To limit the probability of inadequate dimensions, proximity to supports or fastening, which could lead to inadequate restraint of the bottoms of joists, which could lead to excessive twisting of joists, which could lead to an inability to resist expected gravity and lateral loads, which could lead to the excessive movement, deformation or failure of floor assemblies.
Where assemblies are required to provide fire resistance, this is to limit the probability of compromised fire resistance of the assembly, which could lead to harm to persons.