What is the maximum spacing between exterior deck boards?

[ltlyg]

I'm using dried 4x12 timber planks on steel framing to make a commercial boardwalk / deck. I'm concerned that with timber shrinkage the gap between the planks might get too large. BUT, I cannot find a standard or code anywhere that gives a maximum spacing. Can anyone point me to a CODE or STANDARD for reference?

 

[PenneEng]

Ask a carpenter for practical standard. I would imagine they use about a thickness of a nail or so. You should be able to figure expansion of the material. I would say a gap of 1/8" should be about right.