Decision Logic Tree

OSHA suggests using a decision logic tree to evaluate a workplace's requirements for using air purifying respirators.

Below is the text version of this chart. You will also see the graphic version of this chart.

Enter

• Do you intend to use an APR?
• Yes - Go to "Oxygen level is ≥ 19.5%"
• No - This is only for APRs - END
• Oxygen level is ≥ 19.5%
• Yes - You cannot use an APR - END
• No - Go to "Do you need to remove particulates?"
• Do you need to remove particulates?
• Yes - Go to flowchart 1
• No - Go to "You will be using a gas/vapor respirator"
• 1R You will be using a gas/vapor respirator?
• 2R Do you know the contaminants present?
• Yes - Go to "Do you know contaminant concentrations?"
• No - Go to flowchart 2
• 3R Do you know contaminant concentrations?
• Yes - Go to "For a particular respirator you should assume worst case concentrations"
• No - Go to flowchart 3
• For a particular respirator you should assume worst case concentrations.
• Assess workplace environmental factors (humidity, temperature) and workrate.
• Go to flowchart 4

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