WTC heating system or electrical explosions?

[Orphia Nay]

Whilst I've been debating twoofers in another forum, after discussion of the collapses sounding like bombs, a fencesitter asked me a question about the WTC heating system:

"You know, that reminds me of something I was curious about. Does anyone know what type of heating system the WTC's had? Just curious about boilers and sudden pressure differences because of something that came up last week at work. I'll have to see what I can find."


I don't know the answer, and will do some searching, but sometimes round here the quickest way is to just ask.

I'd also be interested to know if the reports of "explosions" before collapse could be explained by things such as boilers exploding, or whether explosions could be caused by other things such as electrical circuits shorting.

 

[Orphia Nay]

Forgot to add: the question also applies for WTC7 and not just the twin towers.

Now I think about it, I don't have a source for reports of explosions pre-collapse, other than William Rodriguez's probable hearing of the jet fuel explosion in the elevator shaft. I do recall seeing sources quite a while ago, but can't remember where.

Apologies if this has all been brought up before.

 

[Gravy]

WTC heating was by steam. The steam is generated at Consolidated Edison power plants and pumped through pipes underground throughout NYC.

 

[Orphia Nay]

WTC heating was by steam. The steam is generated at Consolidated Edison power plants and pumped through pipes underground throughout NYC.

Thanks, Gravy.

That helped me find this:

http://9-11-01.powerquality.com/ar/power_wtc_disaster_causes/index.htm

WTC Disaster Causes Extensive Damage to Electric Infrastructure

Jerry Borland

Online Exclusive, Sep 14 2001

Tuesday's terrorist attack on the World Trade Center (WTC) has had a significant impact on Con Edison's energy infrastructure in lower Manhattan. The fire and subsequent collapse of 7 World Trade Center has permanently damaged two substations located adjacent to the building as well as major electric transmission cables. A third substation located near the South Street Seaport also lost service. Approximately 12,000 customers are currently without electric power.

...

Workers are trying to isolate the WTC area from the system. However, some areas are still unsafe due to the extensive damage.

But I'll keep looking for any reports of electrical or steam explosions during the period after the impacts and before the collapses.

 

[Mobyseven]

WTC heating was by steam. The steam is generated at Consolidated Edison power plants and pumped through pipes underground throughout NYC.

[showing my 'country boy' side]The entire WTC was heated by steam? Is that really effective? How did the upper floors get adequate heating?

No, seriously? As much as I'm a city boy at heart, the city I lived most of my life in is reasonably country (hell, my house was only five mins from a massive area of bush that I grew up exploring), and sometimes it shows...[/showing my 'country boy' side]

 

[Orphia Nay]

Well, some people might argue it was filled with hot air...

ETA: I regret making that comment now.

 

[Gravy]

[showing my 'country boy' side]The entire WTC was heated by steam? Is that really effective?

It is!

How did the upper floors get adequate heating?

The steam is really hot.

The steam system in the lower half of Manhattan is larger than that of the next four largest cities combined. It was started in the 1880s as a way to reduce coal pollution. NYC has seven steam generating plants (three are co-generation plants that produce steam as a byproduct of electricity generation). Water is heated to 1,000 F (540 C). Steam leaves the plant at 350 F at 150 psi (10.3 bar) and flows through over 100 miles of steam mains and many more miles of distributaries.

Central steam heats most of the skyscrapers and other large buildings in Manhattan, as well as powering their air conditioning systems in the summer. Steam is also used by all dry cleaners and hospitals (sterilization).

Con Edison's steam plants are the city's largest water users. At winter peak, the system consumes over 1.5 million gallons of water per hour. Each gallon of water produces eight pounds of steam. Con Ed has a cool robot that inspects, re-mills, and welds steam pipes from the inside.

When you see a classic Manhattan street scene with steam rising from manhole covers, you're seeing the result of groundwater dripping on an uninsulated part of a steam pipe.

 

[Mobyseven]

It is!

The steam is really hot.

