piping Design Requirements for Turbine Systems

7/26/2019 piping Design Requirements for Turbine Systems

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Siemens AGEnergy Sector

This document contains proprietary information. It is submitted inconfidence and is to be used solely for the purpose for which it is furnishedand returned upon request. This document and such information is not to bereproduced, transmitted, disclosed, or used otherwise in whole or in partwithout written authorization.

Document typeNo.: STIM-03.002

Steam Turbine Information Manual

Revision/Date: 14 2010-04-12

Issued by: E F PR SU R&D SV 1

Title

Piping Design Requirements for Turbine Systems

Proj Code UA Content CodeUNID-Nr

Document Status: Preliminary Final


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Piping Design Information for TurbineSystems

Steam Turbine Information Manual Document No.: STIM-03.002

Revision/Date: 14 2010-04-12Page: 2 of 12



Released by: Logar E F PR SU R&D SV 1 Signed Logar 23.04.2010

Reviewed by: Leu E F PR SU R&D SV 1 Signed Leu 23.04.2010

Prepared by: NaskidashviliE F PR SU R&D SV 1

Signed Naskidashvili 23.04.2010Name Org. Unit Signature Date

REVISION SHEET

REVISION REISSUEDATE

SECTION DESCRIPTION OF CHANGE

006 2002-11-22 1, 2, 5.14.1, 5.2.2,

5.2.34.3

National standards (DIN, VGB, etc.) addedWelding and piping design requirements changed

Distance changed from 2.0m to 1.5m

007 2003-08-18 4.4, 5.4Figure 1

4.35.2.2 a

Items addedchangedDescription of 1.5m distance changed.Description of 1.5m distance changed.

008 2004-03-25 2.24.2 4.10

Section revisedSections added

009 2005-04-22 All

Table 1Figure 2

- requirements defined with must- layout changed- table with forces and moments added- table with PED categorization added

010 2007-03-12 4.34.4

Requirements for in- and outlet zones and vibrationsadded

011 2008-03-06 Figure 2 PED table deleted

012 2008-04-24 Table14.15

NPS 0.25 addedDismantling heights of actuators added

013 2009-08-06 Figure 1

Table 1

-Validity of restrictions for the use of socket weldsadded-EQ. (1) und MR =0. deleted

014 2009 2.13.2

4.3

4.14AllAll

valid EG Machinery Directive addedequivalent Length is replaced by pressure drop

non return valve deletedLP deletedtable updatedphrasing about screwed connections changedPower Generation replaced by Energy SectorAuxiliary Systems replaced by Turbine Systems


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TABLE OF CONTENTS1 ...........................................................................................................SCOPE 41.1 Responsibilities of the Pipe Designer:................................................................................ 4

2 GENERAL.................................................................................................................................................. 4

2.1 National Standards............................................................................................................. 42.2 Interfaces............................................................................................................................ 4

2.2.1

Flanges........................................................................................................................... 4

2.3 Connection symbol............................................................................................................. 5

3 PIPING SYSTEM DESIGN REQUIREMENTS .......................................................................................... 5

3.1 Contents and Description of the System Diagrams............................................................ 53.2 Pipe Size and Pressure Drop............................................................................................. 53.3 Allowable Pressure and Temperature................................................................................ 53.4 External Steam and Water Sources................................................................................... 5

4 PIPING DESIGN REQUIREMENTS ..........................................................................................................5

4.1 Connections to components............................................................................................... 54.2 Forces and Moments.......................................................................................................... 6

4.3

In- and outlet zones for regulating and non-return valves.................................................. 6

4.4 Vibrations ........................................................................................................................... 64.5 Draining and Warming of Steam Pipes .............................................................................. 74.6 Piping Slope ....................................................................................................................... 74.7 Pipe routing ........................................................................................................................ 74.8 Branch Connections........................................................................................................... 74.9 Equipment Accessibility...................................................................................................... 84.10 Welded Connections....................................................................................................... 84.11 Threaded Connections ................................................................................................... 84.12 Piping with vacuum......................................................................................................... 84.13 Freeze Protection ........................................................................................................... 84.14 Screw Locking ................................................................................................................ 84.15

Dismantling heights of actuators..................................................................................... 8

5 PIPING SYSTEM FABRICATION REQUIREMENTS ...............................................................................9

5.1 General............................................................................................................................... 95.2 Welding .............................................................................................................................. 95.3 Pretreatment and Cleaning ................................................................................................ 9

Figure 1: Restrictions for the use of socket welds.....................................................................................11

Table 1: Allowable forces and moments .....................................................................................................12


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1 SCOPE

This document covers the requirements for the design of interconnecting piping for the turbinesystems of the stem turbine. The specific scope of interconnecting piping is indicated on theTurbine System Diagrams.

