Piping Layout UDL

7/26/2019 Piping Layout UDL

1/24

TRAINING MANUAL - PIPING

PIPING LAYOUT

Uhde India Limited

DOC No. : 29040-PI-UFR-0025

Rev. : R0

Page : 1

CONTENTS

Page

0.0 Cover Sheet 1

1.0 Introduction 2

2.0 Piping Studies 2

3.0 Thermal Expansion 3

4.0 Critical Piping 3

5.0 Instruments 3

6.0 Piping Arrangement Considerations 3 10

7.0 The Drawings 10

8.0 Piping Arrangement (Typical Sketches) 11 24

App licable Rev is ion:

Prepared:

Date:

Checked:

Date:

App roved:

Date:

First Edition: R0

Prepared: DNL

Date:

Checked: AKB

Date:

Approved: RUD

Date:

File Name: C- 24 Server: PUNE: KUMUS 207 VKO: KUMUS 209

Directory: PUNE: Refer \ Pi \ Training Manual VKO: Refer \ Training Manual


2/24


PIPING LAYOUT

Uhde India Limited

DOC No. : 29040-PI-UFR-0025

Rev. : R0

Page : 2

1.0 INTRODUCTION:

The arrangement of piping is probably the most important consideration affecting the layout of

petroleum, petrochemical and similar types of plants. The following in general, is the order ofimportance in which piping systems should be considered.

Alloy piping or special materials

Large bore piping or lined pipe.

Low temperature pipe or other piping requiring thick and expensive insulation.

Major headers for utilities or auxiliaries.

The routing of lines involving temperature where expansion and contraction necessitatesflexibility which should preferably be inherent in the layout. Pipe shall be arranged in anorderly manner and routed as direct as possible.

2.0 PIPING STUDIES:

After a basic equipment layout has been developed, piping study drawings shall be made forunits which have sufficient size and scope to warrant further investigation of equipmentarrangements, pipe rack widths and the like.

For units or areas which obviously do not require extensive study due to simplicity of pipinginvolved, the piping layout may be started directly which will eventually be issued asconstruction drawings.

Responsibility for determining whether study drawings are required and the extent to whichthey are to be carried, shall rest with Project Piping Engineer.

The study drawings are intended to serve the following purposes:

To confirm equipment locations for review, comments and/or early approval by variousconcerned departments on the plant layout.

As a basic guide to making model, constructions drawings and isometrics.

To help minimize interferences by showing the structural, instrumentation and electricalgroups the intended piping and equipment arrangements.

To enable the analysis of line expansions and supporting systems.

To enable other concerned departments i.e. Pressure vessel, Civil, Structural, Electrical,

Heat Exchanger, Process Departments to develop their work/check their requirements.

In general, study drawings consist of plans, elevations (where necessary) showing unit pipingarrangement fulfilling all conditions laid down in P&ID manifold locations, platform, elevations,instrumentation etc. And schematic routing diagram of piping piping on the racks. They willalso indicate special requirements like monorails for exchanger bundle pulling or catalystloading etc.

Piping Studies are prepared as line diagrams to form the basis of General ArrangementDrawings and the details shown in the case of piping general arrangement drawings forconstruction are not shown to that extent such as control valve manifolds are shown as ablock, only important elevations and arrangements are shown etc.


3/24


PIPING LAYOUT

Uhde India Limited

DOC No. : 29040-PI-UFR-0025

Rev. : R0

Page : 3

3.0 THERMAL EXPANSION:

Arrangement shall provide for flexibility of lines to take care of thermal expansion andcontraction. Large reactions or moments at equipment connection shall be avoided.

4.0 CRITICAL PIPING:

Where dynamic loading, limited pressure drop, or other severe service conditions apply,particular care be taken while routing the piping.

DYNAMIC LOADING

Dynamic loading may be expected when pulsation flow (such as reciprocatingcompressors), high velocity flow, flashing fluid, fluctuating temperature or pressure ormechanical vibration (including wind) conditions exists.

Piping subject to possible dynamic loading shall be carefully designed and checked to

ensure that the size, configuration, mechanical strength, supports and restraints shallprevent excessive stress or vibration.

