Miami Beach, Champlain Towers South apartment building collapse, Part 16 24

[dik]

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Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[FJBnomics]

I was looking forward to reading that.

IanCA, thanks, and you still can, if you want to open it on a desktop or laptop computer. I could not open link on my phone. I felt it was 'Out of Phase' with current topic, and just raising the noise floor of current discussions.

 

[FJBnomics]

@dik, I was wondering whether sulfates would really be an issue in Surfside with that fresh sea breeze.

IanCA, I realize this question was for dik, but I have some thoughts for consideration.

We know from core samples that the interior portion of the structural slab was the part that looked powdery like gypsum. In addition, we know from Morabito's Mechanical Engineer inspection, at least two exhaust fans needed repair (belts and bearings).

I annotated in thread 15 on Morabito's Drawings where the 4 exhaust fans were located. The only air intake I see on plans for exhaust fans is thru the entrance gate to the parking garage.

If you look at the location of fresh air intake from garage gate source to the 4 exhaust fan locations, that results in a stagnant air flow area at South wall from around pool room doors on east side, and along south wall towards the west, where slab to wall connection appears to have failed first.

There is a pool room exhaust fan that is ducted from pool room to planter above structural garage roof deck. The only air intake for that exhaust fan appears to be either a gap between the pool and the East retaining wall, or perhaps a louver in pool room doors to pull air into pool room. This exhaust system is separate in function from the other 4 exhaust fans.

What about auto tail pipe emissions in parking garage and sulfates like sulfuric acid? I believe diesels produce more sulfuric acid at tail pipe than gasoline engines.

We know there was Great water source on top of garage ceiling structural slab.

Point is could the interior change of state concrete layer be due to tail pipe emissions and poor exhaust fan layout and maintenance such that a lot of tail pipe emissions were staying in garage for extended periods to react with interior layer of concrete?

Could we have multiple things going on as far as acid and base reactions at different locations?

 

[spsalso]

Looking over the building plans, the only place that the nasty looking transformer could be is in the NE corner, on the north wall. I base that on the near internal right angle in the wall, the direction of the parked cars, the reflections of the ceiling lights, the placement of one of the columns and the lack of cars parked in the distance, behind the black one.

From the electrical drawing, the only thing in that corner is a three-phase exhaust fan. It is called 3600W in one location and 2HP in another. It is fed by a three-pole 20A circuit breaker. Aside from the ceiling lighting, there was nothing else there on the plans.

The only reason I can think of for a transformer at all is to, uh, transform. Thus, whoever installed that transformer did NOT need 208 three-phase, but something else. It is common not to run a neutral in a circuit designed only for a three-phase load, so that means there was no source for 120V at that location (other than the nearby lighting circuit!).

So, yes, they could have wanted 12/24V. Or they could have wanted 120V.

I will point out that there was a surface mounted 4" square box, to its left, with a blank cover. And a pipe leaves vertically from that box.


Up above this location was a patio/planting area. In examining the plans, I found no indication that an automatic irrigation system was planned or installed. What with that leak, and this transformer where there wasn't one on the plan, I'm still inclined to think we are looking at parts of an added on irrigation system for the garden area above. The leak may have been from the piping system itself, or a failure in the controls that dumped too much water into the planting area, from which it then leaked by a convenient route.

It's a real reach to blame the brown stuff (probably rust, but not for sure) on the pool, or the pool deck membrane, or exposure to salt water or sea air.


spsalso

 

[IanCA]

The only air intake I see on plans for exhaust fans is thru the entrance gate to the parking garage.

Agreed, I came to the same conclusion and based on the information presented in my post on 14 Feb 22 00:34 we know "The concentration of marine aerosol decreases with altitude." or phrased another way we know the concentration of marine aerosols is highest at ground level.

The only air intake for that exhaust fan appears to be either a gap between the pool and the East retaining wall, or perhaps a louver in pool room doors to pull air into pool room.

Agreed and I understand that HVAC best practices dictate a negative static pressure in pool equipment rooms adjacent to occupied spaces to ensure that air is drawn, with added vehicle exhaust fumes, from the garage space occupied by residents while parking their vehicles, into the pool equipment room, rather than vice versa.

The warmed exhaust air from the pool equipment room is then vented upwind (relative to the prevailing wind direction) from the planter at the edge of the parking deck.

 

[IanCA]

@spsalso
Thanks very much for your detailed and systematic evaluation of that condition.

probably rust

If it's not rust, or some similar iron-based corrosion product, how do you explain the hole in the corner of the enclosure?

