 Maintenance outages, turnarounds, or plant shutdowns are complex, and can involve hundreds or even thousands of temporary workers, and are very costly. In our work we have been successful in helping reduce large facility outage durations. The immediate benefits are increased process availability and corresponding revenue and profit. Typical outages are planned and scheduled months in advance and last anywhere from a week to a month or more. Outage duration tactics include streamlining processes such as the shutdown and startup processes, improving the decision making and communications methods, and controlling scope. Another tactic is externalizing tasks, which is by doing work before or after the process goes down, tasks such as pre staging tools and materials, preparing the work site. We’ve also been working to better understand the nature of planning and executing Critical Path work.
We believe that a shorter critical path means an overall shorter outage. To get a shorter critical path you often have to add additional resources which increases turnaround costs. What we want to better understand are the conditions where a shorter outage actually costs less. Typical contractor schedules are 2 ten hour shifts per day. Productivity is believed to drop off significantly after 10 hours due to additional breaks and fatigue. We have applied longer shifts to the critical path and have seen overall duration reduction. We have also had mixed results with the concept of Non Stop Critical Path, also referred to as “tool to tool”. Some types of work are machine rate based, for example tasks such as pipe welding or sand blasting. For this type of work the value is in the “wrench or tool time”. The concept is that the tool never stops. The welder stays on the tool until someone comes, taps the worker on the shoulder, takes the welding rod and keeps on welding. While working spotters make sure the value adding worker never has to go searching for weld rod; an assistant keeps the worker supplied. The tool never takes a lunch break, or goes on treasure hunts; the tool works as close to 24 hours as possible. To do this we have spotters filling in for the workers when they take their breaks, and stagger crew start times.
Shutdowns can have a range of % critical path work. Sometimes the critical path is almost the entire outage work scope; in other cases the critical path work can be as little as 5% of the overall outage effort. We believe that when the critical path is narrow, or a small portion of the overall work, then applying additional labor to the critical path can greatly reduce the overall cost and duration of the outage.
Staffing Non Stop Critical Path of course takes more resource and is a higher operating expense then the normal 2 ten hour shifts. Non Stop Critical Path provides not only an additional 4 hours of shift time compared to 2 Tens, it also adds back two lunches, 6 breaks, and 2 sets of getting to and from the work face, or some 7 or more hours of tool time per day.
The combination of shift patterns, over time, mix of critical path work, equipment rentals, etc. makes it difficult to apply a general rule for all turnarounds as to whether extending shift length or adding labor to the critical path increases or decreases overall outage expenses. So a model is needed to answer the question of under what conditions does applying extra labor to get a shorter outage actually cost less.
Outage readiness is better when all the right people give and receive input at the earliest effective date; bust the silos, jump the walls …
- Everyone shares the goal of being ready to go fast (and safely) when the outage begins, so we’ll benefit from bringing the right people together to ensure we have the right inputs and everyone is working from the same plan
- Close to the shutdown date many key decisions are made and people from a lot of groups are preparing – they all need to be in sync
- Hear one message and one answer to key questions, and those with input have a channel for sharing
What’s different?
- Draft schedule available earlier; honest, because when developed in parallel there’s less rework
- Earlier involvement of key contractors learning about plans and schedules and giving input on what will work
- Greater turnaround leader and scheduler interaction
- Earlier involvement and input from all support groups
- Wider understanding of preparation and externalization efforts
- More focus on any scope changes that occur inside of the gate reviews due to greater exposure to the plan and schedule
 All too often the battle for managing the duration and cost of a planned plant shutdown is lost in the stages of shutting down or the starting up of the operation. While a lot of planning effort usually goes into understanding and coordinating the maintenance work it is the unknowns that that pop up as the process is coming off line, or perhaps more often the surprises that occur when starting up that can throw the best made plans out the window.
Checklists and SOP’s are always good things to have.
Here are a few more things to have on your Startup to-do list …
- As Built plant configuration
- Post maintenance inspection of equipment condition
- Verify and validate maintenance work completion
- Visual and physical checks for leak and pressure
- Instrument performance and controller checks
- Safety and relief valve checks
- Lockout-tagout de-blinding activities
- Utility (steam, air, power, fuel, refrigerant, solvent) availability checks
- Commissioning of units as per Standard Operating Procedure
- No load testing of pumps, motors, compressors, turbines
- Start-up – cold circulation
- Warming up
But even with all of these precautions things can still go wrong, and when they do the clock keeps running. So what to do to reduce risks? How about planning for the unexpected?
- What-if and Failure Modes & Effects Analysis
- Checklists and planned countermeasures
- Dry runs & simulations
- Postmortem and After Action Review – to capture learnings and drive continuous improvement
 Scope and Gantt scrubs, reliability engineering equipment improvement projects, and new technologies are steps we can take to extend the life of equipment or to mitigate obstacles to minimizing outage duration. Some examples of constraint busting include:
- Deferring work based on observation, inspection, and risk assessment
- Installing new man doors can save time by opening up more work faces (parallel work) or making installation easier for utility or handling access (air lines, electrical cables, cranes for lifting)
- A great engineering project example is the practice of swapping equipment rather than repairing in place
- Working non-stop on the critical path, although not easy to do, can also have a big impact on outage duration and costs.
The methodology we apply is Goldratt’s classic Theory of Constraints:
- Identify the Constraint – find the critical path and focus on it
- Decide how to Exploit the constraint – optimize resources
- Subordinate everything else – critical path gets top priority
- Elevate the constraint – open new work faces, overlap shifts
- Repeat – start over
When looking at all of the tasks that occur leading up to, during, and after a planned maintenance shutdown it can be helpful to categorize each task as internal or external. Internal tasks are those that can only be performed when the process is stopped, while External tasks can be done either before shutdown or after starting back up.
Here are examples of tasks often found happening during an outage that, some of or all, could have been done while the process was running:
- Repairs to work done during the outage
- Reinspecting someone’s work
- Waiting for parts, tools, work instructions
- Waiting for a ride to the work face
- Waiting for inspector, permit writer
- Building scaffolds
- Moving materials or tools to the point of use
- Treasure hunts, scavenger hunts
- Preparing reports, making presentations
- Rerunning ‘the schedule’
Being able to see tasks as internal or external is the first step toward reducing the planned shutdown duration.
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