Thread: Stack tips or combination tips
01-06-2000, 11:49 PM #1Batt #2Firehouse.com Guest
Stack tips or combination tips
We have a 1998 100 foot Pierce tower Ladder.
I have a set of stack tips for the pipe in the basket the tips sizes are 1 1/4, 1 1/2 ,
1 3/4 and 2 inch.
I like the reach and "punch" of the stack tips and the lower psi to flow them.
I understand combi tips have places in tanks farm and so, but love the stack tips.
Just throwing it out to see what others do
01-07-2000, 11:21 AM #2KEAFirehouse.com Guest
FLOW TEST FLOW TET FLOW TEST
Get a flow meter, pressure gauges and a pitot and test each tip and any other nozzle to determine what discharge pressure is needed to establish the proper NP and then compare the range of each nozzle type or size, footprint and then make you choice.
If your looking for an application for Tank Farms many other questions come to mine.
Is it going to be used for foam or just cooling?
what product are you trying to protect or extinguish?
Another factor that can make a big difference in your success is what size plumbing to the top of your ladder?
BY flow testing it you will be able to find out its max capability and then work back from there.
First Strike Technolgoies, Inc.
01-07-2000, 04:58 PM #3Tower59Firehouse.com Guest
in my home town we have a sutohen 100' tower
we use stack tips on one of our guns and 1000 gpm combination on other. this way we have best of both worlds.
01-17-2000, 01:08 PM #4STBURNEFirehouse.com Guest
stacked tips should be on the aerial tip. Maximizing steam conversion by breaking up the droplets is not an issue during exterior defensive operations. Rate of flow is all that matters, so why not go with the nozzle that has the least chance of blockage from debris, never requires calibrating, is less expensive, easier to use, and easiest to maintain? There are "once in an apparatus lifetime" events that require a combination nozzle on the aerial tip that may call for keeping this type nozzle in the basket or in a compartment. These are: Hazmat incidents, excellent for mass decon, and excellent for dispersing/mitigating hazmat vapors.
For these cases, a fog tip may be kept on the apparatus. And in the words of one of my good friends "This tip should be kept on the truck in a glass case that reads 'break glass only in case of hazmat' and then hide the hammer so that the operators have to make sure it is what they want to use."
I have witnessed far too many large loss fires where aerial streams on fog patterns never reached the fire because they were eaten up by the thermal currents. The smoothbore leaves no room for error.
01-17-2000, 02:04 PM #5KEAFirehouse.com Guest
STBURNE: I agree with all said except one part.
/ Rate of flow is all that matters/
Extinguishment is determined by both Rate of Flow and Type Stream (water droplets). If suppression is the goal, how can we say that the second part of the equation for fire extingushment doesn't apply?
I agree totally that combination nozzles have no place on an arial. The droplet size of the stream is completly inadequate to reach the fire just as you point out.
According to NFPA the Application Rate & Type Stream determine the speed of suppression with water. The rate of application is commonly referred to as gallons per minute (gpm). The type of stream refers to heat absorption. The two common ways of increasing a stream’s heat absorption is by breaking the stream into smaller droplets and increasing the number of droplets by increasing your gpm.
“To be effective, the water droplet must be formed near the base of the fire, or be large enough to have sufficient energy to reach the seat of the fire despite air resistance, the force of gravity, and the fire thermal column. When droplets are too small they can be deflected by the fire plume, or be evaporated before they reach the base of the fire.”
With this in mind I agree that the Stack tip is the better choice than a combination nozzle.
First Strike Technologies, Inc.
01-18-2000, 08:45 PM #6STBURNEFirehouse.com Guest
KEA-I agree with you 100%. My statement was used for brevity, application rate is all that matters in aerial defensive operations because there is only one stream type that is effective.
01-19-2000, 09:51 PM #7RESQ LOUFirehouse.com Guest
What are the feelings on having an extension on your stack tips. What I mean is if you had a two foot extension or a smooth bore tip that was two foot long with a 1 3/4 or 2 inch tip. Would this give you any additional reach of increase your punch. Will it keep your cone togather longer giving you more reach.
01-20-2000, 04:53 PM #8STBURNEFirehouse.com Guest
Stream straighteners are currently used on most all deck guns and deluge nozzles. I beleive this is what you are referring to. I have always used one when working with master streams but am not sure how much stream quality suffers when not using one.
01-20-2000, 05:57 PM #9KEAFirehouse.com Guest
RESQ LOU & STBURNE:
Depending on the monitor type that you have your tips on, you will see a big difference in stream quality with the stream straightner removed.
It doesn't take but a minute to test the difference of with and without. I highly encourage using one. Our testing has shown that there is little difference in the stream while using the long or short straightner.
RESQ LOU: Chicago at one type made their own tips in the maintenace shop. They were machined from solid brass. Rumors have it that they have a 4' smooth bore (Not sure of the tip size) that they made and have succesfully shot the stream through a 13th floor window. Now I know 130 feet may not seem like much, but when was the last time you tried it straigt up?
First Strike Technologies, Inc.
01-23-2000, 01:21 PM #10BIG PAULIEFirehouse.com Guest
Have any of you tried High pressure smooth bore tip master stream operations? I know that the "books" call for an 80 psi nozzle pressure for smooth bore tips on master streams. It's too bad they don't consult with the manufacturers of the appliances to see what they are really capable of doing. I have personally done operations with high pressure smooth bore tip streams that have made a dramatic difference in the velocity and reach of the stream. Example- 2" tip @ 140 pounds np produced a stream of 1400 GPM that left it's footprint (and I mean a BIG footprint) 360 feet from the appliance. Another good application is an 1-3/4" tip pumped at 115 np producing a stream of 1000 GPM, again with a harder hitting, farther reaching fire stream. This application works well on elevated streams that have a high friction loss in the waterway where higher pressures may not be possible with bigger tips. There are rules to follow with high pressure operations. The appliance should be in the fixed mode, which means attached to the top of the engine and in some cases on elevated platforms or ladders. When it comes to the elevated streams, consult the manufacturers specs to make sure that the flows/pressures are in line with the specs of the unit. When using a fixed appliance on top of the engine, the main rule to follow is not to exceed the inlet pressure of the appliance, that is where the appliance connects to the plumbing. As far as portable guns are concerned, Akron and Elkhart have a maximum inlet pressure of 200 psi. TFT is a little more conservative with a 175 psi inlet pressure. Simply-watch your discharge gauge and do not exceed these pressures. You will find some interesting results with high pressure operations. Of course, a regular maintenance/inspection program should always be done on master stream discharge plumbing regardless of the type of operation that you use.
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