Question: What is the allowable gap between members of a barrier to a ?re-isolated stair? (1) Gaps such that a 125 mm sphere could not pass through the barrier. (2) Gaps such that a 100 mm sphere could not pass through the barrier. (3) There is no requirement for gaps for barriers to ?re-isolated stairs. (4) Gaps such that a 300 mm sphere could not pass through the barrier.