Fluor Piping Design Layout Training Lesson 1 Pipe Stresspdf Better
A better pipe stress PDF starts with a better input file. Fluor-trained designers use this 5-point checklist before releasing the model for analysis:
| Stress Type | Cause | Failure Mode | Design Limit | |-------------|-------|---------------|----------------| | Primary | Pressure, weight, sustained loads | Plastic collapse / bursting | ( S_h ) (hot allowable) | | Secondary | Thermal displacement | Fatigue cracking | ( S_A ) (allowable expansion stress range) | | Peak | Local discontinuities (attachments, supports) | Low-cycle fatigue | Limited via fatigue rules |
Fluor Note: Layout designers focus on secondary stresses – the result of constrained thermal movement.
Intentional over- or under-length installation to reduce operating stress.
Caution: Increases installation stress; requires stress engineer approval. A better pipe stress PDF starts with a better input file
While more robust than pumps, large diameter vessels and thin-walled tanks are susceptible to local buckling or distortion if piping loads are excessive.
Primary Stress – from weight & pressure.
Secondary Stress – from thermal expansion & contraction. Fluor Note: Layout designers focus on secondary stresses
Fluor’s saying: "Primary = strength. Secondary = flexibility."
Stress engineers do not just analyze; they specify supports to control stress.
| Support Type | Function in Stress Control | | :--- | :--- | | Rigid Hanger | Supports weight (Deadweight). Restrains movement in all directions. | | Spring Hanger | Supports weight while allowing vertical thermal movement. Essential for hot lines. | | Guides | Restricts movement in two directions (usually horizontal) but allows vertical sliding. Prevents buckling. | | Line Stops | Stops movement in one specific direction (axially down the pipe). | | Anchor | Restricts all movement (X, Y, Z) and rotation. Creates a fixed point in the system. | not at ends.
Preferred when space allows. Loop dimensions should follow:
Fluor Best Practice: Place loops near midpoints of long straight runs, not at ends.