Always flow the proper amount of water at the right pressure
By Clay Magee | Fire Engineering
In Part 1 of this series, I covered the basics of standpipe systems such as National Fire Protection Association codes, types of standpipes, and pressure reducing valves (PRVs) and pressure restricting devices (PRDs). Now, I will move on to nozzle, hose, and equipment selection.
The age-old debate in the fire service among nozzlemen is smooth-bore vs. combination fog nozzle. Both have their place in the fire service, and both have advantages and disadvantages. However, when it comes to standpipe operations there is only room for one, and that is the smooth-bore nozzle. The first reason to use only a smooth-bore is pressure. Smooth-bore nozzles are low pressure; they operate at their rated flow of 50 pounds per square inch (psi). Why is this important in standpipe operations? Because standpipe systems are low-pressure systems. They operate off as little as 65 psi. Another reason is that standpipe systems are notorious for failure and for not providing the pressure that they should. The first reason is partly because of poor maintenance or improper installation. The second reason is weight. The 2½-inch smooth-bore nozzle can weigh as little as 2½ pounds. Fog nozzles can weigh in excess of five pounds, and some weigh nearly 10 pounds. Granted, this is a play pipe-style nozzle, and I hope this is not what you are carrying on your standpipe packs.
The third reason is their ability to pass debris. Standpipe systems aren’t maintained like they should be. Whether its sediment that has built up over the years (photo 1), or a candy wrapper or soda can (photo 2) that a homeless person stuck down deep in the fire department connection, chances are you’ll face some debris. A smooth-bore can pass a lot of debris than a fog nozzle adjusted to the “flush” position; a fog nozzle will not pass any. Make sure your smooth-bore has no inlet screen. It may sound ridiculous, but they do exist. If you find it, remove it.
(1) Photos by of author.
The fourth and final reason is simplicity. The only moving part inside of your smooth-bore is the ball valve. There are no baffles or springs. This means that there are fewer chances for things to go wrong when you are pushing down a hallway 30 stories up.
A common argument you hear regarding fog nozzles is that they offer protection and hydraulic ventilation. As we all know, a wide fog pattern WILL push fire. You can say it’s not pushing it but, in essence, if the fire can’t come past the wall of fog you have created, it will head in the path of least resistance, which is the opposite direction. A wide fog pattern entrains air from behind you and moves it past the nozzle. That’s how hydraulic ventilation works, right? This may force fire into void spaces and provide extension horizontally and vertically. Also, it is possible to force products of combustion to your rear in a center core construction high-rise.
In a residential building, you are pushing the fire back down the hallway and into any apartment unit that has a door left open after the occupants evacuated. The best protection is to always flow the proper amount of water at the right pressure.
You can operate smooth-bore nozzles at nozzle pressures from 40 to 60 psi. Obviously, the less the nozzle pressure, the less the nozzle reaction and gallons per minute (gpm). The more the nozzle pressure, the more the nozzle reaction, and the more the gpm is flowed.
Following are typical nozzle tip sizes with flows at 40, 50, and 60 psi that you may see on different high-rise packs:
- 15/16-inch: 165 gpm @ 40 psi, 185 gpm @ 50 psi, 202 gpm @ 60 psi
- One-inch: 188 gpm @ 40 psi, 210 GPM @ 50 psi, 230 GPM @ 60 psi
- 1 1/16-inch: 212 gpm @ 40 psi, 237 @ 50 psi, 260 @ 60 psi
- 1 1/8-inch: 238 gpm @ 40 psi, 266 gpm @ 50 psi, 291 gpm @ 60 psi
- 1 3/16-inch: 265 gpm @ 40 psi, 296 gpm @ 50 psi, 324 gpm @ 60 psi
- 1¼-inch: – 293 gpm @ 40 psi, 328 gpm @ 50 psi, 359 gpm @ 60 psi
You may find 15/16-inch tips on 1¾- and two-inch hose. The one-inch tip is a common tip for two-inch hose. The 1 1/16-inch tip is a lesser known but great tip for two-inch hose. With it, you can achieve near commercial flows if you have enough pressure. If you do have enough pressure, you can achieve the flow the 1 1/8-inch tip. The 1 1/8-inch tip can be used on two- or 2½-inch hose. If used on two-inch hose, expect high PDP, which will exceed most standpipe capabilities. An outlet pressure of 100 psi will flow 250 gpm through 200 feet with some brands and grades of two-inch hose; this will achieve a nozzle pressure of 45 psi. Yjr bottom line is that each deptartment must choose hose and nozzles based on the standpipe outlet pressures in their juristiction and the flow capability of their particular brand and grade of hose. More often than not, you will find departments that use this setup coming off an engine for their commercial flow. The 1 3/16-inch tip has been called “the missing tip”; it is relatively new. At a nozzle pressure of 40 psi, it flows 265 psi, the equivalent of a 1 1/8-inch tip; when overpumped at 60 psi, it flows 324 gpm, which is the equivalent of a 1¼-inch nozzle at 50 psi.
