Sudden force surges caused by water hammer, steam hammer, or safety valve relief lift-off. 3. Primary vs. Secondary Stresses
To ensure accurate and reliable results, follow these best practices: Sudden force surges caused by water hammer, steam
| Stress Type | Cause | Failure Mode | Design Limit | |-------------|-------|---------------|----------------| | | 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 | Sudden force surges caused by water hammer, steam