Most people assume oil refineries operate continuously with only occasional maintenance.
While it’s true that modern refineries run 24 hours a day, seven days a week, they can’t operate forever without shutting down.
Every few years, entire processing units are taken offline so thousands of workers can inspect, repair, clean, and upgrade equipment.
This massive operation is known as a refinery turnaround.
A turnaround is one of the largest and most expensive planned events in the oil and gas industry. It can involve thousands of contractors, millions of work hours, and budgets reaching hundreds of millions of dollars.
If you’ve ever wondered why refineries occasionally release more steam, why hotels near industrial areas suddenly fill up, or why companies hire large numbers of temporary workers, there’s a good chance a turnaround is taking place.
Let’s look at what actually happens during one.
What Is a Refinery Turnaround?
A refinery turnaround is a planned shutdown of one or more processing units so maintenance, inspections, repairs, and equipment upgrades can be safely completed.
Unlike emergency shutdowns, turnarounds are scheduled months—or even years—in advance.
Since every day a refinery is offline represents lost production, companies carefully plan every task to complete the work as quickly and safely as possible.
The goal is simple:
Operate safely for another several years before the next major shutdown.
Why Can’t Refineries Stay Running Forever?
Industrial equipment operates under extreme conditions.
Some units process crude oil at temperatures above 400°C (750°F).
Others operate under very high pressures while handling corrosive chemicals and flammable hydrocarbons.
Even with excellent maintenance, equipment gradually wears over time.
During a turnaround, inspectors look for problems such as:
- Corrosion
- Cracked welds
- Erosion
- Fouling
- Heat exchanger damage
- Valve wear
- Instrument failures
- Pressure vessel defects
Finding these problems before they become failures is one of the main reasons turnarounds are so important.
How Often Do Turnarounds Occur?
It depends on the facility and the equipment.
Many major refinery units undergo a turnaround every three to five years.
Some equipment may require more frequent inspections due to regulatory requirements, while newer units may operate longer between shutdowns.
The schedule is carefully balanced between safety, reliability, and economics.
Shutting down too often wastes money.
Waiting too long increases the risk of equipment failure.
Planning Begins Years Before the Shutdown
One of the biggest misconceptions is that companies simply decide to shut down a refinery for maintenance.
In reality, planning often begins two or three years before the first valve is closed.
Engineers, maintenance planners, operations personnel, inspectors, contractors, procurement teams, and safety specialists work together to answer questions like:
- Which equipment needs inspection?
- Which valves should be replaced?
- What modifications are planned?
- Which contractors will perform the work?
- What spare parts must be ordered?
- How many workers will be needed?
By the time the turnaround starts, every major task has usually been planned in detail.
Step 1: Reducing Production
The turnaround doesn’t begin by flipping a switch.
Operators gradually reduce production over several hours—or even days.
Temperatures and pressures are lowered carefully to avoid damaging equipment.
This controlled shutdown allows process units to reach safe operating conditions.
Step 2: Isolating Equipment
Once production stops, equipment must be isolated.
This involves:
- Closing valves
- Installing blinds or blinds/spades
- Lockout/Tagout (LOTO)
- Draining hydrocarbons
- Depressurizing vessels
- Purging equipment with steam or nitrogen
No maintenance begins until operations confirms the equipment is safe to work on.
Step 3: Cleaning the Equipment
Many refinery vessels contain:
- Oil
- Sludge
- Coke
- Sulfur deposits
- Process chemicals
Before inspectors or maintenance crews can enter, equipment must be thoroughly cleaned.
Large vessels are often steamed, washed, and gas tested to ensure safe entry.
Step 4: Inspection
Once equipment is clean, inspectors begin evaluating its condition.
Some common inspection methods include:
- Visual inspections
- Ultrasonic thickness testing
- Radiography
- Magnetic particle testing
- Dye penetrant testing
- Eddy current testing
- Internal vessel inspections
These techniques help identify defects that aren’t visible from the outside.
Step 5: Maintenance and Repairs
This is where most of the work happens.
Thousands of maintenance activities may take place simultaneously.
Examples include:
- Replacing valves
- Repairing pumps
- Installing new piping
- Rebuilding compressors
- Servicing turbines
- Repairing insulation
- Cleaning heat exchangers
- Upgrading instrumentation
- Replacing catalysts
On a large turnaround, hundreds of cranes, forklifts, welders, electricians, scaffolders, and mechanics may be working around the clock.
