The weight of steam required to heat a given quantity of water from a certain temperature to boiling point can be found by the following rule:

Rule

Multiply the number of pounds of water to be heated by the number of degrees temperature the water is to be raised, and divide the product by the total heat of steam at the pressure it is to be used, less the sensible heat at atmospheric pressure. This may be expressed by the formula:

S= (w h)/ (L-l) In which w=weight of steam in pounds w=pounds of water to be heated h=degrees Fahr. water is to be heated L=total heat of steam at pressure used l=sensible heat at atmospheric pressure

Example-How many pounds of steam at 70 pounds pressure will be required to heat 7,500 pounds of water from 48 degrees Fahr. to boiling point?

Solution

{7500 (212-8)}/ (1174-180) = 1237 pounds of steam. Answer.

An empirical rule that is sufficiently approximate for most purposes is to allow 1 pound of steam for 6 pounds of water to be heated. Taking the above example then 7500/6=1250 pounds of steam. Answer.

The temperature of steam at different pressures can be found in Table LIII. To use this table, add 14.7 to the reading of the gauge to get absolute pressure; the quantities desired will be opposite this figure.

Usually 15 pounds added to the gauge pressure to get the absolute pressure will be sufficiently accurate for all ordinary purposes.

Table LII - Properties Of Saturated Steam

Absolute Pressure

Temperature Degrees Fahr.

Heat Units above 32 Degrees Fahr. Contained in 1 Pound of Steam

Weight

1 Cubic

Foot in

Pounds

Volume of 1 Pound in

Cubic

Feet

In Water

Latent Heat

Total Heat

14.7

212.0

180.9

965.7

1146.6

.0379

26.37

15

213.1

181.6

965.3

.9

.0387

25.85

16

216.3

184.9

963.0

1147.9

.0411

24.33

17

219.5

188.1

960.8

1148.9

.0435

22.98

18

222.4

191.1

958.7

1149.8

.0459

21.78

19

225.3

193.9

956.7

1150.6

.0483

20.70

Table LIII - Continued

Absolute Pressure

Temperature Degrees Fahr.

Heat Units above 32 Degrees Fahr. Contained in 1 Pound of Steam

Weight

1 Cubic

Foot in

Pounds

Volume of 1 Pound in

Cubic

Feet

In Water

Latent Heat

Total Heat

20

228.0

196.7

954.8

1151.5

.0507

19.73

21

230.6

199.3

953.0

1152.3

.0531

18.84

22

233.1

201.8

951.2

1153.0

.0554

18.04

23

235.5

204.3

949.5

.8

.0578

17.30

24

237.8

206.6

947.9

1154.5

.0602

16.62

25

240.1

208.9

946.3

1155.2

.0625

16.00

26

242.2

211.1

944.7

.8

.0649

15.42

27

244.3

213.2

943.3

1156.5

.0672

14.88

28

246.4

215.3

941.8

1157.1

.0695

14.38

29

248.4

217.3

940.4

.7

.0719

13.91

30

250.3

219.3

939.0

1158.3

.0742

13.48

31

252.2

221.2

937.7

.9

.0765

13.07

32

254.0

223.0

936.4

1159.4

.0788

12.68

33

255.8

224.8

935.1

.9

.0812

12.32

34

257.5

226.6

933.9

1160.5

.0835

11.98

35

259.2

228.3

932.7

1161.0

.0858

11.66

36

260.9

230.0

931.5

.5

.0881

11.36

37

262.5

231.6

930.4

1162.0

.0904

11.07

38

264.1

233.3

929.2

.5

.0927

10.79

39

265.6

234.8

928.1

.9

.0949

10.53

40

267.2

236.4

927.0

1163.4

.0972

10.28

41

268.7

237.9

926.0

.9

.0995

10.05

42

270.1

239.4

924.9

1164.3

.1018

9.83

43

271.6

240.8

923.9

.7

.1041

9.61

44

273.0

242.3

922.9

1165.2

.1063

9.40

45

274.3

243.7

921.9

.6

.1086

9.21

46

275.7

245.1

920.9

1166.0

.1109

9.02

47

277.0

246.4

920.0

.4

.1131

8.84

48

278.3

247.7

919.1

.8

.1154

8.67

49

279.6

249.1

918.1

1167.2

.1177

8.50

50

280.9

250.3

917.3

.6

.1199

8.34

51

282.2

251.6

916.4

1168.0

.1222

8.19

52

283.4

252.9

915.5

.4

.1244

8.04

53

284.6

254.1

914.6

.7

.1267

7.89

54

285.8

255.3

913.8

1169.1

.1289

7.76

55

287.0

256.5

912.9

.4

.1312

7.62

56

288.1

257.7

912.1

1169.8

.1334

7.50

57

289.3

258.9

911.3

1170.2

.1357

7.37

58

290.4

260.0

910.5

.5

.1379

7.25

59

291.5

261.1

909.7

.8

.1401

7.14

60

292.6

262.3

908.9

1171.2

.1424

7.02

61

293.7

263.3

908.2

.5

.1446

6.92

62

294.7

264.4

907.4

.8

.1468

6.81

63

295.8

265.5

906.6

1172.1

.1491

6.71

64

296.8

266.6

905.9

.5

.1513

6.61

65

297.8

267.6

905.2

.8

.1535

6.52

Table LIII - Continued

Absolute Pressure

Temperature Degrees Fahr.

