This would be a handy reference, to say the least. There is a paper copy in at least one library in Houston, so it's not inconceivable that it's online somewhere, but my searches to date have failed.
It is possible that a digital copy is stored at the NASA Technical Standards System which requires a NASA account to access.
Otherwise, there does not seem to be a browser-accessible copy at all.
A portion of Volume 1 of "NSTS-08209 Shuttle Systems Design Criteria" is available at
which is a pretty amazing shuttle data dump.
The pdf only contains the highlighted sections.