Pump Manual - Developing Fire Streams

Question 1

Max GPM for handline

Answer 1

350 gpm

Question 2

Nozzle Pressure - Smooth Bore

Answer 2

Handline: 50 psi

Master stream: 80 psi

Question 3

Calculating GPM for Solid Bore Nozzles

Answer 3

Freeman’s Formula:

GPM = 29.7 x D^2 x sqrt(NP)

Question 4

Solid Bore tip sizes

Answer 4

15/16”
1”
1 1/8”
1 1/4”

Question 5

Solid Bore Handline - Tip sizes and GPMs

Answer 5

15/16” –> 185 GPM*
1” –> 210 GPM
1 1/8” –> 265 GPM
1 1/4” –> 325 GPM*

*Breakaway nozzle diameter for our 1 3/4” and 2 1/2” pre-connects

Question 6

Solid Bore Master Stream - Tip sized and GPMs

Answer 6

1 3/8” —> 500gpm
1 1/2” —> 600gpm
1 3/4” —> 800 gpm
2” —> 1000 gpm

Question 7

Automatic fog nozzles

Answer 7

Spring is connected to a baffle forming the discharge orifice.

When pressure changes behind baffle, the spring adjusts the nozzle opening to maintain a constant 75/100 psi nozzle pressure. The flow (gpm) will change but pressure remains constant.

Question 8

Constant flow fog nozzle

Answer 8

Flow specific volume of water in all fog patters at a specific pressure (usually 100psi)

Question 9

Adjustable gallonage nozzles

Answer 9

Pump at a set pressure (usually 100 psi), firefighter can adjust flow rate:

30 - 200 gpm for 1 3/4”
95 - 250 gpm for 2 1/2”

pg 20

Question 10

Specialty nozzles - flow and nozzle pressure

Answer 10

Piercing — 125 gpm @ 100psi
Cellar — 250 gpm @100 psi
Chimney — 1-3gpm @ 100 psi
Master stream foam – 350gpm @ 100 psi

All are pumped at 100psi at the tip

pg 20

Question 11

Calculating nozzle reaction for fog nozzles

Answer 11

NR = .0505 x Q x sqrt(NP)

Rule of thumb for 100 psi fog nozzles: Nozzle reaction = Q / 2

Question 12

Calculating nozzle reaction for smooth bore nozzles

Answer 12

NR = 1.57 x D^2 x NP

pg 21

Question 13

Relationship between velocity and size of orifice

Answer 13

velocity varies inversely with the square of the area of the orifice

• doubling the size of the orifice decreases velocity by 4 times
• decreasing the orifice by 3 times increases velocity 9 times

pg 21

Question 14

Calculating velocity when head height is known

Answer 14

V = 8 x sqrt(H)

pg 21

Question 15

Calculating velocity when discharge pressure in psi is known

Answer 15

V = 12.14 x sqrt (P)

P = nozzle discharge pressure in psi
V = velocity in feet per second

pg 21

Question 16

Calculating horizontal reach for a solid stream

Answer 16

S = (0.5 x NP) + 26

S = distance in feet
NP - nozzle pressure

** FOR NOZZLE TIPS LARGER THAN 3/4” ADD 5 TO THE 26 FOR EACH 1/8” INCREASE IN TIP SIZE

Question 17

Calculating vertical reach of a solid stream

Answer 17

S = sqrt (VF) x sqrt (NP)

S = distance in feet
VF = vertical factor (constant from table)
NP in nozzle pressure