I don't think COPPA can be enforced here, because it only applies to account creations. You don't have accounts on IRC. However, as a community, we can very well decide whether we want to allow underage users on IRC.
I personally think that users should not be allowed on IRC if they are blocked on Avatar Wiki. Since they don't make accounts, we cannot truly enforce a rule that states that users of #wikia-avatar have to be over a certain age.
I'm worried that since COPPA specifically mentions chatrooms, the IRC can be seen as an extension of the wiki, and could concievably drag the wiki down if something went terribly awry as far as that federal law went. I don't think all users in the IRC have to have accounts - it's a good way for people to introduce themselves to the community before they decide they want to join fully or not. But discussion is often more PG-13 on the IRC, as it's our place of 'anything goes', and I for one feel really uncomfortable knowing that there are people under 13 in there.
I actually think that people should contain themselves in the first place. We are a wiki with a complicated and strict policy; we cannot have an IRC channel that is filled with inappropriate conversations. If we are to restrict people from going there based on their age, then we must place restrictions on the conversations that happen on there; first stop, limit vulgar language.
I haven't seen any harm coming from having users who are under 13 there before, so that's not a concern for me. As far as COPPA goes, I know that there are rules regarding things like IRC, but that's completely separate from Wikia global policy, which says they can't have accounts.
Plus IRC – if I haven't misread – is developed in Europe, so I'm not sure whether they are, too, as Wikia is, intertwined with the United States laws that limit account creations for what they defined as "underage" people. Thus, as Wikia and IRC are not connected, I do not believe that Wikia policy needs to apply there by default. Again, this is a great time to look at what some people are doing wrong and stop it, rather than try to hide it from younger people.
I'm not really following what you mean with "a great time to look at what some people are doing wrong and stop it, rather than try to hide it from younger people", but if this is to create/reform an IRC policy, then I suggest to take this to the War Room to get some actual results instead of the admin board.
And Lady's right. This whole discussion should go to the War Room. That goes for the under-13 issue as well. The admin noticeboard is where incidents that require attention are reported. It isn't a place to debate or modify policy, and that hasn't changed with the new form it's in now.
Just popping in, being the unofficial IRC guru, but being under 13 IS allowed on freenode. Freenode is ran by the PDPC, which is based in the UK and does not have COPPA laws. If someone is being abusive and disruptive, then they shouldn't be allowed in #wikia-avatar, reguardless of their age. Some <13 year olds are sensible, others not so.