Benefit to running an inline chimney damper on double wall black pipe?

[Light in the Dark]

Who runs double wall pipe inside their home, and a damper? Why do you? What is the benefit? My brother in laws father (who runs single wall black) swears by them. I only see a benefit for taming a fire under very windy circumstances... but I am absolutely open to opinions. Thanks

 

[blueguy]

I have ICC Ultrablack off my stove. I installed their damper and I find that it is working for what I needed. The only weird thing I found about it was that the butterfly valve itself is mostly open due to them laser / plasma cutting out the letters "ICC" in the top part of the plate and a large window in the bottom part. In their literature, they say even fully closed, it's still 20% "open", so I am assuming this is how they accomplish this.

In any case, I only installed the damper two nights ago, and so far, it seems to be helping with the near-overfiring temps when fully closed down I was getting that I was attributing to too much draft in my basement installation. The damper is well made, and was about $50CAD from my local shop. Of course, I had to replace the 24" fixed section of connector off the stove with a 12" slip section which made my little experiment a little more costly, but I am happy so far