Piping Stress Analysis Engineering

IRUP

ENGINEERING DESIGN BASIS

RESIDUE UPGRADATION AND MS/HSD QUALITY IMPROVEMENT PROJECT

INDIAN OIL CORPORATION LIMITED, GUJARAT REFINERY

JOB NO : __6235 ___

DOCUMENT NO. : __H-159__

PIPING STRESS ANALYSIS

0 10/06/2006 For BID DOCUMENT

REV. DATE DESCRIPTION MADE BY CHCKD APPRVD PM

TOYO ENGINEERING INDIA LIMITED MUMBAI INDIA

Total Pages-13

TOYO ENGINEERING INDIA

LTD. ENGINEERING DESIGN BASIS JOB NO. : 6235

ISSUED : DATE: Aug.18/06 (RESIDUE UPGRADATION AND MS/HSD QUALITY IMPROVEMENT PROJECT)

SHEET 2 OF13

DOCUMENT NO. H-156 PIPING STRESS ANALYSIS

Table of contents

Section Page




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1.0 SCOPE

This specification gives directives for the design, selection criteria, methods for pipe stress design for aboveground piping. The intent of this specification is for RESIDUE UPGRADATION PROJECT of IOCL, VADODARA, GUJARAT, India, not to supersede the applicable Codes, but to supplement them with certain conditions not fully covered therein.

2.0 REGULATIONS

The following codes, standards and specifications shall form a part of this specification to the extent specified therein:

2.1 CODES

American Society of Mechanical Engineers (ASME)B31.3 ,2004 Process piping.B31.1 Power piping.IBR Latest edition

2.2 STANDARDS

American Petroleum Institute (API)

API 610 (2004) Centrifugal pumps for general refinery servicesAPI 611 (1997) General purpose steam turbines for refinery servicesAPI 612 (2003) General-purpose steam turbines for petroleum, chemical` and gas industry servicesAPI 617 (2002) Centrifugal compressors for general refinery services.API 618 (1995) Reciprocating compressors for general refinery servicesAPI 661 (2002) Air-cooled heat exchangers for general refinery servicesAPI 560 (2001) Fired heaters for general refinery servicesAPI 686 (1994) Recommended Practices for Machinery Installation and Installation DesignAPI 520 (2000) Recommended Practices for Safety Valve installation

National Electric Manufacturers Association (NEMA)

SM-23 Steam turbines for mechanical drive service

2.3 MANUFACTURER'S STANDARDIZATION SOCIETY (MSS)

MSS SP-58 Pipe hangers and supports.-Materials, Design and ManufactureMSS SP-69 Pipe hangers and supports.-Selection and ApplicationMSS SP-89 Pipe hangers and supports.-Fabrication and Installation Practices




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2.4 AMERICAN INSTITUTE OF STEEL CONSTRUCTION (AISC)

Manual of steel construction.

2.5 REFERENCE SPECIFICATIONS

H-100 Standard Engineering Spec. for Plant LayoutA-6235-049-001 Project Design Basis - PipingH-6235-11-T-130-001 Piping Material Specification

3.0 DESIGN CONSIDERATION

The piping flexibility analysis shall be performed by using CAESAR II software Version 5.0, that contains the codes as mentioned for the project.

The flexibility analysis shall consider the most severe temperature conditions experienced by the piping system which may be due to sustained, start-up, normal operation, shutdown, steam-out or any other upset condition.

Piping flexibility shall be obtained through pipe offset or expansion loops. As far as possible use of Expansion bellows should be avoided.

The piping system shall be designed to avoid the following:

− Piping Stresses in excess of those permitted by the relevant code and standards.− Excessive forces and moments at equipment terminal connections.− Excessive stresses at supporting or restraining elements. − Unintentional disengagement of piping from its supports.− Interface between adjacent lines due to thermal expansion or contraction of the piping

system.− Excessive sag in piping systems, particularly those requiring slopes for drainage.− Special supports requiring complex design details or impractical construction tolerances.

For example, excessive use of spring supports for minor thermal movement (spring support should not be specified for movements of 3mm or less in Non-Strain Sensitive systems).

− Carrying / Supporting pipes from larger diameter headers. This shall be avoided as far as possible.

− Cold spring shall not be used in principle.




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4.0 DESIGN CONDITIONS

4.1 DESIGN CODE

Stress analysis shall be in accordance with ASME B31.3 (2004).

4.2 DESIGN LIFE

All piping systems shall be designed for a life of 10 years counting for an equivalent number of full displacement cycles of maximum 7000, unless otherwise required for severe cyclic conditions

4.3 INSTALLATION TEMPERATURE

Installation temperature shall be used only for reaction loads calculations, however the stress range shall be calculated for difference between the minimum and maximum temperatures, if any

Installation temperature, for all calculation purpose to be considered as belowFor cold lines installation temp = 46.70C.For hot lines installation Temp = 4.4 0C

4.4 FLEXIBILITY TEMPERATURE

Displacement range shall be determined by using the greatest temperature differential imposed by all operating conditions. For the same reason flexibility temperature to be “Design temperature” in the line list. However when necessary maximum operating temperature in lieu of design temperature can be considered.Solar temperature of 70°C (black bulb temperature 70°C) to be considered for analysis purpose for un-insulated, unsheltered Gas line; if design temperature is less than this temperature.

