REFRIGERANTS AND SAFETY PRECAUTIONS

The most prevalent use of asbestos materials aboard ship is in the fabrication and repair of pipe and boiler insulation. The greatest hazard is present when asbestos particles (dust) are in the air. In the interest of personnel safety, the Navy has implemented an asbestos control program. The objective is to eventually replace the asbestos insulating materials with nontoxic materials. In the meantime, the asbestos control program identifies asbestos hazards and implements stringent safety requirements to be followed by personnel working with materials that contain asbestos. Ship personnel are not authorized to remove or repair insulation containing asbestos, except in an operational emergency certified by the commanding officer. Repair and removal work should be referred to the local intermediate maintenance activity (IMA) or contractor. As you know, the greatest danger from asbestos exists when particles of asbestos are in the air, such as during rip-out of old insulation. Rip-out is normally performed by shipyard personnel; however, you may have to enter a space where there are asbestos particles. If you are ripping out old insulation or staying in the space where rip-out is in progress, you MUST wear protective clothing, use a pressure-demand supplied-air respirator (fig. 13-2), and be formally trained on asbestos-handling procedures. After completing your tasks, you MUST proceed to the designated decontamination center to remove the coveralls and respirator and to take a shower. These precautions should remove any asbestos particles and prevent the spread of asbestos dust to other sections of the ship. You should wet down contaminated disposable coveralls. Wet down is a procedure that reduces the possibility of dust being blown off of the coveralls. Then, dispose of the contaminated coveralls in heavy-duty plastic bags. Clearly mark the plastic bags with caution labels to warn personnel of the asbestos hazard. Insulation materials other than asbestos pose health hazards. For additional information on safe working practices involving these materials, consult the NSTM, chapter 635. REMEMBER, where safety is concerned, take nothing for granted. Your actions can have a positive or negative effect on you and your shipmates. REFRIGERANTS AND SAFETY PRECAUTIONS The refrigerants commonly used are fluids, and they are affected by heat, temperature, and pressure in a Figure 13-2.-Disposable protective coveralls and type C respirator. manner similar to water. Many different fluids are used as refrigerants; their selection is based on low boiling points and other desirable characteristics. The following refrigerants are the most commonly used on U.S. Navy ships: R-11, trichlorofluoromethane. R-11 is a colorless liquid or gas. At room temperature, R-11 has a slight ethereal odor (smells like ether or dry-cleaning fluid, tetrachloroethylene). R-12, dichlorodifluoromethane. R-12 is a colorless and odorless gas at room temperature. In high concentration, it has a slight ethereal odor. NOTE: Dichlorodifluoromethane (formerly F-12), is now called R-12. R-22, monochlorodifluoromethane. R-22 is a colorless and odorless gas, which, at room temperature in high concentration, has a slight ethereal odor. R-114, dichlorotetrafluoroethane. R-114 is a colorless and odorless gas, which, at room temperature in high concentration, has a slight ethereal odor. 13-5