BRNAV comply with RNP5 requirement and PRNAV comply with RNP1 requirement.
Not really correct. There are no EU standard for RNP complient equipment. What you are trying to say is: track keeping accuracy of +- 5nm or +- 1nm with equipment certified under TGL 10.
In the future the terms BRNAV and PRNAV will not be used anymore, and RNP1 RNAV and RNP5 RNAV terms will be applied.
Really? reference please?
However, the focus of this topic is to know "Am I allowed to follow a SID or a STAR RNAV on a chart without indication of RNP or B/PRNAV?"
Basically, we need to know how these procedures are certified.
For example, in Italy (from the national AIP), all the STAR RNAV are designed for BRNAV, and the obstacle protection area is RNP5x2+1 nm, so (as stated in the AIP document) is 11 nm of obstacle protection.
So in Italy, if I don't see anything specified on a chart, but only the header "RNAV STAR", I'm allowed to perform that procedure with BRNAV.
How about the rest of Europe?
Have a look here:
EUROCONTROL Navigation Domain - Published AICs
there is no answer to your question which applies in all eu states.