Planning vs Scheduling — Distinct Roles
| Role | Responsibilities | Time horizon |
|---|---|---|
| Planner | Scope the work; identify and reserve materials; write the job plan (steps, tools, permits, estimated hours); identify craft skills required; identify safety requirements (isolation, confined space, hot work permits) | Works 1–4 weeks ahead; never on reactive work |
| Scheduler | Build the weekly schedule from the ready-to-schedule backlog; coordinate with operations for equipment access; assign craft personnel; confirm materials are on-site; issue the schedule Monday morning | 1 week ahead |
| Supervisor/Foreman | Execute the daily schedule; manage exceptions; reassign on reactive priorities; provide feedback on job completions | Day to day |
The planner should not take reactive work orders — their job is to work ahead of the execution team, not alongside them. A ratio of 1 planner to 15–20 craft technicians is typical.
Work Order Workflow
- Request: Any maintenance need is raised as a work order in the CMMS — by operations, maintenance, or PdM systems. No verbal requests — everything in writing
- Approval and prioritisation: Supervisor reviews and assigns priority (Emergency/Urgent/Routine/Shutdown) and approves or rejects. Priority coding determines planning timeline
- Planning: Planner scopes the job, identifies parts and tools, writes step-by-step job plan, estimates craft hours and duration, identifies safety requirements, identifies equipment access requirements
- Ready-to-schedule: When all materials are available and all pre-conditions are met (permits, equipment access confirmed with operations), the work order moves to the ready-to-schedule backlog
- Weekly scheduling: Scheduler selects from the ready-to-schedule backlog to fill craft capacity for the coming week; confirms with operations; issues schedule
- Execution: Technicians execute the planned work; record actual hours, materials used, findings, and any additional work identified
- Feedback and closure: Supervisor reviews completion, signs off; actual vs planned hours compared; lessons learned fed back to planner to improve future job plans
Backlog Management
The maintenance backlog is the total of all open, approved work orders. A healthy backlog contains enough work to keep the team fully scheduled but is not growing uncontrollably:
| Backlog type | Target level | Concern if |
|---|---|---|
| Total approved backlog (weeks of work) | 3–5 weeks of craft capacity | <2 weeks: insufficient work visibility; >8 weeks: growing faster than completion rate |
| Ready-to-schedule backlog (weeks) | 1–2 weeks ahead | <1 week: scheduling from under-planned work; >3 weeks: scheduling bottleneck |
| Emergency/urgent work as % of total | <10% | >20%: reactive culture — planning not effective; investigate why PMs are not preventing failures |
Improving Wrench Time
Wrench time (productive time) studies typically reveal that maintenance technicians spend only 25–35% of their working day on actual maintenance tasks. The remainder is lost to:
| Time loss category | Typical % | Remedy |
|---|---|---|
| Waiting for parts or materials | 15–20% | Pre-kitting: all materials assembled and staged in a kit before the job is scheduled. Never start a job without all materials on site |
| Waiting for permits to work (isolation, confined space) | 8–12% | Permits pre-applied for during planning; isolation schedule coordinated with operations in advance |
| Waiting for equipment access (operations) | 8–12% | Weekly scheduling meeting with operations confirms access slots in advance; no more showing up to find the machine still running |
| Travel and transport | 5–8% | Organise work by area; tool stores located near work areas; vehicle use planned |
| Looking for information (drawings, manuals) | 3–5% | Job plan includes document references; electronic access to drawings via tablet |
| Breaks and personal time | 10–15% | Reasonable — do not target further reduction |
Key Planning and Scheduling KPIs
- Schedule attainment: % of scheduled work orders completed in the scheduled week. Target: >85%. Formula: (WOs completed from schedule / WOs scheduled) × 100
- PM compliance: % of preventive maintenance work orders completed on time. Target: >95% for critical assets
- Planned work as % of total hours: Hours spent on planned work orders / total maintenance hours. Target: >80%
- Emergency/corrective ratio: Emergency work hours / total hours. Target: <10%
- Backlog age: Average age of work orders in the backlog. Rising age indicates scheduling inefficiency or resource shortage