Page 368 - Corrosion Engineering Principles and Practice

336 C h a p t e r 9 A t m o s p h e r i c C o r r o s i o n 337

40

35
30
Temperature (°C) 25 Ambient

20

15
Dew point
10
5
0
0 10 20 30 40 50 60 70 80
Time from loading (hrs)
FIGURE 9.7 Ambient and dew point temperatures as a function of the time
of loading of steel parts stored in a truck parked outdoor for three days.

realistic considering the mass of the steel parts and their partial
insulation from the ambient environment. Figure 9.8 clearly shows
that surface condensation on the vehicle parts was highly probable
during the three nights spent by the truck in the parking lot, with the
second night being the most dramatic.

16

12 No time lag
∆T (Ambient – dew point) 8 4

0

5-hrs time lag
–4
0 10 20 30 40 50 60 70 80
Time from loading (hrs)

FIGURE 9.8 Difference between ambient, with and without a time lag, and
dew point temperature as a function of the time of loading of steel parts
stored in a truck parked outdoor for three days.