Ch. 7 Mathematics for the Driver / Operator

Question 1

Pump Discharge Pressure

Answer 1

The pressure measured at the pump discharge needed to overcome friction and elevation loss while maintaining the desired nozzle pressure and delivering adequate fire stream.

Question 2

Hydraulics

Answer 2

The study of the characteristics and movement of water as they pertain to the calculations for fire streams and fire-ground operations

Question 3

Theoretical Hydraulics

Answer 3

Scientific or more exact fire ground calculations

Question 4

What factors must be addressed to achieve the goal to overcome friction loss and deliver effective fire stream?

Answer 4

Nozzle Pressure
Friction lose in hose line
Elevation loss or gain
Friction loss in the appliances

Question 5

PDP formula (Pump Discharge Pressure)

Answer 5

PDP = NP + FL

NP = Nozzle Pressure
FL = Friction Loss

Question 6

Nozzle Pressure

Answer 6

The pressure required at the inlet of a nozzle to produce the desired water discharge characteristics.

Question 7

NP for all fog nozzles

Answer 7

100 psi (480 kPa)

Question 8

NP for smooth bore handline nozzles

Answer 8

50 psi (350 kPa)

Question 9

NP for smooth bore master stream nozzles

Answer 9

80 psi (560 kPa)

Question 10

NP for distributor nozzles

Answer 10

100 psi (700 kPa)

Question 11

Newton’s 3rd Law of Motion

Answer 11

When one body exerts force on a second body, the second body simultaneously exerts a equal force equal in magnitude and opposite in direction of the first body

Question 12

Nozzle Reaction

Answer 12

is the opposing reaction that occurs as water is expelled from the nozzle or the force that pushes back on the FF when water is flowed.

It is a factor of both the amount of the water as it leaves the nozzle and the velocity at which the water travels. If you change both or one of the factors, the nozzle reaction will change as well.

Question 13

NR formula from a smooth bore nozzle

Answer 13

NR = 1.57 x d² x NP

NR = Nozzle reaction
D = Diameter
NP = Nozzle Pressure

Question 14

Covert PSI to Pascal

Answer 14

1 pascal is equal to 0.00014503773800722 PSI, or 0.001 kPa.

Question 15

How many PSI in 1 kPa?

Answer 15

The answer is 0.14503773800722.

Question 16

GPM formula

Answer 16

GPM = 29.7 x d ² x √NP

Question 17

Friction Loss Formula (FL)

Answer 17

FL = C (Q / 100) ² (L / 100)

FL = Friction Loss
C = Coefficient 
Q = the quantity of water flowing  divided by 100
L = Length of hose in feet divided by 100, or in meters divided by 100