Designation of steel mesh for > 63 mm concrete cover of reinforced concrete column

[ajk1]

The building code requires that reinforced concrete columns that are to have 4 hour fire rating are to have 63.5 mm (2.5") cover over the column verticals and this cover is to have: 1.57 mm (0.062”) diameter wires with 100 mm (4”) openings placed in mid-thickness of the cover.

I would like to specify the official designated mesh that would match this. What would be the standard steel mesh that would correspond to that, both in metric designation and imperial, in terms of wire gauge (metric and Imperial).

Would the imperial be 16 x 16 4x4? I can't find that size on the internet.
And what would be the exact proper official metric designation of this?

 

[jayrod12]

The smallest mesh I can find is 4x4-14/14 or 102x102MW3.2/3.2

 

[JAE]

That is a tiny wire. In the US, the smallest wire that is listed by the Welded Wire Fabric Manual of Standard Practice is 0.135 in. diameter = 3.4 mm (designated as a W1.4).
Here's a source pdf from the WRI:

http://wpvecn3id01.itap.purdue.edu/WWR/images/resources/WWR 500-R-10_Manual of Standard Practice.pdf

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[ajk1]

That is what I found too. I wonder what they use. I suppose it is not often that we need 4 hour fire rating (62.5 mm, 2.5" cover), so maybe that is why I cannot recall the question coming up. I think it arises only with column bars 45M and 55M