Last, the 1¼-inch tip is used by departments across the country. It has a high nozzle reaction and is considered by many to be too much for a two-man nozzle team. Departments with heavy manning, such as the Chicago (IL) Fire Department, use this tip.
A few words on nozzle reaction: Dennis Legear stated that the recommended maximum nozzle reaction for a two-person line is 115 pounds. A 1 1/8-inch nozzle pumped at 50 psi produces a nozzle reaction of 99 pounds. A 1 3/16-inch nozzle at 50 psi produces 111 pounds. Hose and nozzle selection is important! The two go hand in hand. When choosing your “weapons,” you want high-volume, low-pressure systems with acceptable nozzle reaction.
Hoseline selection matters as well. Following is the needed outlet pressure in different size hose at the most common flows for that size hoseline:
- 1¾-inch hose with a 15/16-inch tip flows 185 gpm.
> 150-foot lay: 34 psi FL + 50 psi NP + 5 psi elevation = 89 psi
> 200-foot lay: 45 psi FL + 50 psi NP + 5 psi elevation = 100 psi
> 250-foot lay: 56 psi FL + 50 psi NP + 5 psi elevation = 111 psi
- Two-inch hose with 2½-inch couplings with a one-inch tip flows 210 gpm.
> 150 ft lay: 37 psi FL + 50 psi NP + 5 psi elevation = 92 psi
> 200 ft lay: 49 psi FL + 50 psi NP + 5 psi elevation = 104 psi
> 250 ft lay: 62 psi FL + 50 psi NP + 5 psi elevation = 117 psi
- 2½-inch hose with a 1 1/8-inch tip flows 265 gpm.
> 150 ft lay: 24 psi FL + 50 psi NP + 5 psi elevation = 79 psi
> 200 ft lay: 33 psi FL + 50 psi NP + 5 psi elevation = 88 psi
> 250 ft lay: 41 psi FL + 50 psi NP + 5 psi elevation = 96 psi
Friction loss in numbers are for the latest batch of hose we bought at my department. They may look different than the numbers you are used to seeing from your textbook, but most textbook numbers are outdated because of modern hose construction. When purchasing hose, have the hose manufacture flow test hose for you so you can see the actual flows.
Remember, for standpipe operations, we want a high-volume, low-pressure weapon. We also want commercial or near-commercial flow capabilities, even on residential high-rises. A couple of reasons for this are because of the possibility of wind-driven fires and because of “reflex time.” Reflex time is the time from when you arrive on scene to the time water goes on the fire. What may be a small kitchen fire on arrival could very well be pushing down a hallway by the time you are hooked up and ready to fight the fire.
The average reflex time for high-rise fires is around 15 minutes. Remember, fire doubles in size every minute. Set yourself up for success by putting a 2½-inch hose in service to start. You will be covered for fire flow and low pressures that may be found in standpipe systems.
Departments across the country use anything from 1¾- to 2½-inch hose for their standpipe operations. It is important to spec your hose and nozzle package for your jurisdiction. If all of your mid- and high-rise buildings were built after 1993, then two-inch hose may be a very acceptable choice for you for most scenarios. If your jurisdiction has mostly buildings built before 1993, then strongly consider using 2½-inch hose because of its 65 to 100 psi range. Another thing to consider when choosing hose size is the occupancy type of your buildings. If all of your high-rise buildings are hotels or apartment-type buildings that are compartmentalized, then lower flows in the 210- or 240-gpm range may be acceptable. If you have commercial, open-floor plans that present the opportunity for rapid fire growth, consider higher flows that come for the 1 1/8-inch and 1 3/16-inch tip. It is extremely important to remember that staffing levels should not decide what size hose you buy and use. The fire decides, and you simply supply the staffing, whether through a heavy dispatch policy or an auto mutual-aid call.
The equipment that you have is important, especially the inline pressure gauge (photo 3). This is one of the most important pieces of equipment in your tools for standpipe operations, second only to your hose and nozzles. Its selection and use are just as important as hose and nozzle selection. Unfortunately, it is one of the most overlooked and least understood pieces as well.
