Barlow's Formula Calculator - Pipe Pressure Calculator

Barlow's Formula Calculator - Calculate pipes internal, allowable and bursting pressure

Yield Strength (S_y):

Design Factor (F_d):

Longitudinal Joint Factor (F_e):

Temperature Derating Factor (F_t):

Wall Thickness (t):

Outside Diameter (d_o):

Maximum Allowable Pressure (psi): Maximum Allowable Pressure (Pa): Maximum Allowable Pressure (bar): Maximum Allowable Pressure (kPa): Maximum Allowable Pressure (MPa): Maximum Allowable Pressure (at): Maximum Allowable Pressure (atm): Maximum Allowable Pressure (Torr): Maximum Allowable Pressure (hPa): Maximum Allowable Pressure (inHg):

1. What is a Working Pressure or Maximum Allowable Pressure Calculator?

Definition: This calculator computes the maximum allowable design pressure (\( P_a \)) for a pipe using Barlow's formula: \( P_a = 2 S_y F_d F_e F_t t / d_o \), where \( S_y \) is yield strength, \( F_d \) is the design factor, \( F_e \) is the longitudinal joint factor, \( F_t \) is the temperature derating factor, \( t \) is wall thickness, and \( d_o \) is the outside diameter.

Purpose: It helps engineers and designers determine the safe operating pressure for pipelines, ensuring structural integrity and compliance with industry standards in liquid and gas pipeline applications.

2. How Does the Calculator Work?

Calculations are based on Barlow's formula:

\[ P_a = \frac{2 S_y F_d F_e F_t t}{d_o} \]

Unit Conversions:

Category	Unit	Conversion to SI Unit
Pressure	psi (Pounds per square inch)	1 psi = 6894.76 Pa
	Pa (Pascals)	1 Pa
	bar	1 bar = 100,000 Pa
	kPa (Kilopascals)	1 kPa = 1000 Pa
	MPa (Megapascals)	1 MPa = 1,000,000 Pa
	at (Technical atmospheres)	1 at = 98,066.5 Pa
	atm (Standard atmospheres)	1 atm = 101,325 Pa
	Torr	1 Torr = 133.322 Pa
	hPa (Hectopascals)	1 hPa = 100 Pa
	inHg (Inches of mercury)	1 inHg = 3386.39 Pa
Length (Wall Thickness, Outside Diameter)	in (Inches)	1 in
Length (Wall Thickness, Outside Diameter)	mm (Millimeters)	1 mm = 0.0393701 in

Explanation: Yield strength is converted to psi, and length units (wall thickness and outside diameter) are converted to inches. The result pressure is calculated in psi, then converted to other units.

3. Importance of Working Pressure Calculation

Details: Accurate calculation of maximum allowable pressure is critical for ensuring pipeline safety, preventing failures, and complying with engineering standards for liquid and gas pipelines.

4. Using the Calculator

Tips: Enter Yield Strength (psi, Pa, kPa, MPa, bar), Design Factor (select pipeline type or custom value), Longitudinal Joint Factor, Temperature Derating Factor, Wall Thickness (in, mm), and Outside Diameter (in, mm). Results include maximum allowable pressure in multiple units (psi, Pa, bar, kPa, MPa, at, atm, Torr, hPa, inHg).

5. Notes

Notes: The design factor (\( F_d \)) depends on the pipeline type (liquid or gas class). Typical values are provided and automatically filled when selected. All factors (\( F_d \), \( F_e \), \( F_t \)) should be between 0 and 1. Wall thickness and outside diameter must be positive values.

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