Low Pressure Nozzles

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03-13-2006, 11:38 PM
PITT8TRUCK

Low Pressure Nozzles

We have run multiple tests, used them in the field and it is obvious that low pressure nozzles have advantages. Looking for your opinions. Who is running with 50psi fog or 75psi fog nozzles with breakaway smooth bore? What is your smooth bore diameter?

We are almost set to go 150gpm at 50psi fog, break away with 7/8" tip.

My only big concern is hose kinking. We staff with 4, so if one is at the hydrant, this leaves an officer plus nozzleman, I am not convinced that two persons will be able to manage the kinks, or maybe they will. What do you think?

Should we go 150gpm at 75psi in order to reduce the kinks, even if it increases nozzle reaction?

Hmmm, these are my sticking points. ANY HELP?

Oh by the way we are looking to replace automatic TFT's.
03-13-2006, 11:43 PM
FFFRED

Quote:

Originally Posted by PITT8TRUCK

We have run multiple tests, used them in the field and it is obvious that low pressure nozzles have advantages. Looking for your opinions. Who is running with 50psi fog or 75psi fog nozzles with breakaway smooth bore? What is your smooth bore diameter?

We are almost set to go 150gpm at 50psi fog, break away with 7/8" tip.

My only big concern is hose kinking. We staff with 4, so if one is at the hydrant, this leaves an officer plus nozzleman, I am not convinced that two persons will be able to manage the kinks, or maybe they will. What do you think?

Should we go 150gpm at 75psi in order to reduce the kinks, even if it increases nozzle reaction?

Hmmm, these are my sticking points. ANY HELP?

Oh by the way we are looking to replace automatic TFT's.

Some questions first...

-How do you stretch? Do you pull preconnects...or do you pull what is needed?
-Do you backstretch or do you perform in-line (forward) lay mostly...I would guess the later.
-What is the deployment like? Is it come off in a bundle/pile or is it nicely payed out by the nozzle man or whomever?
-What type of load?
-How long is this memeber at the hydrant, what are his duties after the water supply is secured?
-Do you assign someone to chase kinks?

FTM-PTB
03-14-2006, 12:42 AM
cozmosis

Quote:

Originally Posted by PITT8TRUCK

My only big concern is hose kinking. We staff with 4, so if one is at the hydrant, this leaves an officer plus nozzleman, I am not convinced that two persons will be able to manage the kinks, or maybe they will. What do you think?

We are switching to nozzles very similar to yours in the near future. Many of our members were concerned about hose kinking. However, in side-by-side tests using a flowmeter with our current TFT automatic nozzles, the fixed gallonage nozzles delivered more water while kinked in two than the old nozzles.
03-14-2006, 07:20 AM
Tillerman17

Replacing the TFT"S is a good start. Have you considered simply using a simple shutoff with a 15.16th tip in place of the fog nozzles. You will have the flow you need and avoid the headaches with the fog nozzles. lastly, since raising the PDP is out of the question why not make your hydrant man follow the kinks up th line after charging the hydrant? He doesn't stay there does he? Good luck.
03-14-2006, 08:52 AM
Bones42

We use Akron Breakapart Assault nozzles. 75psi 175gpm. Smooth slug is 7/8". Have not had a problem with kinking hose and plenty of gpm. Easy for 1 guy, even easier with a backup.

We switched from 100psi TFT's to these on all of our 1 3/4" lines. Gives you everything in a simple way, wide fog, narrow fog, straight stream, solid stream.

I hate Saberjet nozzles, move this for that, move this for that. Too complicated.
03-14-2006, 09:30 AM
E229Lt

Quote:

Should we go 150gpm at 75psi in order to reduce the kinks, even if it increases nozzle reaction?

