Can this type natural gas chimney flue pipe be touching insulation, is fiberglass considered flammable? House is 14 yrs old. 
When used as a vent connector a 1 inch clearance to combustibles is usually required by the manufacturer’s installation instructions. Fiberglass is combustible.
Is that a single wall flue liner used as a gas vent?
I don’t believe single wall vent pipe can be used in an attic.
If it is double wall, it may need an insulation shield installed.
Check the manufacturer’s installation instruction via Google. 
Fiberglass itself is not combustible. It can be used as fireblocking.
You need to make sure that it’s double walled. https://www.mtlfab.com/media/Double_Wall_B-Flex_Installation_Instructions-L1927.pdf. Clearance is 1 inch to combustibles. Blown fiberglass insulation is not considered combustible, however paper backing on some fiberglass batts is considered combustible.
What do you know about the vertical batts and their proximity to the vent?
There was no way I could climb down to where pipe came up to check, I just didn’t like how it looked, I turned on the fireplace and it looked like it had been used a lot in the last 14 yrs.
Then I wouldn’t comment on it.
Just to eliminate confusion;
Fiber Glass – Owens Corning PINK Fiberglas ™ is naturally non-combustible and is classified as such per ASTM E 136.
Only the facing if any is combustible.
Thank You, You guys have been a great help
This may help here;
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