(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)

I'm glad I wasn't under this when it fell.
Someones in trouble, I bet, and rightfully so!.

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.

Scary,just scary.

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.

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.

If only they'd used ring shank nails...

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!

gideon,
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".

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).]

There is nothing wrong with plain 'penny' nails. Look at the pics. Any of them broken? No. Just don't load them in direct pull. In shear, and if possible put in 'on the cross' in pairs, they will support massive loads. One pair of 1/8" diameter plain nails [of the correct length for the job] will stand over 600lb in shear. It's the wood that fails! You don't need ringshanks, just an engaged brain!


Alan

IF those trusses were OK to carry the additional weight, then wouldn't it have made sense to just put the conduit on top of them instead of hanging from the bottom?

Electure,
I know what you are saying Scott, but very rarely are any extra loads built into the calculation of trusses, especially in one place on the truss.
They are only made to hold themselves and the roof above up.
Oh and a ceiling or two.
This is just stupidity at it's worst.
On the other side of the coin, it makes you wonder about walking around inside some buildings without a hard-hat on.
Ask at the door, "who wired this place?", if it sounds like they are a handyman, don the skid-lid!.

A nursing home????!!! I'm glad no patients were hurt.

A headache is putting it mildly, I'm sure those pipes would have cracked your skull.

First thing that caught my eye was wood construction for commercial - but I guess that's just my NYC thinking.

Whoever inspected this job might catch heat too.. but really, who in the world could've thought that NAILS would be used in this application. What will be next, an inspection of the mounting methods before conduit is installed? When you think about it though, some AHJ's require inspection of drywall nailing before the mud is applied apparently for similar reasons.

Really is a shame though, in view of the seemingly strong wood construction, with the steel tico joints and all.

I guess the Man upstairs was looking out over everyone that day; a miracle no one was hurt -- thankfully.

Joe

Is kinda strange that all three fell at excatly the same time, when they don't appear to be connected in any way. They appear to be 3 single runs.

What broke on the other side?

There would need to be alot of slack in the runs, for those pipes to fall, unless something else broke and got pulled through the wall.
With those pipes falling 10', there must be 10' missing somewhere else, wouldn't ya think?

This is where we need Paul Harvey. We need to know the "rest of the story".

In pic. #4 you can just see the conduits entering a large pull box. The pull box was anchored with all-thread rod.
The joist the box was secured to failed. When it went everything else cascaded down.
Note: Alan B. These nails pulled straight out. Bending only because of the way the pipes fell. They were not sheared off.
Alan--

Yikes. That's scary, just scary. The roof on an older doublewide gave way recently, because someone installed three ceiling fans along the run of the peak.

Ian A.

4 - 750's? Even in Aluminum that's a huge amount of weight! If I absolutely had to go below those joists, I would've leaned towards 2 hole straps and lags, or even a solidly mounted piece of strut every 10'. That run seems like it would've been so much easier to put on top of the joists, then maybe screw 2 hole straps down...

Unfortunately, every rest home I've seen seems to suffer from 2 ailments. 1) Lowest bidder syndrome. 2) In-house maintenance-itis...

Someone may say "over-engineered", but.....
5 runs of 4" EMT, w/4-600's each. Support?
2-1/4" Unistrut, 5' o/c; 3/4" threaded rod, & 3/4" beam clamps to structure i-beams. 4" strut strap (downside) on each pipe, on each strut. (Locktite on the nuts)

I can sleep at nite!

John

Alan: Wonder if anyone used the EMT to 'hang' other stuff???

They used washers to keep the nails from slipping through - key to realizing it needed something much more substantial to hold it was the 3/8's + hole in the mineralac. The must have been a PITA to hammer..... I would have opted for 90 degree 3/8 rod hangers, to strut and may have doubled up supports for each 10' - Easier to hang on top of the strut that way.

Even tough it may be a moot point because the trusses aren't made to carry them anyway, by laying the conduits on top the load would be spread out evenly on all of them instead of straining the heck out of one of them every 10 feet.

WOW! That is a lot of support and I bet it looks great.

On the other hand if you want to get a little closer to what is really needed and still sleep well the Power Strut site has some great information on engineering supports.

Power Strut

[This message has been edited by iwire (edited 08-11-2006).]

Luckily those feeders didn't fault or you would be facing something like THIS

Or since they were feeders the OCP would've tripped first.

Either way, very lucky no one was hurt.

Iwire: (Bob)

Yes, I thought it looked nice. A lot of layout. I'll see if I have any pics.

'Uni-strut' on this job. 'Power Strut' is carried by another supply house, but he did not seem to interested in this job. Used to have a third 'Kindorf', but that kind of went away. Other supply house had some 'bargain' stuff; no country of origin, no name; 7/8" (thin) could deflect really easy

John

PS: Thanks for the compliment