WTC: Which tower had more deaths?

[Fiver]

I haven't seen a timeline or a minute-by-minute account of the 9/11 attacks on lower Manhattan, but this is how I imagine it went down.

The first plane hit the North Tower. Everyone on the plane died instantly, as well as everyone working on the floors involved by the collision. So the full staff of a normal workday on those floors died.

Then, I suppose, both towers began evacuating. Everyone working above the impact floors (the full staff of a normal workday) was trapped, except for those few who managed to find a stairwell sufficiently free of fire and smoke to climb down to safety.

Eighteen minutes later, the second plane hit the South Tower. Everyone on the plane died instantly, as well as everyone on the floors involved by the collision. This would have been fewer people, since evacuation had begun, right?

Evacuation then continued in earnest. Everyone above the impact floors of the South Tower was trapped, except for those few who managed to find a stairwell sufficiently free of fire and smoke to climb down to safety. But, since the second plane hit the South Tower much lower, there would be more people trapped above it.

The towers collapsed an hour or so later. Is it reasonable to guess most people below the two impacts got away and survived, and so most of the 6,000+ dead were on the floors hit by the planes and higher? Were more of those people in the North tower (because evacuation hadn't begun) or the South Tower (because more floors were above the collision?

[Keeve]

I think the biggest factor is time between impact and collapse. The following times are not exact, but as close as I remember, and good enough for this discussion.

8:48 - north tower hit
9:05 - south tower hit
10:00 - south tower falls
10:30 - north tower falls

So the people in the north tower had almost 2 hours to get out, but in the south tower it was much less.

How much less? Well, that depends. I'm sure some people in the South tower started evacuating as soon as the first plane hit. But I'm sorry to admit that if I was in the South building, I probably would have said, "Okay, it's over. Any EMT's here, go downstairs and help out. The rest of us, let's get back to work."

[Oblong]

I've seen accounts where the second tower was told not to evacuate. I'm sure some continued to evacuate.

Also, the death toll is now up in the air. The official count is the 4000+. However, several news agencies tried their own counting and came up with about 2000 less.

I saw a photograph of firefighters inside one of the towers. It looked like the lobby or a lobby and it was completely empty.

There were people who were still trying to evacuate when they collapsed.

[Running with Scissors]

The New York Times website has a page of graphics, including one entitled Employees in the Twin Towers (sorry, I couldn't make a direct link), which gives a count by floor of victims and survivors of each building. Yes, employees in the south tower were told not to evacuate. Wonder how many deaths that decision cost...

Here's a question I haven't seen asked yet: Didn't it occur to anyone that the north tower would collapse after it was hit? As soon as I was outside with my coworkers (I work several blocks from ground zero, we evacuated as soon as the second plane hit), one of them, who is an engineer by training, said that there was no way that the tower would remain standing. Even though they didn't know that the south tower would be hit, if they thought that there was even a possibility of collapse of the north tower, they should have evacuated everyone in the south tower, since the collapes of the north tower would have done severe damage to the south tower if the latter had not collapsed first.

[OxyMoron]

Uncertain; several of the worst casualty rates have come from the North Tower (Windows on the World, Cantor Fitzgerald), on the floors above the initial impact. In many cases, those folks had no chance to escape at all.

Also, one thing that may have reduced casualties in the South Tower is that many workers arriving in the interval between the two impacts may not have entered the building in the first place. On an average morning, an awful lot of folks arrive in the fifteen minutes between 8:47 and 9:03. Even if the Port Authority didn't seal off the South Tower (I'm not sure if they did or didn't), I feel pretty confident in assuming that a lot of South Tower people didn't go up to their offices.

[Fiver]

frogstein's link told me what I wanted to know (thanks).

WTC1 was hit by a plane with 92 souls aboard.

Of North Tower occupants below the impact, 196 are dead or missing.

For those at or above the impact, 1255 are missing or dead.

Total: 1543. Approximate, of course, and not including firefighters, cops and other rescue workers killed in the collapse.

WTC2 was hit by a plane with 64 souls aboard.

Of South Tower occupants below the impact, 168 are dead or missing.

For those at or above the impact, 478 are missing or dead.

Total: 710, only half as many. Of course, the South Tower had dozens of floors that were untenanted, for some reason, but since most of these floors were below the impact, and the "below the impact" numbers for each tower are roughly the same, I guess that didn't make much difference.

The combined total for the towers is ~2253. So am I correct in assuming that any death toll I see that's much larger than that is including the rescue workers and others lost in the collapses?

[yojimbo]

Originally posted by Oblong
I've seen accounts where the second tower was told not to evacuate. I'm sure some continued to evacuate.

Some did indeed. Read this story of a man who will be missed. ( link courtesy of RTFirefly posted over on Fathom)

From the link.

"The dumb sons of bitches told me not to evacuate," he said during a quick call to his best friend, Dan Hill, who had indeed been watching the disaster unfolding on TV. "They said it's just Building One. I told them I'm getting my people the [expletive] out of here."

[Bosda Di'Chi of Tricor]

This topic is vulgar & morbid, & I've been vulgar & morbid on this board myself.

Moderators?

[lieu]

Why is it vulgar & morbid?

I think it's a completely rational question and has so far been responded to in a respectful manner.

Aren't we all trying to learn from the events? To prevent their recurrence? To preset our minds as how to handle a similar situation?

What happened was vulgar & morbid, learning from it just makes sense.

JMHO.

[Dignan]

Didn't it occur to anyone that the north tower would collapse after it was hit?

I think the only reason the towers collapsed was because of the intensity of the fires. Normally the sprinklers would put out a fire, but the jet fuel made the fires too hot to put out. Which is why the terrorists crashed planes that were going across the country. They were full of fuel.

