I think it’s safe to say that a lot of you have never heard of 2″ hose, or if you have, you never really considered its use. Why? We already have 1 ¾” hose for our interior-attack lines and 2 ½” for our big-water handlines. What more do we need?
Most departments that use 2″ hose use it as a high-flow handline, producing flows of 250 gpm. As far as I’m concerned, this just scratches the surface of what 2″ hose can really produce.
Hold on to your hats and keep an open mind, because I’m about to show you new concepts for using 2″ hose. Don’t expect to see this stuff in the training manuals because it won’t be there. However, be assured that all uses for this hose follow manufacturers’ recommendations for using their products and, more importantly, are safe.
First, let’s take a look at what type of flows 2″ hose is really capable of. Yes, it can flow 250 gpm, but that’s just a starting point. Would you believe that under certain conditions ,flows up to 450 gpm can be produced?
Before we talk about the different methods of deployment and uses for 2″ hose, it’s important to see what this trick hose is made of. There are several hose manufacturers that make 2″ hose, but they use the same basic specifications.
Two brands of 2″ hose were used for this article, Key Dura-Flow and Angus High-Power High Rise. Both are made of rubber nitrile. All concepts discussed in this article will be based on the following 2″ hose specifications:
- Coupling size: 1 ½”
- Burst pressure: 900 psi
- Test pressure: 300 psi
- Operating pressure: 275 psi
- Approximate weight for 50 feet of coupled hose: Angus 18 lbs.; Key 21 lbs.
Note: When it comes to the weight of the hose, lighter is better. Therefore lightweight hose was used for all discharge line concepts and flow tests. Additionally, all discharge line concepts and flow tests were conducted using 200′ discharge lines. Remember: These figures seem to be the most common from the various manufacturers; however, variations are possible.
How does 2″ hose compare to other hose sizes? Let’s take a look at the two most common handline sizes, 1 ¾” and 2 ½”.
1 ¾” hose: Based on a 50′ section of uncharged hose, there’s little to no difference in weight between 1 ¾” and 2″ lightweight hose. The difference in weight in a charged 50′ section between the two is about 20 lbs. The difference in flow capabilities, however, is big. Using a 200′ line, most 1 ¾” hose can flow 280–300 gpm, depending on the brand. On the other hand, 2″ hose can reach flows up to around 450 gpm with the proper nozzle and discharge pressure combination. That’s a pretty significant increase—not bad for a hose that weighs basically the same as the 1 ¾”. Note: There are a couple of hose manufacturers that offer a 1 ¾” that is actually slightly larger in diameter and therefore can obtain flows reaching up to about 390 gpm with the right nozzle combination (for more on larger diameter 1 ¾” hose see “Weapon of Choice” in the June issue of FireRescue, p. 58).
2 ½” hose: Two-inch hose has 1 ½” couplings while 2 ½” has 2 ½” couplings. The difference in weight between the two per 50′ uncharged section is approximately 5–10 lbs., while the difference when charged is 44 lbs. The difference in flow based on a 200′ discharge line can be as much as 50–100 gpm. It should be noted that a 2 ½” line can easily flow up to 600–700 gpm through a master stream, which would significantly widen the gap between it and the 2″ hose. However, for handline operations, flows higher than 500 gpm are not recommended.
Even though there’s just a small difference in weight between the 1 ¾” and 2″ hose dry and charged, the flow increase is significant. Additionally, between the 2″ and the 2 ½”, the difference in weight between the two is rather significant, especially when charged, while the 2″ has almost the same flow capabilities.
As you can see, the water flow capability for the 2″ hose makes it a very desirable small-diameter/large-flow handline choice. Two-inch hose can obtain the flows needed by any standard 2 ½” nozzle, whether it be a smoothbore or combination, by very easily flowing 250–360 gpm and 400–450 gpm with a higher pump discharge pressure and low-pressure nozzle combination.
Is the nozzle reaction a factor in trying to obtain these flows with a 2″ handline? The answer is both yes and no. If firefighters are trying to advance this line while trying to flow water, or just using it standing up ,the answer is most definitely yes, especially at the higher flows. I’m not saying that it can’t be done, it’s just not going to be easy.
But you must consider additional factors when thinking about nozzle reaction. First, how practical is it to be advancing a high-flow line like this? If the fire is hot enough to require flows this high to achieve a knockdown, then is it really safe or, for that matter, even possible to be making an advancing attack? Of course a definite answer cannot be given because every fire is different. As a rule of thumb, though, large fires requiring 250 gpm and higher probably should be knocked down whenever possible from a more distant stationary point and then advanced upon with lower flows to complete the knockdown.
Second, do we need to be standing up with a 250-gpm flow (or higher) handline taking a beating or is there an easier way? As a matter of fact there is an extremely easy way to move the water: Just sit on it! That’s right, one firefighter can in most cases handle flows up to 350 gpm on a 2″ handline with no problem at all, sitting on the hose. By keeping as much hose as possible on the ground in conjunction with the total weight of the firefighter directly on top of the hose, the majority of the nozzle reaction will be directed into the ground, making the line easy to handle. Tip: The surface you’re working on can make a difference. One person is by no means the rule; two definitely works better.
The 2″ high-flow handline works best as a quick-attack blitz line. Compared to a 2 ½” at the same flows, the 2″ line is a lot easier to deploy and maneuver. If a high-flow line of this caliber is needed on the interior for whatever reason, then the 2″ definitely has the advantage over the 2 ½”.
