A confined space is one that is large enough to enter and perform assigned work, has limited or restricted openings for entry or exit, and is not designed to be occupied continuously by a worker. OSHA regulations require employers to prepare written procedures and issue permits for entry into and work performed inside confined spaces.
A permit-required confined space (also referred to as a permit space by OSHA) has one or more of the following conditions: a hazardous atmosphere; a material that can engulf a person who enters; an inside design that could trap or asphyxiate a person who enters; and/or any other serious safety or health hazards.
Atmospheric testing of a permit space is required for two distinct purposes: evaluation of the hazards of the permit space and verification that acceptable conditions exist for entry into that space.
The atmosphere within a confined space is subject to evaluation testing to determine the chemical hazards that are or may become present in the space’s atmosphere, and to identify the steps required to ensure that atmospheric conditions are safe for a worker to enter the space. The testing results and the decisions about what steps to be followed before entry must be evaluated or reviewed by a technically qualified professional, such as an OSHA consultation service, a certified industrial hygienist, a registered safety engineer or a certified safety professional.
Before a permit space can be entered, the atmosphere must be tested using the steps identified during evaluation testing and outlined on the permit by a technically qualified professional. Verification testing is done to make sure that the chemical hazards that may be present are below the levels necessary for safe entry, and that they meet the conditions identified on the permit. The atmosphere should be tested first for oxygen levels, followed by combustible gases, and finally for toxic gases and vapors. A minimum response time for each test must be allowed for the air inside the confined space to be drawn into the equipment and for the sensor (or other detection device) to react to the chemical if it is present.
A permit space should be re-tested routinely during entry or before re-entry to ensure that the atmospheric conditions continue to be safe.
Consult the OSHA Fact Sheet for more information on atmospheric testing in confined spaces.
About the OSHA Training Center
The OSHA Training Center at Chabot-Las Positas Community College District offers high quality Occupational Safety & Health Administration standards-based training for construction, maritime and general industry at its Center in Dublin, California, as well as locations throughout California, Arizona, Nevada, Hawaii and Guam. Programs offered include OSHA safety standards, Outreach Trainer courses, Cal/OSHA standards curriculum, environmental courses and customized onsite safety training.
Upcoming permit-required confined space courses include: Permit Required Confined Space Standard – OSHA 7300, Permit Required Confined Space Entry – OSHA 2264 and Confined Space Rescue Operations (40-Hour) – OTC 304.
For more information and a complete course schedule, visit the OSHA Training Center website or call (866) 936-OSHA (6742).