What is the industry standard for weeps at the bottom of an exterior door with vertical stiffeners and mineral fiber insulation?
There is not an industry standard on weep holes. They are not required and not all manufactures incorporate such a configuration in their doors. If a manufacturer should determine that some sort of drain needs to be part of the door construction, how they accomplish that is up to them—whether by designing it into the door or by drilling holes/slots after manufacturing. A sealed flush cap on the top of the door should be requested if the opening is expected to be located in an area where moisture is expected (e.g. – exterior opening). Some holes in the bottom of the door are used by manufacturers to suspend the doors during coating operations.