Fire-rated doors are quite literally the barriers between life and death. Their most important function is to slow the spread of smoke and flames throughout a building. Because of their vital function, they are subject to audits by fire inspectors on a regular basis. A fire door that is not maintained to code can cause problems during one of these routine inspections – and, more importantly, in the event of a fire.Experts say there are some simple steps facilities managers can take to ensure their buildings’ fire doors comply with local and national fire codes:Make sure it’s on the level. Verify that the doorframe is installed correctly and is not out of plumb.Close the gap. Check for gaps between the frame of the door and the wall, and confirm that the wallboard penetrates the frame throat properly.Don’t cut it too close. If a fire door is trimmed, or undercut, leaving too large a gap between the bottom of the door and the flooring, it will not pass inspection.Look for the mark. Fire doors and their frames must be clearly labeled. Look for the Warnock Hersey Mark, the Underwriters Laboratories Mark, or the mark of another established third-party testing laboratory, for assurance that the door has been tested and fire-rated. Be especially careful of this infringement if your building is being painted or refinished, which often results in obstruction of the certification mark from view.Make sure it’s an open-and-shut case. An automatic door closer is a requirement for every fire door, but can be overlooked during installation or renovations. Without one, a fire door can close too slowly – or not at all.Latch it up. If the fire door’s latch is missing or inoperative, it cannot stay closed. Sign here. Some steel fire doors can get very hot during a fire and trigger the rapid ignition of any combustible material that comes in contact with the door surface. A call to the local building code office or fire marshal can help determine the restrictions on hanging signs on a fire door.Don’t forget the swinging doors. Make certain there are no missing or improperly installed astragals for pairs of swinging doors. Astragals are special hardware that eliminate gaps between doors while closed, preventing the spread of smoke and flame.Helpful hardware. If a tested and certified fire door is being held in place by non-compliant hinges and gaskets, these materials may not hold up to high temperatures, giving the door inadequate support.User error. Propping open a fire door with a wedge, a chair, a box, or a doorstop renders that door useless. Believe it or not, experts say this is the No. 1 problem fire inspectors find during a field inspection. Educating occupants on the dangers of such practices while policing such activity on a consistent basis is one possible solution.The most important rule to keep in mind when preparing for a fire door audit: What, if anything, is preventing the fire doors in the building from closing and staying closed properly?Bob Flores, executive manager for building materials field inspections at ETL SEMKO’s North American operations, Menlo Park, CA, is a leading authority in the field of fire door assembly.