Use and Care Guide

41
TESTING AND INSPECTION
Thrust or Displacement Forces Encountered in
Hydrostatic Testing of Cast Iron Soil Pipe
Pipe Size 1
1
⁄2” 2” 3” 4” 5” 6” 8” 10”
Head,
Feet of Pressure Thrust Thrust Thrust Thrust Thrust Thrust Thrust Thrust
Water PSI lb. lb. lb. lb. lb. lb. lb. lb.
10 4.3 12 19 38 65 95 134 237 377
20 8.7 25 38 77 131 192 271 480 762
30 13.0 37 56 115 196 287 405 717 1139
40 17.3 49 75 152 261 382 539 954 1515
50 21.7 62 94 191 327 479 676 1197 1900
60 26.0 74 113 229 392 574 810 1434 2277
70 30.3 86 132 267 457 668 944 1671 2654
80 34.7 99 151 306 523 765 1082 1914 3039
90 39.0 111 169 344 588 860 1216 2151 3416
100 43.4 123 188 382 654 957 1353 2394 3801
110 47.7 135 208 420 719 1052 1487 2631 4178
120 52.0 147 226 458 784 1147 1621 2868 4554
AREA, OD, in.
2
2.84 4.34 8.81 15.07 22.06 31.17 55.15 87.58
Thrust = Pressure x Area
THRUST FORCES
Thrust or displacement forces are encountered as the pipe is filled with water. The higher the fill, the greater the
force acting to separate a joint. The table below shows the pounds of force tending to cause joint separation when
using pipe from 1-1/2” to 15” and a head of water from 10 feet to 120 feet.
Horizontal pipe and fittings five (5) inches and larger must
be suitably braced to prevent horizontal movement. This
must be done at every branch opening or change in
direction by the use of a brace, block, rodding or other
suitable method, to prevent movement or joint separation.
Heavy Duty or wide body couplings are not a substitute for
proper thrust restraint. Failure to properly restrain branch
openings or changes in direction will result in joint
movement or separation, causing system failure and
potential serious injury.