1.1 Responsibilities of the Pipe Designer:

The pipe designer shall be responsible for the design, analysis and specification of theinterconnecting piping systems in accordance with:

ASME B31.1 when designing according ASME

VGB R503 M and VGB R510 L when designing according DIN EN / ISO

2 GENERAL

2.1 National Standards

Specific standards issued by the following organizations shall apply where referencedin this specification. It shall be the designers responsibility to obtain copies of allreferenced documents and drawings. Unless specific exception is taken and approvedby Siemens Energy, the referenced documents shall be considered binding.

ANSI American National Standards InstituteASME American Society of Mechanical EngineersASTM American Society of Testing Materials

or where required

DIN EN Deutsches Institut fr Normung / European NormISO International Standard OrganisationEG Maschinenrichtlinie/ EG Maschine Directive 2006/42/EGDruckgerterichtlinie / Pressure Equipment Directive (PED) 97/23/EG

2.2 Interfaces

The interfaces are described in the components drawings or in associated pipingconnection list. The piping connections list xxxxx-980133 lists all connections and therelated outlines where these connections are described.

The major steam and condensate connections are described in the drawings xxxxx-980131and xxxxx-980134.

2.2.1 Flanges

Bolts, studs and gaskets for flanges to which purchasers piping or other apparatusconnects are not furnished by Siemens Energy unless noted in the table ofpurchasers connections, or unless the adjacent parts are furnished by SiemensEnergy. Studs, when furnished by Siemens Energy are of suitable length for pipingstandard being used. All bolt holes for circular flanges straddle centerlines unlessotherwise shown.


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2.3 Connection symbol

Connections to be made by purchaser are indicated thus:

X nn(n)

SPG Purchaser

3 PIPING SYSTEM DESIGN REQUIREMENTS

3.1 Contents and Description of the System Diagrams

The system diagrams represent the technical context between components, piping system,instrument & controls, design criteria and the scope of supply. For each interface a numberis given which can also be found in the piping connection list.

3.2 Pipe Size and Pressure Drop

A nominal pipe size (NPS) is given for each pipe on the system diagrams. The NPSrepresents the best size for the volume flow and based on the experience of SiemensEnergy.

The maximum pressure drops are given for pipelines on the system diagrams, where thepressure drops are significant for the working of the system. These pressure drops must

not be exceeded.

If the pipe size has to be changed due to exceeding the maximum pressure drop, SiemensEnergy has to be informed.

3.3 Allowable Pressure and Temperature

On each system diagram a table with the maximum allowable pressures and temperaturesis given for different pipe sections. The pipe designer is be responsible for choosing aproper pipe material for the given pressure and temperature as well as for the adjoiningcomponents.

3.4 External Steam and Water Sources

If external steam and water sources are required which must be provided by the customer,the project specific requirements are included also in the system diagrams and in theSteam Turbine Information Manual. In some cases there are also requirements which mustbe considered for the adjoining systems. For any exceptions to these requirements, thepipe designer must give the reasons for the exception and ask for a written solution.

4 PIPING DESIGN REQUIREMENTS

4.1 Connections to components

The design and fabrication requirements set forth in Sections 5.2.2 below must be

considered especially when using socket welds.


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Where the pipe size is smaller than the component connection the reducer/transitionmay be attached directly to the component

The first increase in the moment of inertia (i.e. diameter and/or wall thickness) must notbe allowed within a 1.5-m (59") zone around the component (see figure 1).

4.2 Forces and Moments

Incorporate those practices necessary for minimizing the forces and moments experiencedby the piping, piping supports, and the equipment to which the piping is connected duringstart-up, transients, and normal operation of the plant.

The piping systems must be sufficiently flexible so that neither overstressing of the pipingnor overloading of attached components occurs.

The allowable forces and moments given in table 1 must be observed for all interfaceswhere no specific forces and moments are given.

4.3 In- and outlet zones for regulating and non-return valves

The correct incoming and outgoing flow is important for the function of regulating and non-return valves. Therefore straight in- and outlet zones in front of and behind the valves mustbe arranged as follows.

Outlet ZoneInlet Zone

[mm]without measurement

[mm]with measurement

[mm]

Regulating Valves 2 X d 3 X d 6 X d

Non-Return Valves 2 X d 2 X d 2 X d

d is a inner pipe diameter.

