The importance of effective maintenance planning and scheduling cannot be overestimated. Yet many asset-intensive industries are still not recognising the benefits this can bring to their organisation, says Gary Tyne CRL, director of Pro-Reliability Solutions
“If you fail to plan, you are planning to fail,” said Benjamin Franklin. Effective maintenance planning and scheduling is a key business process that can help assure asset reliability and assist in achieving production targets.
The differences between planning and scheduling need to be recognised: quite often “maintenance planners” are found to just be scheduling work, and not planning it. Planning considers what activities the maintainer needs to perform, how they are going to perform each activity, what resources are needed to do each task, and what parts are required. Scheduling is setting when you are going to perform the job. Planning is always done before scheduling.
Maintenance plan development
Some maintenance plans are developed using a structured failure modes effects criticality analysis (FMECA) process which will identify the asset failure modes and required maintenance tasks needed to either prevent or predict the failure. These tasks are then grouped into frequencies along with what, who, strategy, and equipment status.
For example: 1-monthly Compressor Lube Insp Offline denotes when, what, who (lube technician), strategy (inspection) and status (offline).
It is important to allocate a status (online or offline) against a maintenance plan. If a plan incorporates both online and offline activities, then generally not all tasks are performed during the execution. That allows for some failure mode inspections to be missed, and ultimately these could result in an unplanned outage.
Online maintenance is performed when the equipment is running, and no availability or production time is lost. Offline maintenance requires the equipment to be stopped and isolated. Each task on the plan will also require a duration. Maintenance plans can be grouped together in a single planned outage.
Emergency unplanned work
Between planned shutdowns asset failures can occur that require an intervention. It is advisable the maintenance planner does not get dragged into dealing with day-to-day equipment failures and end up becoming a reactive planner. This will prevent long-term planning from happening, which in the long run will affect the overall plant availability.
Production and maintenance planning and scheduling
It’s important that the maintenance planner has regular contact with production planners to make sure that equipment is made available for maintenance at the most convenient time so that maximum production is achieved. “Production is King” scenarios can exist, and requesting shutdowns to perform maintenance can be difficult. Working together in partnership is the key to success.
Monitoring shutdown performance and production activity is another element that gets overlooked. Some organisations have annual shutdowns; others have minor interventions throughout the year. Both approaches have benefits and require analysis to determine which approach suits your production type (continuous versus batch).
Case study: food and beverage plant – annual shutdown versus minor interventions
The graph below shows a batch production facility that previously held annual one-week shutdowns. Prior to the annual shutdown, production efficiency dropped by up to 58%. Following the annual shutdown, it took up to 20 weeks to return to pre-shutdown best production efficiency levels.
After analysis of the maintenance workload, it was decided to move away from annual shutdowns and build a programme of minor interventions combined with online condition monitoring activities. This helped with production efficiency consistency and production stability, at the same time as consistently achieving performance targets.
Benefits included elimination of the need for a two-week stock build-up prior to shutdown; simplified production planning and stock control; less time to get back to pre-intervention performance level; increased plant availability, with interventions completed on non-production days; and reduced reliance on contract labour.
Introducing a well-executed planning and scheduling programme requires a dedicated planner and scheduler, and a structured planning business process were everyone understands their individual roles and responsibilities. It will help improve plant availability, achieve production targets, reduce costs and improve plant safety performance.