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5
FREON 12
 
A. SAFEST SHIPBOARD REFRIGERANT
 
5A1. Advantages of Freon 12. Freon 12 is, directly the result of a search for the perfect refrigerant, and it more nearly approaches that ideal than, any other so far discovered. The chemical name of Freon 12 is dichlorodifluoromethane. Its chemical symbol is CC12F2, which means that it contains one part carbon, two parts chlorine, and two parts fluorine. In manufacturing Freon 12, fluorine is substituted for part of the chlorine in carbon tetrachloride, and the result is Freon 12, with byproducts. This substitution has the remarkable effect of lowering the boiling point by 120 degrees, At atmospheric pressure, Freon 12 boils at -21.66 degrees F and freezes at -311 degrees F. Its latent heat of vaporization at atmospheric pressure is about 72 Btu per pound.

Freon 12 has so many advantages that it is used almost universally on ships today. Its advantages are as follows:

1. It is a safe refrigerant.

2. It is nonflammable:

3. It is nonexplosive.

4. It is noncorrosive.

5. Its vapor is nontoxic in quantities up to 20 percent by volume.

6. It will not harm foods, fabrics, furs, and so forth.

7. It is odorless in concentrations of 20 percent or less by volume. In high concentrations if has a slight odor of carbon tetrachloride, of which it is a derivative.

8. It is tasteless.

Additional advantages for operation:

9. It has a low boiling point, -21.66 degrees F atmospheric pressure.

10. It acts rapidly in freezing other substances; its latent heat at 5 degrees F is 69.47 Btu, or much lower than that of other refrigerants.

11. At the high-pressure point of its refrigeration cycle, it operates at comparatively low pressure; hence, the equipment does not require heavy mechanical construction.

  12. At the low-pressure point of its refrigeration cycle, it operates at pressures only slightly above atmospheric pressure, thus reducing the possibility of air entering the system in the event of leakage.

5A2. Disadvantages of Freon 12. Freon 12 has a few disadvantages, but they are far outweighed by its advantages. The disadvantages are:

1. While Freon 12 is nonflammable, it de composes in contact with an open flame at high temperature (1000 degrees F.), giving rise to phosgene, a highly toxic gas, and other decomposition products.

2. It is an excellent loosener of scale and dirt that may be left in or may get into the system. Such material is carried around in the system and is finally deposited in the strainers. However, some damage may also result during its journey. In installation or repair, great care should be taken to prevent the entry of any foreign matter into the system.

3. It does not mix with water. One important reason why air must be kept out of the system is that air almost always contains some water vapor. This water vapor tends to condense and freeze, thus interfering with correct operation, and damaging various valves and other parts of the system,

4. It is absorbed by lubricating oil.

5. SPECIAL NOTE. Liquid Freon 12 must not be spilled on the skin, and extreme care must be taken to prevent even tiny drops from getting into the eyes. The extreme cold produced by Freon 12, nearly 22 degrees below zero Fahrenheit, is such that even a tiny drop may cause the moisture in the tissue of the eyeball near it to freeze, and possibly result in serious injury to the eye. Moreover, because of the readiness with which lubricating oil absorbs Freon 12, there is always some Freon 12 in the oil of refrigerating and air conditioning systems. It is advisable not to

