R-113, trichlorotrifluoroethane. R-113 is a heavy colorless liquid, which, at room temperature, has a slight ethereal odor. R-113 is only used as a solvent, degreaser, and  flushing  agent.  It  is  not  used  as  a  shipboard refrigerant. These   refrigerants,   liquid   and   vapor,   are nonflammable and nonexplosive. Air mixtures of these refrigerants  are  not  capable  of  producing  a  flame.  The products of decomposition have a pungent odor and are very irritating in minute quantities. They give ample warning before dangerous concentrations are reached. R-12, R-22, and R-114 are shipped under pressure in steel cylinders. R-11 and R-113 are normally shipped in drums, although some R-11 is shipped in cylinders for submarine use. The refrigerant cylinders are easily identified by their orange-colored bodies. In addition, the following markings are made on the cylinder to minimize the possibility of misidentification of the gas: l The name of the gas is stenciled longitudinally on   two   diametrically   opposite   sides   of   the cylinder. .  A  decal  bearing  the  name  of  the  gas  may  be attached  to  the  shoulder  of  the  cylinder  90 degrees from the stenciling. WARNING Do not smoke, braze, or weld when refrigerant vapors   are   present.   Vapors   decompose   to phosgene,  acid  vapors,  and  other  products  when exposed to an open flame or a hot surface. The  following  safety  precautions  and  warnings apply to all of the refrigerants listed in the previous paragraphs. l  Exposure  to  large  concentrations  of  fluorocarbon refrigerants can be fatal. Vapors displace air (oxygen) in a space and result in asphyxia. In high concentrations, these  vapors  have  an  anesthetic  effect,  causing stumbling, shortness of breath, irregular or missing pulse, tremors, convulsions, and death. Fluorocarbon refrigerants and solvents should, therefore, be treated as toxic gases. . Initial adverse anesthetic effects of R-113 can be experienced at much lower levels than those of other refrigerants, even though all refrigerants listed here have a   threshold   limit   value   (TLV)   of   1,000   parts   of refrigerant per million parts of air (ppm). l   Personnel   overcome   by   inhalation   of fluorocarbon  vapors  may  develop  cardiac  problems. Remove  exposed  personnel  to  fresh  air  immediately.  If breathing  has  stopped,  apply  artificial  respiration.  Do not permit affected personnel to exert themselves or to exercise. TLVs  refer  to  airborne  concentrations  of  substances and represent conditions under which it is believed that nearly all workers may be repeatedly exposed for an 8-hour day, 40 hours per week without adverse effects. In  addition  to  the  precautions  previously  stated,  there  are other safety measures that should be followed. A few of these methods and precautions are as follows: . Because refrigerants R-12 and R-22 boil at such low temperatures, they may freeze if they are splashed into the eyes or onto the skin. Always wear chemical safety goggles or a full face shield when you work with any  refrigerant.  Wear  along-sleeved  shirt  and  protective gloves. l Vapors of fluorocarbon refrigerants are four to five times heavier than air and tend to collect in low places. Perform refrigerant detection within 2 feet of the deck and in possible air pockets. . Refrigeration machinery spaces should be well ventilated,  especially  when  personnel  are  servicing machinery.  Use  portable  blowers  if  necessary  to  keep the refrigerant vapor levels below the TLV of 1,000 ppm. . Always have two people present when work is being  done  on  refrigeration  systems.  Use  a  halide monitor with an alarm so you can be sure refrigerant vapor  concentrations  in  a  space  do  not  exceed  safe limits. SEWAGE SYSTEM In a continuing effort to control pollution of inland and  coastal  waters,  the  Navy  is  installing  sewage treatment systems on board naval ships. These marine sanitation systems are composed of three subsystems: l l l Flushing  water  system  (provides  flushing  water) Collection  system  (collects  waste) Treatment disposal system (treats and disposes of  waste) Sewage  discharged  by  naval  ships  into  rivers, harbors, and coastal waters and the environmental effects  of  sewage  pollution  are  of  great  concern  to  the Navy. In fact, the Navy is required to control sewage 13-6