INSTRUMENTATION AND PROCESS CONTROL ENGINEERING DESIGN FOR INDUSTRIES

This article provides general information about step by step process of Instrumentation and Process Control Detailed Engineering for industries. Detailed Design Engineering activities are used for designing Instrumentation and Process Control systems for Oil and Gas, Power plants, Refineries, Petrochemicals, etc. Instrumentation and Process Control Engineering design process starts from providing inputs to the Piping Instrumentation diagram to Vendor documents review and approval.

The main documents and drawings as part of the Engineering Design field are as follows,

1. Piping and Instrumentation Diagram

2. Operating and Control Philosophy

3. Control narrative

4. Instrument index

5. Input-output list

6. Specification for Field instruments

7. Datasheet for field Instruments

8. Specification for Control and safeguarding systems

9. Specification for Fire, smoke, and gas systems

10. Technical bid evaluation

11. System Architecture drawings

12. Loop drawings

13. Instrument junction box termination details

14. Marshalling cabinet termination details

15. Instrument cable routing layout

16. Cable schedule

17. Control room layout

19. Cause and effect matrix- Emergency shutdown systems

20. Cause and effect matrix- Fire and gas systems

21. Electrical and pneumatic hookups

22. Instrument cable specification

23. Vendor documents

24. Material take off

25. SIL Studies

Instrumentation and Process Control Engineering design for Industries

Oil and Gas, Power plants, Refineries, Petrochemicals, etc use Instrumentation and process control systems for monitoring control and safeguarding their equipment and process.

The stages of the Project are as follows

1. Concept Engineering

2. Basic Engineering Design

3. Detailed Design Engineering / Engineering Procurement and Construction (EPC) 

Concept Engineering

This is the initial stage of the project where the Client does research about the project such as Power Plant, Refinery, or Oil and gas field development. During this stage, the client will do a study about financing, economic and technical feasibility. The basis of design documents is prepared by Process Engineers. Instrumentation and Process Control Engineers provide basic initial details about the Control system and field instrumentation requirements. Some clients ask for costing also. In that cases, Instrumentation Engineers provide costing based on their previous project experiences. 

Basic Engineering Design

During this stage, a clear idea of the project will be formed. In this stage of the project, all disciplines of Engineering such as Civil, Electrical, Mechanical ( Piping, Static, Rotating equipment ), Process, Instrumentation and Process Control, Project Engineering, etc will have their documents and drawings developed and ready to use for Detailed Design of the project

Detailed Engineering Design / Engineering Procurement and Construction (EPC)

During this stage of all disciplines of Engineering such as Civil, Electrical, Mechanical ( Piping, Static, Rotating equipment ), Process, Instrumentation and Process Control, Project Engineering, etc will develop their documents and drawings ready for procurement and construction. These documents will be used for procurement of Instruments , Control and safeguarding systems, etc. The drawings prepared during this stage will be used for the construction, commissioning, and start-up of the project.

Documents and Drawings for Instrumentation Detailed Engineering

The following documents and drawings are to be prepared for Instrumentation Detailed Design Engineering.   

Instrument Index

This is the basic document prepared as part of Detailed Engineering. This document will be prepared based on the Piping and Instrumentation diagram (P&ID) developed by Process Engineers. All Instruments, valves , Analyzers, etc will be listed in this document. From this document the total number of Instruments, type of Instruments, location of Instruments, size of instruments / valves etc can be identified. This documents will undergo revisions based on changes on Piping and Instrumentation diagrams , may be it will be addition or deletion of Instruments or change of type of instruments etc. This document will be updated regularly by Instrumentation Engineer during detailed design phase of the project.

Instrument Input output list

In this document all Instrument the following will be listed

1. Signal types such as Analog Input, Analog output, Digital input, Digital output etc.

2. To which system the instruments are connected like Control system, Emergency shutdown    system or fire and gas system.

3. Set points

4. Calibrated range

5. Area classification

This document will be used to calculate how many number of Input output cards are required for control or safeguarding system.

Technical Specification of Field Instruments and Valves / Control systems

Technical specification of Instruments and valves will mainly include the following

1. Project Description

2. Items to be supplied by Vendor

3. Inspection and testing of Instruments / Valves requirements

4. Material certifications requirements

5. Spare requirements

6. Training requirements

7. Standards to be followed

8. Documents to be submitted by the vendor

This document will be used for procurement and part of the Request for quotation send to vendor.

