Tier-Based Rest Periods — How Fatigue Rules Work
Tier-Based Rest Periods
Rest period requirements scale with shift length — longer shifts require more rest before the next assignment.
How it works
Instead of a single flat minimum rest period, the system uses graduated tiers based on shift duration:
| Shift Length | Required Rest (Day) | Required Rest (Night) |
|---|---|---|
| Up to 4 hours | 0 hours | 0 hours |
| 5–8 hours | 2 hours | 4 hours |
| 9–10 hours | 8 hours | 10 hours |
| 11–12+ hours | 10 hours | 12 hours |
(Actual values depend on your organization's configuration)
Key features
- Separate day and night tiers — night shifts may require more rest, reflecting different fatigue profiles
- Stack threshold — shifts separated by less than a configurable gap (default 2 hours) are treated as one continuous work block
- Organization-configurable — each organization sets its own rest tiers via Organization Settings
Where IRIS uses this
- Roster generation — IRIS checks rest tiers before suggesting assignments
- Roster Health — violations appear in the Roster Health dashboard
- Conflict detection — the backend validates rest compliance on every assignment
Configuration
Go to Organization Settings → Safety Standards to configure rest tiers for your organization.
Tip: The graduated approach means short shifts (like a 4-hour training session) don't unnecessarily block the next day's assignment.