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Physical Data for HVAC System Design

Physical Data for HVAC System Design 29

2.6 Steam Data

Steam is used for many heating processes in HVAC. Most of the steam
data come from one source, namely, Keenan and Keyes’
Thermodynamic Properties of Steam. This is a fundamental reference
for any engineer working with steam. Table 2.6 provides the basic
steam data, while vapor pressures are included in Tables 2.3 and 2.4
for the computation of net positive suction head available and the de-
termination of cavitation pressures at various operating temperatures.
In HVAC, there are two basic steam pressure ranges: (1) up to 15
psig (250°F) and (2) above 15 psig steam pressure. This is derived
from the American Society of Mechanical Engineers’ (ASME) boiler
codes, (1) the Heating Boiler Code for steam pressures up to 15 psig
and (2) the Power Boiler Code for steam pressures above 15 psig. See
Chap. 19 for additional information on boilers.

TABLE 2.6 Basic Steam Data
Enthalpy, Btu/lb
Absolute Steam Saturated Saturated
pressure, lb/in 2 temperature, °F liquid Evaporation vapor
14.7 212.00 180.07 970.3 1150.4
16 216.32 184.42 967.6 1152.0
18 222.41 190.56 963.6 1154.2
20 227.96 196.16 960.1 1156.3
22 233.07 201.33 956.8 1158.1
24 237.82 206.14 953.7 1159.8
26 242.25 210.62 950.7 1161.3
28 246.41 214.83 947.9 1162.7
30 250.33 218.82 945.3 1164.1
35 259.28 227.91 939.2 1167.1
40 267.25 236.03 933.7 1169.7
45 274.44 243.36 928.6 1172.0
50 281.01 250.09 924.0 1174.1
60 292.71 262.09 915.5 1177.6
70 202.92 272.61 907.9 1180.6
80 312.03 282.02 901.1 1183.1
90 320.27 290.56 894.7 1185.3
100 327.81 298.40 888.8 1187.2
125 344.33 315.68 875.4 1191.1
150 358.42 330.51 863.6 1194.1
174 370.29 343.10 853.3 1196.4
200 381.79 355.36 843.0 1198.4

NOTE: Absolute pressure gauge atmospheric pressures.
SOURCE: Joseph H. Keenan and Frederick G. Keyes, Thermodynamic Properties of Steam,
Wiley, New York, 1936.

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