Buffer burn rate
Also: Buffer burn, Buffer consumption, Buffer penetration, Fever chart, Buffer management
Quick definition: In critical chain scheduling, how fast a time buffer is being consumed compared with how much of the chain of work has been completed — the main signal of whether a project will finish on time.
Explanation
Beginner explanation
If half the spare time is gone but only a quarter of the work is done, the buffer is "burning" too fast and the project is heading for a late finish. Buffer burn compares the two.
Technical explanation
Progress is expressed as two percentages: buffer consumed (penetration) and critical chain complete. Their ratio is the burn rate; a ratio above 1.0 means the buffer is being used faster than work is being completed. Results are plotted on a fever chart (buffer consumed on the vertical axis, chain completed on the horizontal), commonly divided into three zones: green (no action), yellow (plan a response) and red (take corrective action). Tasks that finish early return time to the buffer. Each project and feeding buffer in Critical chain project management is tracked this way.
Practical example
At the weekly review, the project buffer of 20 days has 9 days consumed (45%) while the critical chain is 30% complete. The burn rate of 1.5 puts the project in the yellow zone, so the team prepares a recovery plan to resequence envelope work before it reaches red.
Why it matters
Burn rate gives one early, objective warning signal for the whole project instead of hundreds of individual task variances.
Common confusion
Buffer burn is not float consumption in a CPM schedule: buffers are shared, explicitly sized time reserves, whereas float is the slack that falls out of schedule logic.
- Critical path method (CPM) — Float vs buffer
Standards and references
- Critical chain monitoring (product documentation). Sciforma.Widely accepted professional interpretation
Supports: Buffer consumption, three equal zones (green/yellow/red) and actions, consumption rate, fever chart plotting consumption against completion, early tasks restoring buffer - Critical chain project management. Wikipedia.Widely accepted professional interpretation
Supports: Fever chart of buffer consumption against percentage of critical chain completed
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Cite this entry
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VDC Stack.io. (2026). Buffer burn rate. In VDC Stack.io Knowledge Dictionary. Retrieved from https://vdcstack.io/dictionary/buffer-burn-rate/