"In a smoke compartment that is not fully sprinklered, a gap between the face of a corridor door and the door stop should not exceed 1/4-inch, provided that the door latch mechanism is functioning," states a recent survey & cert memo. "In a smoke compartment that is fully sprinklered, a gap between the face of a corridor door and the door stop should not exceed 1/2-inch, provided that the door latch mechanism is functioning." The clarification applies to corridor doors other than those in required enclosures of vertical openings, exits and hazardous areas. It doesn't apply to smoke barriers, which have other requirements. Read the memo at www.cms.hhs.gov/SurveyCertificationGenInfo/downloads/SCLetter07-18.pdf.