Bottom Sealed Storm Flap
The storm flap is an additional layer of protection that covers the zipper area to prevent hazardous substances entering through the zipper. However, frontline workers often not use adhesive tape to secure the storm flap.
A bottom-sealed storm flap would ensure the flap remains closed and protects the zipper under normal working conditions. Without this design feature, the storm flap may remain open, leaving the zipper expose to contamination from dust or liquids.