It's a real reach to blame the brown stuff (probably rust, but not for sure) on the pool, or the pool deck membrane, or exposure to salt water or sea air.

I'm simply trying to establish that some corrosive liquid was present in the structure. I will go on to propose what I consider likely sources, I welcome you making alternative suggestions or disproving my suggestions.

 

[spsalso]

The picture quality isn't so wonderful that I can truly tell whether there's a hole there or not. Same for the brown stuff.
Maybe the hole, if that's what it is, was caused by something other than the brown stuff.

If it's rust, and the flex was replaced because it was horribly damaged by rust, how did that happen? Could this collection of crap be related to anything other than an irrigation setup? If so, what?

If it's related to irrigation, then I'm assuming there was a long term water problem that happened right above, either a few inches or a few feet. And repairs were, uh, not wonderfully done.

So this establishes the abilities of Maintenance Man, but it doesn't tie in very well to a building falling down; said falling happening on the other side of said building.

Einstein: "Spooky action at a distance."


spsalso

 

[MaudSTL]

Or it could be PCB leaking from an old abandoned transformer. I had a very old doorbell transformer that leaked brown oil just like we see in the photo you’ve been looking at. If it’s leaking old transformer oil, it’s very corrosive and could account for the damage we see in this funky oddity.

 

[Nukeman948]

Fans again

I found a total of six fans with enough capacity for six air changes per hour. Many fans I've seen have two belts so if one is damaged or missing it will still function at a reduced capacity. There should be somewhere you could look up how many cfm of vehicle exhaust to expect from a 120 space parking deck. Then you would have to estimate what the concentration of corrosive contaminants would be. Seems like this might be a problem in every other parking garage there is. Is this one somehow different from all the rest?

​

 

[Nukeman948]

If it’s leaking old transformer oil...

That is a dry transformer. It has no oil to leak out. They are embedded in epoxy resin.

​

 

[FJBnomics]

I found a total of six fans with enough capacity for six air changes per hour.

HaHa! Yes Fans again! I found six (6) as well in garage. Storage Room, Pool Room, and Four (4) for garage parking area.
I liked IanCA's point about the pool exhaust fan was exhausting into the prevailing wind. It is a 1/4 HP 1945 CFM fan that is competing against Four (4) Two(2) HP 12000 CFM fans, and one 1/2 HP 4000 CFM fan for air intake from their shared parking garage gate area. So 52000 CFM fans and their little brother at 1945 CFM, and little brother has the static pressure of duct work to overcome as well.

I wonder how much negative static pressure that 1/4 HP motor is gonna pull on pool equipment room against the 5 other much larger fans? Especially with the 1/4" exhaust having to over come prevailing winds?

And who wants to bet the pool equipment room doors are not always shut?

 

[Nukeman948]

It's funny how you keep finding more fans, right after I point out you missed one.

I'd like to see the math on how much static pressure those fans create with that huge hole at the ramp being wide open. Must be like dividing by zero.

​

 

[FJBnomics]

Nukeman948, I am sticking with six until u tell me there is another one .

You make a great point on static pressure.

 

[IanCA]

Could this collection of crap be related to anything other than an irrigation setup? If so, what?

Everything has a good explanation.

The aerial drift of salt-laden water droplets that are deposited on trees and shrubs causes salt spray damage. When droplets evaporate, the salt’s sodium and chlorine ions can penetrate stems, buds and leaves, causing direct damage.
Maintaining appropriate soil fertility and moisture conditions to reduce additional stresses, and to help combat desiccation.
Leaching the soil with thorough irrigation after salt exposure. Flush salt through the soil by applying 2 inches of water over a 2-3 hour period, stopping if runoff occurs. Repeat this treatment three days later if salt levels are still high

https://www.urbanforestry.frec.vt.edu/STREETS/documents/VTextsalt.pdf

 

[IanCA]

@MaudSTL,
One of the main reasons I'm working on this is because I want to help discover, and share, all of the potential engineering risk factors involved with this incident. Would you be interested in starting a new spreadsheet that we could use to document the potential risks? The items on the list may not have been directly or indirectly involved with, or responsible for, the collapse, but they could be important for helping to avoid future incidents for other structures.

For example, I am thinking about topics such as concrete cover over rebar, column load rating, spans, marine exposure, thermal expansion, waterproofing, maintenance. I think there is a long list that many of the members here have good knowledge of and it would be helpful to have them organized in one place.

