1-Some installations of PE pipe have the pipe lying directly on the earth’s surface. In
this type of installation, the surface under the pipe must be free from boulders,
crevices or other irregularities that could create a point-loading stress situation on the
pipe.

2-On grade placement over bed rock or hard pan should be avoided unless a uniform
bed of material is prepared that will cushion the pipe. If the PE pipe rests directly on
a hard surface, this creates a point loading situation and can increase abrasion of the
outer pipe surface as it “wanders” in response to temperature variations.

3-Intermittent pipe supports should be spaced properly using the design parameters
discussed in the preceding pages. Anywhere unusual loadings or excessive
temperatures are encountered, continuous support should be considered.

4-Supports that simply cradle the pipe, rather than grip or clamp the pipe, should be
from one half to one pipe diameter in length and should support at least 120 degrees
or one third of the pipe perimeter. All supports should be free from sharp edges.

5-The supports should have adequate strength to restrain the pipe from lateral or
longitudinal deflection given the anticipated service conditions. If the design allows
free movement during expansion, the sliding supports should provide a guide without
restraint in the direction of movement. If, on the other hand, the support is designed
to grip the pipe firmly, the support must either be mounted flexibly or have adequate
strength to withstand the anticipated stresses.

6-Heavy fittings or flanges should be fully supported and restrained for a minimum
distance of one full pipe diameter on both sides of the PE pipe. This supported fitting
represents a rigid structure within the flexible pipe system and should be fully
isolated from bending stresses associated with beam sag or thermal deflection.

Piping Stress Analysis for Vacuum Heater⏬

BFW

Process Coil (Single Pass)

Flange leakage check ⏬

Flange analysis is done based on the Kellogg equivalent pressure method. In addition to internal and external pressure, axial force and bending moment can act on flanges as equivalent pressure. The values of axial force and bending moment are determined from analysis without pressure thrust effect.

These internal forces are used to determine the equivalent design pressure of flange pair by formula

Now enter PN into the ASME B 16.5 pressure-temperature rating table associated with flange material. If PN is less than the allowed pressure on the rating table corresponding to the associated temperature then flange will not leak. If flange leak, then reduce bending moment and axial force acting on the flange or select the greater class flange.

CFD simulation of fluid flow around a subsea pipeline The arrows represent fluid particle movement around the pipeline, whilst the sea floor is shows pressure gradient resulting from fluid flow.

GRP Cover - Composite pipe support mattress

GRP Pipeline Protection System

Thrust Restraint Design for Buried Piping⬇️

1) This section presents the design methodology to be used when providing thrust restraint for
buried pressurized piping. It includes guidelines for the design of thrust blocking using the
standard details and special design requirements for non-standard thrust blocks and restrained
joint pipe.

2) For pipe sizes larger than 24-inch, consider the cost of using one of the approved restrained joints or providing concrete thrust blocking to restrain the pipe or fitting. If the cost is approximately equal, design for concrete thrust blocks and if the restrained joints are considerably less expensive, then design for restrained joints unless otherwise directed.