OTHER SEVERE SERVICES

Other severe services include erosive, corrosive, high or low temperature or pressureconditions, or any fluids containing solids. Many such services require alloy or other specialmaterials. Piping in these services shall be routed to minimize the effects of service severityand make most practical use of required special materials.

PIPING AT CONTROL VALVES

Special attention must be paid to any control valve which will contribute to excessive noise orvibration due to Aerodynamics which must be carefully analyzed and designed so that its sizeand configuration downstream of the control valve will minimize these conditions. Specialattention should also be paid for Ejector piping and high vacuum piping.

5.0 INSTRUMENTS:

CONTROL VALVE MANIFOLDS

For control valve manifolds arrangement.

ORIFICE RUNS

Horizontal meter runs are preferred. Necessary straight runs upstream and downstreamorifice plates shall be provided in accordance to api rp 550 part1. Sufficient clearance atorifice flange for installation of instrument piping and seal pots, where required shall beprovided.

6.0 PIPING ARRANGEMENT CONSIDERATIONS:

6.1 PIPE WAY ARRANGEMENT:

In general all piping within process area should be run above grade and piping in trenchesis to be avoided. Pipe bridges, racks and supports should be of the simplest form with aminimum of cross bracing or in filling of steel work to give the maximum freedom for piperouting. On complex plant, pipe bridges or racks may contain two layers of pipe work.


4/24


PIPING LAYOUT

Uhde India Limited

DOC No. : 29040-PI-UFR-0025

Rev. : R0

Page : 4

The plant layout determines the main yard piping runs, The first step in yard piping designis careful study of plot plan and flow diagram. There are various shapes of yard pipingarrangements such as L, I, T and combination of various shapes. Pipe-ways shallgenerally be run overhead for on plot units and shall generally not be more than three

decks high.

To facilitate ease of erection and reduce bending moments, heavy lines (very largediameter lines, large lines full of liquid) should be located as close to the stanchions aspossible. Lines that require a constant fall, such as flare should be run on an extension onthe bent stanchions, the extension being varied at each bent to suit the fall.

Hot lines requiring expansion loops should be run on the outside edge of the pipe-way.This will permit the loops to have the greatest depth over the pipe way and it will make iteasier for the loops to be nested.

Take off elevations from pipe ways should be at a constant elevation consistent with therange of pipe size involved. However, header be located on the pipe way on the side from

which the largest number of off takes are made.

Elevation of yard piping is determined by the highest requirement of the following:

1. Head over a main plant road for major mobile equipment,2. Headroom for access to equipment under yard.

The size of steel or concrete supporting yard piping should also be taken in account whenconsidering headroom. Generally those process lines should be located in the top bankwhich interconnect to nozzles elevated higher than top yard bank. Process lines with oneend lower than the bottom yard elevation and other end above yard can be located oneither yard elevation. If both ends of a process line are lower than the bottom yardelevation, they should be located in the bottom bank. The elevation of a line can also beinfluenced by valves and instruments in the line. Often a more convenient access platformcan be provided for valves arranged in the top yard bank. The preferred location of orificeruns is under the bottom bank for more convenient portable ladder access.

Whenever banks of pipe, either at grade or on pipe bridges or on rack change direction, itis advisable to arrange for a change of elevation. This gives opportunity to change thesequence of pipes at each change of direction. However some large bore lines can makea flat turn when entering and leaving yard.

Pipe economy depends primarily on the length of lines arranged in the yard. Fittings andvalves etc. are relatively few as compared to pipe length Fig 1. shows dimensions whichwill influence piping cost from a yard piping layout stand point. The careful selection ofdimensions between the yard and process equipment and pipe length interconnectingequipment on opposite sides of the yard can minimize pipe length. The distance between

pipe rack stanchions and face of the process equipment should preferably be within 2,000to 3,000mm.

It is preferable to layout a long manifold of control and manual valves with the valve stemsall lined up and the entire arrangement stretching for two or three bays, under the pumpalley. However access ways should always be provided at each bay between rows ofpumps or fences of valve manifolds to gain access to adjacent equipment.

