There really is a difference between commercial doors and residential doors. To begin with, a commercial door must be much more durable since it is expected to have a great deal more use than something only your family might use. Although different businesses, factories, schools, and institutions use many unique and specialized designs, they all do tend to be constructed of a very few common materials.
Outside doors usually get the roughest treatment and a common material for them is steel. With factories, warehouses, and the behind the scenes sections of hospitals and other institutions requiring an extra level of security, steel is the perfect option for door material. While not as inexpensive as some materials, it more than earns its extra cost with extra performance.
A common mixture of materials in retail businesses is the aluminum/glass combination. The aluminum frames provide the strength to withstand constant use and the glass provides a more elegant appearance than a solid opaque door. These doors are every low-maintenance, usually requiring only a good wash to make them shine again. These aluminum/glass combination doors are designed for utility and an ubiquitous profile that ads a touch of familiarity to daily life. While all-glass doors provide more aesthetic appeal, they are not as secure and can be dangerous if shattered despite being constructed of safety glass.
Another durable option which works quite well in most schoolhouse environments is the fiberglass door. While being very durable it is also somewhat expensive. The greatest advantage is that they are very long-lasting, often lasting longer than steel doors. On the down side, they are not much to look at.
Wood is most commonly used for interior doors since they can be damaged by temperature and moisture. Wooden doors have a tradition of being used in offices for the elegant appearance of the color and grain. Wooden doors are also combined with glass to create the vintage office look. With solid bottoms and frame, the glass top half offers visibility and class, especially along hallways.
Price varies as not all wooden doors are solid wood. Cheaper wooden doors are made by wrapping veneer around a central core of particle board and slats. Some have foam or mineral interiors to help absorb sound and help cut down on noise from the other side.
Determining what type of door to use in a commercial structure requires balancing the factors of durability, safety, and aesthetics with cost.