1. ## Nozzle reaction force

Anyone have a good, mechanical method devised for measuring reaction force of different nozzles? We are currently looking into purchasing some constant gallonage nozzles (we currently use older automatic nozzles) and would like some numbers to go along with the arguement for the new nozzles. Thanks for any info you can share!

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Captain Scott Lambert
Seminole Trail Volunteer Fire Department
www.monticello.avenue.org/stvfd

[This message has been edited by stvfd88 (edited March 28, 2000).]

2. We recently performed the tests you're asking about. We built a test stand that measures the torque (basically a 5' swinging arm with a dynomometer to measure force) and did the math for the actual nozzle reaction.

I'm still working on the numbers to get them posted on our web site, but if you'll email me the mfg. and part numbers of the nozzles you're looking at I'll send you our info so you can compare it to yours.

3. Great post! I hope some good ideas come out of this one.
I am sure you are familiar with the mathematical formulas:
NR(solid)=1.57 * d(squared) * NP
NR(fog)=0.0505 * GPM * (square root of)NP

But these formulas are just that and I am sure this is the reason for the post.

One thing I have done in teaching is taken dumbells into the classroom and have each student hold the difference in weight above their head for each type nozzle.

4. Thanks S.Cook for the numbers. I received them today. It seems that the formulas, according to your numbers, give us a high number for the reaction force, which is exactly why I wanted to know if there was a mechanical way to measure this.

Thanks for the posts. I hope they keep coming!

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Captain Scott Lambert
Seminole Trail Volunteer Fire Department
www.monticello.avenue.org/stvfd

5. It may seem to be an antiquated way...but once when I was a career captain we did it the old fashioned way. We got the folks who were selling us the nozzles to let us have a demo and we tried it in our training academy during different exercises. We tested each nozzle we were considering at different nozzle pressures and let the folks on the line tell us what they thought. This worked especially well on testing Solid Bore nozzles. We found that if we went from 50 PSI nozzle pressure to 60 PSI NP on a 15/16" tip we could deliver approximately 210 GPM as opposed to 192 GPM and still have a very managable hoseline with the nozzle flowing. This was for 1 3/4" hand lines. Those GPM may be off a couple pounds either way as I was trying to recreate them from memory. At any rate...field testing proved teh best way for us.

PS>>I saw your department on an auto accident on Rt 29 just up from Aunt Sarahs Pancake house on 3/26/00 @ about 530 pm. Good job!

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