The width and number of banks is influenced by :

1. Number of lines, electrical, instrument trays and space for future lines in the yard, or

2. Space requirement for equipment arrangement under piperack.


5/24


PIPING LAYOUT

Uhde India Limited

DOC No. : 29040-PI-UFR-0025

Rev. : R0

Page : 5

The number of lines can be estimated by preparing piping studies in 1:100 scale with thetotal width (W in meter) will be as follows :

W = (F n s) + A

Where,

F = Safety factor = 1.5 if lines have been laid with the help of process flowdiagram.

n = 1.2 if the lines have been laid with fully completed P&IDs.s = 300 mm (estimated average spacing 250 mm then s = 250 mm)

A in meter is the additional width required

1. for lines larger than 450mm O/D2. for future lines3. for instrument trays (about 750mm to 1000mm)for electrical cables (about 750mm to1000mm)

The total width of rack can be 6M or 12 M having two banks (maximum)

The spacing between yard pipe rack should be 5M to 6M. For lines 1 1/2 below,intermediate support shall be provided where large numbers of small lines are involved.Intermediate supporting frame in between two pipe bends shall be provided whererequired for supporting lines 1 1/2 and below.

6.2 TOWER PIPING:

A tower is usually a major part of a designers area. It is advisable to treat it as a centralpiece of equipment and extend the design around this center. Columns, towers andvertical vessels are to be arranged in a row with a common centerline if of similar size. If,

however, diameters vary considerably, lining up with a common face will be found to bebeneficial.

During the initial stage of piping studies, piping designer should investigate in co operationwith vessel designer about the preference of lined up towers with interconnectingplatforms, for convenient operation and maintenance access. The platforms aresupported from towers. In such cases, slight alterations in tray spacing, internal pipingarrangement, skirt height and tower length can help to put all tower manholes on sameelevations. In turn. lined up manholes will help platform arrangement, providing alsocommon access to valve instrument.

When arranging common platforms for several towers in line, allowance must be madefor the differential expansion between towers. Suitably arranged hinges or slots in the

platforms between towers, which introduce flexibility into the platforms shall be provided.All these feature shall be decided at the early stages of design because they affect goodpiping arrangement.

Main work of tower piping is connected with the proper orientation of nozzles andprovision of access to points of operation and maintenance. Generally, platforms ofmanholes shall be utilized for operating and maintenance access for valves andinstruments. Small valves and instruments are usually arranged outside the platforms andare operated from the ladder. Additional platforms are required for operating valves, lineblinds, relief valves (3 and above, orifice plates, transmitter of a level controller andhandling davit.


6/24


PIPING LAYOUT

Uhde India Limited

DOC No. : 29040-PI-UFR-0025

Rev. : R0

Page : 6

The operating aside is usually under pipe rack, so first ladder on tower should be on piperack side. To handle heavy equipment (large size relief valves, large diameter, lineblinds), a davit is usually needed. The davit should be on the side of the vessel away fromthe rack. The area at grade should be kept clear for a dropout. for bigger diameter

vessels, two davits shall be furnished. If it is located at the top of the tower, it can serve aswell for lifting and lowering the top internals to grade. Clearance for the lifting tackle to allpoints which require handling is essential, as also sufficient access and removal space.For reactor feeding catalyst, a permanent trolley beam over the filling manholes is usuallyprovided with adequate access at grade for lifting and removal of the catalyst.

Fig.1 shows plan with segments of its circumference allotted to piping, nozzles, platformsand ladders, in a pattern which leads to a well designed layout. The completecircumference of the tower is theoretically available to arrange the items. Piping should belocated radially as far as possible.

Fig.1 also shows the principal features such as manholes, platforms and pipe runstypically applicable to Tower piping arrangement. Nozzle elevations are determined by

process requirements and manhole elevations by maintenance requirements. Foreconomy and easy supports, piping should drop or rise immediately upon leaving thenozzle and run parallel and as close as possible.

To make the orientation, follow the following steps:

Tray OrientationRight relationship between process nozzles and tower internals is very important. This isoften influenced by reboiler draw off and return nozzles and orientation by flexibilityconsiderations. Changing from one pass to two pass, the two pass trays shall be rotatedthrough 90 deg. to upper trays.

