I have wanted to write this article for a long time now and wanted to keep it as basic as possible. I was talking with my wife, trying to come up with an opening statement that would be basic and have enough information as possible to explain what I’m trying to say. So here’s what I discussed with her. When we go out in our recreational vehicle, a lot of times we set up campfires, and sometimes when we are ready to call it a night, the fire is still burning so we like to put it out instead of letting it burn unattended. So here’s a question I asked my wife: If you have a choice of putting out this fire, which is in about a four-foot-diameter enclosure, with a squirt gun or a garden hose, what would you choose and why? Her answer was simple: She would choose the garden hose because it would put the fire out a lot faster.
I like to look at YouTube videos of large fires not just for the entertainment factor but for educational purposes. Again, I asked my wife to watch one of these videos, which showed a three-story, wood-frame residential complex, I’m guessing 50 × 100, with the whole front of the structure well involved. Now understand that I was not present at this fire, so I’m not going to really call this a critique of this fire department’s operations-that would not be fair. Instead, I am going to use it as a learning tool. The first line out on this large fire was a 1¾-inch handline that went to the exposure. The second line out was a 2½-inch handline with the triple stack smooth bore tip combination with the entire stack still attached to it. In other words, they were using the one-inch tip and, if it was being pumped correctly, they were getting 210 gallons per minutes (gpm). Because my wife and I have been married 35 years now, and I have been teaching this subject for the same amount of time, she is semi-versed in what my concepts and theories are all about. So I asked her: Is there anything else they could be doing that might put this fire out faster and save the exposure? Without any hesitation, she asked, “Why don’t they fire up the deck gun and blast the heck out of it?”
Avoiding the Blast
The concept of using large flow streams to put out fires is actually pretty simple and, as far as firefighting goes, is also pretty safe for the firefighters. You’ve all heard the statement, “You have to match the gpm to the British thermal units (BTUs).” I go one step further and say that you have to overwhelm the BTUs with the gpm.
A list of reasons fire departments do not practice the overwhelming blast concept includes the following:
- Firefighters do not understand their equipment and capabilities.
- Firefighters don’t understand the fire science of overwhelming BTUs with gpm.
- Lack of training.
- Lack of understanding of water delivery not just from the discharge side of the pump but also in regard to water supply.
- Firefighters tend to do what they have always done.
- It’s not fun.
If your department is one that lacks sufficient water delivery for large fires, I’m sure you can probably relate to some of these and maybe others that I have not talked about. The bottom line: We need to start thinking and practicing these big hits on certain fires to do a better job of controlling and finally extinguishing the fire.
Here is my theory on exposure protection: If there is an exposure problem with first-in companies, there is a decision to make. Do I protect the exposures with water application or do I knock down the problem that is creating the exposure-the fire? If you think that a direct attack on the fire can knock down the fire in seconds to a point where it is not hot enough to impact the exposure, then go for it. If not, then the direct application of water on the exposure is warranted. If you choose to hit the exposure creator, then knock the snot out of it. Hit it with everything you possibly can within your limitations.
I’d like to talk about two topics from my above-mentioned list that will greatly improve the knockdown capabilities of large fires. Usually when I discuss water delivery, I always start with the water supply; however, in this article, I want to start with required streams and then talk about developing the required water supply to feed the streams. The reason for this is simple: A lot of times bigger tips or larger flows are not used simply because crews do not have the water to support them-or at least they think they don’t.
Every apparatus should have at least one designated handline that can be used for a large flow operation, whether it’s preconnected or simply stored in the hosebed. It should have a nozzle that will flow a maximum amount of water based on equipment and department policies. Here’s a good example: a preconnected 2½-inch handline, 200 feet long with the triple stack smooth bore tips, which are all connected to the nozzle. I personally don’t believe in the triple stack tip because even though it gives the firefighter the opportunity to dial in the flow, it seems to never happen. The entire stack is just about always left on the nozzle, which means that the one-inch tip is what is flowing, and if it is pumped right the flow is 210 gpm.
