OSHA Confined Space Regulation and Requirements
The OSHA regulation 29 CFR 1910.146 defines roles and responsibilities for confined space entry. The regulation requires that this program provide a basis for prevention of accidents and fatalities associated with confined spaces. The requirement includes the following:
• Recognition - Confined spaces and the hazards within are identified. Employees and safety representatives are responsible for recognizing and understanding hazards, protecting employees from hazards, and educating employees concerning worker protection and safe work practices.
• Evaluation - Qualified (trained) persons must test the space with suitable instruments. More than one type of testing instrument may be needed. In addition, Safety Data Sheets (SDS) and other reference sources may need to be reviewed to determine the exposure limits for hazardous materials.
• Controls - Procedures describing the specific measures and precautions which allow safe entry are contained in this program. Hazards may be controlled through engineering and/or safe work practices. (Ventilation via exhaust fans may be a good example to consider when/if appropriate.)
• Confined Space Entry Permit - The Confined Space Entry Permit is the heart of the entry control system. A permit is required for each permit required confined space entry. The permit certifies that the hazards have been identified and evaluated and that the required precautionary procedures are in place. The regulation requires a written permit system that insures the proper preparation, issuance, and use of entry permits.
• Training - Employees must be trained so that attendants, authorized entrants, and persons authorizing or in charge of the entry can work safely in and around the confined space. After initial training, employees may need periodic retraining to ensure continued competence in entry procedures and safe job practices.
• Rescue - Entrants and attendants must be specially trained on the proper use of safety and rescue equipment and on emergency rescue procedures for Confined Space Rescue.
Testing the Atmosphere
The atmosphere in a confined space may be hazardous due to: (1) low oxygen levels; (2) flammable or explosive concentrations of gases, vapors or dusts; or (3) toxic levels of gases and vapors. Therefore, the air in a confined space must be tested first for oxygen, then for flammable or combustible gases and vapors, and then for toxic gases and vapors. Before the monitoring process begins, the employer must understand when an employee is considered to be exposed to a hazardous substance. The results of air sampling and exposure monitoring that show the composition of an atmosphere to which an employee is actually exposed (even if the employee is using a respirator) are considered an employee exposure record under 29 CFR 1910.20(c)(5). If the employer as a result of sampling does not allow entry into the confined space, the sample would not be considered as a exposure record because no employee would have been exposed to the atmosphere sampled. It is important to understand that some gases and vapors are heavier than air and will settle to the bottom of a confined space. Also, some gases are lighter than air and will be found around the top of the confined space. Therefore, it is necessary to test all areas (top, middle, bottom) of a confined space with testing instruments that are calibrated in accordance with the manufacturer's recommendations to determine what atmospheric conditions are present. (See Appendix B to 29 CFR 1910.146, Procedures for Atmospheric Testing.) NOTE: Some multi-atmosphere testers require a supply of oxygen to conduct tests. A test for the percentage of oxygen is required to be conducted first.