OK here we go. This debate is as passionate as the smooth bore Vs fog nozzle debate. I am going to take a stab at it. I believe that there are situations that allow for a low friction loss 1-3/4" or 2" handline to be used in a highrise fire. And you say?
Let me step in to the fire (no pun intended... maybe).
To the best of my knowledge, one of the main reasons for NEEDING 2 1/2" for standpipe fire attack is due to increased friction loss due to elevation and reduced pressure availability due to Pressure Reducing Valves (PRV). If your buildings don't fall into these categories, why not look at other options.
The other consideration is smooth bores being used for their high flow/low pressure demands as well as their capability to clear debris (sediment, objects, etc.) w/o interrupting fire attack.
I say, learn about the buildings in your area... if you have a residential high rise w/o PRV then why not use house fire lines. Likewise, if you have a commercial high rise OR presence of a PRV, move up the big boy lines.
The success of the first attack line will determine what else (line, manpower, etc) is needed. Learn your buildings and adjust your tactics accordingly.
There have been several incidents in which the need for "big line" was proven, as well as wind-driven fire conditions that have injured firefighters, and even killed them. They have been documented. If an individual department or officer is comfortable with using something smaller, that's their choice. Certainly not mine. The comment about the speed required to place a 2.5" in service justifies the use of 1.5(!) or 1.75" makes little sense to me. I will agree staffing is an important factor.
However there is little argument that it certainly takes longer time to get a line in service on a standpipe floors above where the engine is parked as oppossed to stretching into a dwelling off the street. To me, that is one BIG reason to begin with a larger flow line due to the fact the second line will be even more time consuming. If your blessed with metro-type staffing, that speaks for itself.
An excellent reference is "Firefighting Operations in High Rise and Stand-Pipe Equipped Buildings" by McGrail based on the Denver, Colo. Fire Department's operations and some proven, justified theory and application. Firefighters that cannot place a larger hose-line in service quickly may be lacking consistent training, or department procedures make extensive use of smaller hose-lines on just about everything. Again, it's simply flow vs. fire.
Open corridors, large open office spaces all have been proven to be ripe for rapid fire spread and heat build-up which usually cannot be effectively handled with the 185gpm or less flows. There should be little argument against or for the smooth bore nozzle with regards to high-rise and stand-pipe use. The reasons for smooth bore are obvious. No matter how hard you pump or how passionate you are with adjustibles, one clogged nozzle while your floors above the engine with fire blowing out an open door into the hallway and...
Another thread on "the big line" listed some facts on 1.75", 2", and 2.5" line with regards to weight and flow. I have some feed-back from the use of 2" hose for high-rise use from Chicago FD both during drilling and actual fire conditions. The info I have was favorable to the 2" line, although in this business you can argue anything. It also involved a particular type nozzle which I have tested and am considering for some applications.
However the best combination for overcoming friction loss with regards to the required minimum of 65psi for standpipe use when equipped with a 200' stand-pipe/ "high rise" hose pack was 100' of 2.5" hose off the stand-pipe discharge (with an in-line pressure guage) and 100' of 2" as a "working length" to achieve a 265 gpm flow using a 1. 1/8" smooth-bore tip (or up to 325gpm with a specific type nozzle...I aint no salesman)
You can be the most aggressive, seasoned crew with the best of luck on your side, and have so far knocked down everything with something smaller than a 2" line for high-rise/mid-rise use, but the simple fact that wind-driven fires HAVE and DO happen in these buildings, and in at least one case kicked the assess of those using TWO 2.5" hose-lines is enough for me to stick with something bigger.
The absolute ONLY way to PROVE what you are ACTUALLY flowing is to pump into a system or replicate both your average and your highest point to discharge, use an acurate, calibrated flow-meter, the actual hose you use (brand, type, etc.) and the actual nozzle used (if they vary, you ned to use each one as they may diffder a little, or substantially) and then you won't have to guess what your betting your life on, you can prove it.
There are other variables such as pressure reducing devices that are on some stand-pipe discharges that reduce the psi for "occupant" use. The Meridian Plaza fire in Philly is good study, as are the Chicago Bank High Rise fires (2) and that wind-driven tragedy in FDNY.
OK here's my 2 cents.I believe that the 2-1/2" handline with the 1-1/8" smooth bore nozzle is a garauntte that you will flow the most water every time. I also believe that in alot of cases the fires are small enough to be handled by 150 gpm flows. This applies to structure fires on ground level as well as in multi story buildings. I understand the difference between the two ,one just deals with hose and the other deals with hose, a plumbed system with many friction loss and pressure problems and elevation. I think both large and small handlines should be taken up and the company officer should decide what to use.