 
18

PROPERTIES OF SATURATED FREON VAPOR
A. S. R. E. STANDARD
Temp. Pressure Volume Density Heat content
from -40 degrees
Entropy from
-40 degrees
Temp.
Deg. F
t
Abs. lb./in.2
p
Gage lb./in.2
pd
Liquid ft.3/lb.
vf
Vapor ft.3/lb.
vg
Liquid lb./ft.3
1/vf
Vapor lb./ft.3
1/vg
Liquid Btu./lb.
hf
Latent Btu./lb.
h
Vapor Btu./lb.
hg
Liquid Btu./lb. deg. F.
sf
Vapor Btu./lb. deg. F.
sg
Deg. F.
t
-409.3210.92*0.01063.99194.580.2557073.5073.5000.17517-40
-389.829.91*.01063.72794.39.26830.4073.3473.740.00094.17490-38
-3610.348.87*.01063.55394.20.28150.8173.1773.98.00188.17463-36
-3410.877.80*.01063.38993.99.29511.2173.0174.22.00282.17438-34
-3211.436.66*.01073.23493.79.30921.6272.8474.46.00376.17412-32
-3012.025.45*0.01073.08893.590.32382.0372.6774.700.004710.17387-30
-2812.624.23*.01072.95093.39.33902.4472.5074.94.00565.17364-28
-2613.262.93*.01072.82093.18.35462.8572.3375.18.00659.17340-26
-2413.901.63*.01082.69892.98.37063.2572.1675.41.00753.17317-24
-2214.580.24*.01082.58392.78.38713.6671.9875.64.00846.17296-22
-2015.280.580.01082.47492.580.40424.0771.8075.870.009400.17275-20
-1816.011.31.01082.37092.38.42194.4871.6376.11.01033.17253-18
-1616.772.07.01082.27192.18.44034.8971.4576.34.01126.17232-16
-1417.552.85.01092.17791.97.45935.3071.2776.57.01218.17212-14
-1218.373.67.01092.08891.77.47895.7271.0976.81.01310.17194-12
-1019.204.500.01092.00391.570.49936.1470.9177.050.014030.17175-10
-820.085.38.01091.92291.35.52036.5770.7277.29.01496.17158-8
-620.986.28.01101.84591.14.54206.9970.5377.52.01589.17140-6
-421.917.21.01101.77290.93.56447.1470.3477.75.01682.17123-4
-222.878.17.01101.70390.72.58727.8370.1577.98.01775.17107-2
023.879.170.01101.63790.520.61098.2569.9678.210.018690.170910
224.8910.19.01101.57490.31.63528.6769.7778.44.01961.170752
425.9611.26.01111.51490.11.66069.1069.5778.67.02052.170604
5**26.5111.81.01111.48590.00.67359.3269.4778.79.02097.170525**
627.0512.35.01111.45789.88.68649.5369.3778.90.02143.170456
828.1813.48.01111.40389.68.71299.9669.1779.13.02235.170308
1029.3514.650.01121.35189.450.740210.3968.9779.360.023280.1701510
1230.5615.86.01121.30189.24.768710.8268.7779.59.02419.1700112
1431.8017.10.01121.25389.03.798111.2668.5679.82.02510.1698714
1633.0818.38.01121.20788.81.828811.7068.3580.05.02601.1697416
1834.4019.70.01131.16388.58.859812.1268.1580.27.02692.1696118
2035.7521.050.01131.12188.370.892112.5567.9480.490.027830.1694920
2237.1522.45.01131.08188.13.925113.0067.7280.72.02873.1693822
2438.5823.88.01131.04387.91.958813.4467.5180.95.02963.1692624
2640.0725.37.01141.00787.68.993013.8867.2981.17.03053.1691326
2841.5926.89.01140.97387.471.02814.3267.0781.39.03143.1690028
3043.1628.460.01150.93987.241.06514.7666.8581.610.032330.1688730
3244.7730.07.0115.90887.021.10215.2166.6281.83.03323.1687632
3446.4231.72.0115.87786.781.14015.6566.4082.05.03413.1686534
3648.1333.43.0116.84886.551.18016.1066.1782.27.03502.1685436
3849.8835.18.0116.81986.331.22116.5565.9482.49.03591.1684338
4051.6836.980.01160.79286.101.26317.0065.7182.710.036800.1683340
4253.5138.81.0116.76785.881.30417.4665.4782.93.03770.1682342
4455.4040.70.0117.74285.661.34917.9165.2483.15.03859.1681344
4657.3542.65.0117.71885.431.39318.3665.0083.36.03948.1680346
4859.3544.65.0117.69585.19.1.43818.8264.7483.57.04037.1679448
* Inches of mercury below one atmosphere.
** Standard ton temperatures.
 