In particular, the velocity of the medium in the pipe has a significant influence on the size ofthe in- and outlet zones. The distances given above are based on the following velocities:

Liquids: 3 m/sSteam (16 bar): 30 m/sSteam (50 bar): 50 m/sSteam (> 80 bar): 80 m/sGases generally 50 m/s

The required in- and outlet zones may only be decreased when the velocity in the pipe isless than the above given velocities. The reduction of distances of the in- and outlet zonescan be carried out in the same ratio as the ratio of the velocities.

4.4 Vibrations

Vibrations can have several causes such as rotating machines like turbines and motors,flows through piping, valves and fittings etc. To avoid serious damage of welds andmaterial, the piping must be supported by means of dampers and guides wherever there isa hazard that vibration can arise.


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Since it is not possible to anticipate if vibrations occur during the piping design, it isrequired that the piping be checked during commissioning. Special attention must be paidto high-frequency vibrations, because they quickly reduce the endurance strength.

4.5 Draining and Warming of Steam Pipes

Incorporate those practices necessary for the prevention of water damage to the steamturbine(s), see STIM-04.001

Incorporate those practices necessary for the prevention of water hammer. The steamlines shall pitch continuously towards the lowest connection. Is it not possible to avoidlow points, they must be well drained in any case.

Incorporate those features that ensure proper warming and drainage of steam systempiping prior to its placement in operation.

4.6 Piping Slope

The following piping slopes shall be applied:

Minimum slope for all systems: 1 (1/5 inch per foot)

Gland Steam System: preferable 2.5 (1/2 inch per foot)

Drain System: preferable 5 (1 inch per foot)

Lines shall pitch continuously towards drain collection points. The minimum piping slopeshall take into account the thermal expansion of the piping. Pockets or low points must beavoided wherever possible. Valve stations in steam lines must be located, wheneverpossible, so that they are at the high point of the system with the lines pitching away oneither side to drain collection points.

The philosophy, however, must be to pitch these lines as steeply as possible becausewhen main cycle systems are warming up quite often the only driving force available todrain the condensate is gravity. This happens because vacuum exists in the lines as wellas in the condenser. Hence there will be little, if any, pressure differential available to helpdrain these systems. Therefore it is essential that these drain lines are properly pitchedand have the necessary flow passing capability.

If a system is to be continuously sloped in one direction provision must be made, for properdrainage of any valve stations incorporated into the system. Valve stations which willrequire drains must be located as near as possible to the condenser drip leg, or otherpoints of collection.

4.7 Pipe routing

The pipe routing shall be according to the system diagrams. For any exceptions to thisrequirement the pipe designer shall give the reasons for the exception and ask for a writtensolution. It is not permitted to connect lines with different pressure ratings.

4.8 Branch Connections

Branch connections for steamBranch line connections must not be made at the bottom of steam headers becausethey will serve as collection points for condensate.

Branch connections for condensate


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Branch line connections must be made at the bottom of steam headers

4.9 Equipment Accessibility

The piping system designs must provide for accessibility to and ease of dismantling ofpiping, instrument connections, and equipment, and in-service inspection. Piping around

equipment and heat exchangers must be arranged and supported to permit ready accessfor maintenance and inspection.

All regulating valves, shutoff valves, bypass valves, check valves, relief valves andequipment which may require servicing must be located so that they shall be readilyaccessible from permanent platforms or ground level.

4.10 Welded Connections

In general, the steam piping systems must be of all welded construction, except thoselocations where flanged fittings are required for flushing, hydrostatic testing, or steam blow.

4.11 Threaded Connections

Threaded connections on steam piping must only be acceptable where no other connectionoptions are available, and then must be seal welded.

4.12 Piping with vacuum

Threaded connections must not be used for systems that operate below atmosphericpressure. An exception to the preceding is for instrumentation connections to vacuumsystems (e.g., thermowells, etc.). In this case the copper or suitable gasket has to be fitted.

Valves must be equipped with a protection against the ingress of air (e.g. seal water,bellow-seal valve).

4.13 Freeze Protection

If required, those features, such as insulating, heat tracing or draining that protect pipingsystems against freezing must be incorporated into the design. This must be applied for allcomponents inclusive modules and valves, see STIM-12.004.

4.14 Screw Locking

All screwed connections must be secured against loosening.

4.15 Dismantling heights of actuators

If not otherwise mentioned, the following heights for dismantling of actuators must beconsidered.


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Size Required dismantling height

[mm]

DN25-DN50 / NVS 1 NVS 2 160

DN65 DN100 / NVS 2.5 NVS 4 200DN125 DN200 / NVS 5 NVS 8 250

DN250 DN400 / NVS 10 NVS 16 400

5 PIPING SYSTEM FABRICATION REQUIREMENTS

5.1 General

The fabrication, inspection and testing of the piping system shall be per the requirementsof ASME B31.1 or where required according VGB R503 M + VGB R510L and STIM s andTransmittal Drawings.

