These doors must stay closed in the event of a fire.
Fire door threshold detail.
Bs9999 2008 recommends for fire doors with cold smoke control that the threshold gap should be either less than 3mm in height or should be fitted with a threshold seal.
Doors over 4 0 wide and 8 0 tall must use heavyweight hinges.
When speaking with manufacturers however a common statement is that a fire doors gap of up to 8 mm underneath the door is permissible.
Doors up to 4 0 wide and 8 0 tall can use standard weight 134 thickness ball bearing hinges.
Backbend return face stop soffit rabbet throat.
E2 as1 includes general door sill details figures 17c and 17d and specific door sill details for masonry veneer figure 73d.
180 thickness latches locks.
Floor levels versus threshold levels.
Door clearances at the door edge of the door frame wood door on the pull side of the door do not exceed clearances listed in 4 8 4 the clearance under the bottom of the door shall be a maximum of 3 4 and 6 3 1 top edges 1 8 metal door top edges up to 3 16.
Thresholds are rarely mandated by the codes and standards for fire doors or smoke doors but when they are used in these applications thresholds must be listed to ul 10c or nfpa 252.
These all show sills positioned at floor level ie not rebated.
Terminology used in describing these frames follows as closely as possible the american national standard for nomenclature for steel doors and steel door frames ansi a250 7.