Nozzles & Manholes

Orientation of nozzles depends on the type of distributors and process requirements.Before detailing, details and type of distributors must be known to the designer. Then hecould produce right orientation of nozzles shall be located on tray area and must beaccessible from ladder or platform.

Temperature connections are usually located in the liquid space of tray downcomers. Insome cases, it could be also in vapor space. In front of thermowell nozzles, a clearance ofapproximately 600mm is required to remove thermowell.

Pressure connections are usually located on the vapor space just below the trays. Allinstrument locations are to be confirmed by process department. Care should be takenwith interference such as between two reinforcing pads, one near the other, nozzle baffle

and down comer and weir dams.

Manholes should preferably be placed on road side on tray area so that it is convenientfor removal and lowering to grade of tower internals. Accessibility, whether internal orexternal is very important and is often not given enough consideration. A balance must bemade between the external accessibility of connections from ladders and platforms andinternal accessibility from shell manholes, handholes or removable section of trays.

For example, a shell manhole opening must not be obstructed by internal piping unlessthe piping is removable through the manholes or can be slung clear from an internalhitching point. In either case, the break flange bolts must be accessible from the manhole.

The following considerations must be made at the initial stage of design as they beardirectly on the external arrangement of tower.


7/24


PIPING LAYOUT

Uhde India Limited

DOC No. : 29040-PI-UFR-0025

Rev. : R0

Page : 7

1. Analyze the functions of the internals.

2. Determine the desirable location of the shell connections relative to external

requirements (piping platforms).

3. Layout of the internal piping required to satisfy preferred location shell nozzle and thepreferred tray orientation, and if necessary adjust these to make a workableadjustment.

Platforms, Ladders and Davit

Platforms are considered as work area for manholes and rest area when an intermediatearea is added, if the height between two work platforms exceeds 9 metres.

Generally, layout analysis should be started from the top of the tower and those havingreboilers should be started from the bottom, but with the designer visualizing the layout asa whole. There will be no trouble in dropping the large lines (such as overhead vapourlines) straight down the side of the column. The lower spaces can then be laid out withpiping and nozzles knowing what space is already occupied by these large vertical lines.

Condensers are often located at grade. In such cases, a large overhead lines drop rightalongside the tower to the condenser at grade. Condensers can also be elevated. Anelevated condenser is more convenient from a tower piping layout standpoint because thelarge overhead line leaves the immediate vicinity of the tower at a high level, leaving thelower section open, say, for a ladder from grade to the first platform.

Whether the condenser is at grade or at an elevated level, the flexibility and thermal loadproblems connected with large diameter overhead lines must be considered.

For valves and blinds, the best location is directly at tower nozzles. Valves in branch

connections or at nozzle should be in a position where the line will be self draining on bothsides of the valve. A dead leg over closed valve collects liquid or solids. The trapped liquidcan freeze, or , when opening the valve, without draining the leg, can upset processconditions.

All instruments should be oriented so as not to obstruct the passage way at the ladderexits or entrance. Convenient access and groupings of instruments and valve will helpinspection and plant operation. Instruments should not be located adjacent to manholes.The manhole cover can damage instruments when being swung open duringmaintenance.

The tower elevation is governed by the following:

1. Net positive suction head requirements if the tower bottom line is a pump suction line.This can elevate the tower bottom tangent line.

2. Thermo siphon type reboiler circuit can also elevate a tower.

3. Gravity flow from tower bottom or from an elevated nozzle can also elevate a tower.

4. Head room requirements.

To support the tower at the chosen elevation, a steel skirt down to grade or a combinationof a short steel skirt and concrete plinths will be required.


8/24


PIPING LAYOUT

Uhde India Limited

DOC No. : 29040-PI-UFR-0025

Rev. : R0

Page : 8

Piping around tower shall be spaced taking into consideration the structural design of thesupporting arrangement. Special care should be taken to see that supports for cold linesdo not interfere with the other pipes. For supporting tower piping from tower shell,designer should select proper type . While locating clips, care shall be taken to ensure

that these clips are not located on the circumferential and longitudinal weld seamsindicated in the vessel date sheet.

6.3 EXCHANGER PIPING:

Refer Figures 4 & 5 for the typical Heat Exchanger Piping Arrangement. Piping shall not run inthe way of built-in or mobile handling facilities. Wrench clearance shall be provided atexchanger flanges.

