal situation we did not create and did not get any say-so in when and where it would happen. Therefore, it is extremely important to make our job as easy to perform as possible. What does this mean when it comes to flowing big water?
• Get rid of the formulas
We have all been taught the formulas for calculating the required fire flow for a structure fire. First of all, who says that one person’s approximation of what the dimensions of a structure are is going to be the same, or even close, to yours or the next guy’s? Second, how sharp are you going to be in your estimation at 2 a. m.? when you are first in and the whole world is on fire? If you are like most of us, things could be a little cloudy. Instead of using this formula, why not break fire flows down into three categories: small, medium and large?
Small fires can be, for lack of better words, the junk fire flows that require small amounts of water to extinguish [50 gallons per minute (gpm) works good]. You know these types of fires–small trash and brush fires or possibly a smoldering fire under the hood vehicle. These are the fires for which we use the booster line.
Medium fires are for the most part the interior compartmentalized structure fires where an interior attack will be attempted. Flows of 120-150 gpm seem to work well on them.
Finally, large fires are basically just that– the big ones. They can be large structures where both the exterior and interior are fully involved or large vehicle fires. Basically, these fires are anything that necessitate more than your standard small-diameter handline to extinguish rapidly. What kind of flows are we looking at? As much as possible based on water supply, personnel, and equipment. I would not hesitate to hit a fully involved two-car garage with a 1,000-gpm stream from a deck gun under the right circumstances. The bottom line is, hit the fire with as much water as you can develop based on the circumstances presented.
• Calculating Engine Pressures
Oh no, not more formulas! Yes, it’s called fireground hydraulics. Books have been written on this subject; in fact, there are even college courses on it. Here’s the scenario. It’s noon, and you’re first in on a ripper. The crews are screaming for water. The first evolution deployed is at least 200 feet of 3-inch hose wyed off to a manifold with two 1¾-inch handlines and one 2½-inch handline. The requested flows are as follows: 1¾-inch, 150 gpm each and 2½-inch, 250 gpm. Quickly, what is your engine pressure? Hurry up! We need the water! We’re getting clobbered here!
Hydraulic formulas have no place on the fireground. They are too difficult and require all of the figures to use. What if you don’t know how much hose is on the ground? The formulas will not work. I really get a kick out of the formula for relay pumping. You’re asked to establish an engine pressure for the source pumper based on the size and length of the hose and flow requirements. The truth is that in a relay pump operation, which could be long, the amount of hose is usually not known. Sometimes it takes two or more units to complete the lay. How about the flows? Most of the time, the actual flow is not known until the evolution is completely set up and engine pressures are established.
Let’s keep it simple. Pump charts can and should be used to develop all engine pressures. Pump charts are reference charts that have precalculated pressures to work with any hose evolution your department will ever have to perform–for example, preconnected handlines, fixed master streams, foam operations, sprinkler operations, high-rise building fire protection systems, and relay pumping. The more exact the engine pressures that are listed, the better.
For some of the make-or-break evolutions, basic math should be all you will ever need. A listing of statistics will help this process, such as the friction loss per 50 feet of hose for all sizes, nozzle pressures, master stream appliance friction losses, elevation gain or loss, and so on.
Always look for the easiest, most simple way to do a task. Can the current method be done at 2 a. m. under a lot of stress and with minimum personnel? If not, then it’s time to reevaluate and find an easier way.
Rule 3. The water’s out there; you just have to go get it!
How many times have you heard the excuse of a poor water supply given as the reason for losing a building to fire? I get a kick out of watching the evening news telling about a major fire where everything was lost and the chief in an interview blames a poor water supply. What’s really funny about this when you look in the background is that you see LDH on the ground and the fire building is in the middle of a major city. Major cities and even normal-size cities for the most part have hydrants available for miles. How then does the water supply problem occur? What usually happens on big fires is that the hydrants closest to the fire building are connected to supply lines. Why? Because they’re the easiest ones to get to. As the fire gets bigger, the water supply in the immediate area of the fire building gets diminished. This is where most departments, especially the ones using LDH, give up and say we are out of water. If we can’t get it with 5-inch lines, then there isn’t any more water. In reality, they are not really out of water in the sense that they cannot obtain morel The water’s out there, they just have to go get it” Long-distance relay supply line operations and water-shuttle operations are two ways to obtain more water.
Preplanning of your high fire flow potential areas in conjunction with taking a good look at what your department’s equipment can produce for a big-flow operation is essential for developing a plan for the big one. Don’t get me wrong. There are situations where true water supply problems exist. However, before throwing in the towel, look at all your options. You never know. You might come up with a solution.
Rule 4. Don’t mess around: just blast it!
Attacking a big fire with a low-flow stream is like elephant hunting with a BB gun. There’s a basic rule of thumb that Mother Nature gives us: “It takes so much water to put out so much fire.” Plain and simple! If the amount of water isn’t enough to put out the size of the fire you’re dealing with, the fire won’t go out, at least not quickly.
Formulas that tell us how much water we need for a building of a specific size. This is good for books, but not for practical application. The bottom line is, Hit the fire with as much water as possible based on your personnel, equipment, and water supply situation in an attempt to overwhelm the fire. If 250 gpm will knock a fire down fairly quickly, then 500 gpm will be even faster.
