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TRIFLEX Windows Rotating Equipment Compliance Reports

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Table of Contents

TRIFLEXWindows User Manual

Introduction to TRIFLEXWindows ...................................................... Chapter 1

Tutorial .................................................................................................. Chapter 2

Menus and Property Sheets .................................................................... Chapter 3

Data Preparation .................................................................................... Chapter 4

Use of Restraints ................................................................................... Chapter 5

TRIFLEXWindows Theory Manual

Outputs .................................................................................................. Chapter 6

Rotating Equipment Compliance Reports .............................................. Chapter 7

1 Rotating Equipment Compliance Reports.................................................... 2

1.1 NEMA SM 23 Compliance Report........................................................ 3

1.2 API Standard 617 Compliance Report ................................................. 14

1.3 ROT - Rotating Equipment Compliance Report................................... 24

1.4 API Standard 610 Compliance Report........................................................... 29

1.5 Vertical In-Line Pumps ....................................................................... 33

1.6 API Standard 610 Sixth Edition Output Discussion ............................. 34

TRIFLEXWindows Piping Code Compliance Reports ....................... Chapter 8

TRIFLEXWindowsDynamic Capabilities ............................................. Chapter 9

Related Engineering Data ....................................................................... Appendix

TRIFLEXWindows Rotating Equipment Compliance Reports

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1 Rotating Equipment Compliance Reports

This preface is meant to introduce the user to the Rotating Equipment Reports contained in TRIFLEXWindows. The following Rotating Equipment Compliance sections have been written to assist the analyst in evaluating the forces and moments exerted upon the equipment casing and nozzles from the piping systems attached to it. From the necessary input data, TRIFLEXWindows will compute the actual forces and moments on the casing and nozzles of the rotating equipment, as well as the allowable forces and moments in accordance with the NEMA Standard SM 23, the API Standard 617, and the API Standard 610, or a manufacturer’s general loading standards. TRIFLEXWindows will then compare the actual loads with those allowed. TRIFLEXWindows will also, by simply coding the existing forces, moments, and the rotating equipment geometry, produce the requested Rotating Equipment Report (see samples).

When working with steam turbines, one frequently must comply with the NEMA (National Electrical Manufacturer’s Association) Standard SM 23.

When working with centrifugal compressors, one frequently must comply with the API Standard 617. This is similar in many ways to the NEMA Standard SM 23.

When working with centrifugal pumps, one frequently must comply with the API Standard 610.

On some occasions, when working with turbines, compressors or pumps, the user is given the allowable nozzle and casing maximum loads by the manufacturer rather than the stipulation of having to comply with one of the standards. The analyst should utilize the Rotating Equipment Compliance Report (ROT) when this situation occurs.

Reactions printed by TRIFLEXWindows in a flexibility analysis are based on the modulus of elasticity of the material as specified by the analyst. Most piping codes allow the analyst to reduce the reactions on the nozzles by the use of the modulus of elasticity at the operating condition. The proper way to do this is to specify the operating modulus when running an analysis with a Rotating Equipment Compliance Report request. The effects of Cold Spring may also be considered in this type of analysis.

TheRotating Equipment Compliance Reports eliminate the need for the analyst to perform manual calculations when checking rotating equipment.


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1.1 NEMA SM 23 Compliance Report

The NEMA Standard SM 23 was written to provide the manufacturer, the engineering consultant, and the client with a specific set of guidelines for the design, selection, shipment, and use of single and multi-stage steam (or other gas) turbines. The criteria for allowable forces and moments on turbine nozzles and casings is established in Part 8 of publication SM 23. The use of expansion joints and good piping design practices are discussed in detail in this publication. The analyst should be certain to read those discussions prior to attempting to design turbine piping systems.

