Answer:
Hot-dip galvanized components can be considered as follows:
Since the emissivity increases abruptly, then remains constant, and is only included as a factor in the Eurocode formulas, you could calculate and use the emissivity for a component with the fire resistance class > 30 by hand in this case (mean value).
ε = [0.35 · 30 min + 0.7 · (total time – start time with lower value (30 min))] / total time
Example with 90 min:
This value takes into account the reduction at the start of the fire.
