straight tips vs combination nozzles

[FROMMER]

My dept. is thinking about making all hi rise packs with straight tips. looking for info. ref. protection with straight tips and any field pro or con.

[UsingAllHands]

To begin, high rise packs / standpipe operations should ALWAYS utilize 2-1/2" hose, altough I know there are many places out there that do not do this. The need for 2-1/2" hose is due to the lower operating pressures standpipes can supply, coupled with long hallways common in high rise buildings (2-1/2" hose has less friction loss) and the need for greater flow rates. High flow rates (in excess of 250 GPM) are necessary because of the potential "blowtorch" effect possible when wind drives the fire out into the public hallway. Having said that, let us examine your question in particular, with regard to nozzle selection.

Straight tips (smoothbores)

Pros:
- High volume of water with reduced reaction force (1-1/8" TIP = 250+ GPM @ 50 PSI N.P.)
- Lower pressures needed to make a usable stream (extremely important, especially when working off of standpipes)
- Greater resistance to clogging from debris (standpipes often have foreign matter inside)

Cons: NONE

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Combination nozzles

Pros: NONE

Cons:
- Greater pressure needed (sometimes impossible off of standpipe) in order to achieve necessary GPM flow.
- VERY EASILY CLOGGED when subject to debris common in standpipe systems.
- Inexperienced operator might subject members and civilians to extreme steam burns if nozzle is taken off of straight stream.
- Even when set in straight stream position, water stream is made up of little droplets reassembled to appear like a smooth column of water. Much of the water in the resulting stream burns up and vaporizes before reaching the seat of the fire and cooling down the burning materials.

Conclusion: Take anything but 2-1/2" hose plus a smoothbore nozzle into a highrise and you must be suicidal.

[FFFRED]

I'll second everthing All Hands said.

Anyone who uses 1 3/4 hose and fog tips in high-rise fires is ignoring what every expert will tell you about high-rise Fires. It is foolish to take such insufficent equipment into an extreemly dangerous type of fire. (Is there any other kind???)

NFPA also tells you not to use Fog tips...
NFPA #14 states [I] “It is very important that fire departments choose an appropriate nozzle type for their standpipe fire-fighting operations. Combination Fog, Constant Pressure, (Automatic) type spray nozzles should not be used for standpipe operations because many of this type require a minimum of 100 psi of pressure at the nozzle inlet to produce a reasonably effective fire stream. In standpipe operations hose friction loss might prevent the delivery of 100 psi to the nozzle. In high-rise standpipe systems with pressure reducing hose valves, the fire department has little or no control over hose valve outlet pressure.” (NFPA #14, Standpipe and Hose Systems, A-5-7.)[I]

Any one think that it is only FDNY guys who think this way...I'll direct you to read the articles written by Chief McGrail of the Denver FD. He is very knoledgable on the subject of High-Rise FF.
Subcribe to www.firenuggets.com and you can see what he and others say. Also I do believe he teaches at seminars from time to time. Look for him.

FTM-PTB