What are the Design Basis Guidelines for an Oil & Gas Industrial Instrumentation Project

General Requirements

The instrumentation must adhere to established engineering practices and procedures outlined in this specification and any other pertinent specifications for the project.

Instruments must undergo review by the Company to ensure compatibility with the Project Specification in terms of design, operability, and maintenance. Only instruments with proven design must be used, emphasizing reliability and appropriate materials.

Process fluids, steam, or water must not be directly measured in local control panels or the central control room; instead, measured variables must be transmitted electronically.

For remote indication and/or control, signals must be converted to electrical signals (4-20mA) at 24VDC for transmission; no pneumatic signals should be sent to the central control room.

Unconventional or unique instruments or instrumentation design practices should be avoided; standardization should be maintained wherever possible.

All measuring instruments should have over-range protection whenever feasible.

Instruments must be made of high-quality materials and manufactured under recognized quality control programs.

Instrumentation should be installed on skid modules whenever possible, including all necessary connections and wiring to junction boxes.

Instruments should be pre-calibrated and function tested in the Vendor’s shop prior to export packing; for PLC-controlled units, Factory Acceptance Testing must be conducted, with the option for the Purchaser to witness at their own cost.

Preferably, PLCs should be used in Vendor packages involving sequence and process control, communicating with DCS and ESD systems via specified protocols.

Vendor-provided drawings must accurately depict field instrumentation installation details, including a Bill of Material, with each drawing representing typical installation details for multiple tagged instruments.

All tube fittings must be 316SS Swagelok or equivalent, with other bulk materials accurately described in terms of material, size, pressure, and temperature ratings.

Flow and pressure transmitters should be line-mounted whenever possible to minimize errors, but accessibility must be ensured.

Instruments in vapor or gas service should be mounted above the sensing point, while those in liquid service should be mounted below; exceptions apply for pressure gauges.

Canopies must not be provided for local control panels; sun shades must be provided for Analyzers and RTU Panels.

When indoors, all vent ports of instruments and regulators using instrument gas must be vented outside the building.

Instruments, associated components, and connections must be installed according to approved installation drawings.

Local control pneumatic instruments should generally have output signals of 3 to 15 psi; electro-pneumatic devices should receive 4-20mA signals from the PLC system.

Instrumentation and control systems should be designed for simplicity, reliability, and minimal maintenance.

Field-mounted instrument housings and exposed parts must be weatherproof and explosion-proof where necessary.

All proposed plastic components, along with toxicity and fire hazard details, must be specified in the Vendor’s quotation.

The project piping specification must determine process connection sizes, types, and ratings for various instruments.

Special attention must be given to material selection for instruments when dealing with highly corrosive fluids or sour service.

All instrumentation and control systems should be designed to operate in a fail-safe mode.

Instruments and components must be carefully selected to suit internal fluid conditions and environmental factors

Packaged supplies must ensure instruments or their connections do not extend beyond the skid limits.

Instrument parts must withstand the corrosive properties of the process fluid they are exposed to.

Seals and purges should be employed as needed to guarantee reliable instrument performance.

Process fluids, steam, or water must not be directly measured in local control panels or the central control room; instead, measured variables must be transmitted electronically.

For remote indication and/or control, signals must be converted to electrical signals (4-20mA) at 24VDC for transmission; no pneumatic signals should be sent to the central control room.

Unconventional or unique instruments or instrumentation design practices should be avoided; standardization should be maintained wherever possible.

All measuring instruments should have over-range protection whenever feasible.

Instruments must be made of high-quality materials and manufactured under recognized quality control programs.