Failure of 1/2" CATV

[Randy A Thompson]

Ahoy mates!

I had an interesting conversation with W8ZD today.  Paul makes connectors
and matching transformers for CATV hardline.  When I told him I had
1/2" hardline, he started warning me about the potential for breakdown
of the foam insulation when running 1KW with a high SWR (more than 2:1).
Since I have a mile of this stuff I was planning to use between the 
shack and two towers, I got a little worried.

Does anyone have experience with 1/2" CATV hardline breaking down?  If so,
what were the circumstances?
Should I even be worried?  If so, should I sell it all and go find some
3/4" or 7/8" CATV cable?

Thanks.

Randy, K5ZD

PS - K1AR, K1AR, When last heard you were saying, "I can't believe I ate
the whole thing!"  Remember to ask John about the Pasta from Hell (911 Pasta)!