PIPING STRESS ANALYSIS BY CAESAR-II SOFTWARE CAESAR MODELING ANALYSIS REPORT FDC PIPING

WHAT MAKES PIPING CRITICAL? Temperature Pressure Occasional loads (Seismic & Wind) Dynamics of the flowing fluid FDC PIPING

WHAT CAUSES STRESS IN THE PIPE? Live and Dead load (Piping component, Insulation, Flowing medium etc.). Line pressure Restraining of pipe expansion or Temperature gradient Discharge reaction (E.g. Relief valves) Seismic / Wind load Dynamics of flowing fluid. Cont…. FDC PIPING

WHY STRESS ANALYSIS IS TO BE DONE? To ensure that all stresses in the piping system are within allowable limits. To limit the loads on the equipment nozzle. To limit the thermal displacement and sagging To limit the loads on the supporting structures & flanged joints. To avoid excessive piping vibration FDC PIPING

WORK FLOW DIAGRAM FOR STRESS GROUP

INPUT FOR STRESS ANALYSIS Stress Isometrics LDT / P&ID Equipment G.A.Drawing Instrument(e.g.PSV/control valve) data sheet FDC PIPING

SOFTWARE USED Piping Stress Analysis Software CAESAR II 4.5 In-house software (Tracking system) SATS SSTS CAESAR CONVERT FDC PIPING

MODELLING Piping Components Piping Equipments Restraints Cont…. FDC PIPING

NODE SKETCH Cont…. FDC PIPING

STRESS ISO MARKUP

CAESAR INPUT SPREADSHEET Start Run Batch Run Allowable Stress At Cold Condition Geometry Allowable Stress At Hot Condition Caesar Modelling Material Selection

RESTRAINT MODELLING

SPRING MODELLING

CONSTANT SPRING

INPUT SPREADSHEET

FORCE MODELLING

BEND MODELLING

SEISMIC FORCE INPUT

PROCEDURE FOR PUMP LINE ANALYSIS

PROCEDURE FOR PUMP LINE ANALYSIS   2. Top suction – Top discharge & 3. Side suction – Side discharge Referring to Fig.2 & 3, node marking 1-2 shows nozzle flange with given flange rating as “rigid” element. Node 2-3 shows nozzle standby with pipe element (Dia equal to pump impeller dia and thickness equal to pipe wall thickness) as rigid element with zero weight from flange welding joint to pump impeller center line. Node 3-4 shows rigid element with zero weight up to center line of the pump. Restraints – 1) The pipe flange to be get anchored as C- Node with pump flange to get nozzle load due to piping reaction. This load value should be less than allowable values. 2) Rigid element at pump C/L to be get anchored i.e. anchor at node4.

PROCEDURE FOR PUMP LINE ANALYSIS

ANALYSIS STATIC ANALYSIS DYNAMIC ANALYSIS FDC PIPING

TYPES OF STRESSES PRIMARY SECONDARY FDC PIPING

TYPES OF LOAD Sustain Load Occasional Load Thermal Load Hydro Test Load FDC PIPING

LOAD CASE DEFINATION L1 WW + HP (HYD) L2 W + T1 + P1 + H (OPE) L4 W + P1 + H (SUS) L5 L2 – L4 (EXP) L6 L3 – L4 (EXP) FDC PIPING

LOAD CASE DEFINATION L1 W + T1 + P1 + H (OPE) L2 W + P1 + H (SUS) L3 U1 (OCC) L4 U2 (OCC) L5 L2 + L3 (OCC) L6 L2 + L4 (OCC) FDC PIPING

CAESAR LOAD CASES DESIGN TEMP. LOAD CASE OPERATING TEMP. LOAD CASE

PROCEDURE FOR PUMP LINE ANALYSIS LOAD CASES FOR PUMP LINE STRESS ANALYSIS Load cases for the pump connected lines are discussed below. 1. Hot Cold Load case: ♦ Both pump operating. When two or more pumps are used in a system then from stress analysis point of view the different load cases are made. Like, ♦ One pump operating & one stand by. (This point to be get discussed with process, what will be the requirement, whether “at any moment only one pump will operate, for more than two pump case”) ♦ Hot Cold analysis to be done at design and operating temperature. ♦ For the pump, which is not operating, ambient temperature should be considered from Tee point ► When two pumps are present in the system hot cold cases can be made as below (Refer Fig. 4).

PROCEDURE FOR PUMP LINE ANALYSIS Case 1: When both pumps are in operating condition, provide design and operating temperature for node 10-20-30-40-A & 20-50-60-B Case 2: When pump “A” is operating and pump “B” is cold, provide design and operating temperature for node 10-20-30-40-A and ambient temperature for 20-50-60-B. Case 3: When pump “B” is operating and pump “A” is cold, provide design and operating temperature for node 10-20-50-60-B and ambient temperature for 20-30-40-A. ► When three pumps are present in the system hot cold cases can be made as below (Refer Fig. 5).  

