[TowerTalk] GRC vs. IMC

[Michael Fox - N6MEF]

I'm curious what people use for mounting pipes (not masts) on larger towers
and why.  For example, when mounting a dish antenna, a vertical pipe is
typically installed.

 

What I mostly see is galvanized rigid conduit (GRC).  But galvanized
Intermediate Metallic Conduit (IMC) also exists.  According to the specs
I've seen, it is 30% lighter and yet has a higher yield strength (GRC=35,000
psi, IMC=50,000 psi).  Also, it is approved in the NEC for all places that
GRC is approved.  So, one would think it would be a natural for tower use,
too.  

 

One difference I'm aware of is that IMC uses a special "organic" coating on
the inside, whereas GRC is galvanized on the inside.  But I can't find any
info on which that is better or worse for an outdoor tower application.

 

Michael

N6MEF