Getting to the Core of Hollow Metal Doors
You can't judge a book, or a hollow metal door, by its outside appearance. The core within the door gives it unique characteristics that may set it apart from another door that appears identical on the surface. Hollow metal doors can be ordered with many different types of cores, each with features that may be seen as advantages or disadvantages, depending on the application. Successful application of hollow metal doors depends on choosing the right type of core, made of the right materials, properly constructed, finished and installed within the door by the manufacturer.
The right core adds the optimum combination of desired properties to a hollow metal door. These may include such qualities as structural integrity and rigidity, sound deadening, fire protection (20 min. to 3 hr.), insulating properties ("U" value or "R" factor), thermal control (temperature rise), and flatness or shape.
Sorting Out the Cores
While various combinations of doors and different types of cores are available, these are some of the most prevalent core types on the market today.