The TRIFLEXWindows generated NEMA SM 23 Compliance Report has been developed to eliminate the costly man-time required to manually check piping system loads on steam turbines. Manual calculations are not only tedious, but the likelihood of mathematical errors is extremely high. By coding all major piping systems connected to the turbine in one analysis and by coding the necessary NEMA 23 screen, TRIFLEXWindows will perform the prescribed checks as defined in Part 8 of this industry standard.

NEMA Coding Instructions

1. Align the centerline of the equipment shaft along either the X- or Z-axis, whichever is more convenient for the analyst.

2. Code the piping system from some point outside of the turbine casing to the face of one of its nozzles. The data point number at the flange face will be referred to later as a nozzle number. Remember not to code the flange that comes with the equipment.

3. From the face of this flange, code a joint data point type to a common point within the casing (normally the point of resolution).

4. Code all piping systems coming into the casing following Steps 2 and 3 above. Up to four (4) nozzles may be coded.

5. Remember that all flanges must have unique numbers. If the common joint point was placed at the location of one of the flanges, two numbers will be required: one for the flange and one for the joint.

6. After completing the final line to this common joint point, an anchor should be placed at this location. This can be achieved by filling in the Anchored? field with a Y on the last input screen. After saving that screen TRIFLEXWindows will bring up an anchor screen so the user may fill in any necessary information.


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7. Code as many NEMA data sets as required. The NEMA data set contains the data point number of each nozzle, the data point number of the point of resolution and the factor number.

Problems containing more than one piece of equipment should have the data sets stacked as follows:


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found to be much higher than the allowable, in which case the allowable force value will be a negative quantity. This negative quantity occurs when the (500) (D) term in the allowable force equation is less than the resultant moment acting on the nozzle. Consequently, the excessive bending moments must be reduced. To lower the magnitudes of the bending moments on the nozzle, the following measures can be employed:

• Add flexibility to the piping system so that the force causing the bending moment will be reduced.

• Insert Restraints (Supports, Guides, or Stops) to reduce or eliminate the bending moment.

If the nozzle forces and moments are acceptable, but the combined forces along an axis or the combined moments about an axis are excessive, then a more detailed examination is required. If the force along any one of the axes is excessive, it will be relatively simple to determine the source of the problem because the forces are algebraic summations of the forces acting on all of the nozzles. Therefore, the analyst should be able to readily identify the nozzle load causing the problem. Corrective measures, as mentioned above, should be employed to reduce the excessive nozzle force.

If the moment about any one of the axes is excessive, the source of the problem is more difficult to locate than when only forces are involved. The moment values computed are algebraic summations of the moments acting at all the nozzles on the casing about a given axis, plus the forces acting on nozzles other than the point of resolution, which will cause a moment about the given axis. The components of the resolved moments at the point of resolution can be directly obtained from the TRIFLEXWindows analysis. The components from each Branch are the moments computed by TRIFLEXWindows at the end of the last data point in each Branch which ties to the Branch Point at the point of resolution. To correct the problem, determine which nozzle is causing the overload situation. Then determine which force or moment must be reduced to bring the components of the combined resultants within the allowable.

If the nozzle forces and moments are acceptable and the summations along and about the axes are acceptable, but the combined resultants resolved at the specified point are not acceptable, then the piping systems attached to the equipment need to be modified only slightly in some manner. This modification will reduce the magnitudes of the components of the combined resultants, and thereby reduce the combined resultant loads resolved at the point of resolution. When problems are encountered by the analyst processing a NEMA analysis, the step-by-step approach outlined above is recommended.


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The second example shows how to generate a NEMA Report when the loads on all nozzles are known. This method may be extended to generate the NEMA Report along with an analysis of any one line (inlet piping for example), provided the other nozzle loadings are known.

The inlet nozzle is represented by data points 5, 10, and 20, and the exhaust nozzle by data points 50, 55, 60, and 65. The turbine casing is modeled as a joint (d.p. 25) and is fixed at the point where it is desired to resolve casing forces and moments. In this example, the casing temperature is assumed to be 70o F and no nozzle movements are given since these were considered when the nozzle loads were determined.

