Corrosion Protection

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sii

sii

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Nebraska
I have an installation where I have to bury RMC in concrete. I am concerned that over time, the pipe will rust and I will have to dig it up and redo the installation. 344.10(B)(1) says this is acceptalbe "where protected by corrosion protection". I assume this refers solely to the original galvanizing of the pipe. Is there some sort of spray-on coating that I can use to get a longer life out of this?
 
From the UL Guide Information for "Rigid Ferrous Metal Conduit" (DYIX).
Galvanized rigid steel conduit installed in concrete does not require supplementary corrosion protection.
Galvanized rigid steel conduit installed in contact with soil does not generally require supplementary corrosion protection.
In the absence of specific local experience, soils producing severe corrosive effects are generally characterized by low resistivity (less than 2000 ohm-centimeters).
Wherever ferrous metal conduit runs directly from concrete encasement to soil burial, severe corrosive effects are likely to occur on the metal in contact with the soil.
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sii said:
I have an installation where I have to bury RMC in concrete. I am concerned that over time, the pipe will rust and I will have to dig it up and redo the installation. 344.10(B)(1) says this is acceptalbe "where protected by corrosion protection". I assume this refers solely to the original galvanizing of the pipe. Is there some sort of spray-on coating that I can use to get a longer life out of this?
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Well before pvc coated conduit came out and still today in 2010 on most projects we brush coat all rigid elbows with black jack bitumen paint 2 coats applied you can brush it on or roll it on or spray it on your choice .
Your supply house has it ask for electrical conduit bitumen its not just tar !


If we run rigid 100 % underground meaning all rigid on the project.

We tape the conduits we apply it to the full length with 1/2 lap of each rap down & each 10 foot stick 1 #in to 6# in with temflex its a pipe tape for electrical conduit it comes in rolls 4 inches wide .

Put the conduit in a mule and one guy spends 8 hours a day for 8 months lots of fun rolling tape .

We dont tape conduits before bends we bend first then tape its just some advice .

Most projects spec we see today & in the past just call out painting the rigid elbows thur the concrete below grade and thur slab but not above slab .


But we never tape the rigid couplings they must be painted only if you tape theres a void for water then rust and its no good .

We run lots of rigid conduit theres a trick with taped conduit in the bender if you get in a jam meaning you forgot a bend and its already taped
spray the conduit with blue cutting & threading fluid you know the stuff we use on aluminum conduit when you thread it works great no slips no rips in the tape while bending and no residue on the shoe .


Or get another stick !
 
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