I am unabashedly an Engine man. I am an operator for my Oklahoma City Metro Area Fire Department.
I am soliciting knowledge from Truckies (I never imagined that combination of words streaming from my keyboard wink, wink..) on the topic of "Big Water" from elevated master streams (i.e. Tower Ladders, Ladder Towers, Snorkels, Aerials).
My Question(s) are as follows:
1. Do your departments subscribe to "big water" as it applies to supplying your Aerial Devices?
By "Big Water" I mean a full tap on the plug to the pumper at the plug which supplies another Pumper at the ass end of the aerial and that pumper relaying water into the aerial device. Basically maximizing all potential water through a full tap and relay pumping utilizing the flows attainable from what is essentially "series" pump operations.
2. If you are a proponent of this supply, what are the advantages?
I have seen flow tests, and this supply configuration can be significantly more voluminous than a simple LDH supply from the pumper at the plug to the aerial, but is that larger volume going to positively affect an operation that has is probably severe already.
Most "surround and drown" operations that I can recall have ended in the same result, that being no extinguishment until the roof fairly burned off the thing. This is mainly because of course, roofs are indiscriminate in what water they prevent from entering the structure.
I ask this question in all sincerity because I can recall my Apparatus Operator's Academy and I know that generally when supplying an aerial, we stretched a reverse from the aerial to the plug and then caught our plug and pumped to the aerial. Basically 1 line of LDH.
I know that is a limited volume of water, but again, I cannot see the importance of supplying more to a structure with likely a roof still at least partially intact.
Barring getting the bucket of a Tower Ladder on the curb and applying water to the underside of the roof/cockloft, I can see no need for "big water" as it is time consuming in its application. Also, I would think that the entire operation is "main limited" meaning that the size of the water main would dictate efficacy.
I am not an authority on this topic. I really want to hear some feedback because I can't see "big water" as a priority on these types of firegrounds, and I want to know whether or not to change my perspective.
Thank You to all contributors.
Fair question Mike. Let me give you my spin.
1- I am recently retired as a District Chief in my department.
2- I teach at my local fire academy and one of the classes I wrote is "Big Fire-Big Water".
The main concept of this class is that most of us are set up and train for little fire. When faced with big fire, we shouldn't apply little fire techniques. We all have pre connects on our engines. We pull up to a house fire and we pull the 1 3/4" pre connect. This will normally allow us to extinguish one or two rooms of the structure. If more than a couple rooms are involved we seem to pull two of these 1 3/4. (Contents and construction come into play here obviously but you get my drift). If we pull up and the whole thing is involved guess what many departments do? Yup, pull that same 1 3/4 inch line. Why, because we mostly go to little fires and that's how we have conditioned ourselves. Some crews may start with a 2 1/2" attack line. Nice thought, but if it's a wood frame 2000 sq foot building you may still not have enough gpm's for the btu's. Won't even get into the mobility debate here. Blitz attack or pre piped master stream or even 500gpm quick attack monitors may be more appropriate. In other words, we should attack small fires with small water but bigger fires call for big water.
3- Let's leave residential and talk commercial/industrial. Name a building type and my district probably had it. Residential, Commercial, Industrial, Wood frame, Concrete, Tilt slab, Type I, Type II, Type III, Type IV, Type V etc. I tried to make it clear to my crews the same way I do to my students that not all buildings are the same, so our initial attack can't be the same. I'm sure most of us can think of a call where we started small and kept playing catch up. Pull another line, pull another line, pull another line. Eventually the fire went out. Not because of anything we did, but simply because we ran out of fuel.
So I believed and teach that any fire showing in a commercial/industrial building you should immediatly think big fire-big water. No one touches that 1 3/4 line for anything other than exposure protection. So if we are going to use big lines, master streams, elevated streams etc. we need as much water as possible. In these instances we attach a gate valve on the 2 1/2 discharge of every hydrant in addition to our 5" LDH. (It's in a hydrant kit we keep on the end of our 5"). This allows us to get extra water from the hydrant. First lay the 5" and charge it for fast water then follow up with 3" attached to the gate. Some call this set up the Full House or Fully Dressing the hydrant. Some departments also carry two of the 2 1/2" gates. One for each side.
You are right about the size of the main and it's ability to supply enough water. We had smaller mains in our residential areas and bigger mains in our commercial areas. The Full House may max out our hydrant in the residential areas and hitting the next hydrant for more water may steal too much from the first hydrant. Again, the main size and configuration comes into play here. In commercial areas this was never a problem.
I also believed in keeping it simple. So on our commercial areas we have hydrants all over the place. No need for a long LDH lay requireing a relay pump. Instead one pumper would hit the hydrant, fully dress it then tandem pump it to the next unit. That's in the gated LDH intake on one side and out the gated LDH intake on the other. No friction loss calculations. Just excess water to the next vehicle. The first unit gets all the water they needed and the excess water goes to the second. We only gave that excess water to our master streams for exterior attack in case the first unit used all the water for some reason. Once you practice this a few times you realize how damn easy it is compared to relay pumping.
Finally, like anything we do we have to practice it to master it. Once it's masterd it takes no more time than a traditional forward or reverse lay and a relay pump operation, and it makes more GPM available to us to use.
Hope that helps... or at least starts a conversation.
Thank You Chief. It certainly does.
Do you have any stats or information regarding how effective the "big water" is fire control?
I am interested because I feel that it would be beneficial here as we are making a push towards this as standard operations at large volume fires. Really what we have is some moderate anecdotal evidence that "big water" is more effective than less "big water" at commercial structures nothing evidence based.
Any info is good. Thank you again.