ES_LineSize User Manual

1. Introduction

2. Basic Equations

3. Major Screens


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1.  Introduction

Pipe line sizing is one of the most frequent calculation in P&ID ( Piping & Instrumentation Diagram) preparation work in power plant engineering.   At the beginning of P&ID preparation, the sizes of all pipe lines are selected first by velocities, while the pipe sizes of major pipe lines such as main steam line, hot reheat line, etc. are finally selected by the pressure drops specified for respective pipe lines.

ES_LineSize is the software to select line sizes by mean velocities.   

Flow velocities used in pipe line sizing are similar among engineers and/or engineering firms, though they may have a little difference.   Normally the flow velocity for a service is provided in a range.   The maximum values of the range is limited by noise or vibration caused by high velocity, while the minimum value is selected in view of economics.

ES_LineSize has a set of built-in flow velocities for various fluids used in power plant engineering.  The built-in flow velocities are in line with the velocities commonly used in international engineering practices.   When user does not specify design flow velocity, ES_LineSize calculates the line size using the built-in flow velocity.

ES_LineSize has also a set of built-in pipe sizes according to ASME B36.10 and B36.19.   When the pipe diameter and thickness calculated are within the dimensions of the Code, ES_LineSize selects the pipe size of the Code.   When the pipe diameter and thickness calculated are out of the Code, the pipe dimensions are presented as calculated.

ES_LineSize calculates pipe thickness according to Clause 104 of ASME B31.1.  ES_LineSize calculates also pressure drops for 100 length unit pipe, one gate valve, etc. for reference.   ES_LineSize has a function to specify design volume flow of gas and compressed air by normal or standard volume flow in addition to mass or actual volume flow.

 

2. Basic Equations   (TOC)

2.1 Continuity Equation

Continuity equation is simple and ES_LineSize uses the following equation.

ID = Sqr(353.7 * MF * v / Vel)

ID = Sqr(353.7 * VF / Vel)

where,

ID

: Inside diameter, mm

 

MF

: Mass flow rate, kg/hr

 

VF

: Volume flow rate, m3/hr

 

v

: Specific volume, m3/kg

 

Vel

: Mean flow velocity, m/sec

 

2.2 Pipe Thickness Calculation

ES_LineSize calculates the minimum pipe thickness in accordance with Equation 3A by internal diameter of ASME B31.1, Clause 104.1.2 with the consideration of additional thickness(A), and then calculates the minimum thickness for pipe selection by the following equation.

     t_sm = t_m / (1 - MfgTol / 100) * BendRadius

where,

t_sm

: The minimum thickness for pipe selection

 

t_m

: The minimum pipe thickness calculated according to ASME B31.1

 

MfgTol

: Manufacturing tolerance, %

 

BendRadius

: Bend radius factor according to Table 102.4.5 of ASME B31.1

 

2.3 Pressure Drop Calculation

Pressure drop is calculated by Darcy equation, and the following resistance coefficients are used for valve and elbow calculation.

 

Gate valve

: 8 * fT

 

Globe valve

: 340 * fT

 

Elbow

: 30 * fT

 

Bend

: 20 * fT (short radius bend, r/d = 1)

 

 3. Major Screens   (TOC)

3.1 Main Screen

Main screen of ES_LineSize consists of four(4) windows as shown above.   Those are System and Pipe List window, System Input window, Pipe Input window and Calculation Result window.

3.2 System and Pipe List Window

The drop-down combo-box of System List shows the list of systems of a project.   When clicking a system in the box, the pipe list of the system is shown at the grid box below.   A system can be added or deleted by the command buttons at the right side.   The title of system can be entered or edited at the combo-box itself.

The grid box of Pipe List shows the list of pipes of the system clicked at the System List box above.   The Pipe List shows some main data of each pipe for ready reference.   A pipe can be added or deleted by the command button at right side.

3.3 System Input Window

At System Input window, the design data of the current system can be entered or edited.   The system data consists of design pressure and temperature, operating condition, fluid and pipe material.

Design pressure and temperature are used for pipe thickness calculation.  

Operating condition is used for pipe diameter and pressure drop calculation.   When mass flow rate is the calculation basis set at Calculation Set Menu, specific volume is required for pipe diameter calculation, while, when volume flow rate is the calculation basis, specific volume is not necessary.   When viscosity values are not given, pressure drop calculation is not performed.

In the Fluid drop-down combo-box, various fluids normally used in power plant are listed.   The selection of fluid at the box is required for ES_LineSize to provide appropriate built-in flow velocity for pipe diameter calculation and to provide the appropriate command button below for operating condition input by built-in fluid property tables.   When gas or compressed air is selected at the Fluid combo-box, input of volume flow rate in Normal(1 atm and 32 oF) or Standard(1 atm and 60 oF) condition is possible.

