1in tip on 13/4 attack line.

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Permalink Reply by Larry Lasich on May 15, 2012 at 12:35pm

What's "great flow"?  185 plus is very do-able.

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Permalink Reply by Robert Kramer on May 16, 2012 at 1:53pm

Sure, I guess it will work and I am sure you could get flows of 185gpm, but at what cost? I was always taught that on solid bore streams, more specifically solid bore hand lines, that the nozzle orifice should not be more than 1/2 the size of the hose line.

Why you ask? This supposedly limits the amount of water that is capable of being discharged in a range tha keeps a good working amount of nozzle pressure for reach and enough pressure in the line that prevents the line from easy kinking. Try it for yourself....you'll believe to.

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Permalink Reply by Stephen H. Higgs on May 16, 2012 at 1:57pm

We have utilized 1 inch s.s. nozzles on 1 3/4 inch hose for many years. This set-up delivers 200 gpm at 50 psi with a FL of 35 to 50 psi in 100 ft. of hose, depending on the hose utilized (low friction) or not. With a 200 ft. attack line you have a PDP of 150 psi. The fire stream is excellent and maximizes the knock-down and punch delivered by the stream. We also utlize 7/8 inch tips that deliver 180 gpm at 50 psi for a FL of 30 to 40 psi in 100 ft. of hose, PDP of 130 psi or less.

 

Both of these streams have great reach and penetration as well as adequate gpm for fire knock-down. They work very well! 

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Permalink Reply by Reed T. Menz on May 16, 2012 at 2:03pm

I think it will shorten your reach.  There is a relationship between the size of the nozzle tip, and the water pressure that creates the reach and allows the gallons to flow.  If you open the tip, you reduce the back pressure which reduces the reach. Those long hallways will become longer.

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Permalink Reply by Larry Lasich on May 16, 2012 at 3:13pm

This sounds like rumor and propaganda to me.

Who told you this and what proof did they offer?  This test was run by the FDNY and you can disregard the 1st Strike results, but the 15/16 is close enough to what you were asking about.

http://www.1ststriketech.com/Testimonies/finalreportFDNY.pdf

Kirk Allen studies this stuff for a living and can point you to actual tests with real numbers:

http://community.fireengineering.com/forum/topic/listForContributor...

Robert Kramer said:

Sure, I guess it will work and I am sure you could get flows of 185gpm, but at what cost? I was always taught that on solid bore streams, more specifically solid bore hand lines, that the nozzle orifice should not be more than 1/2 the size of the hose line.

Why you ask? This supposedly limits the amount of water that is capable of being discharged in a range tha keeps a good working amount of nozzle pressure for reach and enough pressure in the line that prevents the line from easy kinking. Try it for yourself....you'll believe to.

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Permalink Reply by Don Catenacci on July 17, 2012 at 7:00pm

The one inch tip flows 209 gpm at 50 psi, the 15/16 tip flows 182 at 50 psi,and the 7/8 tip flows 160 at 50 psi.  My POC FD uses a 1 1/4 inch slug tip on our 2 inch lines and we flow 300 gpm at just over 40psi at the tip.

 

The reach argument is important if you are doing exterior attacks.  Less important interior where you rarely need more than 20 or 30 feet of reach.

 

To the original poster, a 1 inch tip works fine on 1 3/4 inch hose. 

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