![]() ![]() The atmosphere within the space will be tested to determine whether dangerous air contamination and/or oxygen deficiency exists. The surrounding area shall be surveyed to avoid hazards such as drifting vapors from the tanks, piping, or sewers. If blocking and/or isolation requires entry into the space the provisions for entry into a permit- required confined space must be implemented. ![]() However, where experience or knowledge of industrial use indicates there is a reasonable potential for contamination of air or engulfment into an occupied sewer, then all affected laterals shall be blocked. Not all laterals to sewers or storm drains require blocking. All pumps and lines which may reasonably cause contaminants to flow into the space shall be disconnected, blinded and locked out, or effectively isolated by other means to prevent development of dangerous air contamination or engulfment. If circumstances dictate an interruption in the work, the permit space must be re-evaluated and a new check list must be completed.Ĭontrol of atmospheric and engulfment hazards. ![]() This check list shall be kept at the job site for duration of the job. This list verifies completion of items listed below. The Confined Space Pre-Entry Check List must be completed by the LEAD WORKER before entry into a confined space. A written copy of operating and rescue procedures as required by these procedures shall be at the work site for the duration of the job. ![]() Any employee required or permitted to pre-check or enter an enclosed/confined space shall have successfully completed, -as a minimum, the training as required by the following sections of these procedures. All spaces shall be considered permit-required confined spaces until the pre-entry procedures demonstrate otherwise. Confined spaces may be entered without the need for a written permit or attendant provided that the space can be maintained in a safe condition for entry by mechanical ventilation alone, as provided in § 1910.146(c)(5). A concentration of oxygen in the atmosphere equal to or less than 19.5% by volume.Ĭertification. Equal to or greater than 10% of the lower flammable limit (LFL). If the presence of other toxic contaminants is suspected, specific monitoring programs will be developed. Equal to or more than 10 ppm hydrogen sulfide measured as an 8-hour time-weighted average. The employees could be exposed to the following: If tests for toxic gasses and vapors are necessary, they are performed last.Īppendix C to § 1910.146-Examples of Permit-required Confined Space Programs Combustible gasses are tested for next because the threat of fire or explosion is both more immediate and more life threatening, in most cases, than exposure to toxic gasses and vapors. A test for oxygen is performed first because most combustible gas meters are oxygen dependent and will not provide reliable readings in an oxygen deficient atmosphere. If a sampling probe is used, the entrant's rate of progress should be slowed to accommodate the sampling speed and detector response. When monitoring for entries involving a descent into atmospheres that may be stratified, the atmospheric envelope should be tested a distance of approximately 4 feet (1.22 m) in the direction of travel and to each side. Measurement of values for each atmospheric parameter should be made for at least the minimum response time of the test instrument specified by the manufacturer. Results of testing (i.e., actual concentration, etc.) should be recorded on the permit in the space provided adjacent to the stipulated acceptable entry condition. The atmosphere of a permit space which may contain a hazardous atmosphere should be tested for residues of all contaminants identified by evaluation testing using permit specified equipment to determine that residual concentrations at the time of testing and entry are within the range of acceptable entry conditions. Evaluation and interpretation of these data, and development of the entry procedure, should be done by, or reviewed by, a technically qualified professional (e.g., OSHA consultation service, or certified industrial hygienist, registered safety engineer, certified safety professional, certified marine chemist, etc.) based on evaluation of all serious hazards. The atmosphere of a confined space should be analyzed using equipment of sufficient sensitivity and specificity to identify and evaluate any hazardous atmospheres that may exist or arise, so that appropriate permit entry procedures can be developed and acceptable entry conditions stipulated for that space. Appendix B to § 1910.146-Procedures for Atmospheric TestingĪtmospheric testing is required for two distinct purposes: evaluation of the hazards of the permit space and verification that acceptable entry conditions for entry into that space exist. ![]()
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