Wednesday, May 30, 2012

Role of Piping Engineering and Needs of Various Process Industries


Piping engineering is a specialised branch of engineering dealing with design & layouts of piping network along with the Equipments in a process plant.

These layouts from a complete blue print of the plant & are used for plant construction at site. The most important factors to be considered’ are process requirements, safety, operability, maintenance, compliance with statutory requirements & economy.

Piping Engineering

Responsibilities of piping engineer

Responsibilities piping design engineer begin with:

1) Preparation of plot plan, equipment layouts piping studies, piping specification; 
2) Review of process package; 
3) Giving inputs to civil, vessel, electrical / instrumentation groups for various purposes.

Goes through:

1. Preparation of piping layouts, isometrics, support Drawings; 
2. Stress analysis 
3. Procurement assistance; 
4. Preparation of drawings for statutory approvals; 
5. Preview of vendor drawings; 
6. Coordination with various engineering groups & site.

And ends with completion & commissioning of plant.

Responsibilities of piping engineer

Most important documents produced by design engineer:

1) Plot plan: 
Arranging all plant units in a logical manner to take care of Material flow, statutory requirements, & good engineering Practices. -

2) Equipment layouts: 
Document showing layout of all equipments satisfying the Process requirements, safety & statutory Regulations, operability ease of maintenance & economy.

3) Piping layouts: 
Document showing layouts of piping network to carry fluids From one equipment to another in a process plant satisfying The requirements as mentioned above.

Activities of piping design engineer:

Review of process package:

This activity is carried out prior to start the detail engineering to ensure availability of all the required process data by all engineering groups. This includes the following:

1) Process data required converting P & ID’s to piping layouts like a proper identification of valves, strainers, In-line instruments,

2) Utility summery giving utility consumption for each equipment with duty conditions like pressure, temperature etc.,

3) Conceptual equipment layout drawings for process plant reflecting the process constraints.

4) Process data sheets for equipments.

5) Hazardous area classification etc..

Design planning:

Following information is required for planning the various design activities:

1) Contract instructions,

2) Project design basis & scope of work,

3) Basic engineering Documents.

4) Site design data including facilities around the plot,

5) Contour & survey drawing,

6) Applicable codes, standards & statutory regulations,

7) Project schedule & network,

With all this data plan the detail engineering activities.

Basic engineering documents:

These mainly cover the following documents:

·  Plot plan;

·  Equipment layouts

·  Pipe rack study sketches;

·  Study piping layouts;

·  Piping specification;

·  Utility distribution diagrams;

·  Line list & critical line list;

Details engineering documents:

These mainly covers the following documents:

1) Piping layouts drawings;

2) Material take off (MTO / BOM) for piping items;

3) Nozzle orientation for fabricated equipments;

4) Stress analysis;

5) Piping isometric drawings;

6) Piping support drawings;

7) Fire fighting specification

8) Drawings for statuary approvals,

Other activities:

These mainly cover the following documents:

1) Review of drawings for machinery & other brought-outs;

2) Review of drawings for special piping items;

3) Specification for bellows, spring, hangers etc.;

4) Specification for insulation & painting of equipments & piping items;

5) Updation of P&ID’s based on detailed engineering,

6) Scheme for the erection of equipments in consultation with site engineer.

Review of process package 

Review of P & ID’s:

Following information shall be available in P &ID’s:

1) Legends, notes, abbreviations

2) Line numbers;

3) Location of change in piping specification;

4) Specific requirements like slope, elevation difference break flanges. Minimum running length, process drains & Vents type of heating (jacketing /steam i electric heating) etc.;

5) Proper symbols for piping items;

6) Equipments & nozzle numbers;

7) All instrumentation & control valves, etc;

8) Continuation sheet numbers etc.

P & ID

Review of other documents:

1) Utility summary:

This document shall reflect the various utilities consumed by each equipments with duty conditions like pressure, temperate, flow, state of fluid, critical data like freezing point etc.

2) Conceptual equipment layouts:

This document gives the general arrangement of the Equipments considering the process requirements like Inter-distances & approximate elevations of the equipments;

3) Piping material specification:

Basic material for piping items, valve specifications, special, flanges & gaskets required , any other specific requirement.

4) Type of storage required: This document shall mention the state of the fluid & type of equipment to be used for the storage like API Tank, silo, dehumidified atmosphere (warehouse), bullet horizontal / vertical) etc.

5) Hazard classification:

This documents gives the type of hazard for the fluids being handled ( like class a/b/c, flammability toxicity etc.) & the special precautions to be taken care.

6) Future expansion requirements:

These are to be mentioned by the client & to be taken care for the space requirement during the layout stage.