Now for the question of the day: Can 2″ hose replace 1 ¾” for the standard everyday interior-attack line (100–150 gpm)? That’s up to you. You can compare the statistics in Table 1. The 2″ will be slightly more difficult overall to work with, but I’m not sure how much of that is actually psychological vs. physical. I would recommend an extensive evaluation, including nozzle reaction comparisons at high and low flows and dragging the lines through buildings. Try doing a side-by-side comparison between the two. Don’t tell the firefighters which line is which and see if they can tell the difference.
Most standard high-flow handline nozzles are not rated to flow 400–450 gpm. However, there are a few that are actually rated to flow up to 500 gpm. These nozzles can be used in conjunction with specific water-delivery parts to create a high-flow handline nozzle I like to call the “Big Paulie monster handline nozzle.”
The Big Paulie consists of:
- A TFT 2 ½” x 2 ½” gated nozzle valve with a 2″ waterway;
- A 2 ½” male x 1 ½” female adapter;
- A TFT 5″ stream shaper (2 ½” x 2 ½”);
- A stream-directing handle; and
- A low-pressure nozzle (smoothbore tip either 1 ¼” or 1 ½” in diameter or the TFT Max Force Dual Pressure automatic nozzle).
The 2″ waterway in the nozzle valve allows for the higher flows at a reduced pressure as compared to the standard 2 ½” nozzles that have a 1 3?8″ waterway. The 5″ stream shaper does two things: It straightens out the turbulence created in the nozzle valve and hose at the higher flows, and it gives added leverage to the firefighter in the sitting position. The stream-directing handle also helps maneuver the nozzle by giving the firefighter a more secure and comfortable position to hold on to the nozzle. Finally, the smoothbore tips and the Max Force Automatic produce the stream.
Table 1 shows a variety of nozzle combinations, discharge pressures and flows that are capable with 2″ hose. The Big Paulie nozzle concept works well with all of the mentioned flows but really excels with the higher ones.
Application: High-Rise Operations
Due to the inadequacies of most fire-protection systems in high-rise buildings (inflicted upon us by a lack of understanding of what firefighters need for developing adequate fire streams), even minimum interior-attack flows can be difficult to develop with small-diameter (1 ½” and 1 ¾”) hose. In fact standpipe residual pressures ranging from 60–100 psi are very common. It would be nice to be able to use lightweight 1 ½” hose for high-rise operations, especially when it’s being carried up the stairs,but if it will not flow the water, what good is it?
Many departments strictly use 2 ½” hose with low-pressure nozzles for high-rise applications because of the pressure problems encountered. The 2″ hose offers an alternative to the 2 ½” that’s fairly lightweight.
I conducted two flow tests to show the capabilities of 150 feet of 2″ Angus Hi-Power High-Rise Hose used in a high-rise application. The first test was conducted simulating standpipe residual pressures from 50–100 psi, which would realistically be the low-pressure problem range encountered. The second test used standpipe residual pressures of 120 psi and 150 psi. These numbers represented a fire-protection system that was taken over by fire department pumping apparatus. The nozzles used were considered to be appropriate for high-rise applications. Results are shown in Table 2 .
Application: Portable Master Streams
Let’s paint a scenario. You are on a three-man engine company that’s first-in on a large construction fire. You’re all familiar with how the grounds can be on a construction site, especially when water is applied. Besides getting muddy and slippery, there are obstacles to deal with, such as trenches, dirt piles, trash piles, lumber piles and who knows what else.
The captain orders you to deploy a high-flow line by yourself to be extended to the back portion of the fire area to protect the exposure. What are your options for this line? Let’s say that it’s going to be a handline. Once you’ve woven your way through the obstacle course and positioned yourself, you can start flowing water. The problem with using a handline in this scenario: You have just eliminated one out of the three firefighters on the first-in crew to operate the line. Oh yeah, I forgot to tell you, the next-due engine company is at least 8 minutes away and you’re only covering one of several immediately threatened exposures.
Let’s try this again. Instead of making this line a handline, let’s connect it to a portable lightweight master-stream appliance. The big three water-flow appliance manufacturers (TFT, Akron and Elkhart) sell these appliances. I like to call them mini portable monitors. These appliances all use a single 2 ½” inlet and are lightweight, making them easily deployable by one firefighter. They’re ideal for being supplied by a 2″ discharge line. Additionally, they all have shutoff valves, allowing for firefighter control at the appliance.
What’s nice about this application is that once the appliance is secured and aimed at the target, it can be left unmanned, allowing the firefighter to begin another task, possibly pulling another line. What’s your choice of hose going to be to supply this portable monitor? Why not a single lightweight 2″ line that can flow up to 450 gpm? With a 2 ½” male x 1 ½” female adapter, the 2″ hose can be connected to the inlet of the appliance. It’s almost like pulling a pre-connect.
Firefighters must be ready to adapt to the ever-changing conditions we encounter. It’s extremely important that we keep an open mind to new ideas as they are presented to us and investigate to determine if in fact they’re workable.
I have a golden rule: Unless it’s written by God or the manufacturer, it can be challenged. Two-inch hose has never really been in the limelight. In fact, because of its oddball size, it has even been frowned upon without even being tested to determine if it’s useful. Again, keep an open mind, try it, challenge the books. The manufacturers’ guidelines should be the only limiting factor.[scrollGallery id=2]