Safety Engineering

API RP 520 Part I Single-Phase Liquid Relief Valve Orifice Area calculator

API RP 520 Part I Single-Phase Liquid Relief Valve Orifice Area engineering calculator.

Runnable This tool can run, but independent engineering verification has not been established.

Quick Answer

The api rp 520 part i single-phase liquid relief valve orifice area calculator computes required orifice area from the input values you provide.

Calculator

Required orifice area (m²)
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Result Interpretation

API RP 520 Part I Single-Phase Liquid Relief Valve Orifice Area calculator computes Required orifice area in m^2 using the defined engineering formula and the input values provided. Required orifice area is expressed in m^2. No universal acceptance threshold is defined by this calculator.

Worked Example

Verified calculation

Given:

  • Required mass flow rate = 12.5
  • Liquid density = 920
  • Relief valve set pressure (gauge) = 1200000
  • Superimposed back pressure = 150000
  • Coefficient of discharge = 0.62

Expected Result:

  • Required orifice area = 0.00056211426113972

Engineering Interpretation:

Under the given input conditions, the calculated result is: Required orifice area = 0.00056211426113972 m^2.

The actual numerical result is computed by the Runtime engine using the persisted tool definition. The values shown here come from deterministically validated test cases.

Formula / Method

required orifice area = (required mass flow rate * sqrt(1 / (2 * liquid density * (gauge - superimposed back pressure)))) / (coefficient of discharge * 0.816)

Required orifice area.

Variables

SymbolLabelRoleDescription
mass_flow_rate Required mass flow rate INPUT Required mass flow rate
density Liquid density INPUT Liquid density
set_pressure Relief valve set pressure (gauge) INPUT Relief valve set pressure (gauge)
back_pressure Superimposed back pressure INPUT Superimposed back pressure
coefficient_discharge Coefficient of discharge INPUT Coefficient of discharge
orifice_area Required orifice area OUTPUT Required orifice area

Calculation Steps

  1. Enter the required mass flow rate in kg/s.
  2. Enter the liquid density in kg/m^3.
  3. Enter the relief valve set pressure (gauge) in Pa.
  4. Enter the superimposed back pressure in Pa.
  5. Enter the coefficient of discharge in dimensionless.
  6. Step 1: Compute required orifice area.
  7. Read the required orifice area (m^2) from the results.

Frequently Asked Questions

What does this calculator calculate?

The API RP 520 Part I Single-Phase Liquid Relief Valve Orifice Area calculator estimates Required orifice area based on the input parameters you provide

Why is required mass flow rate important in this calculation?

required mass flow rate is directly proportional to required orifice area. When you enter required mass flow rate in kg/s, the calculator uses it in the engineering formula to compute the output

How should I interpret the result required orifice area?

The calculator outputs required orifice area in m^2. The result is computed directly from the input values using the defined engineering formula

What units should I use for the inputs?

Enter each value in the units shown next to the input field: Required mass flow rate (kg/s), Liquid density (kg/m^3), Relief valve set pressure (gauge) (Pa), Superimposed back pressure (Pa), Coefficient of discharge (dimensionless). Make sure all inputs use the specified units for consistent results

What assumptions does this calculator use?

This calculator uses automatically validated engineering formulas. Results are approximate and should be validated against site-specific conditions, applicable codes, and professional engineering judgment

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