HL7(®) FHIR(®) standard is a new standard aiming to offer more flexible interoperability mechanisms. We present a stand-alone RDF vocabulary as an OWL ontology that defines the primitive and complex data types of the FHIR framework, alongside their validation rules. We address the non-trivial questions of representing FHIR data types as RDF/OWL constructs in a coherent and complete manner. The proposed ontology can be used as a basic framework, where the complexity of a FHIR-based EHR is not required, while still maintaining semantic cohesion with an industry-based standard. It can also be the base for a complete representation of FHIR model as an ontology.