The steam system in the lower half of Manhattan is larger than that of the next four largest cities combined. It was started in the 1880s as a way to reduce coal pollution. NYC has seven steam generating plants (three are co-generation plants that produce steam as a byproduct of electricity generation). Water is heated to 1,000 F (540 C). Steam leaves the plant at 350 F at 150 psi (10.3 bar) and flows through over 100 miles of steam mains and many more miles of distributaries.

Central steam heats most of the skyscrapers and other large buildings in Manhattan, as well as powering their air conditioning systems in the summer. Steam is also used by all dry cleaners and hospitals (sterilization).

Con Edison's steam plants are the city's largest water users. At winter peak, the system consumes over 1.5 million gallons of water per hour. Each gallon of water produces eight pounds of steam. Con Ed has a cool robot that inspects, re-mills, and welds steam pipes from the inside.

When you see a classic Manhattan street scene with steam rising from manhole covers, you're seeing the result of groundwater dripping on an uninsulated part of a steam pipe.

/me learns at least two new things, just from that post!

 

[Gravy]

Heh, I just learned something also. I Googled Con Ed's robot welder name and found out that there's a movie about it.

 

[MRC_Hans]

Heh, I just learned something also. I Googled Con Ed's robot welder name and found out that there's a movie about it.

Damn, I can't see half the links that people post. Maybe it's because I'm currently in China.

Hans

 

[Gravy]

Forgot to add: the question also applies for WTC7 and not just the twin towers.

Now I think about it, I don't have a source for reports of explosions pre-collapse, other than William Rodriguez's probable hearing of the jet fuel explosion in the elevator shaft. I do recall seeing sources quite a while ago, but can't remember where.

Apologies if this has all been brought up before.

There's 118 Witnesses: The Firefighter's Testimony to Explosions in the Twin Towers by Graeme MacQueen in the Journal of 9/11 Stundies Studies.

Note the leading title: almost every quote he includes is a description of something that sounded or looked like an explosion. It's a classic case of taking quotes of context. In fact he tells us that he wants to take the quotes out of context:

Let me begin by stressing that I am interested here only in how these sets of hypotheses are verified and falsified through the direct accounts of witnesses. I exclude all evidence, even where it is indirectly based on eyewitness accounts, that involves measurement, analysis of physical materials, or photographic or seismic records. Obviously, all these forms of evidence are valid, but they are not my focus in this paper.

Here's the main problem with that approach: MacQueen makes no effort to show how the "explosion" quotes he uses (most of which refer to the collapse of a tower) relate to all the other descriptions by first responders which do not describe the events as explosions. By omitting the other descriptions of the same events, MacQueen gives a false impression of what most people described.

In this post I analyze the 31 accounts that MacQueen uses that mention bombs or secondary devices. All refer to the collapse of a tower, and only in a few instances did the witness know that is what was happening.

It's important to know which descriptions of pre-collapse explosions you're referring to. Many people described the impact of flight 175 as an explosion. Then there are these accounts:

1. "Sounded like bombs." Murphy, Keith (FDNY)
2. "A huge explosion." Gorman, Gerard (FDNY)
3. "Sound of popping and exploding." Monchery, Alwish (E.M.T. E.M.S.)
4. "Explosions" Burns, William (Lt. PAPD)
5. "Kept hearing these large boom, boom." Terranova, Rosario (Lieutenant E.M.S.)
6. "Sounded like explosions." Fitzgerald, Anthony (Lt. PAPD)
7. "Like a shotgun going off." Meier, Mark (P.O. PAPD)
8. "Sounded like explosions." Barriere, Wilfred (Det. PAPD)
9. "Sounded like bombs, like blockbusters." Murray, John (Fire Marshall FDNY)
10. "You could hear explosions." Smiouskas, Richard (Lieutenant FDNY)
11. "Sounded like an M-80, that's how loud they were." Pearson, Tim, (Captain, NYPD)
12. "Sounds like a shotgun" (Eric Ronningen)
13. "Sounded like an explosion." Morabito, John (Firefighter, FDNY)
14. "There were lots of explosions." Birnbaum, Jeff (Chief, Point Lookout, NY FD)
15. "Under the assumption that the sounds were secondary bombs." Rodriguez, Andrew (PAPD)
16. "Sounded like bombs. Like a bomb going off. I mean, it was huge." Hayden, Peter, (Deputy Chief, FDNY)

All of those accounts are of bodies hitting the ground after falling or jumping from the towers. A good example of why these accounts must be kept in context.

