API St 2217A-2009 pdf download.
Guidelines for Safe Work in Inert Confined Spaces in the Petroleum and Petrochemical Industries
3.8 inert entry Entry into a confined space with an inert atmosphere starts as soon as any part of the entrant’s body breaks the plane of an opening into the space and triggers the need for rescue capability. “Entry” includes all subsequent activities in the inert confined space. 3.9 inerting The process of eliminating the potential for a flammable atmosphere by using an inert gas such as nitrogen or carbon dioxide to displace oxygen required for ignition. 3.10 lower flammable limit LFL The minimum concentration of a vapor in air (or other oxidant) below which propagation of flame does not occur on contact with an ignition source. The LFL is usually expressed as a volume percentage of the vapor in air. Sometimes called lower explosive limit (LEL). In popular terms, a mixture containing a percentage of flammable vapor below the LFL is too “lean” to burn. 3.11 material safety datasheet MSDS Written or printed material concerning a hazardous chemical and prepared in accordance with OSHA 29 CFR 1910.1200, ANSI Z400.1 or comparable international standard. An MSDS provides data on physical properties, safety, fire, and health hazards for a particular chemical, mixture or substance. 3.12 oxygen-deficient atmosphere An atmosphere in which the oxygen content is below that needed for normal human function without impairment. For inert entry, the typical oxygen content (below 5 % in inert entry situations) is very much less than the oxygen-deficient definition often used (e.g. by OSHA) of “atmosphere containing less than 19.5 percent oxygen by volume” (the OSHA limit is appropriate for areas outside the “hot zone”). Inert entry requires much lower oxygen concentration percentages to provide a working environment minimizing fire hazards by maintaining the oxygen level low enough to prevent combustion.
4 Administrative Controls 4.1 Written Procedures and Guidelines Each employer whose employees perform confined space work in inert atmospheres shall establish and maintain written procedures and a system of authority and responsibility for controlling work in and near these confined spaces. As a minimum, the written procedures shall: a) Be approved by facility management and identify who will authorize inert confined space entry. b) Require that the entrants, entry supervisor, and rescuers be identified (see 4.2 and 6.2). c) Provide for a written confined space entry permit specifically addressing inert entry. d) Require all involved personnel to be trained in the hazards present in confined spaces with inert atmospheres. e) Require all involved personnel to be trained in the use of proper equipment, procedures, and safeguards for their protection. f) Establish a procedure to ensure that training for all personnel is current before the start of each job. g) Establish the requirements for a prejob planning conference that involves representatives of those plant operations affected by the entry to review the written procedures, specific work to be performed, supervisory responsibilities, potential hazards, and safeguards to be followed. Prejob planning shall involve personnel responsible for the overall work on site during the inert entry and those who will be leading the inert entry work. This is often done in “face-to-face” meetings among the people involved. h) Establish appropriate emergency action plans (see 7.7 and 7.8). i) Establish criteria to restrict access to the confined space and the surrounding “hot zone” area to prevent unauthorized entry into the confined space or unprotected exposure to effluent. 4.2 Entry Supervisor Each inert entry shall have an entry supervisor designated by the employer. Before entry begins, the entry supervisor identified on the permit shall sign the entry permit to authorize entry. This safe work practice is also a legal requirement