Tony,
I don't know what national standards are, but in general I would say by default hidden lines should be shown. That said, this is a communications document, so in some instances and maybe many instances, having hidden lines can make for a difficult drawing to read. If not shown I would add a note saying so and then where ever needed create section views to show the geometry or dimension what is hidden. Many, many years ago I was under the impression that it is not a good practice to dimension to hidden lines.
I will add that if there is a standard or standard practice at a company than set the new view default in the drawing dtl file to that standard practice (model_display_for_new_views) and NEVER set that default to follow environment so that every time you open a drawing it changes depending on if you are in shaded, hidden line, no hidden, etc. I have never understood why that is an option or would be desired. Must be for making pictorials and note detail drawings. JS
Regards,
Mark Peterson
Design Engineer
Varel International
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