rcirc-kill-channel-buffers

rcirc-kill-channel-buffers is a variable defined in `rcirc.el'.
Its value is

nil

Documentation:
When non-nil, kill channel buffers when the server buffer is killed.
Only the channel buffers associated with the server in question
will be killed.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 24.3 of Emacs.