Heat Units above 32 Degrees

Fahr.

Contained in 1 Pound of Steam

Weight of

1 Cubic

Foot in Pounds

Volume of 1 Pound in

Cubic

Feet

In Water

Latent Heat

Total Heat

66

298.8

268.7

904.4

1173.1

.1557

6.42

67

299.8

269.7

903.7

.4

.1579

6.33

68

300.8

270.7

903.0

.7

.1602

6.24

69

301.8

271.7

902.3

1174.0

.1624

6.16

70

302.8

272.7

901.6

.3

.1646

6.08

71

303.7

273.6

901.0

.6

.1668

6.00

72

304.7

274.6

900.3

.9

.1690

5.92

73

305.6

275.6

899.6

1175.2

.1712

5.84

74

306.5

276.5

898.9

.4

.1734

5.77

75

307.4

277.4

898.3

.7

.1756

5.69

76

308.3

278.4

897.6

1176.0

.1778

5.62

77

309.2

279.3

897.0

.3

.1800

5.56

78

310.1

280.2

896.3

.5

.1822

5.49

79

311.0

281.1

895.7

.8

.1844

5.42

80

311.9

282.0

895.1

1177.1

.1866

5.36

81

312.7

282.8

894.5

.3

.1888

5.30

82

313.6

283.7

893.9

.6

.1910

5.24

83

314.4

284.5

893.3

.8

.1932

5.18

84

315.3

285.4

892.7

1178.1

.1954

5.12

85

316.1

286.2

892.1

.3

.1976

5.06

86

316.9

287.1

891.5

.6

.1998

5.01

87

317.7

287.9

890.9

.8

.2020

4.95

88

318.5

288.8

890.3

1179.1

.2042

4.90

89

319.3

289.6

889.7

.3

.2063

4.85

90

320.1

290.4

889.2

.6

.2085

4.80

91

320.9

291.2

888.6

.8

.2107

4.75

92

321.7

291.9

888.1

1180.0

.2129

4.70

93

322.4

292.8

887.5

.3

.2151

4.65

94

323.2

293.5

887.0

.5

.2173

4.60

95

323.9

294.3

886.4

.7

.2194

4.56

96

324.7

295.1

885.9

1181.0

.2216

4.51

97

325.4

295.8

885.4

.2

.2238

4.47

98

326.2

296.6

884.8

.4

.2260

4.43

99

326.9

297.3

884.3

.6

.2281

4.38

100

327.6

298.1

883.8

.9

.2303

4.34

101

328.3

298.8

883.3

1182.1

.2325

4.30

102

329.1

296.6

882.7

.3

.2346

4.26

103

329.8

300.3

882.2

.5

.2368

4.22

104

330.5

301.0

881.7

.7

.2390

4.19

105

331.2

301.7

881.2

.9

.2411

4.15

106

331.9

302.4

880.7

1183.1

.2433

4.11

107

332.6

303.2

880.2

.4

.2455

4.07

108

333.2

303.9

879.7

1183.6

.2476

4.04

109

333.9

304.6

879.2

.8

.2498

4.00

110

334.6

305.3

878.7

1184.0

.2519

3.97

111

335.3

305.9

878.3

.2

.2541

3.94

Table LIII - Continued

Absolute Pressure

Temperature Degeees Fahr.

Heat Units above 32 Degrees

Fahr.