In the Pipe Material drop-down combo-box, pipe material for pipe thickness calculation is selected.   The stress values of pipe materials used by ES_LineSize are in accordance with Appendix A of ASME B31.1.   When the design temperature entered by user is higher than the temperature permitted by the Code, a warning message is provided.   A warning message is provided also when the material selected does not match with the pipe schedule number selected in Pipe Input window, e.g. carbon steel material versus stainless steel schedule number.

 

3.3 Pipe Input Window

At Pipe Input window, the design data of each pipe can be entered or edited.   The pipe design data consists of pipe description, design flow, design velocity and the minimum schedule number.  

Design flow can be entered either of mass flow or volume flow, of which selection is made at Calculation Set menu.   If the fluid selected at System Input window is gas or compressed air, design volume flow may be entered in Normal or Standard condition.   If specific volume is entered at System Input window, mass flow is automatically calculated by ES_LineSize when volume flow is entered.   Vice-versa when mass flow is entered.   Actual volume flow is also automatically calculated by ES_LineSize when Normal or Standard volume flow for gas or compressed air is entered.

Design velocity is automatically entered by ES_LineSize when it is not entered by user or user enters zero value.   When user enters the design velocity, ES_LineSize calculates using the design velocity entered by user.    User may change the pipe size selected by ES_LineSize by varying the design velocity.

Minimum schedule selected in Min. Sch. combo-box is used for ES_LineSize to limit the minimum thickness to be selected.   ES_LineSize uses the built-in pipe data having prepared in accordance with ASME B36.10 for welded and seamless wrought steel pipe and B36.19 for stainless steel pipe.    In ASME B36.10 there are pipes with and without wall thickness designations, and there are two kinds of wall thickness designation, i.e. weight designation(Std. XS, XXS) and schedule number.   Further,  for 52 inch NPS and above there are no pipes with wall thickness designation.

The built-in pipe data of ES_LineSize consists of pipes with wall thickness designation only.    That is, the pipes without wall thickness designation have not been included in the built-in pipe data.   Therefore, the pipes in ES_LineSize built-in pipe data can be searched and/or limited by wall thickness designation.   For this reason, ES_LineSize has labelled arbitrarily 0.375 inch wall thickness pipes as STD, 0.5 inch wall thickness pipes as XS and 1 inch wall thickness pipes as XXS for 52 inch NPS and above, and added to the built-in pipe data in order to enlarge the searching range.   When the calculation result shows the nominal pipe size of 52 inch or above, the wall thickness designation shown is not real one existing at ASME B36.10.

ES_LineSize searches only the wall thickness designation same with the minimum schedule selected in Min. Sch. combo-box.   That is, if user selects 40 for the minimum schedule, ES_LineSize searches only the pipes with schedule number designation, while searching only the pipes with weight designation if user selects STD for the minimum schedule.   Therefore, sometimes user may try to choose both of schedule number designation and weight designation if he wanted to select the pipe with thickness close to the calculated thickness.

The command button of [Calculation] is used to start calculation.   In order to input the calculation result to the current pipe in the pipe list, the command button of [Input to Pipe List] should be pressed.    The current pipe is the pipe having cyan color in the pipe list.   Please note that in order to add a new pipe with the calculation result, a pipe has to be inserted in the pipe list by pressing [Insert] or [Insert Aft] button at [System and Pipe List] window, and then [Input to Pipe List] button should be pressed.

 

3.4 Calculation Result Window

      

[Pipe Selected] window shows the selected nominal pipe dimension or calculated pipe dimension if the calculated pipe dimension is out of built-in pipe data.   [Actual Vel] is the actual flow velocity calculated based on the selected pipe dimension.   [Calc Min Thk] is the minimum thickness calculated by ASME B31.1, Clause 104.1.2 with the consideration of additional thickness[Add. Thk].   [Sel Min Thk] is the minimum thickness for pipe selection calculated by the equation of Clause 2.2 above.

[Pressure Drop] window shows the pressure drops of 100 unit length pipe, a gate valve, a glove valve, a standard elbow and a short-radius bend with Reynolds number and friction factors.   [fT] is the friction factor of complete turbulent flow.

 

3.5 Calculation Set Menu Window

In [Calc Set] window, user can select the kind of input flow, i.e. mass flow or volume flow; select gas volume flow condition when the fluid is gas or compressed air; and enter thickness selection basis.

3.6 Fluid Property Window for Operating Condition

Operating condition of the fluid can be entered by the built-in fluid property windows as below.   Please note that the operating condition may be entered directly by user at the [Sytstem Input] window.

3.6.1 Steam or Water

3.6.2 Gas

3.6.3 Fuel Oil

 

3.7 Text Output Window

[Text Output] window shows the calculation result details and can be printed.

 

References :   (TOC)

1. Crane Technical Paper No. 410, Flow of Fluids, Crane Co., 1977

2. ASME B33.1, B36.10 and B36.19

(end)


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