Before handling refrigerant bottles, review the safety precautions listed in Naval Ships Technical Manual, chapter 516, Refrigeration Systems. Refrigerants are furnished in cylinders for use in shipboard refrigeration systems. The following precautions must be observed in the handling, use, and storage of these cylinders:

1. NEVER drop cylinders or permit them to strike each other violently.

2. NEVER use a lifting magnet or a sling (rope or chain) to handle cylinders. (A crane may be used if a safe cradle or platform is provided to hold the cylinders.)

3. Caps on refrigerant cylinders are provided for valve protection. Always keep the caps on the cylinders except when the cylinders are being used.

4. Whenever refrigerant is discharged from a cylinder, always weigh the cylinder immediately and record the weight of the refrigerant remain-ing in the cylinder.

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 a system was designed should ever be introduced into the system. Check the equipment nameplate or the NAVSEA technical manual to determine the proper refrigerant type and charge. Putting the wrong refrigerant into a system can 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 cylinders as rollers and supports.

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. Be sure the threads on regulators or other connections are the same as those on the cylinder valve outlets. NEVER force connections that do not fit.

12. ALWAYS use the correct pressure gauges and regulator with the gas cylinders for which they were intended.

13. NEVER attempt to repair or alter cylinders or valves.

14. NEVER fill R-12 cylinders beyond 85 percent capacity.

15. 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, make sure they are protected against extremes of weather. NEVER allow a cylinder to be subjected to temperatures above 130F.

16. NEVER allow R-12 to come in contact with a flame or red-hot metal! When exposed to excessively high temperatures, (approximately 1,000F or above) R-12 breaks down into phosgene gas, an extremely poisonous substance.

As a freezing agent, R-12 is so powerful that even a very small amount can freeze the delicate tissues of the eye, 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 into the eyes, the person suffering the injury should receive immediate medical treatment to avoid permanent damage. In the meantime, immediately start irrigating and washing the victims eyes gently with water at room temperature for 15 minutes. Make sure the person does not rub the eyes. If R-12 comes in contact with the skin, it may cause frostbite. This injury should be treated as any other cause 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.

Generally, mixtures of R-12 vapor and air, in all proportions, are not irritating to the eyes, nose, throat, and lungs. The refrigerant will not contaminate or poison foods or other supplies with which it may come in contact. The vapor, too, is nonpoisonous. However, if R-12 concentrations become excessive, unconsciousness or even death may result from lack of oxygen to the brain.

SUMMARY

An EN3 should be familiar with the refrigeration plants that are most commonly used aboard naval vessels. You should recognize the major components and know the locations and functions of those parts as well as other supporting equipment in the system. Our discussion of refrigeration plants would be incomplete if you are not made aware of the safety precautions and dangers involved in working with refrigerants. For additional information, you should refer to the Naval Ships Technical Manual, chapter 516.

If you are uncertain as to the major components of a refrigeration system and their functions within the system, you should reread this chapter before continuing to chapter 17.