Notice that terminal points are represented as anchors. Also note that forces and moments are applied at run data points with a limit of three restraint axes per data point.


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1.2 API Standard 617 Compliance Report

The API Standard 617 was written to provide the manufacturer, the engineering consultant, and the client with a general specification for centrifugal compressors in refinery service. The policy regarding allowable forces and moments on compressors is set forth in the API Standard 617 on page 10 in section II, topic number 9. The policy, extracted directly from the API Standard 617, is as follows:

Compressors shall be designed to withstand external forces and moments at least equal to 1.85 times the values calculated in accordance with NEMA SM 23. Whenever possible, these allowable forces and moments should be increased after considering such factors as location and degree of compressor supports, nozzle length and degree of reinforcement, and casing configuration and thickness. The allowable forces and moments shall be shown on the outline drawing.

It is well to note that the second edition of the Standard was written in 1963. Even in 1963 the necessity for the application of special analytical techniques in designing piping connected to compressors was recognized. The most recent edition of the Standard was published in 1979. Analytical techniques have advanced to the point were TRIFLEXWindows will, when coded in the proper fashion, generate a complete analysis of the piping systems connected to the compressor as well as a complete nozzle and casing loading calculation in accordance with the API Standard 617.

API Standard 617 Input Instructions

1. Align the centerline of the equipment shaft along either the X- or Z- axis, whichever is the more convenient for the analyst.

2. Code the piping system from some point outside the compressor casing to the face of one of its nozzles. . The data point number at the flange face will be referred to later as a nozzle number. Remember not to code the flange that comes with the equipment


4. Code all piping systems (items 2 and 3) coming into the casing. Up to four (4) nozzles may be coded.

5. Remember that all flanges must have unique numbers. If the common joint point was placed at the location of one of the flanges, two numbers will be required, one for the flange and one for the joint.


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6. After completing the final line to this common joint point, an anchor should be placed at this location. This can be achieved by entering Y in the ANCHOR? Field of the Node Input screen describing the joint.

7. On the API 617 input screen (found under the Rotating Equipment Menu), code as many API data sets as required. The API data set contains the data point number of each nozzle, the data point number of the point of resolution, and the factor number.

8. Problems containing more than one piece of equipment should have the API data sets stacked back to back as shown next:


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adjacent to the allowable force value. This warning flag indicates that the combination of the actual force and the actual moment is excessive. In most situations, one of the bending moments acting on the nozzle is somewhat higher than the allowable. In some situations it is found to be much higher than the allowable, in which case the allowable force value will be a negative quantity. This negative quantity occurs when the (500) (1.85) (D) term in the allowable force equation is less than the resultant moment acting on the nozzle. Consequently, the excessive bending moments must be reduced. To lower the magnitudes of the bending moments on the nozzle, the following measures can be employed:

• Add flexibility to the piping system so that the force causing the bending moment will be reduced.

• Insert Restraints in the form of Supports, Guides or Stops to reduce or eliminate the bending moment.

If the nozzle forces and moments are acceptable, but the combined forces along an axis or the combined moments about an axis are excessive, then a more detailed examination is required. If the force along any one of the axes is excessive, then it will be relatively simple to determine the source of the problem because the forces are algebraic summations of the forces acting on all of the nozzles. Therefore, the analyst should be able to readily identify the nozzle load causing the problem. Corrective measures as mentioned above should be employed to reduce the excessive nozzle force.

If the moment about any one of the axes is excessive, the source of the problem is more difficult to locate than when only forces are involved. The moment values computed are algebraic summations of the moments acting at all the nozzles on the casing about a given axis, plus the forces acting on nozzles other than the point of resolution (which will cause a moment about the given axis). The components of the resolved moments at the point of resolution can be directly obtained from the TRIFLEXWindows analysis. The components from each Branch are the moments computed by TRIFLEXWindows at the end of the last data point in each Branch (which ties to the Branch Intersection Point at the point of resolution). To correct the problem, you determine which nozzle is causing the overload situation. Then determine which force or moment must be reduced to bring the components of the combined resultants within the allowable.

