Certain devices and technologies are available to ensure that doors automatically close themselves, either for security's sake or to help control accidental heat loss or gain.
Hafele 940.82.568 Sliding Door Fitting, Häfele Slido Classic 80-L, With soft and self closing
Firevault Systems by Chemstore Engineering - Issuu
The History of Door Closers
What is a Fire Rated Door and Do I Need One in Las Vegas?
Physics Based Door With Closing Mechanism (5.0) - Character & Animation - Epic Developer Community Forums
Power Door Closer Mechanisms – Delta Entrance Systems
Self closing door NYC law FLYER NYC (pdf file)
True T-49G-HC-FGD01 Glass Door Reach-In Refrigerator
how to install self closing door hinge
RYOBI > Builders' Hardware > Products > Door Closers > Function
Auto Door Closer Door Closing Mechanism Door Closer Arm Door Self Closer
DENSC C60V - Self Closing Sliding Door Gear with 20 second delayed close
Self closing door closers - Soft close dampers, hinges