Design temperatures used for the calculation of liquid line shall be as shown below. They shall be determined for each segment of piping with the fluid condition taken into account, whether it is flowing or still.For piping through which fluid is flowing.

(1) For piping not heated with tracing or jacket:The Design temperature specified in the Line Index.

(2) For piping heated with tracing:The fluid temperature or 70% of the temperature of heating medium, whichever the higher.

(3) For piping being warmed up by bypass line : 70% of the flowing fluid temperature.




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For piping in which fluid is still(1)For piping without tracing : 70°C

(2) For piping heated with tracing : 70% of medium temp.

For Steam out temperature (Applicable Steam Temperature), consideration shall be given to whether equipment and piping are steamed out simultaneously or separate.

Temperature for internally insulated / lined piping shall be based on heat transfer calculations.

For line connected with pumps, in the stand-by portion of piping without warming by-pass, the temperature decay shall be considered:

4.5 FLEXIBILITY PRESSURE

The flexibility pressure shall not be less than the pressure at the most severe condition of coincident pressure and temperature expected during service, except for occasional variations, where code limitations shall apply i.e. Design Pressure as indicated in line list.For Hydro test Condition, reference to be taken from Line list whether hydro test is required or not.In Stress calculation, Bourdon effect shall be considered for 600 # and Above.

4.6 WIND LOAD

Wind loads shall be considered for pipes with OD 600mm and above including insulation, & above 10m elevation.Wind loading shall be in accordance with Design Specification for Loads (Doc. No. A-6235-110-001).

4.7 EARTHQUAKE

Induced horizontal forces shall be considered and included in the flexibility analysis.Values for earthquake accelerations are to be taken from Design Specification for SEISMIC (Doc. No. A-6235-110-007).The simplified static equivalent method considering only horizontals may be used.

A & B both operating

PUMP A

PUMP B

PUMP A

PUMP B

A operationB stand by

B operationA stand by

PUMP A

PUMP B

( standby )

( standby )

Insta. Temp. Design Temp.

Insta. Temp. Design Temp.




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Concurrent wind and earthquake conditions need not to be considered.

4.8 DISPLACEMENTS

Spaces between outside surfaces of two (2) (un) insulated pipes shall be limited to minimum 25 mm at installation and “0” (zero) mm after displacement, considering the most severe operational conditions (maximum versus minimum) for both piping systems.

4.9 DYNAMIC ANALYSIS FOR TWO PHASE FLOW

List of lines which is having slug flow (Two Phase Line) to be prepared by process and to be submitted to OWNER/TEIL for review.

Dynamic analysis to be performed for all two phase lines having slug flow and Transfer lines in the plant, in order to ensure that such lines are provided with proper supports and there shall be no vibrations in the line during normal operation as well as during start up or any upset conditions.Dynamic analysis to be performed at design temperature and operating temperature.Actual densities shall be considered while carrying out static analysis.The fundamental frequency of the piping system to be checked to avoid resonance. The minimum acceptable frequency criteria to be kept as 7 Hz for Transfer lines and 6 Hz for other lines under dynamic analysis.Also, report to be submitted for mode shape plots up to 15Hz. model displacement output shall be submitted. This report should include boundary condition and other parameter used in dynamic analysis.

4.10 LOADING ON EQUIPMENT

Thrust loads and moments imposed on equipment shall include all loading effects and shall not exceed the equipment manufacturers recommended values.

Thermal movement at the equipment nozzle shall be obtained from the equipment manufacturer or calculated with the data known for the equipment.

When acting loadings are over the allowable values, according to the applicable standard or code, approval shall be obtained from the manufacturer.

In the absence of vendor data, relevant codes like API 610, API 621, NEMA SM23, API560, API661 etc. or any other approved proven international code/practices NOZZLE LOADING shall be as per TEIL’s nozzle loading table attached here with.(Attachment-1)

There is no clear established limit for earthquake loads acting on equipment connections in Codes or Practices. If calculated loads exceed the standard allowable, engineer considerations shall be taken or approvals should be obtained from the Mechanical suppliers on an individual basis.

In determining acting loads on vessels connections, local flexibility of vessel walls may be taken into account, when equipment drawings show that no stiffening other than internal or external vessel stiffeners is present in the vicinity of the connections.

Local flexibility shall not be used for connections other than perpendicular to a circular vessel wall.

Piping connected to nozzles from vertical static equipment running next to the equipment wall shall preferably be supported by means of a bracket close to the nozzle to unload the nozzle from weight and other sustained loadings.




