Jeri,
if it were me, I'd have a physical copy of ANY standard available, if I referenced it in my documentation. But, if you put a copy of the standard in your documentation (like pasting a copy of a standard sampling plan directly into your document), then you should be okay with not having it somewhere on you desk or bookshelf. I ran into this with our registrar a few years back in dealing with an ASTM procedure for ashing coal samples, and this was his recommendation. I like to have a hard copy of any standards we use anyway, but if you directly copy it into your documentation, you shouldn't have to have a hard copy ready somewhere else, IMO.
Joe