The current version of BC Calc online includes both IBC and IRC codes. Versions of BC Framer and MiTek Structure older than 25.3 may not include the IRC without the latest update.
The attached documents explain why we didn't show IRC in the BC Calc® software. One is for the 2012 IBC and the others are for the 2015 IBC reference.
BC Calc® Building Code Reference 2012 IBC IRC Memo
BC Calc® Building Code Reference 2015 IBC IRC Memo
BC Calc® Building Code Reference 2018 IBC IRC Memo
BC Calc® Building Code Reference IBC ASCE 2015 IRC Memo
For further information you may contact EWP Engineering Support: 800-232-0788