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Ceiling Collapse #110911
08/05/06 11:12 PM
08/05/06 11:12 PM
Admin  Offline
OP
Administrator
Member
Joined: Oct 2000
Posts: 3,503
NY, USA
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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Re: Ceiling Collapse #110912
08/05/06 11:19 PM
08/05/06 11:19 PM
Trumpy  Offline

Member
Joined: Jul 2002
Posts: 8,236
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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Re: Ceiling Collapse #110913
08/05/06 11:33 PM
08/05/06 11:33 PM
M
mahlere  Offline
Member
Joined: Nov 2005
Posts: 507
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.

Re: Ceiling Collapse #110914
08/06/06 12:05 AM
08/06/06 12:05 AM
N
NORCAL  Offline
Member
Joined: Sep 2002
Posts: 880
Scary,just scary.

Re: Ceiling Collapse #110915
08/06/06 08:15 AM
08/06/06 08:15 AM
S
steve ancient apprentice  Offline
Member
Joined: Mar 2005
Posts: 169
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.

Re: Ceiling Collapse #110916
08/06/06 11:25 AM
08/06/06 11:25 AM
renosteinke  Offline
Cat Servant
Member
Joined: Jan 2005
Posts: 5,316
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.

Re: Ceiling Collapse #110917
08/06/06 02:12 PM
08/06/06 02:12 PM
G
gideonr  Offline
Member
Joined: Dec 2004
Posts: 161
Edinburgh, Scotland, UK
If only they'd used ring shank nails...

Re: Ceiling Collapse #110918
08/06/06 05:25 PM
08/06/06 05:25 PM
S
SteveFehr  Offline
Member
Joined: Mar 2005
Posts: 1,213
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!

Re: Ceiling Collapse #110919
08/06/06 06:38 PM
08/06/06 06:38 PM
Trumpy  Offline

Member
Joined: Jul 2002
Posts: 8,236
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".

Re: Ceiling Collapse #110920
08/07/06 01:58 AM
08/07/06 01:58 AM
N
NORCAL  Offline
Member
Joined: Sep 2002
Posts: 880
Ring shank me, if the lazy guy had used lags it would not have happened.

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

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