Let’s say that firefighter on the nozzle wants to go bigger and go to the 1¼-inch tip to get 328 gpm. To do this, a different pump discharge pressure needs to be used. Now there’s a communication issue where the pump operator needs to know what size tip is being used on the nozzle to get the correct flow. A lot of times this can be a problem. Here is my recommendation: Keep one size nozzle in regard to its flow capabilities and nothing else. If it’s smooth bore tips, keep the one tip on there that you would like to get the biggest flow from. So instead of keeping the triple stack tip on, just have a 1¼-inch tip. With this setup, the firefighter will know what he is getting and the pump operator will know what to give him. If you choose to go with a combination nozzle, whether it’s an automatic or a fixed gallonage, go to the maximum flow available from the nozzle. Most combination nozzles have a maximum flow ranging from 250 to 300 gpm. The key is to have one flow so there’s no confusion as to what will be delivered on the handline. If it’s an automatic nozzle, pump to the maximum flow that the nozzle is capable of. For example, a 100- to 300-gpm automatic nozzle should be pumped as though it’s flowing 300 gpm. If for whatever reason the firefighter needs to gate down the nozzle, then he can do that on his own without communication to the pump operator.
Let’s paint a fire scenario. You pull up to a triple-wide mobile home in a mobile home park, and it is fully involved. The second-due engine is about a minute away from getting you a five-inch supply line from the hydrant. There is a mobile home on each side of the fire, and they are in immediate danger of lighting up. You have a 750-gallon booster tank, and your pump per National Fire Protection Association specs is designed to give you 500 gpm from the booster tank. Here’s the question: Do you pull lines to protect the exposures or hit the fire and the exposure creator and attempt a quick knockdown, which will eliminate the exposure problems and the danger of fire spread itself? Remember, a knockdown is not necessarily an extinguishment; it is a stifling of the fire to a point where, at minimum, it is not spreading and is not endangering anything else that has yet to burn. With a little bit of experience on how many gpm are needed for specific sizes of fire, the correct decision can be made a big majority of the time. Of course, if you are in doubt whether you can obtain a knockdown, then exposure protection would be the right thing to do. I have done numerous flow tests on actual fires with 500 gpm flows and achieved knockdowns ranging from five seconds to 30 seconds on fairly large structures equivalent to a triple-wide mobile home or what is famously known back East as taxpayers, which are convenience store-sized structures.
Okay, now it’s time to increase the size of the fire. Remember the fire that I described to you that I saw on YouTube that was a three-story apartment complex well involved in the front? Now we’re talking about streams of it least 1,000 gpm-notice I said streams. Again, a study of YouTube fires that are multicompany operations with the big guns flowing reveals a high percentage of the time the entire stack of tips is left on the master stream appliance. In fact, one of the videos I saw had audio with it and you can hear the order being given to use the 13⁄8-inch tip. If that tip is being pumped properly, you can expect 500 gpm. The problem is that the fire is probably a 2,000-gpm fire.
The same decisions need to be made on whether to protect exposures or hit the fire; however, this time one large and more complicated decision needs to be made if you’re going to hit the fire with the proper flow. Where might you get the water from? The fire on YouTube was in a major city and involved a major fire department, meaning that apparatus and fire hydrants were plentiful. This department used five-inch-diameter hose and grabbed the closest hydrants to the fire. I’m not sure why it used the 13⁄8-inch tip, but a common reason for this is because members ran out of water even using large-diameter hose (LDH). I have a little phrase that I like to use all the time, “The water’s out there; you just have to go get it.” Most departments with LDH lay from the closest hydrants, and when they develop water supply issues they give up. Word gets back to the incident commander (IC) that they are out of water, and the IC directs everybody to gate down to where we get streams that will reach the fire. Guess what? The fire eventually goes out.
