What does "30 pp" mean for manuscript submissions?
Some journals restrict by word count, others by page count, yet others by odd hybrids such as counting each figure as a certain numbers of words.  In the case of the journal you mention, it sounds like it is, in fact, page count, with a limit of 30.  

Usually, if there is a page-count restriction, the journal also prescribes submission format more precisely, so you may want to look into that as well...