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Thickness calculation for LG line
Design minimum thickness:
][2 YPEWS
DPt
a
O
+
=
P = 45 bar = 652.5 psi
D0 = 6.625” (6” NB pipe)
S a = 20000 psi (ASME B 31.3, appendix A, Table A-1 – A106 Grade B)
E = 1 (Quality factor from ASME B 31.3, Table A-1 B)
W = 1 (Weld joint strength reduction factor from ASME B 31.3, Table 302.3.5)
Y = 0.4 (Coefficient from ASME B 31.3, Table 304.1.1)
t = ���.� × �.���
������� × × ���.� × �.��
t = 0.1066”
= 2.707 mm
Minimum wall thickness required to satisfy the design rules of the code:
t m = t + c (c - corrosion allowance)
tm = 2.707 + 2
= 4.707 mm
Nominal wall thickness:
tnom = �
�.��� (provision for 12.5% negative mill tolerance)
= 5.379 mm
Referring to ASME 36.10, the nearest commercial NPS 6 pipe whose wall thickness exceeds
5.379 mm is SCH 40 (STD) with a nominal thickness of 7.11 mm .Therefore NPS 6, SCH
40(STD) pipe meeting the requirements of ASTM A 106 Grade B is selected for this application.
Thickness calculation for NG line
Design minimum thickness:
][2 YPEWS
DPt
a
O
+
=
P = 45 bar = 652.5 psi
D0 = 6.625” (6” NB pipe)
S a = 20000 psi (ASME B 31.3, appendix A, Table A-1 – A106 Grade B)
E = 1 (Quality factor from ASME B 31.3, Table A-1 B)
W = 1 (Weld joint strength reduction factor from ASME B 31.3, Table 302.3.5)
Y = 0.4 (Coefficient from ASME B 31.3, Table 304.1.1)
t = ���.� × �.���
������� × × ���.� × �.��
t = 0.1066”
= 2.707 mm
Minimum wall thickness required to satisfy the design rules of the code:
t m = t + c (c - corrosion allowance)
tm = 2.707 + 2
= 4.707 mm
Nominal wall thickness:
tnom = �
�.��� (provision for 12.5% negative mill tolerance)
= 5.379 mm
Referring to ASME 36.10, the nearest commercial NPS 6 pipe whose wall thickness exceeds
5.379 mm is SCH 40 (STD) with a nominal thickness of 7.11 mm .Therefore NPS 6, SCH 40
(STD) pipe meeting the requirements of ASTM A 106 Grade B is selected for this application.
Thickness calculation for PG line
Design minimum thickness:
][2 YPEWS
DPt
a
O
+
=
P = 45 bar = 652.5 psi
D0 = 10.750” (10” NB pipe)
S a = 20000 psi ([ASME B 31.3, appendix A, Table A-1 – A106 Grade B]
E = 1 (Quality factor from ASME B 31.3, Table A-1 B)
W = 1 (Weld joint strength reduction factor from ASME B 31.3, Table 302.3.5)
Y = 0.4 (Coefficient from ASME B 31.3, Table 304.1.1)
t = ���.� × �.���
������� × × ���.� × �.��
t = 0.1731”
= 4.396 mm
Minimum wall thickness required to satisfy the design rules of the code:
t m = t + c (c - corrosion allowance)
tm = 4.396 + 2
= 6.396 mm
Nominal wall thickness:
tnom = �
�.��� (provision for 12.5% negative mill tolerance)
= 7.309 mm
Referring to ASME 36.10, the nearest commercial NPS 10 pipe whose wall thickness exceeds
7.309 mm is SCH 40 (STD) with a nominal thickness of 9.27 mm .Therefore NPS 10, SCH 40
(STD) pipe meeting the requirements of ASTM A 106 Grade B is selected for this application.
Thickness calculation for RG line
Design minimum thickness:
][2 YPEWS
DPt
a
O
+
=
P = 45 bar = 652.5 psi
D0 = 12.750” (12” NB pipe)
S a = 20000 psi (ASME B 31.3, appendix A, Table A-1 – A106 Grade B)
E = 1 (Quality factor from ASME B 31.3, Table A-1 B)
W = 1 (Weld joint strength reduction factor from ASME B 31.3, Table 302.3.5)
Y = 0.4 (Coefficient from ASME B 31.3, Table 304.1.1)
t = ���.� × �.���
������� × × ���.� × �.��
t = 0.2053”
= 5.214 mm
Minimum wall thickness required to satisfy the design rules of the code:
t m = t + c (c - corrosion allowance)
tm = 5.214 + 2
= 7.214 mm
Nominal wall thickness:
tnom = �
�.��� (provision for 12.5% negative mill tolerance)
= 8.244 mm
Referring to ASME 36.10, the nearest commercial NPS 12 pipe whose wall thickness exceeds
8.244 mm is STD with a nominal thickness of 9.53 mm .Therefore NPS 12, STD pipe meeting
the requirements of ASTM A 106 Grade B is selected for this application.