SPREADSHEETS SERIES No. 0003S


Wall Thickness Calculation of Straight Pipes Under Internal Pressure

Calculation as per par. 403.2 Criteria for Pipe Wall Thickness and Allowances by ASME B31.4 for D/t > 20


(Enter values in yellow cells for calculations and in blue cells as information)
DATA INPUT

External Diameter, D =	mm	Material =

Internal design pressure (gauge), Pi =	barg	Design Temperature =			ᵒC
		Design temp. between −29°C and 120°C
Design factor, F =				Well joint factor, E =
See table 403.3.1-1		See table 403.2.1-1
Allow. for corrosion, A =	mm	Spec. min. yield strength, Sy =			MPa

Select T ≥ tn =	mm	After Nominal thickness calculation, tn, as per 403.2.1, it's
		must be selected T ≥ tn from ASME B36.10M or ASME B36.19M
		or ASTM A377 or ASTM A692.

CALCULATIONS

Applicable allowable stress value, S =	MPa			D/t =
				D/t ≥ 20

Thickness for design pressure, t =	mm	t =	PiD
		t =	20S

Nominal thickness as per 403.2.1, tn =	mm	tn = t + A
Minimum thickness required
Nom. pipe wall thickness, T =	mm
from ASME B36.10M or ASME B36.19M
or ASTM A377 or ASTM A692


Wall Thickness Calculation of Straight Pipes Under Internal Pressure

Calculation as per par. 403.2 Criteria for Pipe Wall Thickness and Allowances by ASME B31.4 for D/t > 20


(Enter values in yellow cells for calculations and in blue cells as information)
DATA INPUT

External Diameter, D =	in	Material =

Internal design pressure (gauge), Pi =	psig	Design Temperature =			ᵒF
		Design temp. between −20°F and 250°F
Design factor, F =				Well joint factor, E =
See table 403.3.1-1		See table 403.2.1-1
Allow. for corrosion, A =	in	Spec. min. yield strength, Sy =			psi

Select T ≥ tn =	in	After Nominal thickness calculation, tn, as per 403.2.1, it's
		must be selected T ≥ tn from ASME B36.10M or ASME B36.19M
		or ASTM A377 or ASTM A692.

CALCULATIONS

Applicable allowable stress value, S =	psi			D/t =
				D/t ≥ 20

Thickness for design pressure, t =	in	t =	PiD
		t =	2S

Nominal thickness as per 403.2.1, tn =	in	tn = t + A
Minimum thickness required
Nom. pipe wall thickness, T =	in
from ASME B36.10M or ASME B36.19M
or ASTM A377 or ASTM A692


	Discussion and References
	Information about Wall thickness calculation of straight pipes under internal pressure:
	ASME B31.4 Transportation Systems for Liquids and Slurries, para. 403.2.1

	Tables and Standards
-	ASME B31.4 Specified Minimum Strength - US Units
-	ASME B31.4 Specified Minimum Strength - Metric
-	Table 403.2.1-1 Weld Joint Factors Applicable to Common Pipe Specifications
-	Table 403.3.1-1 Allowable Values for Pipeline System Stresses
-	ASME B36.10M-Welded and Seamless Wrought Steel Pipe
-	ASME B36.19M-Stainless Steel Pipe
-	ASTM A377 Ductile Iron Pressure Pipe
-	ASTM A691 Electric-Fusion-Welded Steel Pipe for High-Pressure Service at High Temperatures

	Equations for Wall thickness calculation of straight pipes under internal pressure (403.2.1):

	For D/t > 20, the wall thickness should be calculated by the equations:

	t =	PiD	(U.S. Customary Units)
	t =	2S	(U.S. Customary Units)

	t =	PiD	(SI Units)
	t =	20S	(SI Units)

	tn = t + A

	The parameters in the wall thickness calculation of straight pipes under internal pressure
	equations above are:
	t = thickness for design pressure, in. (mm).
	Pi = internal design pressure, psig (barg).
	D = external diameter, in. (mm).
	A = sum of corrosion allowance, slots, threads and safety in special areas, in. (mm).
	tn = nominal thickness, in. (mm).
	S = Applicable allowable stress value, psi (MPa), as determined by the following equation:

	S = F x E x Sy		(See table 403.3.1-1 of ASME B31.4)

	Where:
	F = design factor based on nominal wall thickness, see table 403.3.1-1.
	E = weld joint factor as specified in table 403.2.1-1
	Sy = specified minimum yield strength of the pipe, psi (MPa).