How detailed do I have to provide sources
When you first introduce the technical standard in your thesis, you should provide citations to any and all relevant documents.  By "any and all", I mean the set that you are making use of directly, but not previous versions, commentary, or ancillary documents.  Each reference should appear separately in your Bibliography.

After that, you do not need to provide additional citations even when you refer to that technical standard later in the same chapter, or in later chapters.  However, if you are quoting text from the standard, or otherwise you are analyzing/critiquing the standard in detail, then it would be helpful to your readers to provide citations to the specific reference and page numbers.  Sometimes, depending upon the standard, it is more appropriate to cite chapter, section, and subsection numbers.  You say that you are comparing different technical standards.  If so, then it would be very appropriate to provide chapter, section, and subsection numbers for the respective standard sections.  Somewhere on the page (e.g. footnotes) you could provide citation to the technical standard document(s) themselves.