Data sheet for Field Instruments and Valves

Data sheet will mainly specify the following,

1. Type of Instrument or Valve

2. Process data's such as Pressure, temperature, Viscosity etc

3. Material of construction of body, sensor etc

4. Construction details of Instruments / Valves

5. Accessories requirements

6. Certifications required

7. Hazardous area classification

This document will be part of Request for Quotation which is send to vendor

Examples of data sheets are given below

Technical Bid Evaluation

Technical bid evaluation by the following steps,

1. Based on request for quotation vendor sends their technical and commercial offer

2. Technical offer will be reviewed by the Engineering team ( Instrument Engineers)

3. Technical queries will be send to vendor for clarification

4. Bidder will reply to the technical queries

5. If the reviewing Engineer finds the replies from the vendor satisfactory, then queries will be closed. If more clarification is required then the next cycle of clarifications will be send back to the vendor again and sometimes meetings will be arranged to get clarification on queries.

6. After clarification of queries Instrumentation Engineer will prepare a technical bid evaluation sheet comparing all the vendors who have submitted offers and ranking will be given based on offers and technical offers. 

7. Technical bid evaluation sheet will be send to procurement team for the next process

8. Procurement team will evaluate the commerical offer and based on technical bid     evaluation, procurement order will be placed to the successful bidder  

Vendor document review

Vendor document review is done by the following steps,

1. Based on the procurement order meeting will be conducted with the successful bidder to     finalize the documents to be reviewed by the technical team

2.Vendor documents will be reviewed by Instrument Engineers and comments will be send to vendor to clarify or incorporate.

3. Vendor will either incorporate or clarify comments and send them back to Instrument Engineer.

4. If the Instrument Engineer is satisfied with the reply from vendor, the vendor document gets approved.   

System Architecture drawing

System Architecture drawing will have the following details

1. Control system / Emergency shutdown systems / Fire and gas systems 

2. Field Instruments connected to systems mentioned above.

3. Communication with other systems such as Electrical switchgear, HVAC etc

4. Network components 

5. Communication with corporate LAN

This drawing will be part of Control / safeguarding systems request for quotation. Based on this drawing and specification system vendors prepare their proposal.

Loop drawings

Loop drawing represents the connection between Field Instruments and Control systems.

The following details will be in loop drawings

1. Cable connection between Field Instruments and field Junction boxes  

2. Terminal numbers at field instruments and junction boxes

3. Cable number of connected field cable between field instrument and junction box

4. Cable connection between field junction box and marshalling cabinet 

5. Terminal numbers at field junction box and marshalling cabinet

6. Input-output card details such as Channel number, rack number, slot number etc

Instrument junction box termination details

This drawing will include the following details

1. Field cable number for connection between field instruments and junction boxes   

2. Terminal numbers for connecting field cable to junction box

3. Multicore cable number and termination details from junction box

Marshalling cabinet termination details

This drawing will include the following details

1. Multicore cable number and termination details from junction box

2. Terminal numbers for connecting multicore cable at marshalling cabinet side

Marshalling cabinet will be located in the Control building.

Instrument cable routing layout

This drawing shows the following details

1. Field cable route from Instrument to junction box

2. Multicore cable route from the field junction box to control room

Electrical cable crossings, underground piping, underground facilities should be thoroughly checked to avoid fouling during Instrument cable routing. 

Instrument cable schedule

This document will have details as mentioned below

1. Cable from Instrument to junction box

2. Cable from the junction box to control room

3. Type of cable used

4. Length of cable

Control room layout

The control room layout will have the following details

1. Panels such as Control system, Emergency system, Fire and gas panels, etc

2. Location of panels

3. Dimension of panels

4. Location of Human-machine interface

Cause and effect diagram - Emergency shutdown system

This document will have the following details

1. Initiators like Pressure signal high high

2. Final control elements like Emergency shutdown valve

Cause and effect diagram - Fire and Gas system

This document will have the following details

1. Initiators like Fire, smoke and gas detectors

2. Output devices like flashing beacon, sounders, etc

Electrical and Pneumatic hookups 

This document will have the following details

1. Electrical connection to the instrument and junction box, It will indicate cable glands, cable type, installation requirements, etc

2. Instrument tubing, connectors, Installation requirements of transmitter, panels, etc

Material take-off 

This document will have the following details

1. Specification and quantity of installation materials.

2. Quantity of cable glands, impulse tubing, tube fittings, civil foundation requirements, support stands etc