I've read the HapHost terms of service multiple times and couldn't find a single line or word regarding IRC usage on HapHost VPSs.
Are IRC clients allow? Are IRC servers allowed? Are IRC bouncers and such allowed?
As nothing is stated in the TOS I run a simple IRC client that is connect to Rizon and I hope this isn't against your terms of services. If it is against your terms of service you should update them to include rules about IRC usage on your servers.