Page 342 - Facility Piping Systems Handbook for Industrial, Commercial, and Healthcare Facilities

SITE UTILITY SYSTEMS

6.64 CHAPTER SIX

FIGURE 6.34 Flexible pipe bedding.

STRENGTH OF PIPE MATERIALS

Rigid Pipe
All rigid pipe has been tested for strength in the laboratory by means of a three-edge-bearing
test. In order to simplify selection of some piping, a method was developed to eliminate
any difference due to pipe size. Therefore, a D load has been developed by dividing the
actual laboratory strength by the pipe size in feet. In cases where different sizes of pipe
have different strengths, this is not possible. Table 6.22 gives the laboratory design loads
for various pipe material.

Flexible Pipe
Flexible pipe is plastic or corrugated steel pipe. The failure of this type of piping is con-
sidered to occur when the total calculated load on the pipe produces a radial deflection of
5 percent or more of the pipe diameter. Refer to Table 6.23 for the maximum allowable
deflection of various size pipes.

TOTAL LOAD ON BURIED PIPE

To calculate the actual load used to select any rigid pipe, the following formulas can be used:
For pipe using D load:

L × F = L T × SF (6.16)
D
D

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