There was an article some time back about fire ladders and how wooden ones will still be structurally sound after getting quite burnt, while metal ones can lose their integrity well below temperatures where the metal would actually melt.
I think it was in relation to the San Francisco fire department.
And worse, 600 VDC trolley lines, which are closer to the ground than uninsulated distribution feeders. Unlike power lines, trolley wire covers a sizable fraction of street area.[1] Trying to raise even a 20 foot metal ladder is dangerous.
That's fair, but I know of no aluminum I-beams used in modern highrise construction which is the context of my sentence.
Truss roofs are made from steel of various shapes, even I-beams, and wood. I'm only asking for clarification if all truss designs regardless of material are problematic in a fire.
If you're the fire department, and you're moving them around regularly (as opposed to a fixed installation), the weight advantage of aluminum over steel is probably compelling. Wooden ladders are heavier than aluminum, which is part of why you no longer see them for sale at most stores, but they're still lighter than steel.
I think it was in relation to the San Francisco fire department.