PEL Compliance Calculator

Calculate Time-Weighted Average (TWA) exposure and compare against the OSHA Permissible Exposure Limit to assess compliance.

OSHA PEL (ppm or mg/m³)

Segment 1 concentration

Segment 1 duration (hrs)

Segment 2 concentration

Segment 2 duration (hrs)

Segment 3 concentration

Segment 3 duration (hrs)

Segment 4 concentration

Segment 4 duration (hrs)

Tab to move between fields

8-hr TWA

36.25

Exposure ratio (%)72.5%

Total sampled hours8

Action level (50% PEL)25

Status (0=OK, 1=Action, 2=Over)1

Max remaining conc.0

Avg Conc36.25

How to Use This Calculator

Enter OSHA PEL (ppm or mg/m³), Segment 1 concentration, and Segment 1 duration (hrs).
Set Segment 2 concentration, Segment 2 duration (hrs), and Segment 3 concentration.
Adjust Segment 3 duration (hrs), Segment 4 concentration as needed.
Review the 8-hr TWA result.
Use Exposure ratio (%) and Total sampled hours to inform your decision.

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