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Cold Structure Temperature Curves
Now comes the task of defining the temperature profile for the simulation. We must define the key temperature growth, in different parts of the structure, with time. Two aspects of temperature need to be defined: the time-temperature relationship for the fire, and the temperature profile through individual sections. The procedure involves defining particular temperature regimes and then applying these to groups of members with common temperature regimes.
Firstly, the parts of the structure that are to remain at ambient temperature throughout the duration of the fire (i.e. the 'cold structure') must be specified.
A number of common relationships are available for selection from the integral Vulcan library. Other time-temperature relations can be added. In this case, the required relationship is linear, one of the pre-defined cases.
To do this:
1. Open the "Properties | Temperature Curves" dialog box.
2. Select the 'Edit' tab. You will notice that the entire structure has the same initial temperature curve (curve '1').
3. In the box corresponding to 60 minutes of the fire, enter '20.000' as the final temperature (20 degrees celcius is ambient temperature in this example). You will notice that the preview curve changes to a straight, horizontal line.
4. The entire structure is now regarded as being 'cold'. From this point forward, the elements that are not to be treated as 'cold' will have their own temperature curves defined and attached to them...