Contained in 1 Pound of Steam

Weight of

1 Cubic

Foot in Pounds

Volume of

1 Pound in

Cubic

Feet

In Water

Latent Heat

Total Heat

112

335.9

306.6

877.8

1184.4

.2563

3.90

113

336.6

307.3

877.3

.6

.2584

3.87

114

337.2

308.0

876.8

.8

.2606

3.84

115

337.9

308.6

876.4

1185.0

.2627

3.81

116

338.5

309.3

875.9

.2

.2649

3.78

117

339.2

310.0

875.4

.4

.2670

3.75

118

339.8

310.6

875.0

.6

.2692

3.72

119

340.4

311.3

874.5

.8

.2713

3.69

120

341.1

311.9

874.1

1186.0

.2735

3.66

121

341.7

312.5

873.6

.1

.2757

3.63

122

342.3

313.1

873.2

.3

.2778

3.60

123

342.9

313.8

872.7

.5

.2799

3.57

124

343.5

314.4

872.3

.7

.2821

3.55

125

344.1

315.1

871.8

.9

.2842

3.52

126

344.7

315.7

871.4

1187.1

.2864

3.49

127

345.3

316.3

871.0

.3

.2885

3.47

128

345.9

316.9

870.5

.4

.2907

3.44

129

346.5

317.5

870.1

.6

.2928

3.42

130

347.1

318.1

869.7

.8

.2950

3.39

131

347.7

318.7

869.3

1188.0

.2971

3.37

132

348.3

319.3

868.9

.2

.2992

3.34

133

348.9

319.9

868.4

.3

.3014

3.32

134

349.4

320.5

868.0

.5

.3035

3.30

135

350.0

321.1

867.6

.7

.3057

3.27

136

350.6

321.7

867.2

.9

.3078

3.25

137

351.1

322.3

866.8

1189.1

.3099

3.23

138

351.7

322.8

866.4

.2

.3121

3.20

139 140

352.3 352.8

323.4 324.0

866.0 865.6

.4 .6

.3142 .3163

3.18 3.16

141

353.4

324.6

865.1

.7

.3185

3.14

142

353.9

325.1

864.8

.9

.3206

3.12

143

354.5

325.7

864.4

1190.1

.3227

3.10

144

355.0

326.2

864.0

.2

.3249

3.08

145

355.6

326.8

863.6

.4

.3270

3.06

146

356.1

327.4

863.2

.6

.3291

3.04

147

356.6

327.9

862.8

.7

.3313

3.02

148

357.2

328.5

862.4

.9

.3334

3.00

149

357.7

329.0

862.0

1191.0

.3355

2.98

150

358.2

329.6

861.6

.2

.3376

2.96

160

363.3

334.9

857.9

1192.8

.3589

2.79

170

368.2

339.9

854.4

1194.3

.3801

2.63

180

372.9

344.7

851.0

1195.7

.4012

2.49

190

377.4

349.3

847.7

1197.0

.4223

2.37

200

381.6

353.7

844.6

1198.3

.4433

2.26

Table LIII - Continued

Properties of Saturated Steam of from 32 Degrees to 212

Degrees Fahr. at Pressures under

One Atmosphere

Temperature Degrees Fahr.

Pressure

Total Heat of

One Pound

Reckoned from Water at

32 Degrees

Fahr.

Units

Weight of 100 Cubic

Feet Pounds

Volume of

One Pound of

Vapor Cubic Feet

Inches of Mercury

Pounds per Square Inch

32

.181

.089

1091.2

.031

3226

35

.204

.100

1092.1

.034

2941

40

.248

.122

1093.6

.041

2439

45

.299

.147

1095.1

.049

2041

50

.362

.178

1096.6

.059

1695

55

.426

.214

1098.2

.070

1429

60

.517

.254

1099.7

.082

1220

65

.619

.304

1101.2

.097

1031

70

.733

.360

1102.8

.114

877.2

75

.869

.427

1104.3

.134

746.3

80

1.024

.503

1105.8

.156

641.0

85

1.205

.592

1107.3

.182

549.5

90

1.410

.693

1108.9

.212

471.7

95

1.647

.809

1110.4

.245

408.2

100

1.917

.942

1111.9

.283

353.4

105

2.229

1.095

1113.4

.325

307.7

110

2.579

1.267

1115.0

.373

268.1

115

2.976

1.462

1113.5

.426

234.7

120

3.430

1.685

1118.0

.488

204.9

125

3.933

1.932

1119.5

.554

180.5

130

4.509

2.215

1121.1

.630

158.7

135

5.174

2.542

1122.6

.714

140.1

140

5.860

2.879

1124.1

.806

124.1

145

6.662

3.273

1125.6

.909

110.0

150

7.548

3.708

1127.2

1.022

97.8

155

8.535

4.193

1128.7

1.145

87.3

160

9.630

4.731

1130.2

1.333

75.0

165

10.843

5.327

1131.7

1.432

69.8

170

12.183

5.985

1133.3

1.602

62.4

175

13.654

6.708

1134.8

1.774

56.4

180

15.291

7.511

1136.3

1.970

50.8

185

17.044

8.375

1137.8

2.181

45.9

190

19.001

9.335

1139.4

2.411

41.5

195

21.139

10.385

1140.9

2.662

37.6

200

23.461

11.526

1142.4

2.933

34.1

205

25.994

12.770

1143.9

3.225

31.0

210

28.753

14.126

1145.5

3.543

28.2

212

29.922

14.700

1146.1

3.683

27.2