Conduit in parking garages?

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kenman215

Senior Member
Location
albany, ny
New job I'm running has two levels of poured concrete parking garages. I've never done one before, but what I'm finding is that the garage is extraordinarily wet, with droplets forming on the ceiling and walls alike. I don't think that this is from curing as the level I'm on now was outed almost two months ago. I think it's condensation due to the fact that the outside air temp blowing through has been significantly warmer then the concrete. It's bad enough right now that I'm to point that I feel like I should be using compression fittings and wp boxes for my pipe work.

Has anyone done a garage or seen this before? Is it temporary? I truly can't exaggerate how much moisture we're talking about here.
 

mike7330

Senior Member
Location
North America
Open parking garages are wet! I treat it as a wet location. I find EMT rots out, aluminum bell boxes rot.
I have been successful with ridge, clamp backs/ straps, cowboys, and malleable boxes.
I have also used parking deck MC cable
 

kenman215

Senior Member
Location
albany, ny
Open parking garages are wet! I treat it as a wet location. I find EMT rots out, aluminum bell boxes rot.
I have been successful with ridge, clamp backs/ straps, cowboys, and malleable boxes.
I have also used parking deck MC cable

I'm wondering if there's an official classification or if it will be up to the discretion of my inspector. Only problem is I'm 99% sure that my PM quoted the job using primarily emt and ss fittings except near the outside walls. Might end up having to get the AHJ to weigh in on it...
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
From what you've described it's a damp location by NEC definition.

Location, Damp. Locations protected from weather and
not subject to saturation with water or other liquids but
subject to moderate degrees of moisture
.
Informational Note: Examples of such locations include
partially protected locations under canopies, marquees,
roofed open porches, and like locations, and interior loca-
tions subject to moderate degrees of moisture, such as some
basements, some barns, and some cold-storage warehouses.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
New job I'm running has two levels of poured concrete parking garages. I've never done one before, but what I'm finding is that the garage is extraordinarily wet, with droplets forming on the ceiling and walls alike. I don't think that this is from curing as the level I'm on now was outed almost two months ago. I think it's condensation due to the fact that the outside air temp blowing through has been significantly warmer then the concrete. It's bad enough right now that I'm to point that I feel like I should be using compression fittings and wp boxes for my pipe work.

Has anyone done a garage or seen this before? Is it temporary? I truly can't exaggerate how much moisture we're talking about here.

Compression fittings are not raintight... Not sure what you are looking to do.
 

kenman215

Senior Member
Location
albany, ny
They are when you ask for RT compression fittings.:)

That said I would stick with the set screw fittings, they will let any water out that does get in.

That is a good point abou the ss fittings, and I reall think everything on the line volt side will be fine, but what I have serious concerns about is the fire alarm, with both the wire and devices. We might end up havin to go full w.p. on them.
 

mgookin

Senior Member
Location
Fort Myers, FL
New job I'm running has two levels of poured concrete parking garages. I've never done one before, but what I'm finding is that the garage is extraordinarily wet, with droplets forming on the ceiling and walls alike. I don't think that this is from curing as the level I'm on now was outed almost two months ago. I think it's condensation due to the fact that the outside air temp blowing through has been significantly warmer then the concrete. It's bad enough right now that I'm to point that I feel like I should be using compression fittings and wp boxes for my pipe work.

Has anyone done a garage or seen this before? Is it temporary? I truly can't exaggerate how much moisture we're talking about here.

20 years ago I did my first parking garage in this town and it's dry as a bone today. Never had a water problem. We have another garage here in town that's 15 years older than that one and it's dry as a bone and never had a water problem.

And we're in the monsoon capital of the whatever; we get LOTS of rain.
Our temps typically vary by around 13 degrees between day and night. And our annual temp range is narrower than most everywhere else because we never get below the 30's, but condensation would not be an issue there anyway below freezing.

Just wondering, is that garage underground?