If the nozzle forces and moments are acceptable and the summations along and about the axes are acceptable, but the combined resultants resolved at the specified point are not acceptable, then the piping systems attached to the equipment need to be modified only slightly in some manner. This modification will reduce the magnitudes of the components of the combined resultants, and thereby reduce the combined resultant loads resolved at the specified point. When problems are encountered by the analyst processing an API analysis, the step-by-step approach outlined above is recommended.


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The second example shows how to generate an API Report when the loads on all nozzles are known. This method may be extended to generate the API Report along with an analysis of any one line (section piping for example), provided the other nozzle loadings are known.

The section nozzle is represented by data points 5, 10, 15, and 20; discharge nozzle by data points 50, 55, 60, and 65. The compressor casing is modeled as a joint (d.p. 25) and is fixed at the point where it is desired to resolve casing forces and moments. In this example, the casing temperature is assumed to be 70o F and no nozzle movements are given since these were considered when the nozzle loads were determined.

Notice that terminal points are represented as anchors. Also note that forces and moments are applied at run data points with a limit of three restraint axes per data point.


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1.3 ROT - Rotating Equipment Compliance Report

The Rotating Equipment Compliance Report is a multi-purpose capability that has been written to aid the pipe stress analyst in organizing and calculating the forces and moments acting on equipment nozzles and casings. This report is especially helpful in eliminating the hand calculations involved in resolving forces and moments at a given location on the casing. The analyst must specify the allowable forces and moments on the nozzles and the casing. TRIFLEXWindows computes the actual forces and moments acting at each nozzle, resolves these loads to a location specified by the analyst, and compares the calculated values with the allowable value input by the analyst. A piece of rotating equipment (with as few as two nozzles or as many as four nozzles) can be handled. with TRIFLEXWindows automatically revolving the forces and moments about a point specified by the analyst. The specified point may be anywhere on the equipment casing, and the combined resultant forces and moments will be computed about its location. This makes the Rotating Equipment Compliance Report (ROT) handy for calculating forces and moments on expander-compressors, turbines, compressors, pumps, or any other piece of equipment for which nozzle loading allowables are specified by the manufacturer.

Rotating Equipment Compliance Report Input Instructions

1. Align the centerline of the equipment shaft along either the X-, Y-, or Z-axis, whichever is the more convenient for the analyst, and in accordance with loading specifications set forth by the manufacturer.

2. Code the piping system from some point outside of the rotating equipment casing to the face of one of its nozzles. The data point number at the flange face (remember not to code the flange that comes with the equipment) will be referred to later as a nozzle number (NOS=).


4. Code all piping systems (items 2 and 3) coming into the casing. Up to four (4) nozzles may be coded.

5. Remember that all flanges must have unique numbers. Two numbers will be required if the common joint point was placed at the location of one of the flanges, one for the flange and one for the joint.

6. After completing all lines to this common point, an anchor data point type must be placed at the point of resolution. It will also require its own unique number. After the anchor data point, code another joint data point back to the common joint point. If the anchor is already placed at this common point, a zero length joint will be required (see examples).


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7. Code the Vendors Rotating Equipment Compliance input screen as required. Each input line contains the data point number of each nozzle, the data point number of the anchor at the point of resolution, and the allowable forces and moments for each. This requires five lines of input. The last line must be for the anchor data point and which resolution is to occur.

8. Problems containing more than one piece of equipment should have each piece separated by an X line like the following:


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1.4 API Standard 610 Compliance Report


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1.5 Vertical In-Line Pumps


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1.6 API Standard 610 Sixth Edition Output Discussion


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