Planned and unplanned shutdowns occur periodically in many processing and manufacturing industries, including Louisiana refineries. Process technicians and instrumentation (I&C) technicians inspect, calibrate, repair, and replace critical control and measurement devices during plant shutdowns or turnarounds. Technicians typically perform the following plant turnaround activities during these periods. Contact ITI Technical College today for more information.
Plant Turnaround: Isolation And Safety
Isolation and safety during a plant shutdown is the critical process of cutting off, locking out, and verifying the zero-energy state of all power, chemical, and mechanical sources before workers perform maintenance.
During scheduled plant turnaround activities, many non-routine tasks occur simultaneously. Managing these hazards protects employees and contractors from sudden startups, toxic leaks, or electrical shocks. These are the typical technician activities:
Key Types of Isolation
- Electrical: Shutting off breakers, pulling fuses, and applying Lockout/Tagout (LOTO) devices to stop live currents.
- Mechanical / Energy: Blocking moving parts and bleeding down hydraulic, pneumatic, or spring tension.
- Process / Pipeline: Closing valves or installing solid metal blind flanges (spades) to stop hazardous chemicals, steam, or gases from entering a work zone.
Steps in the Safe Isolation Process
- Identify: Find every single energy source connected to the target equipment, including upstream and downstream feeds.
- Shut Down: Turn off the machinery using standard operating steps.
- Isolate: Disconnect lines, close valves, and open switches.
- Lock and Tag (LOTO): Place personal padlocks and dated warning tags on every isolation point so no one can re-energize the system.
- Release Stored Energy: Drain remaining liquids, vent trapped gas, or ground electrical capacitors.
- Verify: Test the equipment (try to start it or check voltage/pressure gauges) to prove it is dead.
Disconnection and Removal Are Next
Disconnection and removal are the safe separation, dismantling, and extraction of machinery, utilities, or components from a facility during a planned operational pause. Process and instrumentation technicians take many key steps and actions at this time. They conduct isolation and de-energization where systems are shut off, locked out, and tagged out (LOTO) to ensure no electrical, chemical, or mechanical energy remains.Fluids, gases, and hazardous materials are cleared from pipes, tanks, and circuits during purging and draining. Mechanical and electrical disconnection follows where wires, conduits, bolts, and physical couplings are unfastened and labeled for tracking. Heavy rigging and lifting teams move components out of the facility for scrap, relocation, or replacement during dismantling and extraction.
Disconnection and removal steps matter for safety, efficiency, and asset protection. They prevent accidental exposure to live power, toxic chemicals, or falling heavy loads. Efficiency is maintained by keeping retrofit or maintenance timelines on schedule so the plant can restart without delay. Assets are protected by removing equipment properly if it is meant to be resold or reinstalled elsewhere.
“Process and instrumentation (I&C) technicians inspect, calibrate, repair, and replace critical control and measurement devices during a plant shutdown or turnaround.” |
Plant Turnaround: Calibration and Maintenance
Plant turnaround activities also include critical inspection, calibration, and overhaul tasks that process and instrumentation technicians perform because they cannot be done while the facility is running, such as:
Calibration Tasks
- Transducers and Sensors: Test and recalibrate pressure, temperature, level, and flow transmitters to ensure sure readings match exact process standards.
- Control Valves: Inspect, stroke, and recalibrate pneumatic or electronic control valves, checking for seat leakage and actuator response.
- Safety Interlocks: Simulate safety logic, emergency shutdowns (ESD), and alarm trips to verify that protective systems will trigger correctly.
Maintenance Tasks
- Overhauls and Repairs: Disassemble, clean, and rebuild pumps, compressors, and heat exchangers, replacing worn seals, gaskets, and bearings.
- Isolation and Safety: Execute Lockout/Tagout (LOTO) procedures to ensure vessels, piping, and electrical circuits are fully depressurized and safe for entry.
- Loop Checks: Verify complete control loops from the field sensor through the PLC/DCS system to the final control element.
Pre-Startup Verification
- As-Left Documentation: Record all calibration data, component changes, and maintenance logs into the computerized maintenance management system (CMMS).
- System Handover: Clear tags, remove isolation, and perform dry runs or cold commissioning with operations before the plant restarts.
How Technicians Handle Reinstallation and Loop Checks
Process technicians and instrumentation specialists handle reinstallation and loop checks during plant startups by methodically verifying documentation, physical connections, and end-to-end signal integrity before introducing process fluids. They go through a reinstallation phase and a loop check phase.Technicians match current loop drawings, P&IDs, and Distributed Control System (DCS) configurations against device nameplates before doing any physical work with a document review. A physical inspection is next, where devices are checked for correct orientation, secure mounting, clean inner surfaces, proper gaskets, and correct instrument tagging. Techs conduct a utility purging and power-up by clearing pneumatic lines of moisture or debris, and electrical circuits are energized while verifying proper voltage output (such as 24VDC) to prevent equipment damage.
A loop check phase follows with continuity testing where multimeters with de-energized circuits confirm wiring integrity and rule out shorts or open circuits. A loop calibrator injects known baseline signals (like 4-20 mA or 0-10V) at the field terminal to verify that the control room display matches the physical input. Control loops are placed in manual mode to test final control element functioning (such as opening and closing control valves from 0% to 100%) and verify physical feedback response. Results, scaling parameters, and alarm setpoints are logged on loop sheets for quality assurance and regulatory compliance for sign-off and handover. Learn more about instrumentation careers in Louisiana’s energy sector.
Pre-Startup Verification Is The Last Step
During the Pre-Startup Verification (or Pre-Startup Safety Review / PSSR) phase of a plant shutdown, process technicians act as the last line of operational defense to ensure equipment, safety systems, and piping are completely ready and safe to re-energize or introduce process fluids. Key Responsibilities of Process Technicians include:
- Line and Blind Audits: Walk down piping systems to confirm all maintenance blinds have been removed, temporary jumpers or bypasses are cleared, and flanges are properly bolted with the correct gaskets.
- LOTO and Clearance Verification: Verify that all Lockout/Tagout (LOTO) devices applied during the shutdown have been legally accounted for, removed, and signed off by authorized personnel.
- Safety and Interlock Checks: Walk through the unit to confirm emergency shutdown (ESD) buttons, fire protection systems, safety interlocks, and alarms are active, unbypassed, and properly configured.
- Utility and Valve Lineups: Align valves, drain low points, clear condensate traps, and verify that plant utilities (such as instrument air, cooling water, nitrogen blanketing, and electrical power) are fully operational and stable.
- PSSR Documentation Signoffs: Complete physical inspection checklists, verify that operating procedures and Process Hazard Analysis (PHA) recommendations are updated, and sign off on readiness packages before introducing hazardous materials.
Now you know what process and instrumentation technicians do during plant turnaround activities and shutdowns. If you want to know more about earning an associate degree in these careers, request more information about our Process Technology (AOS) Associate in Occupational Studies Degree and our Instrument and Control Systems Technology (AOS) Associate in Occupational Studies Degree.
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