A steel security door is constructed of a heavier gauge sheet metal and has steel supports constructed inside the door itself. Often the problems encountered with doors is not the door itself but the hardware used to attach and secure the door. The following are some examples of the problems and corrective actions that can be taken. If the hinges to the door are exposed to the outside the pins can be removed or the hinge could be cut, allowing the door to be opened on the opposite side of the lock One method of prevention is to pin the hinge as shown below. This will prevent the door from being removed even if the hinge has been cut or the pin removed.
Door knobs latches.
External door knobs have an anti shim pin on the latch as shown in the diagram below. When the door is closed, this pin does not enter the recess in the door jam for the latch. If the door is not properly aligned or not installed correctly, the pin will enter the recess for the latch and the latch can be easily jimmied. Offset guard plate. If your door does not close flush, this plate can be easily installed to protect against forced entry.