19

PROPERTIES OF SATURATED FREON VAPOR
A. S. R. E. STANDARD
Temp. Pressure Volume Density Heat content
from -40 degrees
Entropy from
-40 degrees
Temp.
Deg. F
t
Abs. lb./in.2
p
Gage lb./in.2
pd
Liquid ft.3/lb.
vf
Vapor ft.3/lb.
vg
Liquid lb./ft.3
1/vf
Vapor lb./ft.3
1/vg
Liquid Btu./lb.
hf
Latent Btu./lb.
h
Vapor Btu./lb.
hg
Liquid Btu./lb. deg. F.
sf
Vapor Btu./lb. deg. F.
sg
Deg. F.
t
5061.3946.690.01180.67384.941.48519.2764.5183.780.041260.1678550
5263.4948.79.0118.65284.711.53419.7264.2783.99.04215.1677652
5465.6350.93.0118.63284.501.58320.1864.0284.20.04304.1676754
5667.8453.14.0119.61284.281.63320.6463.7784.41.04392.1675856
5870.1055.40.0119.59384.041.68621.1163.5184.62.04480.1674958
6072.4157.710.01190.57583.781.74021.5763.2584.820.045680.1674160
6274.7760.07.0120.55783.571.79522.0362.9985.02.04657.1673362
6477.2062.50.0120.54083.341.85122.4962.7385.22.04745.1672564
6679.6764.97.0120.52483.101.90922.9562.4785.42.04833.1671766
6882.2467.54.0121.50882.861.96823.4262.2085.62.04921.1670968
7084.8270.120.01210.49382.602.02823.9061.9285.820.050090.1670170
7287.5072.80.0121.47982.372.09024.3761.6586.02.05097.1669372
7490.2075.50.0122.46482.122.15324.8461.3886.22.05185.1668574
7693.0078.30.0122.45181.872.21825.3261.1086.42.05272.1667776
7895.8581.85.0123.43881.622.28424.8060.8186.61.05395.1666978
8098.7684.060.01230.42581.392.35326.2860.5286.800.054460.1666280
82101.787.00.0123.41381.122.42326.7660.2386.99.05534.1665582
84104.890.1.0124.40180.872.49527.2459.9487.18.05621.1664884
86**107.993.2.0124.38980.632.56927.7259.6587.37.05708.1664086**
88111.196.4.0124.37880.372.64528.2159.3587.56.05795.1663288
90114.399.60.01250.36880.112.72128.7059.0487.740.058820.1662490
92117.7103.0.0125.35779.862.79929.1958.7387.92.05969.1661692
94121.0106.3.0126.34779.602.88029.6858.4288.10.06056.1660894
96124.5109.8.0126.33879.322.96330.1858.1088.28.06143.1660096
98128.0113.3.0126.32879.063.04830.6757.7888.45.06230.1659298
100131.6116.90.01270.31978.803.13531.1657.4688.620.063160.16584100
102135.3120.6.0127.31078.543.22431.6557.1488.79.06403.16576102
104139.0124.3.0128,.30278.273.31632.1556.8088.95.06490.16568104
106142.8128.1.0128.29378.003.41132.6556.4689.11.06577.16560106
108146.8132.1.0129.28577.733.50933.1556.1289.27.06663.16551108
110150.7136.00.01290.27777.463.61033.6555.7889.430.067490.16542110
112154.8140.1.0130.26977.183.71434.1555.4389.58.06836.16533112
114158.9144.2.0130.26276.893.82334.6555.0889.73.06922.16524114
116163.1148.4.0131.25476.603.93435.1554.7289.87.07008.16515116
118167.4152.7.0131.24776.324.04935.6554.3690.01.07094.16505118
120171.8157.10.01320.24076.024.16736.1653.9990.150.071800.16495120
122176.2161.5.0132.23335.724.28836.6653.6290.28.07266.16484122
124180.8166.1.0133.27775.404.41337.1653.2490.40.07352.16473124
126185.4170.7.0133.22075.104.54137.6752.8590.52.07437.16462126
128190.1175.4.0134.21474.784.67338.1852.4690.64.07522.16450128
130194.9180.20.01340.20874.464.80838.6952.0790.760.076070.16438130
132199.8185.1.0135.20274.134.94839.1951.6790.86.07691.16425132
134204.8190.1.0135.19673.815.09439.7051.2690.96.07775.16411134
136209.9195.2.0136.19173.465.24740.2150.8591.06.07858.16396136
138215.0200.3.0137.18573.105.40540.7250.4391.15.07941.16380138
140220.2205.50.01380.18072.735.57141.2450.0091.240.080240.16363140
 
