FEET-OF-WATER-HEAD TO PSIG

HOW TO CALCULATE PIPELINE FORCES AND PRESSURES.

A. MEASURE THE INSIDE DIAMETER OF THE PIPE LINE IN INCHES.

B. DETERMINE THE MAXIMUM BACK PRESSURE.

 Air pressure is measured in PSIG (Pounds Per Square Inch Gauge). Water pressure is calculated by determining the height of water column in feet above the center line of the pipe. Water height is multiplied by (0.43) to yield water pressure in PSIG. A FEET-OF-WATER-HEAD TO PSIG conversion table is also provided (see Table 1, next page).

C. CALCULATE THE PIPE AREA IN SQUARE INCHES. Area of a circle (square inches) = [Diameter (in inches) x Diameter (in inches) x 3.1416 (pi)] / 4. 

D. CALCULATE THE FORCE THE PLUG MUST WITHSTAND. FORCE = PIPE AREA (in square inches) x PRESSURE (PSIG).

EXAMPLE: A plug must hold a (10) foot column of water above the center line of a 60” diameter pipe. 

PIPE AREA = [60” (dia) x 60” (dia) x 3.1416 (pi)]/ 4 = 2,827 square inches.

PRESSURE = 10 Feet of Water x 0.43 PSIG/Foot = 4.3 PSIG

PIPE AREA (2,827 square inches) x PRESSURE (4.3 PSIG) = FORCE = 12,157 pounds.

Following is the force the plug must withstand

                                                        CONVERSION TABLE

FEET-OF-WATER-HEAD TO PSIG

(Pounds Per Square Inch Gauge)