This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Smoke exhaust duct. aisonline de html Rad und Schwimmsporthalle Berlin Smoke Exhaust Ductwork made of Calcium Silicate Fireproofing Boards Own Achim Hering Firestops Fireproofing DIN Calcium silicate Smoke exhaust ductwork Passive fire protection boards
Page 2023 Free-images.com. All images are Public Domain