PIPE STRESS FUNDAMENTALS

PIPE STRESS MODULES

BASIC CONCEPT TYPES OF STRESS ASME STANDARDS FOR PIPING ALLOWABLE STRESS AS PER CODE NOZZLE LOAD LIMITING CODES PIPE STRESS ANALYSIS

BASIC CONCEPT

TYPES OF LOAD

PRIMARY LOAD

SECONDARY LOADLOADSTRESSRESISTANCE DEVELOPED IN THE MATERIAL AGAINST APPLIED LOAD

PRIMARY LOADS ALL SUSTAIN TYPE OF LOADS

DEAD WEIGHT

PRESSURE

OCCASIONAL LOAD (SESMIC / WIND)

SECONDARY LOADS LOADS DUE TO DISPLACEMENT

THERMAL DISPLACEMENT

DISPLACEMENT DUE TO TANK SETTELMENT

MOVEMENT DUE TO VIBRATION

TYPES OF STRESSPRIMARY STRESS SUSTAIN STRESS OCCASIONAL STRESSSECONDARY STRESS EXPANSION STRESS STRESS DUE TO VIBRATION NOT SELF LIMITING / NON CYCLIC SELF LIMITING / CYCLIC IN NATUR

ANSI STANDARDS FOR PIPING ASME B31.3 :-PROCESS PIPING

ASME B31.1 :-POWER PIPING

ASME B31.4 :- PIPELINE TRANSPORTATION SYSTEM FOR LIQUID HYDROCARBON & OTHER LIQUID.

ASME B31.8 :-GAS TRANSMISSION & DISTRIBUTOR PIPING SYSTEM

STRESS AS PER CODE Sustain stressAs per 31.3 codeWhere:- SL = Sum of longitudinal stress due to wt., pr., and other sustain loadingsFax = Axial force due to sustain loading Am = Metal cross section area (mm2) ii , io, = In-plane and out-plane stress intensification factorMi Mo = In-plant & out-plane bending moment due to sustain loading in (N-mm) Z = Section modulus, (mm3) t = Nominal thickness (mm) Sh = Basic allowable stress at the operating temp. (KPa)Expansion stress rangeAs per 31.3 code SE = Expansion stress range K Pa

Sb = Resultant bending stress St = Torsion stress = 1000 * Mt / 2Z

SA = Allowable expansion stress range SA = f(1.25Sc + 0.25Sh) --- Sc and S h are available in table A1 of 31.3 codeOccasional stress As per 31.1 codeAs per ASME B 31.3 code under clause 302.3.6 only states that the SUM OF LONGITUDINAL STRESSES DUE TO SUSTAINED AND OCCASIONAL LOADS SHALL NOT EXCEED 1.33 TIMES THE BASIC ALLOWABLE STRESS i.e. < K Sh

ALLOWABLE STRESS AS PER CODEALLOWABLE STRESS IN CODE ARE BASES ON MATERIAL PROPERTIES As per the ASME B31.1 ( Minimum of )

1/4TH OF UTS OF MATERIAL AT OPERATING TEMPERATURE

1/4TH OF UTS OF MATERIAL AT ROOM TEMPERATURE.

5/8TH OF YIELD STRENGTH OF THE MATERIAL AT OPE TEMPERATURE

5/8TH IF YIELD STRENGTH OF THE MATERIAL AT ROOM TEMPERATURE.As per the ASME B31.3 ( Minimum of )

1/3RD OF UTS OF MATERIAL AT OPERATING TEMPERATURE

1/3RD OF UTS OF MATERIAL AT ROOM TEMPERATURE.

2/3TH OF YIELD STRENGTH OF THE MATERIAL AT OPE TEMPERATURE.

2/3TH IF YIELD STRENGTH OF THE MATERIAL AT ROOM TEMPERATURE.

NOZZLE LOAD LIMITING CODES Centrifugal pumps API 610 / ISO 5199

Centrifugal compressors API 617

Reciprocating compressors API 618

Steam turbines NEMA SM 23

Air cooled heat exchanger API 661

Fired heaters API 560

LIMITING THE STRESSES AS PER RELEVANT CODE LIMITING THE DEFLECTION SAG AND FOULING LIMITING THE EQUIPMENT NOZZLE LOAD ESTIMATION OF LOAD FOR DESIGNING PIPE SUPPORTS TO CHECK THE PROPER FLEXIBILITY OF PIPING SYSTEM PURPOSE OF STRESS ANALYSIS

PIPE STRESS ANALYSIS INPUT REQUIRED SOFTWARE USED CAESAR II , 4.5 VER. LOAD CASES TO BE ANALYSED OUTPUT OF STRESS ANALYSIS

INPUT REQUIRED STRESS ISOMETRICS LDT AND P & ID EQUIPMENT GA DRAWING MECHANICAL DATASHEET

SOFTWARE USED CAESAR-II ,4.5 VERPIPING INPUT

CAESAR SPREADSHEETNODESDIMENSIONSIZETHICKNESSCORR. ALLOWINSL THKDGN TEMP.OPE TEMPDGN PR.HYDRO PR.MATERIALFLUID DENSITYINSL DENSITY

SUPPORT MODELLINGSUPPORT

EXAMPLE OF SUPPORT ON PIPE Gravity Rest Support

VARIOUS TYPES OF OTHER SUPPORTSSpring Supports Variable and Constant effort

LOAD CASES TO BE ANALYSEDBATCH RUN

RESULT OF ANALYSIS

STRESS ISOMETRIC WITH MARK UP

LOAD SUMMARY SHEET

DATASHEET FOR PIPE SUPPORTS

SPS DRAWING OUTPUT OF STRESS ANALYSIS