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The San Franciso Fire Department makes its own wooden ladders by hand

gizmodo.com

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Re: The San Franciso Fire Department makes its own wooden ladders by hand

#331

Post by lsiebert »

ghaff wrote: post #194
hinkley wrote: post #132

Earlier quoted context omitted.

I think the low yield strength of aluminum also plays a role here, as one guy mentions. But I’m surprised thermal conductivity didn’t rate a mention. There was a time when aluminum bikes were new but before the parts likely to bend were replaceable where many a bike owner had to buy a new frame due to misadventure. You can only bend aluminum once, then you’re done. When they started making cogsets with more than six…

The other property of aluminum that is relevant for some uses (but likely not ladders for most uses) is that, unlike steel, it doesn't have a well-defined fatigue limit. Therefore, it can eventually fail after a large number of even relatively small loads that don't visibly deform the material. That's one of the main service limits on airframes.

Definitely true. Steel will stretch or bend if overloaded but aluminum is brittle enough that it will break once but without any warning of fatigue that may have occurred.

Now, in this case I wouldn't want to use steel, because it rusts and is heavier and neither are good for fire fighting.

Re: The San Franciso Fire Department makes its own wooden ladders by hand

#332

Post by Doxin »

qiqing wrote: post #89

Favorite excerpt: "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."

Wood is a surprisingly good building material for surviving fires. A nice thick wooden beam can take days to burn through in a house fire where e.g. a metal support would yield as soon as it gets hot enough.

Re: The San Franciso Fire Department makes its own wooden ladders by hand

#333

Post by Naritai »

jonahhorowitz wrote: post #60
Naritai wrote: post #43

Earlier quoted context omitted.

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?

Re: The San Franciso Fire Department makes its own wooden ladders by hand

#334

Post by nasredin »

segmondy wrote: post #287
Cofike wrote: post #195

Earlier quoted context omitted.

You should see some streets in San Francisco. No way that a fire engine is fitting on those.

They do, they have the trucks were the rear wheels can turn as well

Every time I see them I still think being the rear driver of a ladder truck is the best job ever.

You have your own cabin, you wear a headset. And you only work when making a turn.

Re: The San Franciso Fire Department makes its own wooden ladders by hand

#335

Post by ptha »

morsch wrote: post #311
dalbasal wrote: post #302

Earlier quoted context omitted.

Just as a side point... A lot of architects like this idea from an aesthetic or architectural-sociological reasons. Living in em.. these as houses don't give you a lot of privacy. People walk by, less than a meter from where you're sitting. They sometimes stop to look at your TV. You get used to it, but it's not the kind of thing people go looking for on purpose.

Put stores or offices in the ground floor. Or have a raised ground floor.

I like the half basements, but they have their issues: http://copenhagenbydesign.com/blog/2015/5/21/half-up-and-hal...

Re: The San Franciso Fire Department makes its own wooden ladders by hand

#336

Post by jack_quack »

BanazirGalbasi wrote: post #86
jack_quack wrote: post #73

This is super cool but I'm positive this is also super wasteful

You should try reading the article. They specifically state that they re-use components whenever possible, and they regularly service their ladders to keep them in good condition. Aluminum ladders only have a 7-8 year lifespan vs some of the ladders they use going on 60 years before being taken out of commission.

I don't just mean wasteful in terms of materials, but also in terms of man-hours, equipment needing to be owned and maintained. Once all factors for the total cost of ownership are taken in to account I highly doesn't it's efficient. It's like everyone growing their own vegetables.

Re: The San Franciso Fire Department makes its own wooden ladders by hand

#337

Post by tripzilch »

LMYahooTFY wrote: post #296
arkis22 wrote: post #266

Earlier quoted context omitted.

That's kind of a silly thing to say given that the government of SF spends hundreds of millions of dollars on the homeless a year.

My immediate reaction is incredulity at the notion a city could spend hundreds of millions on its homeless population and still have a homeless population... Are there further details/good articles you would be able to provide?

Now I kind of wonder how many homeless they have in SF. Because if it's 10,000 homeless people (that would be over 1% of its 800k population), they get to spend $10,000(s) on each one ..

So either: they got a ridiculous amount of homeless people, or they got a ridiculous hole in their wallet, or the city doesn't actually spend 100s of millions on the homeless.

Re: The San Franciso Fire Department makes its own wooden ladders by hand

#338

Post by [deleted] »

52-6F-62 wrote: post #316
petee wrote: post #192

Earlier quoted context omitted.

We use them because they are osha mandated, and have to be rated for like 350lbs. And aluminum will just kink and bend the first week on the job. Huge downside to fiberglass is they are UV sensitive - i've seen ladders just crumbling because they were left in the sun

I worked for a supplier to the industry for a little while heading an electrical department, but spent some time in hardware maintenance as well. I saw plenty of those things nearly bleached white if they lasted long enough.

[deleted]

Re: The San Franciso Fire Department makes its own wooden ladders by hand

#339

Post by DannyBee »

coryfklein wrote: post #246
DannyBee wrote: post #224

Earlier quoted context omitted.

"These ladders last decades" Then literally this entire process is a complete waste of time, because they will never stay at any moisture content over this time period.

The point is to bring them to the natural moisture content due to the average San Francisco humidity. Once they are there they will stay there because the average humidity is relatively constant.

I understand the goal (I've been woodworking for 20+ years).

Wood does not react to average humidity, it reacts to current humidity.

Defects occur because of sudden changes the wood cannot "handle" (IE it's not elastic enough, etc), not because the average is too high or low.

Over decades, the likelihood of that happening seems quite high.

Re: The San Franciso Fire Department makes its own wooden ladders by hand

#340

Post by DannyBee »

donarb wrote: post #284
DannyBee wrote: post #226

Earlier quoted context omitted.

"I bet the expert woodmakers doing this job have very good reasons. Reasons that you haven't thought of.. Seriously, these people are experts. They probably know their job, really, really well." This is just a random appeal to authority. If you would like to be constructive, please be constructive. First, there is one person doing this. Or was. It was Jerry Lee, who recently retired. He did it for 30 years. In fact,…

Isn't a forestry handbook a "random appeal to authority"?

Actually, no, it's a very very very well thought out resource that has references to where the research comes from and citations for it's data.

It may come as a surprise, but this really is engineering. People have been studying wood as an engineering material for a very long time, and there are a large number of published studies on pretty much anything you can think of from drying rates to density to you name it.

Take a look at https://www.fpl.fs.fed.us/products/publications/several_pubs...

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