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    HVAC Systems · Refrigeration — ASHRAE 15 Safety

    Oxygen Deprivation Limit (ODL)

    The refrigerant concentration at which displaced air lowers oxygen to an unsafe level. For nontoxic, nonflammable refrigerants the ODL often governs the allowable charge in a confined space.

    Safety note

    A large leak in a confined space can displace oxygen and cause asphyxiation with no warning odor — ventilate before entering.

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