Door Assembly Clearance Requirements NFPA 80-Current Editions   • The clearance between the top and the vertical edges of the door, the frame, and the meeting edges of doors swinging in pairs shall be 1/8" - 1/16" for Steel Doors. • The Clearance between the top and vertical edges of the door, the frame and the meeting edges of doors swinging in pairs shall not exceed 1/8" for Wood Doors. • The clearance under the bottom of a door and non- combustible surface where no sill exists shall be a maximum of 3/4". • The clearance under the bottom of a door and raised non-combustible sills shall be a maximum of 3/8". • Where the bottom of the door is more than 38" above the finished floor, the clearance under the bottom of a door shall be a maximum of 3/8" (i.e. Dutch Doors).