Kalkulasi ukuran pressure safety valve untuk gas/vapor, liquid, dan fire case. Berdasarkan standar API 520, API 521, dan ASME Section VIII.
Default 21% (fire / external heat, single device).
Constant + built-up.
Blocked-in / maximum inlet flow.
| Komponen | mol % | Komponen | mol % |
|---|---|---|---|
| Methane (C1) | n-Hexane (C6) | ||
| Ethane (C2) | n-Heptane (C7) | ||
| Propane (C3) | Nitrogen (N2) | ||
| i-Butane (iC4) | CO2 | ||
| n-Butane (nC4) | H2S | ||
| i-Pentane (iC5) | Water (H2O) | ||
| n-Pentane (nC5) | Hydrogen (H2) |
relatif terhadap air @ kondisi relieving.
untuk koreksi Kv (set 0 = non-viscous).
hingga ketinggian 7.6 m (25 ft) dari sumber api.
temperatur uap saat relieving.
Vapor 0.975 — gunakan Kd sertifikasi valve.
1.0 tanpa rupture disk · 0.9 dengan.
| Relieving Conditions | |
| Relieving pressure P₁ (abs) | 1,224.696 psi |
| Backpressure P₂ (abs) | 14.696 psi |
| Overpressure | 21 % |
| Fluid & Flow | |
| Wetted area A_ws | 40.000 ft² |
| Environment factor F | 1.000 |
| Heat input Q | 432.5 kBTU/h |
| Latent heat λ | 350.0 BTU/lb |
| Required flow W | 1,235.7 lb/h |
| Relieving temperature | 180.0 °F |
| Molecular weight M | 80.00 g/mol |
| Specific heat ratio k | 1.100 |
| Compressibility Z | 0.9500 |
| Sizing — API 520 | |
| Flow regime | Critical (sonic) flow |
| Critical pressure Pcf (abs) | 716.054 psi |
| Kd / Kb / Kc | 0.975 / 1.00 / 1.00 |
| Required effective area A | 0.009 in² |