Section 1915.135 - Powder actuated fastening tools(a) The section shall apply to ship repairing and shipbuilding only.(b)General precautions.(1) Powder actuated fastening tools shall be tested each day before loading to ensure that the safety devices are in proper working condition. Any tool found not to be in proper working order shall be immediately removed from service until repairs are made.(2) Powder actuated fastening tools shall not be used in an explosive or flammable atmosphere.(3) All tools shall be used with the type of shield or muzzle guard appropriate for a particular use.(4) Fasteners shall not be driven into very hard or brittle materials such as cast iron, glazed tile, surface hardened steel, glass block, live rock, face brick or hollow title.(5) Fasteners shall not be driven into soft materials unless such materials are backed by a substance that will prevent the pin or fastener from passing completely through and creating a flying missile hazard on the opposite side.(6) Unless a special guard, fixture or jig is used, fasteners shall not be driven directly into materials such as brick or concrete within 3 inches of the unsupported edge or corner, or into steel surfaces within 1/2 inch of the unsupported edge or corner. When fastening other material, such as 2 * 4 inch lumber to a concrete surface, fasteners of greater than 7/32 inch shank diameter shall not be used and fasteners shall not be driven within 2 inches of the unsupported edge or corner of the work surface.(7) Fasteners shall not be driven through existing holes unless a positive guide is used to secure accurate alignment.(8) No attempt shall be made to drive a fastener into a spalled area caused by an unsatisfactory fastening.(9) Employees using powder actuated fastening tools shall be protected by personal protective equipment in accordance with the requirements of subpart I of this part.(c)Instruction of operators. Before employees are permitted to use powder actuated tools, they shall have been thoroughly instructed by a competent person with respect to the requirements of paragraph (b) of this section and the safe use of such tools as follows: (1) Before using a tool, the operator shall inspect it to determine that it is clean, that all moving parts operate freely and that the barrel is free from obstructions.(2) When a tool develops a defect during use, the operator shall immediately cease to use it and shall notify his supervisor.(3) Tools shall not be loaded until just prior to the intended firing time and the tool shall not be left unattended while loaded.(4) The tool, whether loaded or empty, shall not be pointed at any person, and hands shall be kept clear of the open barrel end.(5) In case of a misfire, the operator shall hold the tool in the operating position for at least 15 seconds and shall continue to hold the muzzle against the work surface during disassembly or opening of the tool and removal of the powder load.(6) Neither tools nor powder charges shall be left unattended in places where they would be available to unauthorized persons.47 FR 16986, Apr. 20, 1982, as amended at 61 FR 26351, May 24, 1996