We describe a process algebraic approach to the semantics of replicated systems. We extend a subset of CCS with a replication operator to model systems with replicated synchronous majority voting. Based on an operational semantics, we define a bisimulation semantics. As the bisimulation semantics does not characterise fault tolerance we define preorders which introduces a hierarchy of faulty processes and fault tolerant processes. We then show how a similar ordering on modal- formulae can characterise the fault preorders.