I had an AHJ tell me today that a NFPA 13R system can't be a glycol system; it automatically becomes a NFPA 13 system. However, when you read 13R 2013 section 5.4.3 it says that the system "shall be installed in accordance with NFPA 13" My interpretation is that the design and calculation of the system is in accordance with 13R still but the installation is in accordance with NFPA 13 section 7.6 "Anti-freeze Systems". I'm not sure the system in question will calc out using 900 sqft. I also didn't bid this project putting heads in every bathroom and closet, plus it opens the door to requiring protection in the attic. Curious if anyone has run into this before?