Extending Turnaround Intervals Without Increasing Risk
By Clayton Smith and Gordon Lawrence
Extending turnaround intervals can improve production uptime, but only within defined operational and regulatory limits. A successful strategy requires evaluating inspection constraints, event size, and organizational capacity to avoid increasing risk.
Key takeaways
- Extending turnaround intervals can increase uptime but introduces operational and regulatory risk.
- Regulatory inspection requirements and process limits set boundaries on how far intervals can be extended.
- Longer intervals often lead to larger and more complex turnaround events.
- Workforce capacity and contractor availability can limit execution of extended turnarounds.
- Economic benefits must be weighed against increased cost, downtime, and logistical constraints.
Extending turnaround intervals is a common strategy used by refineries and process plants to increase uptime and improve profitability. However, longer intervals introduce operational and regulatory risks, along with added organizational constraints, that must be carefully evaluated.
This blog discusses the key considerations when examining the feasibility of extending the interval between regular maintenance turnarounds. It looks at the reasons why facilities might pursue extended intervals and the risks involved, along with the practical factors that determine whether extending intervals is viable over the long term.
What is a maintenance turnaround?
Maintenance turnarounds (sometimes called shutdowns or outages) are necessary events in the long-term operation of any facility that uses large equipment and machinery in a continuous production process. Equipment may be subject to regulatory inspection to confirm that it remains safe for operation, or it may require repairs or cleaning.
If a process runs continuously, then much of the equipment may only be accessible when the plant is shut down. In this state, it is not producing product and there is consequently a lost production opportunity. As a result, the plant needs to be shut down only when absolutely necessary to ensure safe and efficient production as well as compliance with local regulations; it also needs to be turned around and restarted as quickly as possible.
Why extend turnaround intervals?
There are three main reasons to defer turnaround work. (Strictly speaking, the correct term would be to “postpone,” since the work is being postponed to a definite future date rather than indefinitely.)
- Capture favorable market conditions by postponing the entire turnaround for weeks or months so the site can produce as much as possible to sell at a high price.
- Manage budget constraints by reducing the turnaround scope and deferring selected work to a future event.
- Improve long-term production efficiency by postponing the entire turnaround for one or more years as part of a broader shift in operating strategy.
The first two reasons were covered in an earlier blog. In this article, we will concern ourselves with only the third reason: extending the turnaround interval for a longer term.
Reasons for extending the turnaround interval typically revolve around a desire to better optimize production uptime. If a facility can extend the intervals between turnarounds and hence undergo fewer turnarounds over its 20-to-30-year life expectancy, this should result in less overall downtime and more time producing product
Issues and risks involved in long-term interval extension
There are naturally some issues and risks involved in the long-term extension of a turnaround interval.
Practical limits to extension
There are natural constraints on how far turnaround intervals can be extended:
- Government regulatory constraints such as statutory inspection of pressure vessels. Although there may be some opportunities to extend the inspection interval with Risk-Based Inspection (RBI) techniques, there is inevitably a limit to how far this can be extended before the vessel needs to be inspected internally.
- Process limitations such as catalyst life or known fouling issues. This can, to an extent, be addressed through catalyst choice and process design to minimize fouling, but again, a limit will eventually be reached.
- Internal company procedures for equipment maintenance strategies specifying overhaul of equipment after a defined time interval. These can be reviewed and extended where practicable, but there will be a limit beyond which it will be felt unwise to extend.
Increasing turnaround size and complexity
Longer intervals typically result in larger and more complex turnarounds. More corrective maintenance accumulates over time, while preventive maintenance scope expands to address longer run lengths.
There will come a point where the disadvantages of increased cost, execution time and complexity will outweigh the advantages of a longer production run-length.
Organizational and workforce constraints
One of the commonly overlooked risks we see in industry relates to the organization, infrastructure and contract workforce. As turnaround size increases, it will place ever-increasing strain on:
- The organization’s capacity to manage and supervise turnaround work effectively
- Site logistics and the capability to cope with the sheer number of contract workers coming through the gate to do the work.
- The local contractor workforce’s ability to staff up with sufficient contract workers of the required skills and experience.
Indeed, whereas over the past 15 years we saw a trend towards increased turnaround intervals in a drive for production efficiency and better multi-year cost in benchmarking studies, we are now seeing the beginnings of a trend the other way. Sites are realizing that turnarounds have become too large for their organizations, and especially for their contractor workforce, to handle. (But discussion of the future availability of skilled field contractors is a topic for another day!)
Reduced flexibility for capital projects
Extending turnaround intervals also reduces opportunities to tie in capital improvement projects. While not strictly a risk, this can affect decision making. The payback for a project may be delayed because it cannot be tied in and commissioned as quickly as the site would like.
How to evaluate whether to extend turnaround intervals
There are several key factors to consider when looking at the viability of extending turnaround intervals at a site.
Assess the maximum turnaround size the site can manage
In our experience, this is the constraint most frequently overlooked by clients, but it is currently the primary reason why some, having over-extended, are now reconsidering and returning to shorter turnaround intervals.
When evaluating this aspect of turnaround strategy, Becht’s turnaround execution experts look at a number of factors, including:
- Worker density across the site
- Availability of owner field supervisors
- Availability of local contractors
Examining this element first establishes an upper boundary of turnaround event size, beyond which it would be ineffective to reach.
Evaluate the estimated event cost vs. interval extension benefit
A site needs to consider the tradeoff between improved production from the extended interval and the larger turnaround that ultimately results. A larger event typically leads to higher execution costs and increased downtime because of the additional time needed to execute the work.
In conjunction with our inspection and discipline engineers, Becht’s turnaround specialists can help to estimate the likely turnaround event size, cost and execution time, allowing for a clear comparison against the expected production gains.
Determine practical inspection and maintenance limits
There will be limits on how far a site can safely extend the interval between inspection, cleaning or overhaul of equipment. Our turnaround and inspection experts can partner with on-site statutory inspection engineers in assessing the safest way to extend statutory inspection intervals using such techniques as RBI.
Similarly, our process engineers and chemical cleaning experts can work to minimize issues with catalyst exhaustion and equipment fouling, as well as assess whether equipment maintenance routine intervals are too conservative and could be extended.
Assess the impact on feedstock and product supply
As the turnaround itself grows, its duration also grows, which may place strain on feedstock or production storage and on the site’s ability to meet customer supply agreements. Becht’s strategic planning team can examine this vital area and determine where the limits lie.
Conclusion: Balancing uptime and risk
There may well be economic advantages to extending turnaround intervals. But those advantages need to be carefully weighed against the constraints of a range of issues, including organizational limits and statutory inspection requirements.
Need advice or counsel for extending your own turnaround interval? Contact a Becht expert to discuss your future plans.
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