14
HOW TO CALCULATE PIPELINE FORCES AND PRESSURES.
A. MEASURE THE INSIDE DIAMETER OF THE PIPELINE 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
centerline 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.
WATER WILL ACCUMULATE BEHIND ANY PLUG BLOCKING A
FLOWING LINE.
The ow will gradually increase the water column height
behind the plug. Prior to installing a plug, the user must determine the
maximum water height that may accumulate during plug use.
DANGER ZONE
WATER
BRACING
DETERMINE MAXIMUM
WATER HEIGHT THAT MAY
ACCUMULATE ABOVE PIPE CENTER
INFLATION
PRESSURE
GAUGE
READ BACK
PORT
To Next Page
Loading...