20

allow such contaminated oil to remain on the hands. Never touch the face with oily hands, especially near the eyes.

a. REMEDIES. If Freon 12 should come in contact with the eyes, the following first aid treatment should be given immediately:

1) Do not rub the eyes.

2) Put drops of sterile mineral oil in the

  eyes as an irrigant; if no sterile oil is available, use any clean oil.

3) If any irritation at all continues, the eyes should be washed with either a weak boric acid solution or a sterile salt solution, not exceeding 2 percent sodium chloride (table salt).

4) The person should receive medical attention at once.

 
B. SAFETY PRECAUTIONS
 
5B1. Keep Freon 12 out of eyes. Human beings are so constituted that familiarity with danger causes a gradual loss of consciousness of it. But remember that this does not cause Freon 12 to lose its freezing power. Always wear goggles in charging, testing, or repairing a Freon 12 system (see remedies in Section 5A2a).

5B2. Keep lubricating oil used in plant away from eyes. Invariably some Freon 12 is dissolved in lubricating oil used in the system. If such oil comes in contact with the eyes it is likely to cause damage by freezing the tissues.

5B3. Do not drop Freon 12 cylinders. Care must be taken not to drop a Freon 12 cylinder, either accidentally, or when putting it down. A fall or hard bump may cause damage to the valve, or change the pressure within.

  5B4. Do not fill Freon 12 cylinders beyond 80 percent capacity. The pressure-temperature relationship of Freon 12 is so positive that a rise in temperature always means a corresponding increase in pressure. Therefore, always leave at least 20 percent of the Freon 12 cylinder unfilled in order to provide a cushioning effect in case the pressure should increase.

5B5. Keep open flame away from Freon 12 cylinders. Open flame must be kept away from Freon 12 cylinders and they must not be heated above 120 degrees F. The safety plugs on these cylinders melt at 157 degrees F.

5B6. Never attempt to taste Freon 12. Since its freezing power is extremely high, never attempt to taste Freon 12.

 
C. FREON 12 CYLINDERS
 
5C1. Storing Freon 12. Freon 12 is transported and stored in cylinders, often called bottles. In the cylinders, Freon 12 is a liquid (with some gas also present), because, although it vaporizes at -21.66 degrees F under atmospheric pressure, it is charged into the cylinder under a pressure of 70 to 75 psi, and under this pressure Freon 12 remains in the liquid state. This particular pressure is used because it corresponds to a temperature of 70 degrees to 74 degrees F, which is ordinary room temperature.   Standard Navy Freon 12 cylinders contain 50 pounds of liquid Freon 12. The cylinders weigh 35 pounds when empty, and 85 pounds when containing the proper amount of Freon 12. All Navy Freon 12 cylinders are marked for identification, with a black body and a yellow neck. The test pressure for Freon 12 cylinders is 350 pounds. The bottoms of the cylinders are concave, so that in case of accident, they push out and keep the cylinder from blowing up.
 
D. THE PROPERTIES OF FREON 12
 
5D1. Table of Freon 12 properties. The tables on pages 19 and 20 list the various properties of Freon 12 that may be needed in   refrigeration work or in the operation of systems for temperatures ranging from -40 degrees to 140 degrees Fahrenheit.
 
21

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