I am familiar with your CTS collapse spreadsheet posted 25 Jul 21 17:20, but I suspect that is difficult to contribute to because it may require the explanation of multiple complex factors, but the individual risks can be considered independently and may be easier to agree upon. The headings could be: risk factor, evidence, conditions, category, identification & monitoring methods, proposed mitigation.

What do you think?

 

[zebraso]

Everything has a good explanation.

For example here is the flex that is feeding the fan in SW corner. It is running up from low on the wall. And yet again there is a drip tray running over to the wall so the water can track the cable to it's source. If the transformer video image was mirrored this could be the spot but it's not because the escutcheons on the care are correct. So I guess one just has to imagine this in the NE corner. But that would mean water is on the floor there as well. One question is if this fan is 3 phase does, it make sense that the cable would be coming from down on the wall. For example it would not need a transformer. per se. But is it a wet location thing to use one for isolation? Just more dumb questions.

Edit: I just realized that where the flex disappears a bit up high, that three phases could be going to the fan and one phase down to another mystery transformer. There is always a piece missing.

 

[spsalso]

The drip tray looks to be on the near side of the first column away from the wall. And the "flex" is on the wall. Don't see how water from the former could get to the latter.

It seems extremely unlikely that that is flex, anyway. IF it's supplying the fan, it would have been installed by AT LEAST a drug-crazed apprentice, who would have used conduit. 'Cause it's already straight. And easier to pull. And you don't HAVE to pull a ground wire.

I think it more likely that it's a half-assed water line, used for my latest hobby-horse, planter irrigation. There's an isolated planting area just above.

As I mentioned earlier, you can't use one phase of 208 3-phase without a neutral. And there aren't too many electricians who throw in a free neutral when they're supplying a 3-phase motor. I have, but then I'm a thoughtful and considerate guy.

spsalso

 

[zebraso]

Yeah I saw the tray goes to the column. But I thought there was another frame that showed a tray extending back along the side of the column. Anyway there are so many drip trays if you step through that walkthrough that there are likely more than one resting on a pipe or conduit at a wall. I wasn't saying there is another rusty transformer necessarily or even another transformer here.
If you use 1 phase of 208 with a neutral it would be 120 right? What your saying is you have to run another line with a neutral. And a free neutral would be an "illegal" ground. How would you get 208 to a transformer and why would anyone do that if they could just run 120 separately?

Edit: I realize 208 is 120*3^(1/2) and where that comes from.

 

[spsalso]

"If you use 1 phase of 208 with a neutral it would be 120 right?"

Yes

"What your saying is you have to run another line with a neutral."

I am saying, minimally, you have to add a neutral wire. Whether or not you have to run another hot ("another line") can be a matter for discussion. But without a neutral, you don't have any 120V.

"And a free neutral would be an "illegal" ground."

I'm not sure what a "free" neutral is. It is VERY BAD FORM to use the ground as a neutral. Only Maintenance Man's younger brother would do that, which is why he is only hired for summer work installing insulation in attics.

"How would you get 208 to a transformer and why would anyone do that if they could just run 120 separately?"

If you've got 208 three phase at a location, you can use TWO of those wires, which gives you single phase 208. A transformer can then be used to step it down to 120V. (Or 24V. Or 12V.) What it does NOT give you is a grounded neutral. The reason why one might do this transformer thing is that you have ONLY 3 phase at your work location and it is a long way over to a source of 120V. With that transformer, now you do--pretty much what happened in our brown-topped example in Florida.

I'm not too interested in exploring possible code violations when some DOES do the above. I'm talking more about physical reality.

If I was a building inspector and found such a thing, I might let it pass for a light duty "control system" or something. Maybe. If it didn't look dangerous. Perhaps.

When I do typical industrial stuff, I do separate systems for the three phase and the single phase. I don't mix them. I DON'T do that thing above. If I need 120V, I take it off of the single phase 240V/120V system. And I do that even if I'm doing 240V three phase. I DO tend to run a neutral with the three phase, because once in a great while, someone will buy new equipment that includes some little bit of 120V. It's happened. Once or twice.


spsalso

 

[Nukeman948]

If I need 120V, I take it off of the single phase 240V/120V system.

This building didn't even have a 240v/120v system.

​

 

[zebraso]

Got it. You make a lot of sense. And I think I understand the mind set of maintenance guy's little brother. Code violations her per se are not too interesting. But if little brother is running loose it could be a factor in "something".