NEW WEAPON FOR HIGH-RISE | HOSE BUNDLE
Overcoming Standpipe Low Pressures
There are three primary ways the fire department can compensate for the potentially lower pressures of standpipes in high-rise
buildings. We can pump to the FDC to increase pressures; we
can use hose that offers lower friction loss characteristics; and we
can use low-pressure nozzles. The research objective was to test
hose and nozzle combinations that could provide high flows at the
pressures we might expect from a high-rise standpipe.
Field Testing Equipment
In assessing what other departments were using for high-rise
packs, I made contact with a number of fire departments that have
significant high-rise profiles, including Long Beach, Los Angeles,
Denver, Las Vegas, Chicago and New York. The research revealed that many major cities (New York, Chicago, Denver) used
hose packs of 2 ½-inch diameter hose with 1 1/8-inch smooth
bore nozzles. Clearly this combination would provide the lowest
possible friction loss hose together with the lowest pressured
nozzle (50 psi) and would allow for a target flow of 250 GPM.
LAFD was unique in that they choose to use two-inch hose with
a low-pressure (75psi) fixed-gallonage 200 GPM fog nozzle.
The use of a fog nozzle with standpipes is debatable because
of potential debris clogging the nozzle, but Los Angeles has had
favorable results and continues to use it with success today. Las
Vegas has recently been re-evaluating its high-rise packs and
were looking at a new 1.88-inch hose made by Key Hose called
Combat Ready (marketed as 1 ¾-inch) that actually is 1/8th larger
than 1 ¾-inch and 1/8th less than two-inch hose. The friction loss
characteristics are substantially less than a typical 1 ¾-inch hose.
In evaluating different hose I looked at our standard County Fire
1 ¾-inch hose, a Niedner lightweight 2 ½-inch, and the 1.88-inch
Combat Ready Key hose. In evaluating nozzles, I included a
standard County Fire 1 ½-inch Task Force Tip (TFT ) Thunder Fog
selectable nozzle (100 psi), both 2 ½- and 1 ½-inch smooth bore
nozzles at 50 psi with a variety of tip sizes, and a low pressure 1
½-inch TFT Metro break-apart nozzle that was available in 50 psi
and 75 psi. The TFT break-apart nozzle is a fog nozzle that can be
converted to a smooth bore by unscrewing the fog nozzle from the
shut-off valve. The inside of the shut-off valve is bored to a smooth
bore diameter. We tested 7/8, 15/16 and 1-inch versions.
The field test involved subjecting different hose and nozzle
combinations to different pressures, simulating potential standpipe outlet pressures and measuring flows, evaluating the weight
and the different ways to bundle the packs, and testing different
techniques of carrying fire attack hose bundles and equipment up
a stairwell. We also assessed nozzle reaction and maneuverability
of the hose line.
There is no doubt a 2 ½-inch hose with 1 1/8-inch smooth bore
tip will provide the biggest knock down potential with a flow of
250 GPM. Even though the 2 ½-inch hose is heavier and more
difficult to maneuver than a 1 ¾- or 2-inch, its ability to deliver the
maximum amount of GPMs to overcome the potential BTUs of a
high-rise fire is undeniable.
200 GPM fixed-gallonage nozzle. I actually believe LAFD has “hit
the sweet spot” between flow and maneuverability with the use
of 2-inch hose and a 200 GPM low pressure (75 PSI) nozzle. I
didn’t feel 2-inch hose was a viable option for our department, so
I wanted to see if it was possible to reach the same target flow of
200 GPM with the 1.88-inch Combat Ready hose given similar
pressures. In order to compensate for the lower friction loss of the
2-inch hose I looked at using a lower pressured nozzle (50 psi) with
the 1.88-inch hose. I tested several smooth bore nozzles, but liked
the versatility of a 185 GPM at 50 psi TFT Metro fixed gallonage
brake-apart nozzle. The flows were extremely impressive. Below is
a chart illustrating the difference between our standard County Fire
1 ¾-inch hose with a 100 PSI nozzle versus the Combat Ready
1.88-inch hose with the TFT Metro fixed-gallonage 185 GPM at 50
PSI break-apart nozzle.
The TFT Metro fog nozzle is able to be unscrewed from the
shut-off valve to be used as a one-inch smooth bore nozzle. This
feature gives you the ability to remove the fog nozzle in the event
it becomes clogged with debris or you want the penetration of a
smooth bore. The threads can be protected with a quarter turn of
the thread protector collar. If you have a need to extend the line,
you can simply shut down the nozzle, remove the fog nozzle, add
hose and a spare nozzle (from the high-rise kit) on the added
hose and maintain forward progress without having to shut down
the line at the standpipe. It’s an extremely versatile