User Guide

Steam Tables

Heat quantities and temperature-pressure relationships

are useful in a wide range of trap application problems.

This data is presented in Table 30-1 Properties of

Saturated Steam.

How the Tables Are Used

In addition to determining pressure-temperature rela-

tionships, you can compute the amount of steam that

will be condensed by any heating unit of known btu

output. Conversely, the tables can be used to determine

btu output if steam condensing rate is known.

Flash Steam

Flash steam is the steam formed when hot conden-

sate under pressure is released to a lower pressure.

The steam table (page 30) tells why it is formed. The

amount that will be for

med can be computed.

For e

xample, condensate at steam temper

ature and

under 100 psig pressure has a heat content of 308.8

btu’s per pound (see Column 4 in steam table). If this

condensate is discharged to atmospheric pressure

(0 psig), its heat content instantly drops to 180 btu’s

per pound. The surplus of 128.8 btu’s re-evaporates

or flashes a portion of the condensate.

The percentage of the condensate that will flash to

steam can be computed as follows: Divide the differ-

ence between the high and low heat contents (from

Column 4) by the latent heat at the lower pressure

and multiply by 100. Using the example above –

308.8 minus 180 = 128.8; 128.8

÷ by 970.3 (latent

heat at 0 psig from Column 5) = .133; .133 x 100 =

13.3%. Thus 13.3% of the condensate by weight will

flash to steam.

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