One of the flow tests that seems to be in every highrise handline class is the one that reflects realistic standpipe pressures. This is done from the discharge of an engine company. They usually start at about 30 psi to reflect the First meridian Highrise fire disaster. A 1-3/4" line is flowed with a tft nozzle with horrible results. The following numbers are from the same type of flow tests except instead of an automatic nozzle a 50 psi at 150 gpm fixed gallonage nozzle was used. An 1-1/8" nozzle was used on the 2-1/2" The 1-3/4" hose was made by KEY fire hose and is called COMBAT READY. The following pressures were used with the the matching flows. These were 150' lines.
30 psi 60 gpm
60 psi 120 gpm
80 psi 135 gpm
100 psi 160 gpm
120 psi 175 gpm
150 psi 185 gpm
Using a 1" smooth bore with this 1-3/4" hose we got the following
The minimum 30 psi np started at 50 psi residual pressure.
Again this is the flow tests that are usually done to prove the need for 2-1/2" handlines all of the time. These tests are not done under realistic conditions and can be misleading. Here's why. .A minimum code for multi story systems with building pumps pre 1993 is 65 psi standpipe residual pressure. However this is based on a required 500 gpm flow. With this being said when a 2-1/2" line is flowed from a real system the standpipe pressure will not be 65 psi. In fact it could be 30 psi or more than that. Did you ever wonder why people teach to keep a firefighter on the stand pipe to gate it down if needed because of too much pressure? Its because you are not flowing 500 gpm which the system is rated at, therefore the residual pressure is not 65 psi, it's higher. As an example lets take a look at the flows I presented. Try 100 psi. with the 1-3/4" line with the 1" tip we got 202 gpm with a 46 psi np
With the 2-1/2" we got 303 gpm with a 66 np.
After 1993 the system pressure requirements went up tov 100 psi. Thats 35 psi more to work with. In Las Vegas the code requires 125 psi residual pressure at 500 gpm. I witnessed a building pump test where the requirement was 750 gpm at 125 psi because to the amount of outlets. After flowing the 750 gpm we had a residual pressure of 150 psi. They had to detune the pump to meet the 125 psi mark. Oh yea, this was on the roof of a 44 story building.
Here is something else that you may not realize. If operations are based on the system doing the work without FD intervention then the standpipe residual pressure will continue to drop when more lines are cut in raising the flow . If the FD takes over the system the pump operator has the ability to monitor his pdp and raise the RPMs to maintain the pressure thus allowing for more flow without a pressure drop.
Finally I say this. Know your buildings and your capabilities and use what you think works best.
I like your work, Paul, but you miss a critical question - what is the flow required to fight a fire? As we all know, we're basically using water to soak up heat faster than the fire can create it...so what is gallonage for a particular structure fire?
I'll go dig through my books and see if I can find some equations to post, but the amount of heat that water absorbs when it goes to steam is huge (514cal/gram IIRC) so you are absorbing a ton of heat if you apply it correctly. Look how much knockdown these guys got with an 1 1/2"
Thanks Paul. Great stats. It's amazing, great comments and info from experienced high-rise members but its obvious most are only opinions and from non experienced high-rise members which are way off. Recent test results showing the dramatic increase in interior temperatures during wind-driven fire conditions. 20 years ago fire doubled every minute. Now with new products, it's been proven by NIST that today fire doubles 10X's faster.
When you have fought one of these fire breathing dragons up close and personal it’s easy to better understand why you bring the big guns and greatest possible GPM's to win that battle. For this reason, 1 1/2" and 1 3/4" attack lines are not brought to the fire floor and are against high-rise operational procedures in most big cities.
When windows are in tack, the fire is mainly contained and a fast organized attack with a 2 1/2" gets us quick results. Unfortunately when windows fail it’s a different story. Real life scenario, fire engulfs the entire 2,500 sq. ft apartment, including the entire 8’ X 200’ hallway extending into several apartments. Our last extra alarm wind-driven high-rise fire, it was estimated from the damage that interior temperatures reached nearly 2500°F. The hallway was a flame thrower blowing completely horizontal. That is not the first time and won’t be the last. Next time and every time my team faces this possibility they will be equipped with at least 200’ of 2 ½” attack line giving us the maximum GPM’s.
