exposure problems and the danger of fire spread itself? Remember, a knockdown is not necessarily an extinguishment; it is a stifling of the fire to a point where, at minimum, it is not spreading
and is not endangering anything else that has yet to burn. With a
little bit of experience on how many gpm are needed for specific
sizes of fire, the correct decision can be made a big majority of
the time. Of course, if you are in doubt whether you can obtain
a knockdown, then exposure protection would be the right thing
to do. I have done numerous flow tests on actual fires with 500
gpm flows and achieved knockdowns ranging from five seconds
to 30 seconds on fairly large structures equivalent to a triple-wide
mobile home or what is famously known back East as taxpayers,
which are convenience store-sized structures.
MASTER STREAMS
Okay, now it’s time to increase the size of the fire. Remember
the fire that I described to you that I saw on You Tube that was a
three-story apartment complex well involved in the front? Now
we’re talking about streams of it least 1,000 gpm—notice I said
streams. Again, a study of You Tube fires that are multicompany
operations with the big guns flowing reveals a high percentage of
the time the entire stack of tips is left on the master stream appli-
ance. In fact, one of the videos I saw had audio with it and you
can hear the order being given to use the 13⁄8-inch tip. If that tip is
being pumped properly, you can expect 500 gpm. The problem is
that the fire is probably a 2,000-gpm fire.
The same decisions need to be made on whether to protect expo-
sures or hit the fire; however, this time one large and more compli-
cated decision needs to be made if you’re going to hit the fire with
the proper flow. Where might you get the water from? The fire on
You Tube was in a major city and involved a major fire department,
meaning that apparatus and fire hydrants were plentiful. This
department used five-inch-diameter hose and grabbed the closest
hydrants to the fire. I’m not sure why it used the 13⁄8-inch tip, but a
common reason for this is because members ran out of water even
using large-diameter hose (LDH). I have a little phrase that I like
to use all the time, “The water’s out there; you just have to go get
it.” Most departments with LDH lay from the closest hydrants,
and when they develop water supply issues they give up. Word gets
back to the incident commander (IC) that they are out of water,
and the IC directs everybody to gate down to where we get streams
that will reach the fire. Guess what? The fire eventually goes out.
Here’s what needs to be done. First, if a master stream is going to
be used for a sustained water delivery operation (in other words, not
a tank water blitz attack), the goal should be to supply the rating
of the appliance. Most fixed mounted master stream appliances on
engine companies are rated to flow 1,250 gpm. This is not achievable with the two-inch tip, which is the largest in the stack because
Truck 2 sets up an elevated stream operation, getting a water
supply from a relay that Engine 7 is setting up via a manifold at
Truck 2’s location. Engine 6 connects a supply line to the same
manifold to supplement Truck 2’s water supply.
Engine 8 is needed to deploy 21⁄2-inch handlines and gets a water
supply from Engine 6 and Engine 1. They will determine whether
the line is discharged to Engine 8 or set up in a dual pump operation. Truck 1 and Engine 2 tie into each other via dual pumping.
