The focus of the present paper is on the specification of routing and resource allocation systems. Such systems can be described as a set of shared resources and a set of products. The products utilize the resources in order to be manipulated according to a certain specification. This product specification consists of a set of operations that are to be executed in a certain order by specific resources. This results in a desired product route through the resource system, and hence the product specification is also called a routing specification. The process algebra petri net (PPN) formalism, i.e. a combination of petri nets and process algebra, implies efficient and less complex models for routing specifications compared to PNs and automata descriptions. The aim of this paper is to show how the PPN language can be used in order to simplify the specification of desired routes of the chemical batch process.