Japan workplace heatstroke prevention guidance and public WBGT warning bands.
Open Japan MHLW WBGT Warning System in the interactive Guidance Wiki →
No standalone formula is published for this standard; see programmable logic and parameters below.
| WBGT (°C) | Light 180 W | Moderate 300 W | Heavy 415 W | Very heavy 520 W |
|---|---|---|---|---|
| 24 | Safe (below 25) | Safe (below 25) | Safe (below 25) | Safe (below 25) |
| 25 | Caution (25–28) | Caution (25–28) | Caution (25–28) | Caution (25–28) |
| 26 | Caution (25–28) | Caution (25–28) | Caution (25–28) | Caution (25–28) |
| 27 | Caution (25–28) | Caution (25–28) | Caution (25–28) | Caution (25–28) |
| 28 | Warning (28–31) — rests should be provided often | Warning (28–31) — rests should be provided often | Warning (28–31) — rests should be provided often | Warning (28–31) — rests should be provided often |
| 29 | Warning (28–31) — rests should be provided often | Warning (28–31) — rests should be provided often | Warning (28–31) — rests should be provided often | Warning (28–31) — rests should be provided often |
| 30 | Warning (28–31) — rests should be provided often | Warning (28–31) — rests should be provided often | Warning (28–31) — rests should be provided often | Warning (28–31) — rests should be provided often |
| 31 | Severe Warning (31–35) — heavy exercise/work should be restricted | Severe Warning (31–35) — heavy exercise/work should be restricted | Severe Warning (31–35) — heavy exercise/work should be restricted | Severe Warning (31–35) — heavy exercise/work should be restricted |
| 32 | Severe Warning (31–35) — heavy exercise/work should be restricted | Severe Warning (31–35) — heavy exercise/work should be restricted | Severe Warning (31–35) — heavy exercise/work should be restricted | Severe Warning (31–35) — heavy exercise/work should be restricted |
| 33 | Severe Warning (31–35) — heavy exercise/work should be restricted | Severe Warning (31–35) — heavy exercise/work should be restricted | Severe Warning (31–35) — heavy exercise/work should be restricted | Severe Warning (31–35) — heavy exercise/work should be restricted |
| 34 | Severe Warning (31–35) — heavy exercise/work should be restricted | Severe Warning (31–35) — heavy exercise/work should be restricted | Severe Warning (31–35) — heavy exercise/work should be restricted | Severe Warning (31–35) — heavy exercise/work should be restricted |
| 35 | Extreme (>35) — stop work | Extreme (>35) — stop work | Extreme (>35) — stop work | Extreme (>35) — stop work |
| 36 | Extreme (>35) — stop work | Extreme (>35) — stop work | Extreme (>35) — stop work | Extreme (>35) — stop work |
This standard's declared inputs do not include acclimatization status, so results do not vary by it.
Required inputs: wbgtC
Optional inputs: japanWbgtC, japanWbgtSource
This standard was added to the calculator.
Get notified when Japan MHLW WBGT Warning System changes — threshold changes, scope and legal-status changes, additions and removals. Changes that permit more heat exposure than before are labelled as such.
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