Guide to Automatic Nozzles
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Transcript Guide to Automatic Nozzles
Fire vs. Water Flow
What’s the best size for an “attack line?”
What factors are the highest priority on your
department?
Maximum flow
Maximum mobility
Speed-How fast and how much
Ease of deployment and pickup
Personnel available
Water supply available
13/4” ?
Pump Pressure for 125 GPM
452 psi
156 psi
150 feet
150 feet
136 psi
150 feet
105 psi
1”
1½”
1¾”
2½”
150 feet
(100 psi nozzle pressure)
Larger Attack Hose Lines Equal...
Higher initial attack flow capability
Less friction loss
Longer hose lay capability
Using more of pumps capacity
Higher Flows Equal...
Quicker fire knockdown
Personnel spend less time in “combat”
More lives saved
More property saved
Fire Ground Hydraulics?
P.S.I.?
Nozzle pressure?
200?
150?
The Preconnect...
The Preconnect is always the first line off
The first two lines down fight most of our fires
Can they handle most anything our department is “normally”
going to fight?
The Pre-Con 150 Play
150’ of 1¾” @ 150 psi = 150 GPM
Works “most” of the time
It’s the easiest and most often
practiced
Simplifies pump operation (only
one pressure works)
But... is it the right choice,
THIS time??
How will we handle 90% of our fires?
90% of our fires result
in 10% of our losses
however,
10% of our fires result
in 90% of our losses!
I got it,
Chief!!
Will we count it as
a great “save”...
... or a futile
training exercise?
ISO Ratings
Insurance Service Offices
Grading of fire department’s capabilities
and equipment
For determining fire insurance premiums
Not an application rate formula
NFPA Water Supply Formulas
For pre-planning water supply
To determine total quantity of water needed
For a single structure
Or a group of buildings
Type of construction
Occupancy rating
Exposures
Refer to NFPA 1231 Suburban & Rural Water Supplies
Iowa State University Formula
GPM = L x W x H
100
L = Length
W = Width
H = Height
Fire knockdown in 60 seconds or less
Normally for enclosed areas
Can be used in pre-planning water
requirements for a building or room
National Fire Academy
Formula for Quick Size-up...
GPM = L x W
3
L = Length
W = Width
Fire knockdown in 30 seconds or less
Multiply GPM by number of floors involved
Can be adjusted for actual % of involvement
Choose appropriate size & number of attack
lines based on GPM required & other
situational factors
Formulas & Fire Loading of Structures...
Iowa State University
Formula
National Fire Academy
Formula
Developed in the 1950’s
Fire load mostly organic
materials
Ventilation tactics utilized
less often
Attack often from outside due
to lack of breathing apparatus,
protective clothing, & other
safety equipment
Current information
Fire load contains more
synthetics
Synthetics produce more
BTU’s per pound & increase
smoke & noxious gas output
Ventilation and interior attack
tactics utilized
Increased water flow required
due to increased heat output