Here’s what needs to be done. First, if a master stream is going to be used for a sustained water delivery operation (in other words, not a tank water blitz attack), the goal should be to supply the rating of the appliance. Most fixed mounted master stream appliances on engine companies are rated to flow 1,250 gpm. This is not achievable with the two-inch tip, which is the largest in the stack because of appliance restrictions. A 1,250-gpm master stream appliance has a maximum allowed inlet pressure to the device of 200 per square inch (psi), and based on the 1,250-gpm flow with a 100-psi nozzle, pressure with a combination nozzle can only flow up to 631 pounds nozzle reaction. In my testing, I have found that a 1,250 appliance cannot reach 1,250 with the two-inch tip because of the nozzle reaction limitations. So, with that being said, either use a combination nozzle for 1,250 gpm or set the goal for a fixed master stream with the two-inch smooth bore tip for 1,000 gpm.
Here is another example of a maximum flow operation from a single unit. The unit is a 2,000-gpm elevated platform with a pump. Department standard operating procedures require a 2,000-gpm flow, so here is the evolution that will produce it efficiently. The quint gets the initial water supply with five-inch hose from the closest hydrant. Unless the fireground area is already being tapped by multiple hydrant use, or if it’s known that the hydrant is weak, I don’t see a need to make this line a relay pump operation; however, it would not be wrong to set it up as one. Most hydrants cannot supply 2,000 gpm, but even if a hydrant can, one of the issues that will be encountered with this operation is an extremely high revolution per minute (rpm) from the engine on the quint. What I recommend is to automatically lay a second five-inch supply line back to a hydrant and set up for a relay/tandem pump operation, which will bring in the extra water if needed and will assist the engine of the quint by lowering its rpm because of the pressure being brought in from the relay.
Whether a high-flow handline or master stream is going to be placed into service, it needs to hit the fire. I know you are thinking, does this guy think we are stupid? Not at all. What I mean is, move the stream around to hit as much fire as you can from your location. So often I see that when a big stream is aimed into a fire, it looks like a big drill trying to drill a hole. It doesn’t move. It almost seems like crews are trying to fill the building up with water from that point.
Water Supply Evolutions
When a multiple master stream operation is going to be put into service to fight a sustained fire, this means that you have to have the water supply to deliver this flow. If the water is not available from the closest hydrants from the initial supply line, then another engine needs to reverse out to a more distant hydrant that is hopefully on another loop and relay pump. This is something we used to do all the time before LDH. Big water meant putting pumps on hydrants to pump to the engines that were delivering the water. LDH has made a big change in water delivery. However, the real magic in the hose realistically is for small fires that allow hydrant pressure to deliver the required flow. When it comes to the big fires where multiple master streams are needed, more than likely we need to go back to the old days in regard to our operations and set up the relay pump operations to move the required water. The good thing is that LDH used in the relay will really move a lot of water, especially compared to dual 2½- or three-inch lines used in the old days. As a little side note: It takes five 2½-inch lines to equal one five-inch line and four three-inch lines to equal one five-inch line.
The logic for the IC should be not to wait for a water supply issue to arise. Expect it. Be proactive and immediately start the resources to set up for large water supply evolutions. Designate companies to start the reverses to other hydrants and set up for relay pumping. If the extra water is uncertain at the time, don’t charge the supply lines; just charge the hookups to the hydrant. If it turns out that the water is not needed, then an uncharged line will be a lot easier to pick up. By having the line laid, it will only take a couple of minutes to charge. On the other hand, if you wait to lay the line until the water is needed, the time frame for water is now looking like at least 15 to 20 minutes. Be proactive.
If you agree with the concepts I have discussed and how they can be implemented, especially on large fires with multiple master streams working, I will tell you firsthand that freelancing is not an option for implementing the operation. Can you imagine individual units trying to set up multicompany operations that require specific hydrants and specific hoselays? A water supply or water management officer needs to be inserted into the command structure specifically to design the hose evolutions. The water supply officer takes his orders from the IC in regard to the required flows and appliances to be used and implements it with the required hose evolutions, which includes apparatus.