Heat Exchangers Get Special Attention
Heat exchangers are among the hardest-working pieces of equipment in a refinery.
Over time, fouling builds up inside the tubes, reducing heat transfer.
During a turnaround, exchangers are often opened so crews can:
- Clean tubes
- Replace damaged tubes
- Repair leaks
- Inspect tube sheets
- Perform pressure tests
A clean heat exchanger can significantly improve refinery efficiency.
Catalyst Replacement
Many refinery processes rely on catalysts.
These materials gradually lose effectiveness due to contamination and normal wear.
During a turnaround, old catalyst may be removed and replaced with fresh material.
Because catalyst replacement can be hazardous, specialized contractors often perform this work.
Safety During a Turnaround
A turnaround introduces hazards that don’t normally exist during routine operations.
Examples include:
- Confined space entry
- Hot work
- Heavy lifting
- Working at heights
- Simultaneous operations
- Increased vehicle traffic
- Temporary power systems
For this reason, safety meetings, permits, and inspections become even more important.
It’s not unusual for thousands of work permits to be issued during a single turnaround.
Why Are There So Many Contractors?
Many refineries normally operate with a relatively small workforce.
During a turnaround, that workforce may double or even triple.
Specialized contractors are brought in for tasks such as:
- Welding
- Scaffold erection
- Insulation
- Painting
- Electrical work
- Instrumentation
- Non-destructive testing
- Crane operations
Some large turnarounds involve more than 5,000 additional workers.
Why Hotels Suddenly Fill Up
Communities near major refineries often notice a sudden increase in hotel occupancy during turnaround season.
That’s because contractors travel from across the country—and sometimes internationally—to work on these projects.
Restaurants, hotels, rental companies, and local businesses often experience a noticeable economic boost.
The Most Difficult Part: Starting Everything Again
Many people assume the hardest part is shutting the refinery down.
In reality, startup can be even more challenging.
Every repaired system must be tested.
Instrumentation must be calibrated.
Operators verify valve positions.
Utilities are restored.
Equipment is restarted in a carefully planned sequence.
Only after extensive testing does the refinery gradually return to full production.
A successful startup depends on weeks of planning and close coordination between operations, maintenance, and engineering teams.
Interesting Facts About Refinery Turnarounds
- Some turnarounds involve more than 100,000 individual work orders.
- Large refinery shutdowns can cost hundreds of millions of dollars.
- Certain turnaround activities continue 24 hours a day using rotating shifts.
- Years of planning may go into a shutdown that lasts only a few weeks.
- A single day of lost production at a large refinery can represent millions of dollars in revenue.
Common Myths
“The refinery shuts down because something broke.”
Not usually.
Most turnarounds are carefully planned long before any equipment reaches the end of its service life.
“Everything stops.”
Many refineries continue operating other process units while only specific sections are shut down.
“It’s just maintenance.”
Maintenance is only one part of a turnaround.
Inspections, equipment upgrades, regulatory compliance, engineering projects, and process improvements all happen during the shutdown.
Final Thoughts
Refinery turnarounds may not receive much public attention, but they are among the most complex industrial projects carried out anywhere in the world.
They require years of planning, thousands of skilled workers, and an unwavering commitment to safety.
Although shutting down a refinery is expensive, the alternative—allowing critical equipment to operate indefinitely without inspection—would be far more costly.
The next time you hear about a refinery turnaround, remember that it’s not a sign of failure.
It’s one of the reasons modern refineries continue operating safely and reliably for decades.
Frequently Asked Questions
How long does a refinery turnaround last?
Most refinery turnarounds last between two and eight weeks, depending on the size of the facility and the amount of work being performed.
Why are refinery turnarounds so expensive?
The cost includes maintenance, inspections, contractor labor, replacement parts, equipment upgrades, and lost production while the refinery is offline.
Do refineries completely shut down during a turnaround?
Not always. Many facilities shut down only selected process units while the rest of the refinery continues operating.
Can people get temporary jobs during a refinery turnaround?
Yes. Turnarounds often create temporary employment opportunities for welders, scaffolders, electricians, mechanics, inspectors, instrument technicians, crane operators, safety professionals, and many other skilled trades.