Plot plan

Plot plan shows overall areas & locating co-ordinates of:

1. Process unit 
2. Raw material storages 
3. Finished product storage 
4. Utility generation areas 
5. Pipe racks 
6. Electrical receiving and distribution substation 
7. Facility blocks e.g. Work shop ,weigh bridge, canteen, 
8. Administration lock, security , car/lorry park etc. 
9. Flare system, 
10.Effluent treatment, 
11.Green belt, 
12. Future requirements etc.

Following document are required to develop the plot plan:

·  Plot boundary and contour survey 
·  Access road, rail road 
·  Incoming utilities e.g. Electrical, Power, Water, 
·  Feed stock etc. 
·  Wind direction 
·  Facilities around the plot etc.

Factors to be kept in mind while developing the plot plan:

1. Statutory requirement e.g.
  • factory inspector 
  • chief controller explosives 
  • tariff advisory committee 
  • pollution board 
  • local bodies 
  • aviation authorities 
  • hazardous area classification

2.Site contour, drainage, effluent disposal, plant roads, space for pipe rack, underground lines etc.

3.Process & clients requirements

4.Material movement & workers management

Ensure the following while developing the plot plan:

1) Utilities are closed to process plant to cut down the length of pipes & cable racks

2) Raw material and finished product warehouse / tank ages are close to access road/rail road

3) Utility areas are kept near to each other as utility operators are common.

4) Wind direction taken care of while locating chimneys cooling tower etc.

5) Effluent disposal is towards natural plot gradient

6) Hazardous tank ages are at safe distance from process plant.

Equipment layout

Equipment layout must show the following:

All equipments including tanks, vessels, process Pumps and other rotating machinery giving three locating Co-ordinates.

1) Package items 
2) Pipe racks 
3) Electrical & instrument cable trays. 
4) MCC and control rooms 
5) A/C ducting 
6) Offices & maintenance areas 
7) Building features including columns, beams, walls, floor Openings, staircases, passages etc. 
8) Show tube removal space for heat exchangers 
9) Show monorails lifting bays & hoists etc.

Consideration must be given to the following while

  • Developing equipment layouts 
  • Process requirements 
  • Operations & maintenance requirements 
  • Hazardous area classification 
  • Safety requirements 
  • Factory inspector’s requirements 
  • TAC requirements 
  • Civil requirements 
  • Erection / dismantling requirements 
  • Future provisions

Basic engineering documents

Pipe rack study sketches:

These are prepared taking into account requirements of piping, electrical & instrument cable trays to be routed between various plant areas.

These documents are used by civil, piping, electrical and instrument group to prepare detailed construction drawings.

Study piping layouts:

Prepared to show routing of critical process lines which could affect functioning of plant. This document reviewed by process licensor and forms basis of detailed piping layout drawings.

Piping specifications:

These documents specifies in detail all piping items required for the plant.

Various piping items required for a particular duty condition, depending on type of fluid; line pressure & temperature are listed under one specification class.
  • Utility flow diagram (UFD) 
  • This document is similar to P&ID’s 
  • Prepared based on utility summary 
  • Prepared based on utility summery furnished by process group 
  • Shows utility generation and distribution in the plant.

Line numbering and line list

All process and utility lined appearing in P&ID’s and UFD’s are given unique serial numbers on these documents the operating, design and test conditions, insulation & painting requirements are listed on line list.

Critical line list

All line requiring stress/vibration analysis etc. Are listed in this document

Piping Layouts

Document required to develop piping layout:

1) Equipment layouts 
2) Process P&ID’s 
3) Utility P&ID’S 
4) Line designation list 
5) Piping specification 
6) Equipment data sheets /vendor drawings 
7) Civil drawings 
8) Inline instrument details 
9) Insulation requirements 

Following points shall be kept in mind while developing piping layouts

Process requirements e.g.

Slopes, vents & drains, barometric leg for vacuum lines
  • Instrument requirements e.g. 
  • Straight length for flow measurement 
  • Location of control valves, safety valves, 
  • PLS, TIS, etc. 
  • Safety requirements 
  • Operations & maintenance 
  • Accessibility 
  • Service /hose stations, safety showers

Piping layouts is required by site for construction to prepare isometrics & into instrument group for hook-ups.

Piping layouts must consider

  • Process requirements operations & maintenance requirements area classification
  • Safety requirements factory inspector’s requirements TAC
  • Requirements civil requirements erection / dismantling requirements future provisions.

Stress analysis

Why stress analysis?

Stress analysis is carried out for all lines covered in critical line list. This is to ensure flexibility of lines operating at elevated Temperatures and also to ensure that load on equipment Nozzles is within remissible limits due to expansion of piping. Stress sketches are prepared in isometric form on STD stress sheet showing location of all supports.