PROCEDURE FOR PUMP LINE ANALYSIS CASE6: W+P1+T5 (OPE) ………Pump “A” at operating temp and Pump “B” standby. CASE7: W+P1+T6 (OPE) ………Pump “B” at operating temp and Pump “A” standby. CASE8: W+P1 (SUS) CASE9: WNC (SUS) CASE10: L2-L8 (EXP) CASE11: L3-L8 (EXP) CASE12: L4-L8 (EXP) CASE13: L5-L8 (EXP) CASE14: L6-L8 (EXP) CASE15: L7-L8 (EXP) ♦ For load case no 2, 3, 4, 5, 6,7and 8 pump nozzle load is checked and it should be within acceptable limit as specified by vendor or API 610. ♦ For load case no 1, 8, 10, 11,12,13,14 and 15 stress value is checked and it should be less than allowable stress as specified by relevant code. ♦ For load case no 9 (WNC case) deflection is checked at pipe flange for cold alignment case as discussed in earlier topic of WNC load case. B. Load Cases for Static Analysis (Three Pumps A, B & C) CASE1: WW+HP (HYD) CASE2: W+P1+T1 (OPE) …Three pumps at design temperature. CASE3: W+P1+T2 (OPE) …Three pumps at operating temperature. CASE4: W+P1+T3 (OPE) ….Pump “B&C” at design temp and Pump “A” standby. CASE5: W+P1+T4 (OPE) …..Pump “A&C” at design temp and Pump “B” standby. CASE6: W+P1+T5 (OPE) …..Pump “A&B” at design temp and Pump “C” standby. CASE7: W+P1+T6 (OPE) …..Pump “B&C” at operating temp and Pump “A” standby. CASE8: W+P1+T7 (OPE) …..Pump “A&C” at operating temp and Pump “B” standby. CASE9: W+P1+T8 (OPE) …..Pump “A&B” at operating temp and Pump “C” standby. CASE10: W+P1 (SUS) CASE11: WNC (SUS) CASE12: L2-L10 (EXP) CASE13: L3-L10 (EXP) CASE14: L4-L10 (EXP)

PROCEDURE FOR PUMP LINE Case 1: When three pumps are in operating condition, provide design and operating temperature for whole system. Case 2: When pump “A” is cold and pump “B & C” are operating, provide design and operating temperature to node 10-20-30-70-B & 20-50-60-C and ambient temperature for 30-40-80-A. Case 3: When pump “B” is cold and pump “A & C” are operating, provide design and operating temperature to node 10-20-30-40-80-A & 20-50-60-C and ambient temperature for 30-70-B Case 4: When pump “C” is cold and pump “A & B” are operating, provide design and operating temperature to node 10-20-30-40-80-A & 30-70-B and ambient temperature for 20-50-60-C. 2. WNC (Weight No Content) Load case: The basic philosophy for “WNC” is by what magnitude the piping flange displaced at the mating point while cold alignment. For “WNC” case, make the pump flange anchor node free and replace the spring support to rigid support. Go in load case spread sheet, drag the “WNC” from side menu to load case row and select “Sustain case”. Run the case and get the displacement at the pump nozzles, this displacement should be less than 1mm (or consult mechanical department to get allowable deflection). 3. Load Cases in CAESAR-II for two pump connected system Load cases for stress analysis of two pump connected piping system are discussed below. Same philosophy is applicable for more than two pump connected system. Abbreviation: W = Weight; T= Temperature; HP = Hydro Pressure; WW = Water Filled Weight; WNC = Weight No Contents; P = Design Pressure. U1 = Uniform load (NS Seismic); U2 = Uniform load (EW Seismic); A. Load Cases for Static Analysis (Two Pumps A & B) CASE1: WW+HP (HYD) CASE2: W+P1+T1 (OPE) ………Both pumps at design temperature. CASE3: W+P1+T2 (OPE) ………Both pumps at operating temperature. CASE4: W+P1+T3 (OPE) ………Pump “A” at design temp and Pump “B” standby. CASE5: W+P1+T4 (OPE) ………Pump “B” at design temp and Pump “A” standby.

CAESAR OUT PUT

REPORT INTERPRETATION Displacement Restraints Restraints Summary Global Element Forces Local Element Forces Stresses Sorted Stress Code Compliance FDC PIPING

REPORT INTERPRETATION Hanger Table Hanger Table W/Text Input Echo Miscellaneous Data Load Case Report Warnings FDC PIPING

OUTPUT SHEET

REPORTING Stress Analysis Query Front Sheet Caesar Title Sheet Stress Isometrics with markup Load summary sheet Spring / Bellow data sheet SPS drawing Caesar Load summary sheet FDC PIPING

SAQ SHEET

CAESAR DUMP

RESTRAINT OUTPUT

SPRING DATASHEET

SPS DRAWING

BELLOW DATASHEET

LOAD SUMMARY SHEET

COMPLETED STRESS ISO FDC PIPING

PRACTICAL SESSION DEMONSTRATION OF CAESAR

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