Note#109
Stress Analysis
- Permissible load variation is determined as the ratio of (Travel x Spring rate / Load ) based on max. operating condition.
- Cold Load = Hot Load + Movement x Spring Rate (For pipe movement up)
- Cold Load = Hot Load – Movement x Spring Rate (For pipe movement down)
- the load variability shall be up to 25% throughout the total travel. However, for critical systems such as piping connected to pumps, compressors, reboilers, etc. lesser load variation is required to meet the allowable load requirements.
- if the load variation exceeds the allowed value, in the same load range selects a spring with lower spring rate. Else, select higher size spring.