# Insulation touching chimney meta flex flue pipe **URL:** \ **Category:** Misc. Discussion\ **Created:** [March 6, 2020, 10:14pm UTC](https://forum.nachi.org/t/insulation-touching-chimney-meta-flex-flue-pipe/162392 "2020-03-06T22:14:27Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![smorris1](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/smorris1/32/59905_2.png) [@smorris1](https://forum.nachi.org/u/smorris1)\ **Post date:** [March 6, 2020, 10:14pm UTC](https://forum.nachi.org/t/insulation-touching-chimney-meta-flex-flue-pipe/162392/1 "2020-03-06T22:14:27Z")
Can this type natural gas chimney flue pipe be touching insulation, is fiberglass considered flammable? House is 14 yrs old. ![DSCN9747](https://global.discourse-cdn.com/internachi/original/3X/a/8/a84e4d0ff96c2615bcdcaaab663bd1a9246107ec.jpeg) ![DSCN9748 (2)](https://global.discourse-cdn.com/internachi/original/3X/8/d/8d1ab4035dba888fccb8776631b049c5643c8c83.jpeg) ![DSCN9746](https://global.discourse-cdn.com/internachi/original/3X/9/3/930402f2e9bb4184bd3952ee43144d180d5fd64b.jpeg) ![DSCN9686](https://global.discourse-cdn.com/internachi/original/3X/8/b/8b4d39565a92955cde1a7ab375cfa6834adfb732.jpeg) ---
**Author:** ![rcloyd](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/rcloyd/32/173058_2.png) [@rcloyd](https://forum.nachi.org/u/rcloyd)\ **Post date:** [March 6, 2020, 10:24pm UTC](https://forum.nachi.org/t/insulation-touching-chimney-meta-flex-flue-pipe/162392/2 "2020-03-06T22:24:51Z")
When used as a vent connector a 1 inch clearance to combustibles is usually required by the manufacturer’s installation instructions. Fiberglass is combustible. ---
**Author:** ![lkage](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/lkage/32/347658_2.png) [@lkage](https://forum.nachi.org/u/lkage)\ **Post date:** [March 6, 2020, 10:51pm UTC](https://forum.nachi.org/t/insulation-touching-chimney-meta-flex-flue-pipe/162392/3 "2020-03-06T22:51:46Z")
> [@smorris1](#): > > Can this type natural gas chimney flue pipe be touching insulation, is fiberglass considered flammable? House is 14 yrs old 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. 😄 ---
**Author:** ![cevans](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/cevans/32/244194_2.png) [@cevans](https://forum.nachi.org/u/cevans)\ **Post date:** [March 6, 2020, 11:57pm UTC](https://forum.nachi.org/t/insulation-touching-chimney-meta-flex-flue-pipe/162392/4 "2020-03-06T23:57:13Z")
Fiberglass itself is not combustible. It can be used as fireblocking. ---
**Author:** ![cevans](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/cevans/32/244194_2.png) [@cevans](https://forum.nachi.org/u/cevans)\ **Post date:** [March 7, 2020, 12:06am UTC](https://forum.nachi.org/t/insulation-touching-chimney-meta-flex-flue-pipe/162392/5 "2020-03-07T00:06:48Z")
You need to make sure that it’s double walled. [https://www.mtlfab.com/media/Double\_Wall\_B-Flex\_Installation\_Instructions-L1927.pdf](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? ---
**Author:** ![smorris1](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/smorris1/32/59905_2.png) [@smorris1](https://forum.nachi.org/u/smorris1)\ **Post date:** [March 7, 2020, 12:11am UTC](https://forum.nachi.org/t/insulation-touching-chimney-meta-flex-flue-pipe/162392/6 "2020-03-07T00:11:58Z")
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. ---
**Author:** ![cevans](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/cevans/32/244194_2.png) [@cevans](https://forum.nachi.org/u/cevans)\ **Post date:** [March 7, 2020, 12:14am UTC](https://forum.nachi.org/t/insulation-touching-chimney-meta-flex-flue-pipe/162392/7 "2020-03-07T00:14:58Z")
Then I wouldn’t comment on it. ---
**Author:** ![mcyr](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/mcyr/32/173319_2.png) [@mcyr](https://forum.nachi.org/u/mcyr)\ **Post date:** [March 7, 2020, 12:23am UTC](https://forum.nachi.org/t/insulation-touching-chimney-meta-flex-flue-pipe/162392/8 "2020-03-07T00:23:03Z")
> [@rcloyd](#): > > When used as a vent connector a 1 inch clearance to combustibles is usually required by the manufacturer’s installation instructions. **Fiberglass is combustible.** 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. ---
**Author:** ![smorris1](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/smorris1/32/59905_2.png) [@smorris1](https://forum.nachi.org/u/smorris1)\ **Post date:** [March 7, 2020, 12:34am UTC](https://forum.nachi.org/t/insulation-touching-chimney-meta-flex-flue-pipe/162392/9 "2020-03-07T00:34:03Z")
Thank You, You guys have been a great help ---
**Author:** ![mcyr](https://sea2.discourse-cdn.com/internachi/user_avatar/forum.nachi.org/mcyr/32/173319_2.png) [@mcyr](https://forum.nachi.org/u/mcyr)\ **Post date:** [March 7, 2020, 12:36am UTC](https://forum.nachi.org/t/insulation-touching-chimney-meta-flex-flue-pipe/162392/10 "2020-03-07T00:36:13Z")
This may help here; > **[How to Guide: Using Flexible Venting for a Direct Vent Fireplace](https://www.northcountryfire.com/blogs/news/how-to-guide-using-flexible-venting-for-a-direct-vent-fireplace)** > >  Napoleon's Freedom Flex venting can simplify gas fireplace installations and reduce costs compared to rigid venting systems.  I have included lots of links throughout this post to make finding the right parts easier.  > What is flexible...