Why is WTC 7 as hot as WTC 1 & 2???

Originally posted by ANOK

Originally posted by avingard
There were several tanks of diesel fuel used for emergency generators inside building 7. Some of it was under pressure. The resulting fire fueled by the diesel probably did much to weaken the steel too.

Engineers from the New York State Department of Environmental Conservation investigated oil contamination in the debris of WTC 7. Their principal interest was directed to the various oils involved in the Con Ed equipment. However, they reported the following findings on fuel oil: "In addition to Con Ed's oil, there was a maximum loss of 12,000 gallons of diesel from two underground storage tanks registered as 7WTC." To date, the NY State Environmental Protection Agency (EPA) and DEC have recovered approximately 20,000 gallons from the other two intact 11,600-gallon underground fuel oil storage tanks at WTC 7.

It is worth emphasizing that 20,000 gallons (of a maximum of 23,200 gallons) where recovered intact from the two 12,000-gallon Silverstein tanks. So, it is probable that the 20,000 gallons recovered was all of the oil in the tanks at that time. Since the oil in the Silverstein tanks survived, we can surmise that there was no fire on the ground floor.

Note that the size of a 12,000 gallon tank would be a little less than 12 feet by 12 feet by 12 feet (if built as a cube).

Source

I'm not really sure on how to read your source.

There was 43,000 gallons of diesel stored there. SOme was on the first floor, some on the 5th. And all the generators had day tanks also.

At this point then, the best i can postulate is that the diesel may have started fires much in the same way as jet fuel did in the towers. The fuel started the fires, but weren't a significant contributor to the total BTU's.

The office fires would be the main source.

Originally posted by OrionStars
Exactly where were generators sitting inside WTC 7?

Why would anyone place high rises over underground diesel tanks?

Why would anyone put generators and diesel fuel tanks inside a high rise? Generators have to be vented. To much heat on diesel tanks can cause the vapors to start getting extremely active, placing undue pressure on inside of the tank walls if placing them in a closet.

All good questions.

But all these issues are known and regulated before someone can put generators into a building. Ventilation. Fire protection. etc. No one is just slinging gen sets into unused closets and firing 'em up when the power goes out.

The towers had 20,000 gallon tanks also BTW.

Where were they? wtc.nist.gov...

Originally posted by MikeVet
various oils involved in the Con Ed equipment

That line is very interesting IE 'various oils'

There was an emergency generation capability in that building of approximately 20MW in total plus an existing substation with a maximum rating quite probably far in excess of that 20MW figure (it was only emergency backup generation). All that generation would need to be coupled to the busbars via very large transformers which would probably contain as much or even more volume of mineral oil than that of diesel in the fuel tanks. I'd include the distribution transformers, switchgear and current transformer enclosures in that volume plus the lubricating oil sumps & reservoirs for the generators themselves.

The building was constructed over the pre-existing substation so it occupied a 5 story high void within the building. There's only sketchy information I could find on the configuration of the backup generation but the normal arrangement for such setups is for the generators to auto-start and deadbus close onto the bus when an undervoltage relay indicates loss of power. Part of the start-up sequence involves auto opening of solenoid & motorised valves in fuel and lubrication lines. The power was interrupted from reports I've seen.

The diesel was probably a minor component of the total fuel load of that building.

Like I said once - if there was ever a building with a built-in death wish this was it.

reply to post by MikeVet


That plumbing job must have cost them a fortune, including if the generators were set on higher floors in the high rise, and their tanks were way down below the floors, on which generators were set.

HVAC venting all the way to the roof can get very pricey.

It would get more expensive for plumbing - if they had secondary tanks on floors to feed off primary tanks down below at ground level or below ground level.

Generators are only supposed to temporarily substitute in place of electrical feed when the electric company power goes out. That is normally done outside at ground level for generator placement.

I know all this because I happen to have a whole house generator feeding off natural gas when I need it.

I wonder what it cost for that artificial gravity feed equipment to run diesel fuel uphill, particuarly if it was way uphill.

Originally posted by OrionStars
I know all this because I happen to have a whole house generator feeding off natural gas when I need it.

I wonder what it cost for that artificial gravity feed equipment to run diesel fuel uphill, particuarly if it was way uphill.

We're not talking about a baby generator for a single house here - the emergency generation capacity of that building was sufficient to supply over 5000 domestic houses at peak load time IE over 20,000 kilowatts and the largest motor-generators were installed at the floor level of the pre-existing power station for obvious reasons.

'that artificial gravity feed equipment to run diesel fuel uphill' is a technology developed a long time ago - most of us know it as a fuel pump though

Edited: for a spelling faux pas


[edit on 8/1/2008 by Pilgrum]

Originally posted by Pilgrum

Adjustment to my previous post:
The floor of the power station was indeed the 5th floor of the building which makes things even worse for the building under stress. There were 10 transformers at ground level, 12 on the 5th floor and 2 on the 7th floor.

The construction isn't exactly unique either
I know of 2 buildings in Sydney which are similar although on a smaller scale. One is about 9 stories high and all substation with transformers over 2 stories high at ground level, the other is a highrise office building with 4 floors of substation at the base.