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How to create great preventive and corrective maintenance work orders

With a complete understanding of the importance of maintenance and reliability, let’s dive into the work of maintenance and take a look at an overview of work management processes:

  1. Work identification

  2. Work planning

  3. Work scheduling

  4. Work execution

  5. Work close out (completion and analysis)

We’ll tackle each of these in more detail in this series of blog posts starting this week with work identification and what makes a great work order.


Work identification

Work identification comes from many sources including operations, maintenance and new projects. From a maintenance standpoint, there are two main types of work orders:preventive (or scheduled) and corrective (or unscheduled).

Preventive or scheduled maintenance work orders

This refers to scheduled, routine maintenance (and inspection) activities to prevent constantly unplanned downtime and equipment failure. These work orders include resources requirements, checklists, instructions and notes. Predictive maintenance is a type of preventive maintenance, as it is scheduled. It differs only in that preventive maintenance is scheduled regularly, whereas predictive maintenance is scheduled based on asset conditions.

Types of preventive maintenance work orders include:

Time-based work orders - These work orders are based on the calendar. They are scheduled and can include regulatory requirements. They are work orders that are created based on a scheduled, time-based maintenance plan.

Failure finding work orders - These work orders are targeted at finding hidden failures that are typically associated with protective or safety functions like trips transmitters and pressure safety valves. This equipment does not, and is not, required to function until or unless something else fails, which is why you won’t know whether it works or not under normal operating conditions. These work orders don’t fix any detected issues, they simply find them.

Risk-based work orders - These work orders are prioritized using a risk assessment methodology. Maintenance staff is assigned to maintain the assets that carry the greatest risk in case of failure; risk being defined as the likelihood of failure multiplied by consequences of the failure.

Condition-based work orders - If it is possible to determine that a piece of equipment is in the early stages of failure, it may be possible to take steps to prevent it from failing completely. Condition-based monitoring (CBM) monitors the actual condition of the asset to determine what maintenance needs to be done, and work orders are only carried out when there are signs of upcoming failure, or of performance.

Predictive work orders - Predictive maintenance requires condition monitoring. While CBM work is only done when there are signs of failure, predictive maintenance is carried out to actively reduce the likelihood of failure. Certain factors allow maintenance teams to predict when equipment failure could occur, and then schedule maintenance tasks in an attempt to prevent it from occurring.

Corrective or unscheduled, on-demand work orders

Corrective maintenance is also referred to as run-to-failure, reactive, or unscheduled. Unfortunately, these are the majority of maintenance work orders for most operators.


Types of corrective maintenance work orders include:

  • Emergency work orders - When an unplanned asset breakdown occurs, emergency work orders track the reactive maintenance activities including what happened, what was done to correct it, and how to prevent it from recurring. Emergency maintenance is three to five times as expensive as preventive maintenance, typically leads to longer equipment outages and has more production impact.

  • Corrective or deferred work orders - These are created when a maintenance technician discovers an issue while conducting other maintenance work order tasks. Unlike emergency work orders, these work orders are then prioritized, planned and scheduled because the issue was identified in time.

What makes a great work order?

Complete information - Clarity on what maintenance technicians are being asked to do, including a completion date and clear instructions, helps reduce the risk of recurring problems through effective cause analysis and solution planning. Complete information requires a title and description of the task, the name of the requestor, the name of the assigned worker with contact information, and the necessary tools or support for completion.


Clear, timely communication - Timely communication of an issue, its severity, and expectations on time to resolution ensures everyone involved is on the same page. It makes the entire team aware of the same expectations, allowing for further conversations on amending expectations based on other priorities.

Effective job prioritization - Creating, implementing, and consistently using a set of standardized prioritization rules with every work order gives maintenance teams a clear understanding of what jobs need to be done next.


Compliance data inclusion - It is imperative that compliance requirements are satisfied. Including this data with each work order is important. Data aggregation can help.


In our next post, we’ll take a look at how work identification in big industry has traditionally been managed, and how technology is revolutionizing efficiency.


Interested in learning more about digital transformation? Download the full whitepaper on solving the biggest maintenance challenges in the energy and mining industries here.




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