NYC titanium heat exchanger fire

Detailed teaching unit — workers flame-cutting a titanium heat exchanger in a Manhattan basement post-9/11, generating hydrogen when garden-hosed, leading to small hydrogen explosion and subsequent lawsuit against the fire department.

I've had a couple of cases of titanium fires. One was in New York City not long after 9/11, just a few blocks down. These guys were cutting up a titanium heat exchanger in the basement of a building. They had all these people, none of whom could speak English because they could be hired for a nice low wage, and they gave them oxyacetylene torches and sent them in to flame-cut this huge titanium heat exchanger. When you do that you create fine powders, some completely combusted but some not. When things would get too hot they had a garden hose, and they'd spray it on there — and the workers noticed that sometimes when they sprayed the garden hose the flames got bigger rather than smaller. That's because they were generating hydrogen — oxidizing the titanium and generating hydrogen.

Backward-reference to a previously-discussed case. Cited to make the point that water spray on burning titanium generates hydrogen and amplifies the fire.

Not that titanium tubing won't corrode. I've had under-deposit corrosion attack on titanium tubes if you just let dirt get in the system. One time in New York — I think I told you about the titanium fire — these guys were spraying water on a titanium fire, and when you do that you get titanium oxide plus hydrogen, so you actually end up creating a bigger flame because you're generating hydrogen by spraying water on burning titanium.

Post-9/11 skyscraper in NYC; titanium heat exchanger took on East River silt through a misopened valve; under-deposit corrosion; non-English-speaking workers brought in with oxy-acetylene torches. Used to demonstrate that titanium *can* corrode and *can* burn when its protective oxide is breached.

I had a case where some guys in New York City, just after 9/11, in another skyscraper, had a titanium heat exchanger. You can corrode titanium. In this case they got some silt — someone opened the wrong valve, and they got all the East River silt into their heat exchanger, which is a real problem. You get what we call under-deposit corrosion attack, and titanium can corrode under some of those conditions, and it did. They had to replace this heat exchanger. They hired immigrants who couldn't speak English, because they were the only ones who would just do this and wouldn't ask questions. They went in with oxy-acetylene torches. You can flame-cut titanium — you'll learn about that when you take my flame's department — lots of smoke.