DrFixIt Illustrates The Properties of Saturated Steam.A Chart Showing The properties of Saturated Steam, Definition of Terms and practical example. DrFixIt Illustrates The Properties of Saturated Steam with regard to Temperature, Sensible Heat, Latent Heat, Total Heat and Specific Volume 

Gauge Pressure PSIG 
Temperature Degrees F 
Sensible Heat BTU/lb 
Latent Heat BTU/lb 
Total Heat BTU/lb 
Specific Volume Cu Ft / lb 
0  212  180  971  1151  26.8 
10  239  207  953  1160  16.5 
20  259  227  939  1166  11.9 
30  274  243  929  1172  9.46 
40  286  256  920  1176  7.82 
50  298  267  912  1179  6.68 
60  307  277  906  1183  5.84 
70  316  286  898  1184  5.19 
80  324  294  891  1185  4.45 
90  331  302  886  1188  4.25 
100  338  309  880  1189  3.89 
150  366  339  857  1196  2.74 
200  388  362  837  1199  2.14 
250  406  382  820  1202  1.75 
300  421  398  805  1203  1.47 
350  435  414  790  1204  1.27 
400  448  428  777  1205  1.12 
450  460  439  766  1205  1.00 
500  470  453  751  1204  0.89 
For example, a radiator has an internal steam volume of 16.5 cubic feet. One pound of steam at 10 PSIG would occupy the entire internal volume of that radiator and the total amount of heat available would be 1160 BTU.
Now, lets crank our example boiler up to 450 PSIG. Now, one pound of steam occupies 1 cubic foot of volume at this pressure. The example radiator will now hold 16.5 x 1 = 16.5 pounds of steam. 16.5 pounds x 1205 BTU's total heat per pound =19882.5 BTU's.