In the US actually it is UL/CSA (Canada) and NFPA code that must be followed.
Anywho, one question that comes to mind is this: If your current panel has no more room, will it also have to be upgraded to one with bigger main breaker & bus bars to feed the sub panel? How about the utility line feeding the house? If the main needs to be upgraded for higher current service then the 2nd panel probably becomes moot because a new panel will have more slots for circuits...
I should have clarified, the panel isn't completely full, there are are two single slots available. However, if the main breaker needed to be upgraded, why would I install a sub panel? Also, I'm no electrician, but I'm fairly sure the utility line feeding the house isn't saturated either lol, that seems like a bit much. I'll have to get an electrician out to assess my situation though.