Sounds like it may have some health and maintenance issues in its future.
 

kenman215

Senior Member
Location
albany, ny
20 years ago I did my first parking garage in this town and it's dry as a bone today. Never had a water problem. We have another garage here in town that's 15 years older than that one and it's dry as a bone and never had a water problem.

And we're in the monsoon capital of the whatever; we get LOTS of rain.
Our temps typically vary by around 13 degrees between day and night. And our annual temp range is narrower than most everywhere else because we never get below the 30's, but condensation would not be an issue there anyway below freezing.

Just wondering, is that garage underground?

Sounds like it may have some health and maintenance issues in its future.

1 level below, 1 above, both sweating profusely. We just had a sub 40 degree night followed by a 70 degree day. I was thinking the condensation was caused by the warm air blowing across the cold concrete in a high humidity environment. But, alas, I'm an electrician not a meteorologist, so who knows
 

mgookin

Senior Member
Location
Fort Myers, FL
1 level below, 1 above, both sweating profusely. We just had a sub 40 degree night followed by a 70 degree day. I was thinking the condensation was caused by the warm air blowing across the cold concrete in a high humidity environment. But, alas, I'm an electrician not a meteorologist, so who knows

I'm going to guess it's a result of the concrete mix they use because of the cold climate up there, or maybe a sealer they put on it afterwards to prevent sprawling.
 

Pizza

Senior Member
Location
Minnesota
Does the garage have heat, make up air or exhaust fan?
If it does than it should be a dry location and water could be draining in from an unfinished portion of the building?



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kenman215

Senior Member
Location
albany, ny
Does the garage have heat, make up air or exhaust fan?
If it does than it should be a dry location and water could be draining in from an unfinished portion of the building?



Sent from my iPhone using Tapatalk

None of the above. Mgookin might be on the right track. Masons are back on site next week, I hope to find out something from then.
 

ADub

Senior Member
Location
Midwest
Occupation
Estimator/Project Manager
Bad concrete work can take a ridiculously long time to stop sweating from what I've seen. Add drastic and inconsistent temperature shifts to that and you might have an explanation. I've personally only ever used rmc in parking garages but it was always speced that way


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mgookin

Senior Member
Location
Fort Myers, FL
None of the above. Mgookin might be on the right track. Masons are back on site next week, I hope to find out something from then.

At least the underground level should have mechanical ventilation if less than 50% or more of the area of 2 opposing walls are not open to free air. Maybe that system is not up and running yet.

Greater airflow will mitigate accumulation of condensation.
 

iwire

Moderator
Staff member
Location
Massachusetts
We'll have to agree to disagree on that one. I've personally strapped PVC every two feet and still seen it sag. Only like it for underground...

I am not a fan of expossed PVC but if it is sagging with supports every 2' you are doing something wrong.

Either your supports are not letting the PVC move (which the code requires) or you are not installing expansion joints where needed.
 

iwire

Moderator
Staff member
Location
Massachusetts
That is a good point abou the ss fittings, and I reall think everything on the line volt side will be fine, but what I have serious concerns about is the fire alarm, with both the wire and devices. We might end up havin to go full w.p. on them.

The following is not about code, just my experience servicing walk-in coolers and freezers.

In my experience the way to have a water problem with the wiring is the use of water tight wiring methods. Seems counter intuitive but in most cases seems to be true.

It is always where the water is trapped in a box, conduit, LB etc where the problem happens.

Fire alarm devices are a problem and while I might be inclined to use WP wiring methods I would also be drilling small drain holes in the bottom of low spots. Or trim the bottom of a gasket making the boxes more like a 3R enclosure, you try to keep water out but provide a place to drain if it does get in.
 

kenman215

Senior Member
Location
albany, ny
At least the underground level should have mechanical ventilation if less than 50% or more of the area of 2 opposing walls are not open to free air. Maybe that system is not up and running yet.

Greater airflow will mitigate accumulation of condensation.

You are absolutely right with your presumptions, but, believe it or not, the ground level, which is completely open, has the exact same problem. I think you might have been on track with your previous post as to the cause. I'll let you know what I find out from the masons next week.
 
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