 

[ref]

The idiotic nature of those Journals is beyond belief.

 

[AZCat]

So did the steam go to steam-to-hot water heat exchangers in the basements or mechanical floors and then the hot water was piped up to hot water coils in the air handlers, or did the air handlers have steam coils?

In other words, were there steam pipes running throughout the building? I'd be surprised, since this is a low pressure system.

 

[T.A.M.]

The idiotic nature of those Journals is beyond belief.

Idiotic Academics in ----> Idiotic Cyberjournal out.

TAM

 

[Mr. Skinny]

So did the steam go to steam-to-hot water heat exchangers in the basements or mechanical floors and then the hot water was piped up to hot water coils in the air handlers, or did the air handlers have steam coils?

In other words, were there steam pipes running throughout the building? I'd be surprised, since this is a low pressure system.

I'd be interested in knowing the answer to this as well, for no other reason than simple curiousity at this point.

AZCat, what do you consider the cutoff for low/high pressure?

We have a similar system to this where I work (steam heating from underground central supply).

I also discovered that the steam was also required in the summer when the air conditioning is in use. The steam is used to warm the air to acceptable levels. If steam is lost, the building is unbearably cold!

 

[AZCat]

I'd be interested in knowing the answer to this as well, for no other reason than simple curiousity at this point.

AZCat, what do you consider the cutoff for low/high pressure?

We have a similar system to this where I work (steam heating from underground central supply).

I also discovered that the steam was also required in the summer when the air conditioning is in use. The steam is used to warm the air to acceptable levels. If steam is lost, the building is unbearably cold!

The cutoff between low pressure and medium pressure steam systems is (IIRC) about 150 psi. We don't deal with steam a lot here in Southern Arizona (for obvious reasons) but I have done some work at the local VA hospital which is a steam system.

Sometimes the way a system is set up, the air handler contains a cooling coil (either chilled water or refrigerant) that cools the air to the lowest temperature requested by the system. Various "zones" then reheat the air going to them (either with a steam coil, hot water coil, or electric resistance coil) to the temperature requested by that particular zone. Interior zones (those with no exterior walls) will generally require higher temperatures than exterior zones, because they require less cooling.

Of course there are a million other ways to design a system, but that should give you an idea.

 

[Crungy]

I also discovered that the steam was also required in the summer when the air conditioning is in use. The steam is used to warm the air to acceptable levels. If steam is lost, the building is unbearably cold!

That is correct Sir Slender. Common sense would lead the layman to think that the heating systems would not be required during the cooling season. Heating is needed to counter over cooling. I always design a summer operating condition for a boiler.

Back to the WTC. Interesting that NYC has a "campus" steam system. Chicago has the same for chilled water. You should see them big ass chillers that provide the chilled water.

I'm curious about a few things.

Was the steam condensate pumped and piped all the way back to the central boiler plant? In some (very) older buildings I've seen the condensate drain just dumped into the storm piping. Now a days this is obviously a code violation.

What type of perimeter heating was used? With those full height windows, baseboard heating alone wouldn't suffice. Aesthetically, I doubt that they would have went with large cast iron radiators.

Any pressurized system, especially one involving large head (vertical distance) requirements can and do go boom. Design pressures for the mechanical piping in the WTC must have been at the limits of pipe manufacturing. These types of issues often put a finanical ceiling on the height that a skyscraper could be built. I've seen many, many a picture of the aftermath from incorrectly designed systems. Also, any motorized component can provide the spark for a big boom. After the Texas City blast, BP requires all spark producing equipment to be a minimum of three feet of grade, due to the possibilty of iginiting the heavy hydrogen sulfide that lingers at towards the ground.