Approximate required safety-valve throat area from steam capacity and set pressure using the ASME Section I formula.
Formula
$$ A = \frac{W}{51.5 \cdot P \cdot K_d \cdot K_b \cdot K_{sh}} $$
Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| $W$ | Steam capacity | kg/h | boiler rating |
| $P$ | Set pressure absolute | bar | boiler design |
| $K_d$ | Valve coefficient of discharge | - | valve data sheet |
| $K_b$ | Back-pressure correction | - | ASME I |
| $K_{sh}$ | Superheat correction | - | ASME I |
| $A$ | Required throat area | mm² | result |
Sources
- ASME BPVC Section I.