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Chris Mc Loone |
Right, I know, the headline is stating the obvious.
I guess in looking at the cover and thinking about some of the hoselays I’ve seen at FDIC International-for training purposes-and some recent photos I posted on www.fireapparatus.com from Steve Redick, it just reminded me that when we are looking to move large amounts of water over large distances, it’s not as simple as laying the line and hooking it up to the engine. Logistically, it’s a real challenge.
In these pages, we discuss the technology and equipment behind moving water-single- vs. two-stage pumps, various size pumps, relay valves, intake valves, pressure relief valves, remote control valves, manual valves, large-diameter hose (LDH), etc. Although we don’t get into tactics in these pages, it’s almost impossible to avoid talking about them when discussing moving water long distances.
For example, in my area, recent LDH drills aren’t including relay valves. Gone are the days of pumpers that would often break down in relays, necessitating that trucks be connected to relay valves so if a pumper went down, it could be disconnected so another pumper could tie in. These days, our fire apparatus have become so reliable, some local experts espouse eliminating the relay valves and putting the trucks themselves back inline. Is one way better than the other? It all depends on how you operate as a department. Keep everyone on the same page and, of course, it doesn’t matter. Just remember if you’re in a relay and you’re running a two-stage pump to switch from pressure to volume if you exceed more than half the capacity of your pump. As a side note, I’ve participated in LDH relay drills where I operated a truck in the middle of a relay and others where the truck has been on the hydrant. Our trucks have two-stage pumps. I have exceeded 1,000 gallons per minute (gpm) once.
Personnel numbers affect everything we do on the fireground. Large municipal departments have the luxury of knowing who and how many are coming. Rural or suburban departments that are 100 percent volunteer don’t always know who, how many, or when help is going to arrive. Whether you are setting up an LDH relay or a tanker operation, shuttling water from a source to the scene, setting up to move large amounts of water takes time. Know where your water is-whether it’s a pond or lake or your biggest water main. I visited the Philadelphia (PA) Fire Department (PFD) a few months ago, and I asked about its water supply. I think the question came up during a discussion about single- vs. two-stage pumps. In any event, the PFD has an excellent relationship with the water company, and it has maps of the water mains. It’s not so easy where I live. Generally, we know where the water is and what we will need to do to get it. But, it’s not an exact science and takes some work in the beginning of an operation. Most importantly, it takes time. Fewer personnel means it takes even more time.
We have a variety of flavors of “seasoned” engineers in my department. Some have a good feel for what they are doing whether or not they remember friction loss equations for LDH. They are good at what they do and are the best of the best in the township. We have others who can do the math for these things so quickly in their heads that I marvel how fast they figure things out. There are others who absolutely embrace the math and the science behind large flows, plotting graphs for flows based on different hydrants and water sources. There aren’t