BY TOM SITZ
The preconnect hoseline is probably the most commonly stretched attack line in America today. It is by far the easiest line to stretch for the understaffed engine company. Everything about the preconnect should be preconfigured, making it a stretch that can be done almost on autopilot. Its length is predetermined (hopefully by members who thoroughly understand their response district). Its engine pressure should be predetermined and is probably marked somewhere on the pump panel. Some departments make a line or mark on the pump panel gauge so all the operator has to do is continue to throttle up until the needle hits the mark. Marking your gauges is a good thing; anything you can do to apply the KISS principle in this job is usually a good thing. If the occupancy into which you are stretching can be covered by the length of hose in your preconnects and the fire is within its gpm, the preconnected handline can be one of your best friends.
However, there are also several pitfalls with the preconnected line. The autopilot stretch is the first one and the most discussed. The firefighter exits the engine knowing he is going to work and pulls a preconnected line even before he considers the building setback, building area, occupancy, reflex time, and size of the fire itself, just to name a few size-up concerns.
The above items are training issues and can be corrected by discussing target hazards and what lines will be needed to cover them. Also, practice how you estimate your stretch by looking at an occupancy and estimating how much hose you think you need to cover it. Then measure the actual stretch distance with a measuring wheel to see how accurate that estimate was. These two training techniques—in addition to some scenario-based engine company drills in which you actually come up with a realistic scenario (maybe based on one of the target hazards you talked about), stretch, charge, and advance lines—are keys to becoming an efficient aggressive engine company.
Another pitfall is built into how some departments set up their preconnected hoselines. Some departments set up their preconnected lines with various lengths; 150-foot, 200-foot, and 250-foot preconnects are pretty common, and some departments have one of each. This gives the engine firefighter a little more versatility on the fireground when he can pull the longer line because he did a good size-up and knows that the 200-foot preconnect will be short.
 1. Photo by Ken Myllykoski. |
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However, there is a large negative associated with having different lengths of preconnects. Let’s say that the initial preconnected handline is 250 feet long and this attack team needs a backup line for support because of rapid fire development or, even worse, it gets trapped and needs another line to effect a rescue. The backup team’s or rapid intervention company’s (RIC) natural inclination will be to pull another preconnect because the initial team is on the end of a preconnected hoseline. But, if the initial team is on the end of a 250-foot preconnect and the backup team/RIC pulls a 200-foot preconnect because that is the one next to the deployed line, it will never get the nozzle up to the team in trouble.
This is especially true if a mutual-aid company is staffing your backup/RIC line functions. Even members of your organization may miss the fact that the line they are stretching as a backup is 50 or 100 feet short of the original line, especially in a very stressful, time-compressed situation, such as when firefighters are cut off from their means of egress.
Another common pitfall that is easily overlooked is associated with mixing the size of your preconnected lines. Having a 21/2-inch line preconnected with your 13/4-inch lines can be an excellent setup. The 21/2-inch preconnected line can be set to handle your small to medium commercial or industrial occupancies based on your preplanning. The problem lies in the fact that the 21/2- and 13/4-inch preconnects will require different engine pressures. All of our preconnects are 200 feet long for structural firefighting. We have two 13/4- and one 21/2-inch preconnected lines on our engines. We use low-pressure, fixed-gallonage fog nozzles (straight stream only for interior operations).
The 13/4-inch requires an engine pressure of 140 psi to flow its required 150 gpm, and the 21/2-inch requires an engine pressure of 80 psi to flow the required 250 gpm. When we have 13/4- and 21/2-inch preconnects in service, how do we get the proper pressure to each line?
The correct answer to the question is you would gate the 21/2-inch because it requires the lower pressure. Gating back the 21/2-inch is fairly simple to do if it is going in service after the 13/4-inch is charged. In our system, if the 13/4-inch goes in service first, the engine pressure will be 140 psi; when the 21/2-inch preconnect gets stretched, our operators know that they need to pump that line at 80 psi. When the 21/2-inch team members get to the point of entry and call for water, the operator will tell them that he needs to gate back the line to the proper pressure, so they need to open the nozzle outside the structure and continue to flow water while the valve is being pushed in. Remember, you cannot gate back a line that is not flowing water—it is a closed system. Once the line is charged and the nozzle closed, you could gate that line back until there is only a 1/4-inch opening in the valve, and it would still read the same pressure as the engine pressure. Only after the nozzle is opened and water starts to flow would the pressure drop down to nothing. It’s the same principle as when there is a kink in the line. The 21/2-inch team can shut down and advance only after it gets the OK from the pump operator.
Things can get complicated, however, when the 21/2-inch goes in service first. In my experience, it is pretty rare for a 21/2-inch to go in service on a structure fire and not have additional 13/4-inch attack lines come off the truck at some point in the operation. This will most likely occur with a strip commercial fire where a 21/2-inch takes the fire occupancy and 13/4-inch lines are stretched into exposures to check extension. With this setup, when the 21/2-inch preconnect gets stretched first, the operator will charge it at 80 psi, and the line will disappear into the smoke.
Now when the 13/4-inch preconnects, which require 140 psi at the pump, get stretched into exposures, how do we gate back the 21/2-inch? First, we have to throttle up to 140 psi engine pressure, giving the 21/2-inch 60 more psi than the team members need, which they will probably notice if they are flowing water. Next, we have to coordinate with them to keep the line flowing while they are inside the structure, probably in a pretty hostile environment where the 21/2-inch may be needed for attack and they will have to continue to flow water until the pump operator tells them it is OK to shut down the line. If possible, try to avoid gating back a line that is engaged in fire suppression.
Our department’s solution to this problem: When we stretch our 21/2-inch preconnect, we throttle up the engine to the 13/4-inch pressure (140 psi) and gate the 21/2-inch back to 80 psi while flowing water. Then we mark our 21/2-inch valve with a painted line when it reads 80 psi and the engine pressure reads 140 psi. We do this several times after making the initial mark to verify that the mark is in the correct spot (photo 1).
Our operators are trained so that it does not matter which preconnected line comes off the engine first; the engine pressure is set at 140 psi. When we place a 21/2-inch preconnect in service first, the operator throttles up to 140 psi and pulls the 21/2-inch valve up to the painted line. Now with the nozzle closed, the 21/2-inch gauge will read 140 psi, but when the nozzle is open, the pressure drops to 80 psi. Now, the pump operator can look at the 21/2-inch gauge and tell if the 21/2-inch nozzle is open or closed based on its reading. If he looks at the gauge and it is reading 70 psi, he knows that the nozzle is open and he needs to open the valve a little more to make up the 10 missing psi.
We also scored the valve so that it is permanently marked where the paint should go. We recommend that you check this mark at least annually to make sure it is still accurate. We have been using this system for almost 10 years and have not had any problems. But it is possible that the older a valve gets, the more likely it is to get some extra play in it, which could affect the pressure given at the mark. If you test it and it is off, you could have the valve adjusted and tightened so it is back to its original mark, or just remark it.
The preconnected line is a tool to be carried in your mental toolbox (your head). Like all the other tools you carry, it is not appropriate for every situation (PPV). A proper size-up is critical for hoseline selection. Consider holding the stretch for a couple of seconds while the company officer completes his size-up. At a second-floor fire in a converted dwelling, what may be a preconnect fire if you stretch through the front may not be a preconnect fire if you have to stretch through the rear, because the stairs may be there. In most communities, a combination of preconnected and dead/static loads will give the engine company the best chance for a rapid stretch and knockdown of the fire.
TOM SITZ is a lieutenant and an 18-year veteran of the Painesville (OH) Fire Department.
