Applicable Regulations & Effective Discharge Area
Applicable Regulations
Set Pressure Specified by Law or Standard
| No. | Applicable Law or Standard | Set Pressure | ||
|---|---|---|---|---|
| 1 | High Pressure Gas Safety Act | Pressure not exceeding the allowable pressure of the equipment, including the maximum tolerance limit of the rupture disk | ||
| 2 | Pressure Vessel Construction Standard | Pressure not exceeding the maximum operating pressure of the equipment, including rupture disk tolerance | ||
| 3 | Regulations on the Control of Hazardous Materials | Article 19, Paragraph 2 | Tanks with operating pressure of 0.02 MPa or less | 0.02–0.029 MPa |
| Tanks with operating pressure exceeding 0.02 MPa | Not more than 1.1 times the operating pressure | |||
| Article 28-31 | Not more than 1.1 times the maximum operating pressure | |||
Effective Discharge Area
There are several calculation formulas for the effective discharge area of rupture disks, depending on the applicable laws or standards governing the vessel in which the rupture disk is installed.
For details of the formulas, refer to the applicable laws or standards.
Calculation Table for Discharge Capacity or Discharge Area
| Liquid | NO. | Applicable Law or Standard | Formula | Explanation of Symbols |
|---|---|---|---|---|
| Steam | 1 | JIS B 8226-1 | Qm = 5.25KCA (P + 0.1) × 0.9 | Qm: Discharge capacity (kg/h) K: Discharge coefficient (0.73) C: Coefficient based on steam properties A: Discharge area (mm²) P: Relieving pressure (MPa) |
| 2 | Pressure Vessel Construction Standard | |||
| Gas | 1 | JIS B 8226-1 | Qm = KC′AP₁√(M/ZT) × 0.9 | Qm: Discharge capacity (kg/h) K: Discharge coefficient (0.73) C′: Value based on the adiabatic index (k = Cp/Cv) A: Discharge area (mm²) P1: Relieving pressure (absolute pressure, MPa) M: Gas molecular weight Z: Compressibility factor T: Gas temperature at discharge-determining pressure (K) |
| 2 | Pressure Vessel Construction Standard | |||
| 3 | High Pressure Gas Safety Act | W = ACKP₁√(M/ZT) | W: Discharge capacity (kg/h) A: Discharge area (cm²) C: Value related to the adiabatic index K: Discharge coefficient (0.71) P1: Pressure determining discharge capacity (MPa, abs) M: Molecular weight of the gas Z: Compressibility factor T: Gas temperature at discharge-determining pressure (K) |
|
| 4 | Nuclear Power Generation Equipment Standard Design and Construction Code (JSME S NC1) |
Qm = C′KdAP₁√(M/ZT) × 0.9 | W: Discharge capacity (kg/h) Kd: Discharge coefficient (0.864) C′: Coefficient based on k and P₂/P₁ A: Discharge area (mm²) P1: Relieving pressure (absolute pressure, MPa) M: Gas molecular weight Z: Compressibility factor T: Gas temperature at discharge-determining pressure (K) |
|
| Liquid | 1 | JIS B 8226-1 | Qm = 5.09AfuK′√(ΔPδ) | Qm: Discharge capacity (kg/h) A: Discharge area (mm²) fu: Kinematic viscosity correction factor for liquid K′: Discharge coefficient (0.62) ΔP: Differential pressure between liquid inlet and outlet (MPa) δ: Liquid density (kg/m³) |
| 2 | Pressure Vessel Construction Standard | |||
| 3 | High Pressure Gas Safety Act (Relief Valve) | W = 16100KA√PG | W: Discharge capacity (kg/h) K: Overall discharge coefficient (0.6) A: Flow area (cm²) P: Relieving pressure (MPa) G: Specific gravity of the fluid at inlet temperature |