If the holes are neatly cored and have the correct annular space they may be able to be wrapped with a fire wrap (usually there is too much congestion to allow an acceptable wrap).
If the congestion is too great and the core is not much bigger than the pipe/service penetrating then they can be wrapped at the slab level and a fire mortar plinth poured around them all encapsulating all the wraps (effectively raising the slab height).
If the slab is not cored neatly and the holes are too large to do either of the above, then the space around the pipe-work would be boxed (if possible), or packed with a batt material (Dacron) then wrapped and a fire rated foam slab will be poured. Both methods are acceptable solutions, but the mortar slab is more effective and considerably cheaper to install. Also see buzz bar pics in the first section.