what is the low pel for oxygen in confined space entry

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Oregon Occupational Safety and Health Division Oregon Administrative Rules Division 2 ## Non-Mandatory Appendix B to [redacted phone] - Potential Confined Space Hazards What follows is a compilation of hazards and conditions which may compromise safe confined space entry and/or rescue procedures. The list is not exhaustive. Specific confined spaces may have hazards unique to that space. All hazards need to be evaluated and eliminated or controlled prior to entry. Consider hazards that may be present initially as well as those that may develop during the course of work. ## Atmospheric hazards: - · Oxygen deficiency - · Oxygen enrichment - · Inert gases used to exclude oxygen (for example, nitrogen, helium, steam, freons, argon, or carbon dioxide) - · Flammable or explosive gases, liquids, vapors, mists, fibers, or dusts - · Toxic dusts, mists, fumes, smoke, vapors, fibers, or gases - · Airborne biological contaminants, including molds, bacteria, viruses and other potential disease-inducing agents Engulfment hazards presence of materials that can capture or surround an -entrant: - · Avalanche of materials - · Surrounding and suffocating - · Trenching cave-ins - · Drowning - · Bridged materials which collapse when stepped on ## Falls from heights Falling objects (tools, structural materials, debris) Harness or lifeline snag points (e.g., agitator blades, piping, screws, etc.) ## Configuration of space: - · Complexity of internal structure - · Inwardly sloping walls or floors - · Tight and/or narrow diameter spaces - entrapment - · Access restricting rescue Ignition sources -examples include: - · Grinding - · Welding, cutting, burning, brazing

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space in which the atmosphere is not within acceptable limits. 2022-79 ## Exception re entry 2022-79 262.052 Despite section 262.051, an employer or a contractor may, if the hazard control measures identified in the code of practice are in place, permit an employee to enter or remain in a confined space in which the per -centage of oxygen is less than 19.5 % by volume. 2022-79 ## Testing atmosphere 2022-79 262.06 (1) Prior to an employee entering a confined space, an employer shall ensure that a competent person tests the atmosphere of the confined space, taking into consideration the stratification of air contaminants and oxygen to ensure that the atmosphere is within accepta -ble limits. 262.06 (2) The results of a test referred to in subsection (1), including the time and date the test was conducted, shall be documented and posted conspicuously at the en -trance to the confined space. 2022-79 ## Atmosphere within acceptable limits 2022-79 262.061 (1) The atmosphere of a confined space is within acceptable limits if - (a) the percentage of oxygen is not less than 19.5% by volume and not more than 23% by volume, - (b) the concentration of an air contaminant does not exceed 50% of the lower explosive limit or lower flammability limit of the air contaminant when the confined space work is cleaning or inspecting and does not create a source of ignition, - (c) the concentration of an air contaminant does not exceed 10% of the lower explosive limit or lower pace clos dont l'atmosphère n'est pas dans les limites ac -ceptables. 2022-79 ## Exception - entrée 2022-79 262.052 Par dérogation à l'article 262.051, l'em -ployeur ou l'entrepreneur peut permettre au salarié d'en -trer ou de demeurer dans un espace clos dont la teneur en oxygène est en volume de moins de 19,5 % si les me -sures de contrôle des dangers indiquées dans le code de directives pratiques sont en place. 2022-79 ## Vérificat…

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## 29 CFR 1910 (OSHA) NOTE: Some materials-hydrogen fluoride gas and cadmium vapor, for example-may produce immediate transient effects that, even if severe, may pass without medical attention, but are followed by sudden, possibly fatal collapse 12-72 hours after exposure. The victim 'feels normal' from recovery from transient effects until collapse. Such materials in hazardous quantities are considered to be 'immediately' dangerous to life or health. Inerting means the displacement of the atmosphere in a permit space by a noncombustible gas (such as nitrogen) to such an extent that the resulting atmosphere is noncombustible. NOTE: This procedure produces an IDLH oxygen-deficient atmosphere. Isolation means the process by which a permit space is removed from service and completely protected against the release of energy and material into the space by such means as: blanking or blinding; misaligning or removing sections of lines, pipes, or ducts; a double block and bleed system; lockout or tagout of all sources of energy; or blocking or disconnecting all mechanical linkages. Line breaking means the intentional opening of a pipe, line, or duct that is or has been carrying flammable, corrosive, or toxic material, an inert gas, or any fluid at a volume, pressure, or temperature capable of causing injury. Non-permit confined space means a confined space that does not contain or, with respect to atmospheric hazards, have the potential to contain any hazard capable of causing death or serious physical harm. Oxygen deficient atmosphere means an atmosphere containing less than 19.5 percent oxygen by volume. Oxygen enriched atmosphere means an atmosphere containing more than 23.5 percent oxygen by volume. Permit-required confined space (permit space) means a confined space that has one or more of the following characteristics: - (1) Contains or has a potential to contain a hazardous atmosphere; - (2) Contains a material that has the potential for engulfing an entran…