Thanks. Of all places, I found this on Wikipedia:
Required navigation performance (RNP) is a type of
performance-based navigation (PBN) that allows an aircraft to fly a specific path between two 3-dimensionally defined points in space.
RNAV and RNP systems are fundamentally similar. The key difference between them is the requirement for on-board performance monitoring and alerting. A navigation specification that includes a requirement for on-board navigation performance monitoring and alerting is referred to as an RNP specification. One not having such a requirement is referred to as an RNAV specification.
Based on this, can I presume that if you are RNP-5 certified you are also certified to operate in BRNAV airspace?