The evacuation strategy in case of a fire (I believe) was to evacuate the floor with the fire and a few of the floors above and below where the fire was located. The stairs weren't made to handle an evacuation of the entire building at one time.

[Running with Scissors]

Originally posted by Dignan

I think the only reason the towers collapsed was because of the intensity of the fires. Normally the sprinklers would put out a fire, but the jet fuel made the fires too hot to put out. Which is why the terrorists crashed planes that were going across the country. They were full of fuel.

True, but people knew that a plane had crashed into the building, and that jet fuel was burning. Shouldn't someone have called a building engineer (I imagine they'd even have one on retainer) immediately after the first plane hit, asking if they thought a collapse was even possible, let alone likely?

[Keeve]

Frogstein, when you heard about the crashes, did these ideas occur to you?

I never dreamed it would collapse. If the planes had hit lower, then yes, I would have thought of it. But so high up, it never entered my mind.

[Running with Scissors]

The thought did not occur to me, but as I said, it did occur to a coworker who was an engineer. Why wasn't an engineer consulted? That's what I'm trying to figure out.

[lieu]

It didn't occur to me either. I thought it might burn for days and there was going to be terrific damage but I almost had a wreck when I heard it was falling.

Never, never, never in my wildest dreams...

[KCB615]

Didn't it occur to anyone that the north tower would collapse after it was hit?

Standard fire service doctrine (prior to WTC) has been that high rise buildings do not collapse in fires. Before the 11th, there have been some rip-roaring fires in high rise buildings. Two that jump right into my head are the One Meridian Plaza fire in Philadelphia (2/23/1991), and the First Interstate Bank fire in Los Angeles in (I think) 1988.

The Meridian fire burned for something like 9 hours, burned 8 floors (22 through 30) of a 38 story building. The fire was estimated at >2000 degrees for long durations, and still the building stood up. Collapse was expected, and the fire was fought from neighboring buildings, but it didn't fall down.

The First Interstate Bank fire was along the same lines. I think the fire was on a floor in the -teens, autoexposed up the side of the building (out a window and up to higher floors), and was a cast-iron female dog to put out. Again, collapse was expected, but the building stood up.

Rationale since these two fires has always been that you have a decent amount of time to put a fire out in a highrise. The fire resistance of the building components is immense (8+ hours for some major components), and the systems built into the buildings help control and confine the fire. With WTC, between the shock of the impact (compromising the fire resistive features), and the large area ignited by the aircraft with a very hot fire, the building didn't fare as well as any of us would have expected.

For what its worth, FDNY is world-renowed for their ability to predict structural collapse. One of their retired chiefs, a brilliant man named Vincent Dunn, litterally wrote the book on the collapse of burning buildings. If FDNY didn't think it was coming down, no one would have thought it was coming down.

[Running with Scissors]

Just the sort of response I was looking for. Thanks.

[rocking chair]

re:collapse

meridian did burn for hours. and when the firm i worked with did survey work after, it did unbelievable damage to the structure. it did not reach the temps that were in wtc with the jet fuel. it also had working sprinklers above the fire that helped put out the fire. they were not able to get water on the fire at wtc. also due to the damage in the core from the planes many of the sprinkler on the impacted floors and above did not work.

there was a discussion panel sponsored by the aia, in philly 2 weeks ago on the wtc collapse. many of the participants believed that wtc was one of the few structures that could have handled the impact. most felt that any other building even empire state would have collapsed with in minutes of impact. one of the panelist is a stuct. eng. in the firm i work with. he told me that none of them thought a building in philly would have taken that kind of hit. (great...)

my main concern since wtc, is getting better escape routes out of a building. there are ada rules abounding, however none of them address how to get a person in a wheelchair out of a building. most buildings that are to code or above are fire rated for 2-4 hours. as we saw sometimes you don't have that kind of time. they are starting to discuss fire rated elevators now, mostly in hospitals where you have people who are bed-bound.

during the panel discussion mention was made for having fire elevators and non-core escape routes. they better talk fast!

[KCB615]

Meridian Plaza did have sprinklers, but they were up on the 30th floor. The ten heads put the fire out after 19 hours of it burning its way up from the 22nd floor. The water that was applied by the fire department was negligable, since the only streams that were effective were from neighboring buildings. Improperly adjusted Pressure Reducing Valves on the standpipes prevented hose streams from being used, so hose had to be hand-laid up the stairwells. After the hose was laid out, falling window glass kept cutting through hose lines on the ground outside. Thank god we don't have big high rises around here (max I'd go to is about 14 stories).

This excerpt is from a US Fire Administration report on the Meridian Plaza fire:

Structural Conditions Observed
Prior to deciding to evacuate the building,firefighters noticed significant structural displacement occurring in the stair enclosures. A command officer indicated that cracks large enough to place a man ’s fist through developed at one point.One of the granite exterior wall panels on the east stair enclosure was dislodged by the thermal expansion of the steel framing behind it. After the fire, there was evident significant structural damage to horizontal steel members and floor sections on most of the fire damaged floors. Beams and girders sagged and twisted --some as much as three feet --under severe fire exposures, and fissures developed in the reinforced concrete floor assemblies in many places. Despite this extraordinary exposure, the columns continued to support their loads without obvious damage.

Yeah, I'd say "unbelieveable damage" is one way to put it. I also agree with you 100% that some better means of egress have to be developed. The concept of defend-in-place and areas of refuge work just fine for your "normal" fire, but when the feces impact the rapidly oscillating air movement device, you've got a lot of people in a place they really shouldn't be.