# Thickness calculation for LG line - CEP GLOBE Course/images/01.21.04.17(pipe... · Thickness...

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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.