Chapter 19. -REFRIGERATION AND AIR CONDITIONING PLANTS 



Ventilation is accomplished chiefly by means 

 of fans which supply and exhaust through ven- 

 tilation duct systems. Most fans used in duct 

 systems are of the axial-flow type, but some 

 centrifugal fans are used. Bracket fans are used 

 to provide local circulation in certain spaces. 

 Portable fans are used for such purposes as 

 temporary ventilation of compartments after 

 painting, exhausting toxic gases from closed 

 spaces and tanks, and cooling hot areas around 

 machinery while repairs are being made. 



SAFETY PRECAUTIONS 



Refrigerants are furnished in cylinders for 

 use in shipboard refrigeration and air condition- 

 ing systems. The following precautions must be 

 observed by personnel handling, using, and stor- 

 ing these cylinders: 



1. Never drop cylinders nor permit them to 

 strike each other violently. 



2. Never use a lifting magnet or a sling 

 (rope or chain) when handling cylinders. A crane 

 may be used if a safe cradle or platform is 

 provided to hold the cylinders. 



3. Caps provided for valve protection must 

 be kept on cylinders except when the cylinders 

 are being used. 



4. Whenever refrigerant is discharged from 

 a cylinder, the cylinder should be weighed 

 immediately and the weight of the refrigerant 

 remaining in the cylinder should be recorded. 



5. Never attempt to mix gases in a cylinder. 



6. NEVER put the wrong refrigerant into a 

 refrigeration system! No refrigerant except the 

 one for which the system was designed should 

 ever be introduced into the system. In some 

 cases, putting the wrong refrigerant into a sys- 

 tem may cause a violent explosion. 



7. When a cylinder has been emptied, close 

 the cylinder valve immediately to prevent the 

 entrance of air, moisture, or dirt. Also, be sure 

 to replace the valve protection cap. 



8. Never use cylinders for any purpose other 

 than their intended purpose. DO NOT use them 

 as rollers, supports, etc. 



9. DO NOT tamper with the safety devices 

 in the valves or cylinders. 



10. Open cylinder valves slowly. Never use 

 wrenches or other tools except those provided 

 by the manufacturer. 



11. Make sure that the threads on regulators 

 or other connections are the same as those on 

 the cylinder valve outlets. Never force connec- 

 tions that do not fit. 



12. Regulators and pressure gages pro- 

 vided for use with a particular gas must 

 NOT be used on cylinders containing other 

 gases. 



13. Never attempt to repair or alter cylin- 

 ders or valves. 



14. Never fill R-12 cylinders beyond 80 

 percent of capacity. 



15. Whenever possible, store cylinders in a 

 cool, dry place, in an upright position. If the 

 cylinders are exposed to excessive heat, a 

 dangerous increase in pressure will occur. If 

 cylinders must be stored in the open, take care 

 that they are protected against extremes of 

 weather. NEVER allow a cylinder to be sub- 

 jected to a temperature above 125° F. 



16. NEVER allow R-12 to come in contact 

 with a flame or red-hot metal! When exposed 

 to excessively high temperatures, R-12 breaks 

 down into PHOSGENE gas, an extremely poison- 

 ous substance. Because R-12 is such apowerful 

 freezing agent that even a very small amount 

 can freeze the delicate tissues of the eyes, 

 causing permanent damage; it is essential that 

 goggles be worn by all personnel who may be 

 exposed to a refrigerant, particularly in its 

 liquid form. If refrigerant does get in the eyes, 

 the person suffering the injury should receive 

 medical treatment immediately in order to avoid 

 permanent damage to the eyes. In the meantime, 

 put drops of clean olive oil, mineral oil, or 

 other nonirritating oil in the eyes, and make 

 sure that the person does not rub his eyes. 

 CAUTION: Do not use anything except clean, 

 nonirritating oil for this type of eye injury. 

 (NOTE: If large leaks are indicated, the soap 

 method should be used to detect leaks; for 

 minute leaks, the halide torch should be em- 

 ployed.) 



If R-12 comes in contact with the skin, it 

 may cause frostbite. This injury should be 

 treated as any other case of frostbite. Immerse 

 the affected part in a warm bath for about 10 

 minutes, then dry carefully. DO NOT rub or 

 massage the affected area. 



R-12 is considered a fluid of low toxicity. 

 However, in closed spaces, high concentrations 

 displace the oxygen in the air and thus do not 

 sustain life. If a person should be overcome 

 by R-12 remove him IMMEDIATELY to a well- 

 ventilated place and get medical attention at the 

 earliest opportunity. Watch his breathing. If 

 the person is not breathing, give artificial 

 respiration. 



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