Garage Dryer Duct

Have any of you seen this before and how would you write this up? The aluminum dryer duct on my last inspection exited the laundry room directly into the garage and it had a 90 bend that ran vertical to a dryer vent monted on the roof. The Duct had (2) 90’s and was approx 27’ length with the bends. The vertical duct in the garage was 18" from the garage dry wall and was only “supported” were it exited the wall and roof. The duct was basic duct thickness and pieced together is ~3 foot sections. Nothing was protecting the duct from damage and it very flimsy. There was cardbord boxes pushed against it. I could easily move it from side to side with little effort. I wrote this as safety hazard and that it needed to be replaced (including no supports and exceed length standards). My main question is how should I have written this up regarding the fire hazards and what standards apply to ducting in the garage.

All ducting located in the garage that penetrates the firewall should be 26 gauge sheet metal. It sounds like a relocation of the original. Any evidence of an original location elsewhere?

It would be a fire hazard because of the lint!

The 2006 edition of the IRC states the following concerning ducts that penetrate garage walls and ceilings:*R309.1.1 Duct Penetration

Ducts in the garage and ducts penetrating the walls or ceilings separating the dwelling from the garage shall be constructed of a minimum No. 26 gauge (0.48 mm) steel sheet or other approved material, and shall have no openings in the garage.*Read and