We have no such rules but this did come up during our recent (disastrous) 'team building' exercise - it seems some people have difficulty concentrating in our open plan office.
We now have rules which state how many people can discuss something at someone's desk (no more than 2), and for how long (no longer than 10 mins), before a proper meeting room should be used........*sigh*

In the case of our IT support department, it's all via a ticket system now, which works well.

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Bring on Summer!