1" rigid floor flange strength?

DaveNay

Klaatu barada nikto
SUPER Site Supporter
Up at the cabin in Canada I am planning on installing a light fixture at the end of the pier.

I have a vapor tight light fixture that I am going to put up with rigid conduit. A floor flange screwed to the pier deck, followed by a 10' length of conduit, then two 90 deg sweeps and finally the light fixture.

Any opinions on whether the floor flange will be strong enough to support the conduit and fixture through a Canadian winter? The flange is malleable iron, so I don't know how good it will resist the pressure from a windy, ice covered January day.
 

Jim_S

Spammer Hammer
GOLD Site Supporter
Dave, I would worry about the conduit failing in the last thread just above the floor flange. That's the weakest point. Can you use larger conduit like maybe 1 1/2" and put a reducing bell on top to drop down to the 1" for the 90's?

Put the flange and the bell on with plenty of pipe dope to fill the top part of the threads so you won't get any freeze damage.

Jim
 

DaveNay

Klaatu barada nikto
SUPER Site Supporter
Dave, I would worry about the conduit failing in the last thread just above the floor flange. That's the weakest point. Can you use larger conduit like maybe 1 1/2" and put a reducing bell on top to drop down to the 1" for the 90's?

Put the flange and the bell on with plenty of pipe dope to fill the top part of the threads so you won't get any freeze damage.

Jim

Hmmm...that's odd (to me) that you are more concerned with the strength of the pipe threads instead of the flange itself.

I can easily step up to 1 1/2 pipe, I have'nt bought the pipe yet.
 

FrancSevin

Proudly Deplorable
GOLD Site Supporter
pipe threads cut out half of the steel in the wall. Weakest point is where the moment arm places the most pressure against the flange.

It is also where even the galvanizing is removed by the threading and will corrode.
Clean it well and paint it there.

Pipe dope yes but also drill a hole in the deck inside the flange before you insert the pipe. This will let water and condensate, which will find a way inside your pipe tower somewheres, to drain.
 

DaveNay

Klaatu barada nikto
SUPER Site Supporter
pipe threads cut out half of the steel in the wall. Weakest point is where the moment arm places the most pressure against the flange.

It is also where even the galvanizing is removed by the threading and will corrode.
Clean it well and paint it there.

Pipe dope yes but also drill a hole in the deck inside the flange before you insert the pipe. This will let water and condensate, which will find a way inside your pipe tower somewheres, to drain.

The deck will have a hole already to feed the UF cable through and up the pipe to the fixture.

I will throw a can up RustOleum in my gear.
 

Jim_S

Spammer Hammer
GOLD Site Supporter
I've seen flanges and pipe stubs used to mount antennas on buildings or water towers. I've seen a lot of pipes broken but very few flanges. I have seen several mi flanges bent though.

Jim
 
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