easy question. It has no fixed size. It should be relative the scale of the drawings and|or building. That said, however a good rule of thumb is that it should be 4.5x the thickness of a wall.

I'm sorry I just pulled that number from my ass...I just know the size is relative. Sorry

I mean the size in the paper space NOT in the model space.

There's no one standard for something like that - it's an aesthetic thing that each firm determines for themselves. The size of the circle has to interact with the font and text size that you're using, as well as whether you're putting a single number or letter in there (for instance labeling the section "A") or putting more information (for instance "A/A5.0.4"), etc.

I just measured one of ours and it has a 1/2" diameter in paper space. Feel free to adopt that as a world standard!

7/16" in ps. i believe that is standard, but don't quote me on that.

15/32" in our case. don't ask me - i didn't set 'em up.

The only standard to consider (at least in cali) is that Building Deptartments requires a min. of 1/8 text size.

we use 1/2" dia. (paper space) for section tags, detail tags & drawing numbers in title blocks.

I think the 1/8" text size(in paper space) is what drives most symbol sizes.

According to the AIA Drawing Standards the standard size is 5/8" dia. If you can get your hands on a copy, it'll have standard sizes for anything you can think of in a CD set. Of course you don't have to follow them, but it gives you a good starting point.

The 5/8" dia. was a little too big for our taste so we use 1/2" dia. also.

interesting. try this

Thank you guys for your generous help. I got confirmed our firm is using 1/2" dia too.