520 CHAPTER 20 1957 Guide tant that: (1) the total pressure drop does not exceed the initial gage pressure of the system, and in actual practice it should never exceed onehalf of the initial gage pressure; (2) the pressure drop is not so great as to cause excessive velocities; (3) there is a constant-initial pressure, except on systems specially designed for varying initial pressures, such as the sub-atmospheric, which normally operate under controlled partial vacua and orifice and vapor systems, which at times operate under, such partial vacua as may be obtained due to the condition of the fire; and (4) the rise in water due to pressure drop does not exceed the difference in level, for gravity return systems, between the lowest point on the steam main, the heating units, or the dry-return, and the'boiler water line.

540 CHAPTER 20 1957 Guide being fastened to the bucket.

724 CHAPTER 28 1957.

994 CHAPTER 40 1957 Guide Sound Control 995 confined to a channel or duct, the intensity values are averaged over the cross-section.

1 L' i. i : ;-!

1188 CHAPTER 49 1957 Guide any house or apartment.

CATALOG DATA SECTION INDEX TO ADVERTISERS HEATING VENTILATING AIR CONDITIONING GUIDE, 1957 A A-J MFG CO., 3601 E. 18 St., Dept.

104 CHAPTER 5 ,1958 Guide y Case 11. of Table 2 fits the conditions of the problem if only free conyec tion heating of the pipe is assumed.

362 CHAPTER 14 1958 Guide be completely evaporated below 680 F are likely to undergo cracking in vaporizing type burners, with the resulting possibilities of smoky combus tion and residues in the oil burner.

458 CHAPTER 17 1958 Guide , . shall be, not less than .the area of the largest flue or vent connector, plus 50 , : per cent.of the areas of the'additional flue or vent connectors. . ;> 3.

700.

728 s CHAPTER 28 1958 Guide Table 3.

794 1.2 a O CHAPTER 31 1958 Guide QaI------------- ------- -------------- ------------------------------------------ ------- ------- ------- ------- ------- --------------------- ------- ---------------------------------- 0 100 200 300 400 300 T-TEMPERATURE UNDER ACTUAL OPERATING CONDITIONS-F Fig. 4.

820 CHAPTER 31 1958 Guide CONDUCTIVITY OF INSULATION (k) (BTU PER HOUR PER SQ ET , PER DEG FAHR PER INCH THICKNESS) Fia.. 17.

914 CHAPTER 36 H3NI 3MvnOS U3d SOMHOd - 3afKS3dd 3imOS9V 1958 Guide hdni aavnos H3d soNnod - 3anss3dd simossv practical purposes, the specific volume and the enthalpy of any subcooled refrigerant can be taken as equal to the values read from the tables for a saturated liquid at the same temperature.