Process Control Specification for Packaged Equipment

1. Scope – This Article describes process control requirements for packaged equipment and design guidelines to ensure installation, operating, and maintenance objectives.

2. Packaged Equipment References

References are made in this article to the following documents. 

D02-D02 Engineering Tools and Data Structure
G19-S01 Machinery Protection System
R01-E01 Field Instrumentation Design Criteria
R07-E01 Selection of Control Valves
R07-E03 On Off Valves
R08-E01 Process Analyzer System Design Criteria
R10-S01 Specification for Instrument Piping, Tubing and Material
R11-C01 General Instrument Installation Criteria
R11-C02 Standard Installation Drawings-Instrumentation
Control System Design Criteria
Safety Instrumented System Implementation Guidelines
Programmable Logic Controller Specification
Supervisory Control and Data Acquisition System Specification

X05-E01 Process Control Cabling and Wiring
X05-S02 Local Control Panel Specification

3. Abbreviations and Acronyms

DCS – Distributed Control Systems
RIB – Remote Instrument Building
RTD – Resistance Temperature Detector
SIS – Safety Instrumented Systems
SCADA – Supervisory Control and Data Acquisition System

4. Process Control Specification for Packaged Equipment 

4.1. General Information

4.1.1. Process control systems shall be specified in sufficient detail to provide the means for proper installation and to ensure a design that will provide the operating department with a reliable and maintainable control system.
4.1.2. It is Client intent to standardize on the variety of process control vendors within a plant. To accomplish this, all vendors of packaged equipment shall conform to this requirement as close as possible. The exception being that some packaged equipment requires specific instrumentation which is unique for the application. In that case approval shall be obtained prior to implementation.

5. Packaged Equipment Design Considerations and Specifications

5.1. Control Systems

5.1.1. Packaged equipment shall be monitored and controlled from DCS.
5.1.2. If independent control sub-systems are required, such as PLC based systems, Company approval shall be obtained. These systems shall be connected to DCS for monitoring from control room.
5.1.3. Refer to Programmable Logic Controllers (PLC) Specifications for the specification of PLC systems.
5.1.4. Refer to Supervisory Control and Data Acquisition System (SCADA) Specification for the specification of SCADA Systems to establish user interface in case DCS will not be the main control platform.
5.1.5. Normally Vendor shall provide standard PLC logic and narratives for process control functions, if PLC is approved by SABIC as control system. Vendor shall review and approve the documents if the implementation is done by others.

5.1.6. Control system spare capacity shall be specific to project.
5.1.7. All packaged equipment safety interlocks shall be implemented in SIS. Vendor shall provide logic diagram, narratives and other required documents to implement safety functions in the SIS. Final configuration and programming shall be reviewed and approved by vendor if the implementation is done by others.
5.1.8. Vendor shall physically segregate control and safety functions. Refer to Control System Design Criteria and Safety Instrumented Systems Implementation Guidelines for details and descriptions.
5.1.9. Process control and safety applications shall use separate transmitters with separate connections to the sensing point.
5.1.10. For machinery protection system requirements and details refer to SES-G19-S01.

5.2. Field Instruments

5.2.1. Field instruments shall be in accordance with SES-R01-E01.
5.2.2. Electronic transmitters shall be smart two-wire types, of high accuracy, with full digital communication.

5.2.3. Sunshade shall be provided to protect instruments from direct sunlight, refer to SES-R11-C02.
5.2.4. For instrument process connection refer to SES-R11-C01.

5.3. Analyzers

5.3.1. Analyzers and shelters shall be provided in accordance with SES-R08-E01.
5.3.2. As a minimum, templates for analyzer/shelter data sheets shall be as per SES-D02-D02 EDDMS seed files.
5.3.3. Vendor shall develop analyzer package and get SABIC approval prior implementation.  
5.3.4. Analyzers necessary for efficient operation of the unit, or required by environmental and safety regulations, shall be furnished or recommended by the packaged equipment vendor.  
5.3.5. Analyzers mounted near the sample point shall be properly protected from the environment and physical abuse. Vendor shall furnish analyzer, sampling system, and rack as per SES R08-E01.

5.3.6. Analyzer operation shall not be affected or compensated by ambient or sample temperature fluctuations, or barometric or sample pressure changes.
5.3.7. Vendor shall select all material suitable for sample stream content, surrounding atmosphere, and line specification.
5.3.8. Analyzer installations and shelters shall not cause obstructions and encumbrances to other equipment.