I think you should be setting you flow goal at 180 gpm. JMO
03-14-2006, 02:07 PM
PITT8TRUCK

We use mainly preconnected attack lines, 150, 200, 250, anything longer needed is connected off of a 3" leader line. We use a minuteman hose load all have a hundred feet on your shoulder and we normally stretch from the pumper. We have hydrants every 300ft and good water pressure so we normally forward lay with the engine and it is positioned near the building leaving room for the truck. The hydrant person is to make connections, follow the supply line back to the engine, grab a tool, and follow the line in to his officer. He or she should be chasing the kinks. But I will be honest, training and discipline of hose management are definetly needed. Always a bundle of people at the tip.

Thanks again
03-15-2006, 06:20 AM
TriTownship600

Honest Question

What are the advantages to lower line & nozzle pressures?
03-15-2006, 07:58 AM
Tillerman17

Quote:

Originally Posted by TriTownship600

What are the advantages to lower line & nozzle pressures?

TriTown, Simply put, fog nozzles requiring 100psi at the tip call for higher PDP to achieve the required GPM's. Low pressure fogs require less PDP making your life on the knob a little easier. 50psi smooth bore tips are while requiring less PDP will deliver 185 GPM making your life even easier.
03-15-2006, 11:26 AM
FyredUp

PITT8TRUCK...

Both my volly and career FD use the 200 at 75 psi combo nozzle.

My career fd uses it with a 15/16 slug tip behind the combo nozzle on 1 3/4 inch hose. My volly FD uses it with a 1 1/4 inch slug behind the combo nozzle on 2 inch hose.

We have not had an issue with kinking. These are fixed gallonage nozzles and not automatics.

We have been using these for several years and our guys love them. If I can be of further help let me know.

FyredUp
03-16-2006, 09:34 AM
MG3610

Consider this option...

A 150 GPM at 75 PSI combo tip (akron assault) with 1" smooth bore slug.

This offers you two seperate flow capabilities without any pump discharge pressure change.

Figure it this way...

The 150@75 tip has FL of 35 PSI per 100' and a NP of 75. 35+75= 110 PDP fpr 100' line.

The 1" tip (210 GPM) has a FL of 62 PSI per 100' and a NP of 50. 62+50= 112

For any match of combo tip and smooth bore tip ideally you want a combination that doesnt require a pump pressure change to allow the smooth bore tip to flow its rated flow, for simplicity sake. To determine which two tips are a good match, simply make sure the friction loss for the goven flow rating plus nozzle pressure for each nozzle tip (smooth bore and combo tip combination) adds up to the same number.

To calculate the difference...

Combo tip first: Nozzle pressure+friction loss=PDP (for given length of line)
Subtract 50 from the above calculation to determine the FL difference at 50 PSI tip pressure. Look up on a chart the closest FL to your answer and thats the SB tip flow youll need. Find the closest SB tip/flow match.

7/8"=160 GPM
15/16"= 180 GPM
1"= 210 GPM

You can also opt for akron Assault 150@50 tip with 7/8" smooth bore for essentially equivalent flows at the same tip pressure (50).

Hopefully I explained that correctly and did all my math right!
03-16-2006, 10:33 AM
Bones42

MG3610, last night during drill we ran the flow meter to check. We used 1 3/4" line at 150' with Akron breakapart nozzle, the smootbore is 7/8". At approx. 125psi, gpm from nozzle was 175 with adjustable and 185 without.

I agree entirely with you on the nozzle choice as it gives those common flows with common pressure and lots of options. :)
03-16-2006, 03:00 PM
fdsq10

On our Engine we have a Elkhart SM 30F nozzle on 2 crosslay's, 15/16 smooth bore on our 2nd 1 3/4. On our 1 1/2 trash line we use a marauder akron 95gpm nozzle. For our high rise hose we us the LA 200 @ 75psi break a way to a 15/16 smooth bore nozzle.
03-16-2006, 10:10 PM
NonSurfinCaFF

Just a thought on the 50psi vs 75psi, if you go with the 50 psi, its one less thing for the engineer to worry about, just 50 psi for smoothbore and fog.