Ductwork Collapse Into Resort Pool in Aurora Colorado

[jar546]

I am posting a few links here and a video of the aftermath. Essentially, round, metal ductwork fell from the ceiling onto patrons in and around a pool. Six people were injured, 2 of the critically. It is obviously too early to know what happened and of course the lawsuits will begin shortly which will lead to an engineering investigation. I have the following thoughts about this, especially after watching a video and hearing a younger girl crying for help. It got me thinking about the system and the importance of compliance with codes. There are a few possible scenarios with this that I am speculating about.

1. It is possible that it was properly designed to handle the weight, but not in the corrosive environment of an indoor pool. Vibration could be an additional factor.
2. It is possible that it was improperly designed altogether.
3. It is possible it was properly designed but the installation was not per specs by the contractor and was not caught by the building department.
4. It is possible that the system was modified after installation which added weight but inadequate support.
5. There is a very high probability that there was a lack of maintenance or inspection of the supports, especially in this type of environment.
6. It is possible it could be a combination of all 5 above.

When any equipment is hung in a ceiling above, it is usually forgotten about and assumed that it is permanent. Unfortunately, the environment the equipment is in is a major factor. Corrosive or vibration-heavy areas do need regular inspections. Some of you may say that this is a rare occurrence, but maybe it is rare to make the news. A similar event happened in a school here in Palm Beach County but that involved a bank of overhead conduit falling down and through the suspended ceiling. That situation leads to specification changes for contract work that forbids using powder-actuated connectors into the bottom of concrete, a very common practice in the construction industry.

6 injured, 2 critically, when HVAC unit falls into indoor pool at resort

"(We) just kind of heard a big groan, and we looked up and it was just like a domino effect," one guest said.

www.kiro7.com

Metal ductwork collapses, injures 6 at Colorado resort pool

Fire officials say six people were hurt when part of a heating and ventilation system collapsed at a resort pool in Colorado, and two people have been hospitalized with life-threatening injuries. Aurora Fire Rescue said there were 50 to 100 guests in the pool when the collapse occurred Saturday...

apnews.com

 

[e hilton]

Before your time … 1960’s if i recall … a ceiling/roof collapsed over a swimming pool in switzerland, i think. Killed several. Corrosive atmosphere corroded the supports.

 

[ICE]

To get a sense of the scale, that's a person standing near the duct.

 

[ICE]

 

[jar546]

I am going to speculate that these may have been used. What are your thoughts?

 

[steveray]

I am going to speculate that these may have been used. What are your thoughts?

I am going to say whatever they used wasn't adequate......I don't see anything still attached to the duct and also nothing hanging from the ceiling which is a little weird.

 

[bill1952]

Was that a sprinkler pipe flowing in the background?

 

[fatboy]

Was that a sprinkler pipe flowing in the background?

That is what I figure, one of the interviews a woman reports "dark sludge" was spewing out of a pipe. We had a Civic Center that one of the sprinkler pipes froze, when it thawed, it left a greasy black mess.

 

[Yikes]

A long time ago I assessed the building condition of a vacant historic YMCA. The structural engineer looked at the roof trusses above the pool and found that all the metal connectors were corroded and useless.

 

[north star]

@ ~ @

Yikes, ...for clarity, do you mean that all of the metal connectors on EACH
truss were corroded and useless, or something else ?

@ ~ @

 

[e hilton]

.

 

[ICE]

I have inspected a few jobs that have large duct such as this. I was not impressed with the meager support. All it takes is a concern from the inspector and the engineers beef it up. The last one was a megachurch. The money that went into that church was staggering. The finish materials came from around the globe.

Obviously the support was insufficient and the environment played a role. The attachments should not cascade in failure.

 

[fatboy]

"Obviously the support was insufficient and the environment played a role. The attachments should not cascade in failure."

And it could have started from just one failure, and compounded after that. More and more weight on the support next down the line...........

 

[classicT]

The attachments should not cascade in failure.

And it could have started from just one failure, and compounded after that. More and more weight on the support next down the line...........

I'd say that almost all if not all failures occur in a cascading sequence. As fatboy points out, as an initial failure occurs, the load redistributes and can swell to the point where a catastrophic failure occurs. Once the initial energy required to result in a failure occurs, the forces at play only increase. It would only be reasonable to assume that the failure started at a single point and then spread quickly. Multiple points of attachment were likely deficient for any of the reasons suggested by Jar, but the failure likely started at a single point.

I do agree with you ICE that a cascading failure "should not" occur. The engineering should account for some redistribution of load within the system. That said, where is that required in the code?

 

[Plumb-bob]

Thanks for posting and discussing this, I would not have been aware of it otherwise. Good food for thought

 

[klarenbeek]

They may have used a cable hanging system I see used alot (not sure if I would say the name here). That would explain why you really can't see any hangers.

If done right it is a good system but you have to follow the instructions. Not sure how it would hold up in a corrosive environment though. I did look online and they do have a stainless steel system that is corrosion resistant

 

[steveray]

I can see the hangers (I think) a little better in EH's pics...single point, but can't tell if it is a rod, cable, or strap at each "beam".....

 

[Yikes]

@ ~ @

Yikes, ...for clarity, do you mean that all of the metal connectors on EACH
truss were corroded and useless, or something else ?

@ ~ @

Yes, the connectors on each truss were useless.