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Comment by lisper | Hacker News Reader

> one can't help but suspect that sheer tradition is a somewhat significant factor

Only if you didn't read the article.

"There's a city-specific reason why San Francisco has stuck with wood rather than swap over to metals, and the answer lies in looking up. The high-voltage cables and wires that guide the city's (oft-maligned) public transport system Muni, and trolley cars crisscross above nearly every street, mean that ladders made of conductive elements are generally just too dangerous to use."

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And only if you're also about 40 years behind ladder tech - notice the stepladders in the "A view of the main repair facility" photo?

They're nonconductive fiberglass.

They're stronger than wood, lighter than wood, don't need to be oiled/varnished, don't require cutting down old-growth trees, and aren't susceptible to moisture damage.

You can buy them exhaustively tested, mass produced, in whatever quantities you require for a couple hundred dollars - probably an order of magnitude less than these artisanal wooden ladders.

Can fiberglass ladders be refurbished and used for decades, or do they weaken and need to be replaced as the epoxy ages? Does the cost of replacement outweigh the cost of refurbishment?

How about the aluminum cross braces of your fiberglass ladder, how do those hold up in the high heat of a structure fire? What does that do to service life?

>They're nonconductive fiberglass

They're also not being used right next to flames.

Yes, fiberglass can be made that won't buckle under both weight and heat, but not at the same price point as wood.

Because wood reacts so well to fires?

Oddly, yes. Sufficiently dense wood takes a lot to ignite and burns quite slowly, and I assume they coated it to make it even harder to get started.

I would bet another advantage of wood is they fail gracefully.

From article:

"We had one ladder here that was fully involved in a fire for 25 minutes, and the whole tip of it—six feet—was crispy. It looked like a log you pull out of a campfire," Braun says. "That can't go back in service but we were curious, so we put a new halyard [rope used to hoist ladders] on it for a load test. Even in that condition, it passed."

Yep. That's one of the reasons wood also makes a great construction material.

I would add that aluminum ladders tend to be bouncy because there's very little mechanical damping. I've climbed 30' aluminum ladders and in the middle it's like being on a trampoline. You have to go slow. Wood ladders seem better for racing up and down.

There are plenty of ladders on the market that are non-conductive. None of them are wood because wood is conductive. (though wood does have some interesting fire properties that probably make them better anyway)

In fact in the article, the way the wood is tested for moisture content is with a conductivity test.

How conductive? I'd expect dried wood would have a pretty high resistance.

Only if you didn't read the article.

Did you read the comment you're replying to? I said very specifically "SF does have some good reasons for sticking with their wooden ladders". And note that I said "a somewhat significant factor" NOT "the only factor" or even "the biggest factor".

In fact, I did read the article, and I see nothing that contradicts the suggestion that tradition is "a somewhat significant factor" in their continued use of wooden ladders.

> Did you read the comment you're replying to?

Yes.

> I said "a somewhat significant factor" NOT "the only factor" or even "the biggest factor".

That's true. But even "somewhat significant" isn't justified by the facts.

> SF does have some good reasons for sticking with their wooden ladders

And they have one overwhelming reason: aluminum is not an option because of the overhead muni lines.

So it's possible that tradition has a role, but there's no evidence that it is even "somewhat" significant.

And they have one overwhelming reason: aluminum is not an option because of the overhead muni lines. So it's possible that tradition has a role, but there's no evidence that it is even "somewhat" significant.

If you're operating under the assumptions that A. all the relevant information is in the article and B. everything in the article can be taken at face value, then I can see how you would arrive at that conclusion. So fair enough. I didn't mention it earlier, but I'm operating from a place of applying additional knowledge and perspective that comes from over a decade as a firefighter.

Anyway, I doubt we'll ever really know for sure. In either case, SFFD do a great job, so mad props to them regardless of what kind of ladders they use.

It doesn't explain why they couldn't just buy wooden or fiberglass ladders though. I'm sure there are many vendors who would be happy to fill such a contract.

Wood doesn't fail suddenly. Fiberglass does.

So why don't they buy wooden ladders?

According to the article this is one of two places in the entire country making these ladders.

What kind of ladders do the power line companies use?

What kind of ladders to the power line companies use?

Doesn't matter. The electric company isn't hanging on the outside of a building that's on fire.

No, it does matter because everyone on this site is a genius and the firefighters don't know what the hell they're doing.

I work at a power company. For portable ladders, we use both wood and fiberglass. However we don't fight fires so we don't take fire or heat ratings into consideration and we maintain a minimum distance of 10' (or OSHA minimum approach distance for qualified electricians/linemen) between a ladder and anything energized.

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