7/23/2019 16'' Santan-SKG (Hot-tap Calculation)

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 I. PROJECT DATA

Project name : 16" Santan - SKG Material Spec. :Type of services : Gas Pipe nominal : 16 Inch

Type of project : In-service Welded split sleeve Pipe OD ( Do ) : 16.000 Inch

Operationg Pressure ( P1 ) : 610 Psi Nom. Thickness : 0.281 Inch

Operating temperature : 99oF ( 37.22 )

oC Act. Thickness ( t ) : 0.281 Inch

Actual Flow rate : 68.6 MMCFD Pipe ID ( Di ) : 15.438 Inch

 II. FORMULA

Assume temperature at base of HAZ ( T2 ) = 750  oC, or  1382

oF

Depth of HAZ ( do ) = 30% t = 0.3 x 0.281 = 0.084 Inch

Thickness correction ( tc ) = t - do = 0.281 - 0.084 = 0.197 Inch

Diameter correction ( Dc ) = Do -2 do = 16.000 - 2 x 0.084 = 15.831 Inch

T2-T1 - 37.22

Ln T2 /T1 Ln / 37.22

Allowable stress from design construction of is :

= 0.55 x 42000 = Psi

90% of allowable term stress ( Se ) 90% x 23100 = Psi

Maximum Allowable Pressure ( refer to ANSI B 31 - 8 formula )

2 x tc x Se 2 x 0.197 x 20790

Dc

Area of Pipe cross section ( A ) Pi x Di ̂ 2 3.1416 x 238.33184

4 x 144

Required minimum flow rate ( QMO ) = 1.312 fps x A = 1.312 x 1.300 = 1.705

P1 + Ps QMO Ts

Required Minimum Flow Rate ( QMS ) = -------------- x -------------- x ------------- =Ps Z T1 + 460

624.7 1.705 520

14.7 0.8 559

Required Maximum Flow Rate :  No limit

 III. RECOMMENDATION 

Based on the above calculation for in-service welding job can be performed, if maintain pressure below 517 Psi,

with continued minimum flowrate is MMSCFD (maximum flow rate No limit MMSCFD ) during welding.

Badak :

Prepared by Approved by

Firman. A Kusmaryanto D. / Hary Hardiman

Risk Based Inspection Team Inspection & Certification Supt.

Cuft/Sec.

  Cuft/Sec.

WELDING HOT TAP CALCULATION SHEET

23100

Ft2

 =

 =750

15.831

576

750

  MMSCFD7.30

oC, or 

1.300

22-Jan-09

84.28

VICO Indonesia

=

INSPECTION & CERTIFICATION

459= 237Stress Correction ( LMT )

=

P

7.30

 =

 =

=

Psi

Grade X42

ANSI B 31.8

20790

= 517

x x   =

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