Let’s look at a very common scenario that most cities deal with, a mobile home fire. Let’s say that we’ve got a full assignment responding to a mobile home fire. The first-in engine company has laid a 5-inch supply line from the hydrant 300 feet away. It has 500 gallons immediately available from the booster tank and is faced with two immediately threatened exposures, one on each side of the fully involved mobile home. What usually happens is that the crew will pull preconnected handlines to cover the exposures until the water supply can be established. The key here is to protect exposures while conserving the water from the booster tank. With two lines out, you know as well as I do that there is a chance of draining that 500-gallon booster tank before the supply line is charged. And guess what? The fire that was creating the exposure problem is still there and is probably burning with more intensity, and now you’re out of water. Have you conserved water or wasted it?
Let’s use the same scenario but change the initial attack. We’re still going to lay the supply line, but this time instead of pulling the preconnects, we’re going to get on top of the engine, swing that deck gun around ,and blast the fire building with everything we’ve got (most booster tank operations can produce only 500 gpm), and knock the fire out. If we don’t knock it completely down, there’s a real good chance that we will turn it into a lazy type fire that is going nowhere instead of a raging inferno. This should take only 15-20 seconds. At a 500-gpm rate, a 20-second blast will use only 166 gallons of water. The above mentioned operation is known as a “blitz attack.”
Rule 5. The only thing too much water will do is put the fire out faster.
Question: If it takes 30 seconds for a 200-gpm stream to extinguish a fire in a building, then will a 500-gpm stream take more or less time to extinguish the same fire? The answer is obviously less time. This is simple stuff. Don’t be afraid to throw as much water as possible in the given situation to put the fire out. The key to this operation is to overwhelm a fire, stopping it as quickly as possible, and then shutting the stream down. If done correctly, there is a real good chance the fire will be extinguished faster and with less water.
Rule 6. It’s easier to design a pumper to flow large volumes of water and not need it than it is to flow large volumes of water from a pumper not capable of doing it.
All pumpers should be designed for flowing large volumes of water. This involves big pumps, large plumbing, large master stream appliances, multiple large intakes, and LDH–the larger, the better. This decreases the friction loss in all parts of the water-delivery system, which decreases the horsepower needed from the engine of the pumper. All this makes for a more efficient operation. It is extremely possible to double a pump’s capacity with a unit designed for big flows. It will easily handle the small flow needs as well. Now, let’s turn it around. How easy will it be for a unit designed with standard plumbing, appliances, and hose to push the big water?
Rule 7. Pump it up!
Here is another one of those Mother Nature rules: “Water moving through fire hose, nozzles, and discharge plumbing require a positive pressure.” High-flowing and hard-hitting streams can require higher than normal engine pressures to produce. We in the fire service can sometimes be paranoid of these higher pressures for fear of equipment failure and potential accidents. Well not to worry! The manufacturers of all of our fine equipment also have that fear. That is why they have designed their equipment to withstand the pressures needed for the big-water operations. Take a look at this list of statistics:
- All water-passage components within the fire pump system of a fire apparatus have to be able to withstand 600 psi.
- Most small-diameter handline type hose today comes with a 400-psi service test pressure. According to National Fire Protection Association standards, this pressure needs to be 10 percent higher than the maximum operating pressure. That gives us a maximum working pressure of 360 psi.
- Manufacturers of master stream appliances have given us a maximum working pressure ranging from 175 to 200 psi, depending on the make of the appliance.
Now keep in mind that when these pressures were established, the manufacturers knew that firefighters would be using it and could possibly mess up and over-pump it, so a safety factor was built in. The above-mentioned equipment can actually withstand more than the cited maximum pressures. What does all this mean? It means that 1¾-inch can produce 300-gpm streams, 2½-inch and 3-inch handlines can produce 600 to 800-gpm streams, and smooth bore tips on master stream appliances can operate at nozzle pressures reaching 175 psi, capable of producing killer streams.
Rule 8. Unless it’s written by the manufacturer, it can be challenged!
Training in the fire service is provided by hand-me-down information from fire service textbooks, fire department standard operating procedures, and fire department instructors. The fire service, as is the rest of the world, is ever changing. We need to be able to adapt to these changes and sometimes improve or change the way we do things. For some reason, the fire service, when it comes to water delivery, tends not to want to change, as is evident from some of the information out there. We need to take a hard look at how we do things and see if there is need for improvement. Don’t be afraid to invent new procedures and techniques that may enable us to do our jobs better. Just because it’s not written yet doesn’t mean it can’t be done. Don’t be afraid to be the pioneer. The only limiting factors in our quest for improvement should be the manufacturers’ guidelines established for the equipment being used.
Paul Shapiro is director of Fire Flow Technology. He is a nationally recognized instructor on large-flow water delivery. He is also a retired engineer from the City of Las Vegas (NV) Fire Department. He has authored numerous articles for fire trade magazines. He has been in the fire service since 1981 and is author of Layin’ the Big Lines and produced the first in a series of videos on large-flow water delivery. He is available to answer questions; he can be reached at (702) 293-5150 or Layinline @aol.com.