Split sleeves are typically not supported by anything other than the wall itself. They could be held in by compound on drywall or mortar in block applications.
If your "fire rated" walls or ceilings are true fire rated assemblies,
then there should be a Registered Design Professional [ RDP ]
to design an approved type of sleeve to be installed in that
particular assembly.
There is more to this than simply sticking a pipe sleeve in to
a fire rated wall or ceiling.
true fire rated sleeves are not generally supported by the drywall system. The sleeves also must extend a certain amount past the wall also to the best of my knowledge.
Whoever is doing the life safety consulting on this job needs to provide a listed detail for the given penetration. He's the one (and the detail) who prescribe the methods of installation.
If all you're working on is an electric permit and there is no GC, plans & etc. then the supplier of the sleeve should be able to give you direction.
If none of that works ask your inspectors what s/he'll be looking for at time of inspection.