6.4 PUMP AND TURBINE PIPING:

Pump suction piping shall be arranged with particular care to avoid vapor pockets or

unnecessary pressure drop. Eccentric reducers, properly oriented to avoid vapour pockets,shall be used for line size reduction. Figures 7, 8 and 9 show the typical Pump PipingArrangement.

Pump location

Where practical, line up center lines of all discharge pump nozzles.

Access to Pump and Turbines

Piping at pumps and turbines shall be arranged to provide maintenance access aroundpumps and turbines. Removable spool pieces shall be provided as appropriate to permitmaintenance without major disassembly.

Weight and Thermal Stresses

Suitable supports or anchors shall be provided and located for piping to pumps and turbinesso that excessive weight and thermal stresses will not be applied to the casings and accessareas around pumps and turbines are kept free. Careful design consideration shall be given topiping configuration to minimize these stresses.

6.5 COMPRESSOR PIPING:

Large centrifugal or reciprocating compressors shall be on a raised floor design so that pipingand auxiliaries can be located below main operating platform.

Vibration

Particular attention shall be given to design of piping subject to vibration from dynamic loadingassociated with reciprocating compressors. Suctions and discharge lines shall be securelyclamped and small piping around compressors and on the same support as suction anddischarge lines shall be well braced to reduce vibration.

Reciprocating compressor suction and discharge piping shall be run on sleepers at grade, if atall possible. This arrangement permits simple and effective clamping of the lines.

Removable spool pieces shall be provided at compressors where needed to permitmaintenance without major piping disassembly.


9/24


PIPING LAYOUT

Uhde India Limited

DOC No. : 29040-PI-UFR-0025

Rev. : R0

Page : 9

Suction piping to centrifugal compressors should be designed to allow sufficient straightlength i.e. 5 D minimum of pipe immediately ahead of suction nozzle, to allow dissipation ofundesirable flow distortion caused by elbows, valves, or other fittings upstream and velocity inline.

6.6 BURNER PIPING AT FIRED HEATERS:

Burner piping shall be kept clear of all access and observation openings. Adequate spacefor removal of heater tubes shall be kept for its maintenance. Piping to the burners shallbe made using unions, flexible connectors to provide for easy and convenient removal ofburners for maintenance

Supply piping of fuel gas shall be arranged for equal flow distribution and shall beprovided with condensate leg, knockout pots or other approved methods for the collectionand elimination of condensate.

6.7 OFFSITE AND YARD PIPING:

Offsite

The various systems involved in Offsite piping are as below:

Raw product import and its storage

Intermediate / finished product storage

Product Dispatch / loading facilities

Utilities

Various system of utilities are as below:

Steam, condensate and boiler feed water system. Compressed air system

Service (plant) air

Instrument air

Cooling water system

Caustic soda system

Flare system

Fire protection system

Storage Tank

There are mainly two types of storage tanks:

Cone roof tank Floating roof tank

Tank dyke or Tank Farm

Storage tanks are grouped in the dykes which are like earthen dams all around a group oftanks. The design of these dykes is governed by the regulation of the chief inspector ofexplosives who approves the design and arrangement of tank farms and overall plant safetyand fire protection system. There are numerous safety regulations out of which pipingdesigner must know

Tank spacing on the basis of product classification.

No support, electrical or any other installation shall be allowed in the tank farm other thanthose connected with particular tanks.


10/24


PIPING LAYOUT

Uhde India Limited

DOC No. : 29040-PI-UFR-0025

Rev. : R0

Page : 10

The tank dyke height shall not exceed more than 2 m

Pumping Station

Normally three types of pumping facilities are provided as follows:

Feed charge pumps

Intertransfer pumps

Loading pumps

1. Try to group the pumps of common service together at one location2. Pumping station should be accessible from road.3. Sufficient space around pump should be kept for operation and maintenance.4. Pump leakage and dripping of valves should be connected to underground drainage

system.

Yard Piping

In Offsites, piping are run on concrete sleepers, which are minimum 300mm high from thegrade level. The span between two sleepers should be minimum 5m irrespective of sizes ofpipes.