Hopefully we’ll be able to open the door for just enough time to cool a portion of the fire before our face pieces start melt on our skin. If you have a your recommended 1 3/4" garden hose line you’ll probably still be in the staging area hiding.
We use 2 inch line with a smooth bore nozzle. These are not pre-connected, we use them for all kinds of fires, used the set up on a 10th story fire in a grain elevator penthouse yesterday, worked great. It was 9 degrees out, Tower-ladder 2 forced entry (had to cut the hinges off a door and the welded hasp) E-8 and E-7 hiked up the 10 floors, E-3 supplied water to L-4's water pipe and E-8 hooked the 2 inch on the end of the pipe (7th floor) and in through a window and up to the fire. Went 2 alarms, but a quick knockdown once the 2 inch line was put to work.
good video put completely unrelated to Hi-rise job. Thats all wood and out in the open. Hi-rise fires are mostly compartmentalized and can get really hot from the contents. Ventilation is also very limited so the heat doesn't have many places to go.
Some of the older masonry high-rises have traditional, residential-style windows that are easy to vent.
Even modern steel and glass curtainwall construction can be vented, although it takes more work. A bigger problem is that the fire sometimes autovents the curtainwall upwind or crosswind to the fire, which can spread the fire rapidly.
In those cases, rapid firespread is a bigger problem than is simply unventilated heat.
High-rise glass curtain wall construction can self-ventilate well below flashover temperatures. Although life safety is first, it's of the utmost importance to contain and extinguish a self-ventilated high-rise fire. A larger diameter line may be more difficult to maneuver but the reduced friction loss and increased GPM is imperative. The first arriving companies will need all the H20 that can be supplied. It is not recommended that pre-connected hose lines be used as your attack line.
"Hopefully we’ll be able to open the door for just enough time to cool a portion of the fire before our face pieces start melt on our skin. If you have a your recommended 1 3/4" garden hose line you’ll probably still be in the staging area hiding."
Not necessarily so in the first case and completely speculative in the second...
If the fire conditions are as you describe in your "hallway blowtorch" scenario, it is unlikely that a 2.5 inch line will be adequate to contain, let alone extinguish that fire.
Using the National Fire Academy flow formula GPM = L x W/3 x % involved, for 100% involvement, the formula would be GPM = 200 x 8 /3. or 533.3 GPM. You'd need a minimum of two 2.5 inch lines at maximum flow to even get close to extinguishing that hallway if it were fully involved, not counting any other fire blowing back into the hallway from an interior exposure.
Using the same formula for a 1.75 inch line flowing 185 GPM from a 15/16's smoothbore tip, you'd need three 1.75 inch lines to get the same ballpark GPMs as you'd get with the two 2.5 inch lines. (I use the 185 GPM figure as that's what my department's Akron Assault 1.75 inch nozzles flow in the smoothbore configuration. Your mileage may vary.)
You can also feet 2.5 inch to the fire floor either up the stairs or via a standpipe, then wye it down into two 1.75 inch lines. If you're fighting a high-rise fire, preconnects aren't part of the discussion for fires above the 2nd floor, regardless of hose diameter.
I have nothing against 2.5 inch handlines, but exactly which line you need is going to be situational, even in high-rise fires.
"...why not use house lines?" A lot of the time, those lines are not in good condition and are not dependable. They can have missing nozzles stolen for the scrap value of the brass or have dry-rotted liners, for example. If you're counting on using house lines, you have to KNOW that they're in place, intact, dependable, and accessible to the firefighters but not the fire. If I want to KNOW that my hose meets that criteria, I'm going to take my own hose.
On the other hand, if you get caught in a high-rise WITHOUT a hose line, then use the house line! In 1994, Memphis Fire Department had two LODDs - members of Engine 7 who were cut off by a fire while searching a high rise without a line. They died a few feet from an intact, servicable house line that could have saved their lives, per the incident analysis, if memory serves.
"But the crew from Snorkel 13 may have made a significant impact on the course of the incident had it been aware and taken advantage of the occupant-use hose system. Instead, the crew was overcome by a frenzied occupant. Often firefighters are trained to disregard the use of occupant-use hoselines due to concerns about maintenance of the equipment. In this case, however, even poorly maintained hose might have provided a worthwhile alternative until additional firefighters arrived and advanced lines from the west stairway riser."
In other words, when it comes to house lines, "You pays your money and you takes your chances." but as a last resort, they're better than noting.
Thanks for bringing it up, it's an important part of the discussion.