Protected Beam Temperature Curves
Next, we must define the temperature growth profile in the protected beams, which have a much slower rate of heating than the unprotected members:
In this case the protected beams have been assumed to reach 513 degrees at the fire resistance time of 60 minutes (as this is the basis on which suppliers determine protection thicknesses) with a quasi-linear increase from 20 degrees in that time.
To do this:
1. Open the "Properties | Temperature Curves" dialog box.
2. Select the 'Add' tab. A new curve (curve '3') is automatically generated.
3. In the 'Type' drop-down box, select the 'trom file' option. Browse for the 'Protected_Beam.txt' temperature curve and open this. As before, the preview window will show a graphical representation of the curve.
4. Click the 'Add' button to place the curve on to the database for this example.
5. Select the 'Attach' tab and curve 3 from the drop-down menu. Choose the 'Attach to beams' option and click those beams that require protection:
6. Click the 'Attach' button.