Stress analysis ensures

1. Integrity of pipe & piping components against pressure and dead weight. 
2. Flexibility of pipe from thermal expansion. 
3. Safety of nozzles to the connected critical equipments 
4. Proper supporting against dead weight, thermal expansion & occasional loads like & earthquake 
5. Proper selection and specification of special supports like spring hangers and expansion joints.

Stress analysis is carried out for

  • Stress critical lines 
  • Elevated temperature lines 
  • 80 NB & above > 260 deg c. 
  • 150 NB & above> 120 deg c

Jacketted lines

  • Equipment critical lines
  • Lines connected to rotating machinery - pump (API 610), turbine (NEMA - SM23) reciprocating compressor
  • Fired heater (API 560), air cooler(API 661), reformer vessels with brittle linings
  • Analysis to ensure the nozzle loads within stipulated maximum
  • Specified by codes /equipments vendors.

Support critical lines

Two phase flow lines very thick & very thin lines. That is, lines ha ving dia to wall thickness ratio in the range 10 < D/T > 90 relief critical lines. Relief valve discharge lines flare header, liquid blow down lines downstream of bursting disc.

How Stress Analysis is carried out?

Stress analysis is carried out using software like “CAEPIPE” output data is tabulated on stress sketch. A typical stress sketch giving input and output data is enclosed nozzle loadings on equipments is transmitted to vessel /mechanical group for approval if it exceeds permissible limit.


Statutory approvals

Various statutory bodies:

1) Chief inspector of factories 
2) Chief inspector of boilers 
3) Chief controller of explosives
A) Petroleum act & rules ( for storage tanks)
B) Gas cylinder & static & mobile pressure vessel rules
4) Oil industry safety directorate 
5) Tariff advisory committee 
6) Pollution control board 
7) Local bodies ( Municipal / District authority, port authority, Aviation authority, highway authority etc. 
8) electrical inspection 
9) town planning authority.

Responsibility of piping engineering at site

List of the major activities

1) Supervision of fabrication & erection of equipments and piping. 
2) Co-ordination with clients, contractors, & detail engineering office. 
3) Planning & monitorin g the work for timely completion of the project. 
4) Conduct welding procedure & performance qualifications 
5) Assure the quality of work done by contractors. 
6) Maintain QA/QC records. 
7) Assure the lifting equipments tools & tackles are in proper condition. 
8) Check the alignments of equipments. 
9) Assure the work is carried out as per P & ID’s, layouts drawings & isometrics. 
10) Check critical pipe supports 
11) Check visual inspection & radiography of weld joints 
12) Check insulation & painting as per the specifications

Responsibility of piping engineering at site Testing of piping

Witness the hydrostatic / pneumatic

Testing of pipelines as per the procedures commissioning

Mechanical commissioning of rotary equipments and water trial runs of systems
 Piping engineering saving manhours

Computer in Piping Engineering

Software used in piping design & engineering following is the list of little software available in the market:
  • Autocad I Microstation
  • PDS / PDMS ( 3D plant design system)
  • Auto plant / Tata -Cape auto flow
  • Caepipe / Ceaser-II / Triflex

Advantages and uses of various software packages

A) Autocad / Micro Station

1) Useful for piping application:

A) P&ID’s 
B) Plot plans 
C) Equipments layouts 
D) Piping plans 
E) Isometrics 
T) Piping support drawings


A) Replace drawing board 
B) Neat drawings 
C) Fast modifications 
D)Copying of identical parameters

PDS / PDMS ( 3D - Plant Design System)

Salient features

A) 3D software input data via forms & menus

B) 3D model easy conceptualizing of plant layouts

C) On line clash detections

D) Various information obtained PDS/PDMS

• Piping layouts
• Ducting layouts
• Cable tray layouts
• Isometrics & material take-off

E) Customization

F) Various discipline engineers working in their design modules like civil Engineers on structural & piping engineers on piping module etc.

G) Ability to get inputs from various engineering disciplines without fi1ndering their data

H) reporter module

I) Linking to in- house M to program for procurement & line wise report

J) Piping specification in users format

Software for stress analysis

  • Caeser – II
  • Triflex

Advantages of above software

• Time saving, problem which used to consume weeks can be solved within minutes.

• Accurate results

• Can solve problems with number of anchors and number of piping branches which By manual method is unthinkable Can solve problems consisting of occasional loads and various combination of Loads.
  • Network setup
  • Refer enclosed line diagram
  • Giving network component
  • Connectivity both for LAN and WAN

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  1. saale , mit ka course materilas ka CUT COPY PASTE kiya hai , ANU malik kaam BAAP ,, shame on u

  2. bey,, apna kuch article likhna( MIT course materials ka Puttar)



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