By placing this inline gauge on the standpipe outlet, you are essentially moving the engine’s pump panel to the floor below the fire. As a nozzleman, can you imagine not having an assistant operator or engineer with you to set the correct pressure? That’s what you are trying to do if you do not have an inline gauge.
Standpipes are low-pressure systems. Depending on the year that the system was installed, the minimum required pressures are 65 and 100 psi. Sometimes, because of PRVs, incorrect PDP pressures from the engine or misinstallation of equipment during the building process may have pressures that are even lower. Not only may you not be aware of low pressure but imagine having a rookie open the valve that is producing 175 psi and you have 150 feet of 2½-inch on the deck. You are in the fight of your life, not against the fire but the nozzle.
It is important to understand how to use the inline pressure gauge correctly. To obtain accurate readings, the nozzle must be open fully and flowing water when the “control man” dials in the pressure. When closed, the static pressure of the nozzle will read much higher than the flow pressure when it is open. Also, a “trick of the trade” is to use a label maker and place the needed pressures for your size hose at 150-, 200-, and 250-foot lays so you don’t use the hand method when you should be putting water on the fire. These gauges are important! If your department won’t buy you one, get some guys together and buy one for your company.
The standpipe bag is also an essential element to your engine’s high-rise response readiness. Obviously, hose and nozzles are essential for putting water on the fire, but I cannot tell you how many engine companies I have seen (including both of my own departments) that do not have any of the other essential gear readily available. Most companies would find themselves on the floor below the fire only to realize that they do not have the equipment they need to make the connection to the standpipe.
Do you have a spanner wrench with you each time you carry your standpipe equipment into the building? Think about how hard it is to remove a cap from the side discharge on your engine. The standpipe outlet cap is removed even less than the one on your engine. You’ll most likely need it to break the standpipe outlet cap outlet and to tighten your hose onto the outlet.
Following is recommended equipment for a standpipe bag. Some of the more “random” pieces of equipment are explained have explanations for the reason behind carrying it. As you read through the list think about what you readily have access to on your engine to carry into a high-rise building on an alarm call or reported fire.
- Bag. Any bag will do; something that can be carried easily, preferably with a shoulder strap. My company uses an old medical bag that had been taken out of service.
- Inline pressure gauge.
- Hydrant gate valve. This valve (non-ball gate) is an excellent addition for two reasons. First, it allows fine tuning of the pressure. Often, standpipe valves may be hard to turn. Adding a gate valve allows you to open the standpipe all the way and then make adjustments in pressure with the gate valve. Second, PRVs are designed to operate with the valve all the way open. Adding a gate valve allows you to turn the valve all the way open and then control your pressure with the gate valve.
- Secondary nozzle. Use this to extend the hoseline when used with a 1½-inch female to 2½-inch male increaser. It’s also carried in case there is a mechanical failure with primary nozzle.
- Lightweight 30° or 60° elbows. These are used to keep kinks out of the hose when making connections in a standpipe outlet box. There are some great lightweight elbows marketed strictly for high-rise operations.
- A 1½- inch female to 2½-inch male increaser. This extends the hose when you have stretched short. The smooth-bore tip is removed from your primary nozzle, essentially leaving a ball gate valve with a 1½-inch connection.
- Spanner wrenches. One will do, but two is better.
- Pipe wrench. An 18-inch lightweight aluminum pipe wrench can turn on a stuck standpipe wheel or used for more leverage when removing a standpipe outlet cover.
- Door chocks. Keep a handful around for chocking doors.
- Wire brush. This cleans off rust and paint from the standpipe outlet, which could make your hose connection difficult if it is left in place.
- Spare standpipe hand wheel. This turns the standpipe valve open if the hand wheel is missing.
- Various small tools. Keep a compliment of screw drivers and a ring of hex tools to assist in removing any mechanical PRDs.
All of this information ties in together. The building systems and knowledge of them should determine a lot of things for you and your department. In part 3, I will cover different types of popular hose loads.
Clay Magee is an instructor with Magic City Truck Academy and a Firefighter/Paramedic with Birmingham (AL) Fire and Rescue and Chelsea Fire and Rescue. He is currently assigned to Rescue 20 at Birmingham. Clay began his career with the East Oktibbeha Fire Department in 2004 while attending Mississippi State University. He has been with Birmingham Fire since 2013. He has a passion for forcible entry and high-rise operations. He holds a bachelor’s degree in business administration from Mississippi State University, an associate’s degree in Fire Science from Columbia Southern University, and multiple certifications from the Alabama Fire College.