houadfel (asker) Apr 6, 2013:

OK, that was helpful, in fact, by digging a little bit more, i think I found the answer to my question. inv is the acronym of invert, in french 'radier' which is a flat area usually at ground level but not necessarily and as you pointed out a datum given the reference value 100.00FT.
http://www.contractortalk.com/f62/brick-invert-channel-w-bri...

Tony M Apr 6, 2013:

More info In this document:

http://www.darden.com/pdf/about/red_lobster_ebrochure_2011.p...

on the 'sanitation' plan, they refer to the main restaurant floor level (?) as INV 100'00", and then other floor levels are referred to as slightly lower figures, suggesting this could very well be some kind of local altitude datum of some kind; I note that this document is from the US, so it looks like the usage may not be just CA!

Tony M Apr 6, 2013:

Aha! Actually, I can't help wondering if these aren't heights after all; on the example plan you quote, there are a range of INV figures around 90ft, and a TOP figure of the same order of magnitude; more significantly, those figures appear to reduce as we go downstream on the drains.

Here in France we have a mean sea-level datum that has an abbreviation like this, I'm wondering if maybe this is some kind of CA equivalent?

houadfel (asker) Apr 6, 2013:

I should have put FT instead of the confusing ' notation. Sorry about that. These are horizontal distances. The inv. is a not a project specific reference. You can find it in city drainage plans like this one:
http://cms.burlington.ca/AssetFactory.aspx?did=23689

Tony M Apr 6, 2013:

@ Asker Well, if you already knew that for sure, it would certainly have helped to say so!

So in fact, you're really just asking about 'INV.' — and I fear it is extremely likely that this is a project-specific abbreviation, which we may not be able to help you with; do you have any other clues at all in your plans? If it were some kind of reference, I'd expect at least a few other things to be referenced to it as well, which might give a clue...

From the nature of this building project, does it look like it will be a horizontal distance, or is it conceivable it could be a vertical one?

houadfel (asker) Apr 6, 2013:

98.00' is definitely a distance in feet.

Tony M Apr 6, 2013:

Brainstorming Just possible it could be 98°00', specifying the angle at which they should be fitted; that would seem to represent quite a steep fall, but depending on the function and exact installation, I suppose it might be possible.

Other idea: could it be 98.00 feet? Could this be with respect to some datum that they are referring to as 'inv.'? This could be consistent with the use of @ (= at).