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#110911 - 08/05/06 08:12 PM Ceiling Collapse
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Quote:
These photos were taken several years ago in a nursing home. The conduit runs were above a lay-in ceiling. When they came down they broke water lines, gas lines, and the branch circuit and alarm / communications wiring. It was difficult working the scene with the lay in fixtures swinging from their whips, some still lit on the emergency circuit, with water on the floor.

Many years earlier some helper put up the conduit hangers with common nails, and the electrician snapped the pipe in place. I'm sure it looked right for inspection. Inspectors can't find hidden defects, but time does.

Fortunately no one was hurt.

Alan Nadon
(Notes with Images say that these were 3 runs of 4" EMT with 4 - 750 kcmil Alum in each. 100' long pulled loose from ceiling. Conduit was secured every 10' with Minneralac #9 held by a 3" nail. 2/93)











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#110912 - 08/05/06 08:19 PM Re: Ceiling Collapse
Trumpy Offline


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Registered: 07/05/02
Posts: 8211
Loc: SI,New Zealand
Quote:
3 runs of 4" EMT with 4 - 750 kcmil Alum in each. 100' long pulled loose from ceiling. Conduit was secured every 10' with Minneralac #9 held by a 3" nail


I'm glad I wasn't under this when it fell.
Someones in trouble, I bet, and rightfully so!.
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#110913 - 08/05/06 08:33 PM Re: Ceiling Collapse
mahlere Offline
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Registered: 11/17/05
Posts: 507
Loc: New Jersey
this is the type of situation that gives you shivers as a contractor.

here you are years after an install, and some guy who may or may not work for you anymore, has just given you an incredible headache.

Hopefully the insurance is current.
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#110914 - 08/05/06 09:05 PM Re: Ceiling Collapse
NORCAL Offline
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Registered: 09/25/02
Posts: 865
Scary,just scary.
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#110915 - 08/06/06 05:15 AM Re: Ceiling Collapse
steve ancient apprentice Offline
Member
Registered: 03/04/05
Posts: 169
Loc: west springfield,mass
The more I see stuff like this the more I shudder. All to save time and a little money. Shoddy and disgusting. Do it right the first time. Someone is in big trouble and rightfully so. Im glad no one was hurt.
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#110916 - 08/06/06 08:25 AM Re: Ceiling Collapse
renosteinke Offline
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Registered: 01/22/05
Posts: 5316
Loc: Blue Collar Country
This just boggles my mind! Now, I might- just might- see this being done if the nails went into solid wood.... but a nail won't even hold itself in sheetrock alone!

Then there's the lack of imagination shown.... I see 4" pipe, I "imagine" the mother of all pulls, and think "heavy." I just can't fathom anyone relying on a simple nail!

I'm amazed it stayed up as long as it did.
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#110917 - 08/06/06 11:12 AM Re: Ceiling Collapse
gideonr Offline
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Registered: 12/18/04
Posts: 161
Loc: Edinburgh, Scotland, UK
If only they'd used ring shank nails...
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#110918 - 08/06/06 02:25 PM Re: Ceiling Collapse
SteveFehr Offline
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Registered: 03/19/05
Posts: 1195
Loc: Chesapeake, VA
For structural engineering purposes, a 16D Common nail is rated for 141 lbs of pullout strength in nailing two 2xs together, and 165lbs in nailing 1/2" sheathing to 2xs, IIRC.

The wood looks OK in those photos, so I wouldn't suspect rotting or water. Vibrations or something else must have loosened them over time, causing them to fail. Either way, nails are the WRONG thing to use in that application, no question about it!
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#110919 - 08/06/06 03:38 PM Re: Ceiling Collapse
Trumpy Offline


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Registered: 07/05/02
Posts: 8211
Loc: SI,New Zealand
gideon,
Quote:
If only they'd used ring shank nails...

Yeah,
I was originally thinking the same thing.
A standard nail has nothing really for the wood to grip to.
Even if I was going to use nails to hold something like this up (not likely though) I'd at least have the sense to use either an annular ring type or even a "Twist-Nail".
_________________________
Let's face it, these days if you're not young, you're old - Red Green grin
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#110920 - 08/06/06 10:58 PM Re: Ceiling Collapse
NORCAL Offline
Member
Registered: 09/25/02
Posts: 865
Ring shank me, if the lazy guy had used lags it would not have happened.



[This message has been edited by electure (edited 08-07-2006).]
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