5.4. Temperature Instruments

5.4.1. All temperature instruments shall be provided in accordance with SES-R01-E01.
5.4.2. Thermowells shall not be located upstream of orifice assemblies.
5.4.3. In vertical lines above rotating equipment, thermowells shall be located such that in the case of failure of the thermowell, process fluid or instrument devices will not fall into the rotating equipment.

5.5. Level Instruments

5.5.1. All level instruments shall be provided in accordance with SES-R01-E01.

5.6. Flow Instruments

5.6.1. All flow instruments shall be provided in accordance with SES-R01-E01.

5.7. Pressure Instruments

5.7.1. All pressure instruments shall be provided in accordance with SES-R01-E01.

5.8. Control Valves

5.8.1. All control valves in throttling service shall be provided in accordance with SES-R07-E01 and control valves in on-off service shall be provided in accordance with SES-R07-E03.

5.9. Instrument Air

5.9.1. If instrument air is required to any skid mounted instruments, vendor shall install one air header on the skid for instrument air distribution.
5.9.2. Each air user shall be provided with a shutoff valve, a filter-regulator and a piped output pressure gage. Volume booster shall be provided where needed to reduce valve stroke time.  

5.9.3. For instrument air lines installation refer to SES-R11-C01.
5.9.4. In general, clean, dry instrument air with a dew point of minus -40 deg C shall be supplied to the packaged equipment.
5.9.5. For piping, tubing and materials for instrument air refer to SES-R10-S01.

5.10. Wiring and Enclosures

5.10.1. The skid mounted packaged equipment shall include junction boxes installed at the edge of the skid for instrument’s signal connections.
5.10.2. Refer to SES-X05-E01 for process control cabling and wiring.
5.10.3. If 230 Vac power supply is required to any skid mounted instruments, vendor shall install one power distribution panel on the skid and shall be responsible for distribution of power to instruments on the skid. Each instrument requiring 230 Vac shall have a breaker to isolate it from all other instruments for maintenance. Manually selectable 127/230 Vac power supply units or equipment shall not be used.
5.10.4. For local control panels furnished with packaged equipment refer to SES-X05-S02 for details and descriptions.
5.10.5. With extreme environmental conditions as stated, all instrument enclosure shall be properly ventilated and air conditioned for the proper function of the enclosed instrumentation.

5.11. Instrument Installation

5.11.1. All instruments shall be installed according to the vendor’s instructions, and SES-R11-C01.
5.11.2. All instrument pipe and tube materials shall be provided in accordance with SES-R10-S01.

6. Tagging

6.1. All instruments, panel mounted devices, junction boxes, enclosures, cabinets, etc provided by vendor shall have tag numbers and name plate. Refer to SES-R11-C01 and SES-X05-S02 for details and descriptions.

7. Inspection and Testing

7.1. Vendor shall inspect, check and test all instrumentation to verify full compliance with the drawings and specifications listed in the purchase order. Each Company reserves the right to inspect and witness testing of all instrumentation and electrical wiring prior to shipment from vendor’s factory.

7.2. Vendor shall notify normally three weeks in advance of any scheduled acceptance test. Prior to the acceptance test and checkout by inspector, vendor shall have completely tested all instrumentation and control systems and made appropriate corrections if required. Vendor shall certify all test documents after the acceptance checks.

8. Documentation

8.1. Vendor shall be responsible for updating and providing as built documentation after the system is installed and commissioned.
8.2. Refer to Control System Design Criteria for documentation details and descriptions.

9. Shipping

There is some general methods for shipping of packed equipment related to control system.

9.1. Any instrument that shall be removed from the equipment prior to shipment shall be tagged and boxed separate from any mechanical parts or equipment. The container shall state the following: “Attention: Instrument Warehouse”

9.2. Owner’s shipping address, purchase order number, and other pertinent information stated in the purchase order shall be included on each package. An index of “shipped loose” items shall be prepared by the Vendor and submitted for Owner review, prior to shipment.

9.3. Control panels shall be shipped as a unit, completely assembled and wired to terminal strips with necessary instrument housings, controls and related equipment. Instruments shall be installed as necessary for panel checkout. Any slide-in or slot-mounted instruments shall be removed and placed in the original or superior packing for shipping.

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