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4.11 FLANGE LEAK CHECK ANALYSIS FOR RELIEF VALVE

Flange leak check analysis for relief valve piping to be performed.

A List of all lines for which flange leakage calculation is required to be prepare by piping dept and to be submitted for review by OWNER/TEIL.

Reaction forces including both momentum & static pressure effects due to safety valve popping shall be ascertained in the connected piping according to API RP520 for systems discharging to atmosphere. The effect of these forces on the piping supports and the anchors of the piping system shall be calculated to ascertain that the allowable limits at these locations are not exceeded.System stresses in the inlet and outlet piping portions at safety valves also shall be kept within the allowable limits, inclusive of the distribution branching points in the inlet portion.These reactive forces shall not lead to any leakage at the flanged joints present in the system. To ascertain these necessary calculations for checking leakage at the flanged joints shall be performed.

ASME B31.3 does not describe the evaluation method of flange leakage. Therefore, the force (tension) and moment at a flange are converted into the equivalent pressure, and added to design pressure for evaluation. The evaluation for leakage at a flange connection is carried out by following procedure.

Flange subjected to analysis is selected based on thefollowing criteria

• for 900# and Above

• For Safety valve for which Min. pressure

Difference will be 8Kg/cm²

4.12 ANALOG ANALYSIS

For pulsating lines connected to reciprocating compressors/pumps analog study shall be carried out. Reports shall include both acoustical and mechanical studies.

M

G

F

F




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SUPPORT SPAN

Either the stresses or requirements for minimum Natural Frequency of the piping system will limit the pipe spans.Stresses due to the sustained loadings and pressure which shall not exceed the basic allowable stress at temperature, or the maximum deflection due to sustained loadings between two (2) supports which shall be the lesser of 15 mm or half (0.5) times the outside diameter.Vertical deflections in piping system in horizontal run between two adjacent supports due to sustained loading = 3 mm (max) for all steam lines and for all line Longitudinal expansion/contraction to be limited to 200mm (maximum)




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5.0STRESS CATEGORISATION

Piping route Planed is to be verified in its strength to finalize the piping route. On the premise that flexibility study shall be carried out for all piping systems, following three methods shall be applied to verify flexibility in piping system.Category 1: Exemption from formal flexibility analysisCategory 2: Simplified methodCategory 3: Comprehensive analysis

7.0 STRESS CATEGORISATION BASIS

Design Temperature up to

-150

°C A

ND

BE

LO

W

-150

°C

-120

°C

-60°

C

-20°

C

20°C

70°C

120°

C

200°

C

300°

C

300°

C A

ND

AB

OV

E

Compressor 2” and Above

Reciprocating pumps

2” and Above

Rotating equipment /

Centrifugal Pump

2” O O O O O O O O O O O

3” and above

Cold Box, Aluminum

Exchanger, Air Cooler, and

Furnace

2” O O O O O O O O O O O

3” and above

Line class 900 lb rating and above

2” to 4” O O O O O O O O O O O

6” and Above O O O

Non-Ferrous lines

2” to 4” O O O O O O O O


Non-metallic lines2” to 4” O O O O O O O O


Flare headers 8” and Above

Differential Settlement

Greater Than 50 Mm, From Tank,

Vessel, Equipment, Or


8” and above




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-150

°C A

ND

B

EL

OW

-150

°C

-120

°C

-60°

C

-20°

C

20°C

70°C

120°

C

200°

C

300°

C

300°

C A

ND

A

BO

VE

Lines with thermal cycles greater than

7000

2” TO 6” O O O O O O O O O O O

8” And Above

Lines with external pressure or jacketed

piping

2” TO 4” (Core) O O O

6” And Above (Core)

Two phase flow (slug) / surge


6” and Above

Safety Valve with pressure difference of

10 kg/cm²

2” to 6” (Inlet) O O O O O O O O

8” and Above (Inlet)

Remaining CS / SS lines

Critical line list to be prepared on above points, as well remaining lines to be identified as shown in following Chart ON NEXT SHEET

Legend :

Stress Category 1

Stress Category 2

Stress Category 3

O




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1) For Carbon Steel or Low Chrome Pipe




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2) For Stainless Steel Pipe

8.0 STRESS REPORT

The reports shall at least comprise of the following:- Basic input data and calculated conditions- Layout isometric and supports configuration including gaps/limit stops- Calculated member forces and stresses for different load cases- Forces, moments and displacement reports- Spring Hangers design parameters- Additional requirements (reinforcement pad etc.)- Flange leakage checks if applicable.- WRC 107/WRC 297 checks.- Allowable Stress Range.- Expansion Bellow parameters- Design calculations for adequacy of supporting elements- Loads at interface B/L with ISBL/OSBL if any.- Analysis of segments till nearest anchor at battery limit- Basis of allowable forces and moments & wherever applicable vendor given allowable

loads/moments.- Allowable equipment load check- Codal check

Piping Stress Analysis Engineering

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