There isn't a sweeter sound in the world to cooped up students than the final bell. They immediately stampede out of the building, barreling through anything between them and the great outdoors.
School architects and facility managers have learned that wood doors can’t withstand this type of abuse day after day. Steel lasts much longer than wood due to its natural strength and durability.
When steel does get damaged, it's easy to repair: just apply bondo, sand and paint it, and the door looks like new again.
The old knock on steel doors was that they looked too industrial. Nowadays, they can have attractive finishes, stile & rail designs, and embossments to make them attractive. Steel also offers extensive LEED credits due to being 100 percent recyclable.