Math Equations

Question 1

Discharge Rate (Smooth Bore)

Answer 1

GPM = 29.7 x d² x √NP

Question 2

Nozzle Reaction for Solid Streams

Answer 2

NP= 1.57 x d² x NP

Question 3

Simple nozzle Reaction for solid streams

Answer 3

Q/3

Question 4

Nozzle Reaciton for Fog Stream Nozzles

Answer 4

0.0505 x Q x √NP

Question 5

Friction Loss

Answer 5

CQ²L

Question 6

Elevation Pressure

Answer 6

0.5H

Question 7

PDP

Answer 7

NP+TPL

Question 8

Condensed Q Friction Loss

Answer 8

Q² (3”)
Q²/5 (4”)
Q²/15 (5”)

Question 9

Percentage Method Available Water from a hydrant

Answer 9

Percent drop= (Static-Residual)(100)/Static
≤10 =3 lines
11-15=2 Lines
16-25=1 Line
>25=0 lines

Question 10

First Digit Method

Answer 10

First Digit of static x 1, 2, or 3
1x factor ≤ First digit + 3 lines
2x factor ≤ 2 lines
3x factor ≤ 1 line

Question 11

Squaring the lines

Answer 11

Static - Residual pressure of hydrant
That difference x (number of lines)²
ex. 60-52=8
8 x (2)²= 32psi drop taking your hydrant to 28 psi residual a 3rd line would be discouraged.

Question 12

Determining maximum lift

Answer 12

1.13x Hg

Question 13

Pressure Correction

Answer 13

(Lift + Total intake hose FL)/2.3

Question 14

NPDP @ Draft

Answer 14

PDP = Pressure Correction

Question 15

Pool volume square

Answer 15

7.5 x W x L x D

Question 16

Pool Circular

Answer 16

7.5 x π x r² x D

Question 17

Water Shuttle Flow Rate

Answer 17

(0.9 x TS) / Trip Time

Question 18

Travel Time

Answer 18

0.65 + (1.7 x Distance)

Question 19

Handling Time

Answer 19

Fill site + dump site

Question 20

Tender Flow Rate

Answer 20

(0.9 x TS) / Travel Time + Handling Time

Question 21

Foam Application Rate

Answer 21

Flow / Area