HYDRAULIC EQUATIONS / FORMULAS

Question 1

% DROP IN PUMP INTAKE PRESSURE

Answer 1

STATIC - RESIDUAL (100) / STATIC

70-63 (100) / 70 = 10%

Question 2

ESTIMATED STATIC PRESSURE

Answer 2

1st line - 2nd line (with same GPM) / 2 + 1st line

Question 3

HOW MUCH DOES 1 CUBIC FT. OF WATER WEIGH AND HOW MANY GALLONS IS IT?

Answer 3

1 CUBIC FT OF WATER WEIGHS 62.5lbs AND CONTAINS 7.5 GALLONS

TO DETERMINE WEIGHT OF WATER THE TOTAL GALLONS CAN BE MULTIPLIED BY 8.35lbs OR THE NUMBER OF CUBIC FT CAN BE MULTIPLIED BY 62.5lbs

Question 4

FORMULA TO FIND THE CAPACITY IN GALLONS OF A RECTANGULAR CONTAINER

Answer 4

L x W x H x 7.5

Question 5

FORMULA TO FIND THE CAPACITY IN GALLONS OF A CYLINDER CONTAINER

Answer 5

6 x (D)2 x H

NOTE: FOR GREATER ACCURACY SUBTRACT 2% OF THE TOTAL

Question 6

HOW TO CALCULATE HYDRANT PRESSURE

Answer 6

GPM = 27 (D)2 x sq root of PRESSURE

P = pressure using pitot tube
D = diameter

Question 7

FORMULA TO SOLVE FOR NOZZLE REACTION

Answer 7

NR FOG = GPM x sq root of NP x .0505
NOTE: quick formula for fog nozzle is divide the GPM times 2.

NR SB = 1.5 x (D)*2 x NP

Question 8

FORMULA FOR THE AREA OF A CIRCLE

Answer 8

PIE (R)2 OR 3.14 (R)2

Question 9

RELAY PUMPING EQUATION

Answer 9

TFL+GL-GG / MAX PP-IP
OR
TFL+GL-GG / 250-10

Question 10

FORMULA FOR SMOOTH BORE NOZZLE GPM

Answer 10

30 x (D)*2 x sq root of NP