The underground facilities such as cooling water header, effluent collection lines, servicewater lines, drinking water lines, sanitary effluent lines, electrical cable trenches, street lightcable trenches, storm water drains, etc. are run close to the road.

An overall study of pipe routing diagram must be prepared carefully because an improvementin this can save a large amount of piping. Using various piping standards of pipe spacing, thewidth of the sleeper is determined. A final figure is arrived at by adding 20 to 30 % morespace which should be kept as a future expansion provision. Pipe-way bridges for crossingthe road are also determined by the study. Once the routing of various lines is finalized, thenext step is to decide the relative elevation of pipe sleeper, tank pad and pumping station.

Suction lines must be self draining towards the pump and at the same time, the pipe sleeperelevation should not exceed beyond certain limits so that the jump at road crossing is avoided.The sequence of lines should be adjusted in such a way that there are minimum bends and

jump overs.

Tank Farm Piping

Whenever there is common inlet and outlet of the tanks, there will be a valve manifold, whichconnects incoming and outgoing lines. These manifolds should preferably be located outsidethe tank farm and approachable from the road. Valves operating platform and cross overshould be provided wherever found necessary for operational ease.

Some times, because of excessive tanks settlement, the piping at tank connections are

overstressed. As such, these pipings are to be analyzed thoroughly. Over stressing of pipetank connection can be avoided by placing first pipe support sufficiently away from tanknozzle.

7.0 THE DRAWINGS:

The piping general arrangement drawings prepared considering all the above aspects are thedrawing for constructions.

In order to have ease in construction, isometric drawings of each one are prepared based onthe general arrangement drawings. Isometrics are drawn proportionally only and are not toscale. The isometrics form the basis for fabrication of piping. Normally, 2 and above lines arecovered by isometrics.


11/24


PIPING LAYOUT

Uhde India Limited

DOC No. : 29040-PI-UFR-0025

Rev. : R0

Page : 11

8.0 PIPING ARRANGEMENT (TYPICAL SKETCHES):

FI GURE - 1


12/24


PIPING LAYOUT

Uhde India Limited

DOC No. : 29040-PI-UFR-0025

Rev. : R0

Page : 12

FIGURE - 2


13/24


PIPING LAYOUT

Uhde India Limited

DOC No. : 29040-PI-UFR-0025

Rev. : R0

Page : 13

FIGURE - 3


14/24


PIPING LAYOUT

Uhde India Limited

DOC No. : 29040-PI-UFR-0025

Rev. : R0

Page : 14

FIGURE - 4


15/24


PIPING LAYOUT

Uhde India Limited

DOC No. : 29040-PI-UFR-0025

Rev. : R0

Page : 15

FIGURE - 5


16/24


PIPING LAYOUT

Uhde India Limited

DOC No. : 29040-PI-UFR-0025

Rev. : R0

Page : 16

FIGURE - 6


17/24


PIPING LAYOUT

Uhde India Limited

DOC No. : 29040-PI-UFR-0025

Rev. : R0

Page : 17

FIGURE - 7


18/24


PIPING LAYOUT

Uhde India Limited

DOC No. : 29040-PI-UFR-0025

Rev. : R0

Page : 18

FIGURE - 8


19/24


PIPING LAYOUT

Uhde India Limited

DOC No. : 29040-PI-UFR-0025

Rev. : R0

Page : 19

FIGURE 9


20/24


PIPING LAYOUT

Uhde India Limited

DOC No. : 29040-PI-UFR-0025

Rev. : R0

Page : 20

FIGURE - 10


21/24


PIPING LAYOUT

Uhde India Limited

DOC No. : 29040-PI-UFR-0025

Rev. : R0

Page : 21

FIGURE - 11


22/24


PIPING LAYOUT

Uhde India Limited

DOC No. : 29040-PI-UFR-0025

Rev. : R0

Page : 22

FIGURE - 12


23/24


PIPING LAYOUT

Uhde India Limited

DOC No. : 29040-PI-UFR-0025

Rev. : R0

Page : 23

FIGURE -13


24/24


PIPING LAYOUT

Uhde India Limited

DOC No. : 29040-PI-UFR-0025

Rev. : R0

Page : 24

FIGURE - 14

Documents

Piping Layout UDL