Back Draft Damper Dryer Vent

Can anyone tell me what year it became code for the dryer vent hood to be equipped with a back draft damper? I find 90% bonnet style vents at roof level.

Thanks!

Can’t tell you how far back but the first I-Codes in 2000 required it. You can see this in Section M1501.1 at the free viewing of historical codes at the ICC site http://www.iccsafe.org/content/historical-free-resources/.

Since your in Texas it is interesting how our SOP does get specific in the dryer vent section about some specific conditions but not about this requirement. Also of interest is to read the range hood vent requirements when exhausted to the outside and note what’s missing.

It’s a judgement call but I do call it out every time since they are not protected from birds and insects (bees, etc.).

Thank you!!