8x8x16 lightweight CMU has a 2 hour fire rating using the equivalent thickness formula.
Code Requirements for Determining Fire
Resistance of Concrete and Masonry Construction
Assemblies, ACI 216.1/TMS-0216 (ref. 1)
Go here for the full info:
http://www.ncmaetek.org/etek/pdf_brand.asp?pdf=TEK 07-01C.pdf&si=468.jpg
Code Requirements for Determining Fire
Resistance of Concrete and Masonry Construction
Assemblies, ACI 216.1/TMS-0216 (ref. 1)
Go here for the full info:
http://www.ncmaetek.org/etek/pdf_brand.asp?pdf=TEK 07-01C.pdf&si=468.jpg