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1.5 ORDER OF TESTING
The internal atmosphere shall be tested using an approved, properly calibrated Atmospheric Testing Device, in the following sequence:
• Oxygen (acceptable criteria between 19.5 and 23.0%). Oxygen monitoring equipment shall be set to alarm if the oxygen content falls below 19.5 percent.
•Flammable gases and vapors (acceptable criteria less than 10% of the lower explosive limit (LEL), e.g., a reading of 0.5% methane).
•Carbon monoxide (CO) (acceptable criteria less than 35 parts per million [ppm]).
•Tests for toxic vapors and gases, if necessary. Entry level for toxic substances shall not exceed the Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (PEL), regardless of the anticipated length of entry.
Interactive 1.1 Atmospheric Testing
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