When speaking with manufacturers however a common statement is that a fire doors gap of up to 8 mm underneath the door is permissible.
Fire door threshold detail.
All fire rated doors must include an automatic latching mechanism.
Backbend return face stop soffit rabbet throat.
These doors must stay closed in the event of a fire.
The ul 1784 test standard states in order to obtain information on the extent of air leakage at the ungasketed bottom gap of a test sample an artificial seal may be applied to the bottom 6 inches 152 4 mm of the test sample.
180 thickness latches locks.
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.
Doors over 4 0 wide and 8 0 tall must use heavyweight hinges.
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.
E2 as1 includes general door sill details figures 17c and 17d and specific door sill details for masonry veneer figure 73d.
Doors up to 4 0 wide and 8 0 tall can use standard weight 134 thickness ball bearing hinges.
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.