5.2 Welding

It is the responsibility of the welding contractor to match the weld end of the adjoining pipewith the weld end of the SIEMENS PG component in terms of the weld end preparationaccording to ISO 9692 or ASME B16.25, the inner pipe diameter and the wall thickness ofthe connection. The following have to be taken into consideration:

5.2.1 All connections of SIEMENS PG components are supplied with butt weld ends

5.2.2 Siemens recommends that only butt welds are used. If socket welds are used forpiping which is connected directly to the turbine or to any components forming partof the turbine (such as bearing casings) the following requirements must be

observed:

Socket welds are not be allowed within a 1.5-m (59") zone around thecomponent (see figure 1 ).

The selected wall thickness must be at least twice the value of the minimumwall thickness calculated with Formula (3) in Section 104.1.2 of ASME B31.1.

Piping subjected to pronounced pressure fluctuations (e.g. pressure pulsation) suchas in the case of the control oil module must only be butt welded.

The design engineer must pay particular attention to ensure that pipes carryingflammable fluids (e.g. turbine oil) are sufficiently screened/protected from hotcomponents (such as main steam pipes). With regard to components supplied bySiemens, this could require the implementation of additional measures by thecustomer. This must not affect the functional performance of the componentssupplied by Siemens.

5.3 Pretreatment and Cleaning

All piping must always be treated and cleaned after fabrication at the manufacturer andsite. Since the piping can become dirty through improper storage and/or during assembly,pre-cleaning must be done.


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Every piece of pipe which is prepared for final assembly must be subjected to cleaning.Inner surfaces must be metallic bright, de-scaled and free of contamination (sand, dirt).

Before the actual preparation for assembly the pipe section must be inspected visuallyfor cleanness and damage. If fouling (e.g. rust) can be observed, mechanical cleaningmust be performed.

If several pipe sections are to be jointed together, the individual pipe sections must becleaned. The same applies to pipe sections which must be machined at the site.

Cleaning is necessary by every grinding, cutting lengths as well as every cuttingoperation for nozzles, studs, etc. in a pipe.

Note:Intensive and proper pretreatment and cleaning can reduce the flushing andcleaning time drastically.


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Figure 1: Restrictions for the use of socket welds

Figure 1 shows restrictions for the use of socket welds exemplary on the bearing casing. Theserestrictions are valid for all steam turbine components.

ST- Component(e.g. bearing casing)

ST- Component(e.g. bearing casing)


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Table 1: Allowable forces and moments

For all piping connections where no special allowable forces and moments are given, the values inthe following table must be taken.

THE ALLOWABLE RESULTANT FORCES (FR) ARE BASED ON NEMA STANDARDS SM 24PARAGRAPH-9.4.6, ALLOWABLE FORCES AND MOMENTS ON STEAM TURBINES,

THE ALLOWABLE RESULTANT MOMENTS (MR) ARE BASED ON B31.1 DESIGN CRITERIA,CALCULATING THE EXPANSION STRESS (SR) AS PER PARAGRAPH 102.3.2, EQ.(1), ANDUSING STRESS INTENSIFICATION FACTORS BASED ON AN UNREINFORCED FABRICATEDTEE (APP.D).

THE ALLOWABLE REACTIONS ARE PROVIDED FOR THE STEAM TURBINE OIL, DRAIN ANDGLAND STEAM PIPING CONNECTIONS ON THE TURBINE. THEY ARE BASED ON THENOMINAL SIZE OF THE CONNECTION.

FR MRNominal Pipe Size

DN / NPS Newton Pound Newton-Meter Inch-Pound

DN8 / 0.25 178 40 14 120

DN15 / 0.50 363 80 46 400

- / 0.62 408 90 52 450

DN20 / 0.75 454 100 58 500

DN25 / 1 680 150 115 1000

DN32 / 1.25 907 200 207 1800

DN40 / 1.5 1134 250 288 2500DN50 / 2 1361 300 369 3200

DN65 / 2.5 1814 400 692 6000

DN80 / 3 2268 500 1152 10000

- / 3.5 2722 600 1500 13000

DN100 / 4 3175 700 2305 20000

DN125 / 5 3629 800 2881 25000

DN150 / 6 4536 1000 4610 40000

DN200 / 8 5097 1300 9220 80000

DN250 / 10 6804 1500 13825 120000

DN300 / 12 7258 1600 18440 160000

DN350 / 14 7938 1750 20169 175000

piping Design Requirements for Turbine Systems

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