What standard does Ernest Maier use for CMU fire ratings?

Ernest Maier CMU complies with the 2014 edition of ACI/TMS 216.1, which is referenced by both the 2015 and 2018 International Building Code for concrete and masonry fire resistance.

What is equivalent thickness and why does it matter?

Equivalent thickness is the calculated solid material cross-section of a CMU unit. Building codes use this value to determine how long a wall assembly will resist fire. A higher equivalent thickness means a longer fire resistance period.

Can adding plaster to a CMU wall improve the fire rating?

Yes. Plastering one side of a CMU wall with 1/2 inch of 1:3 gypsum and sand plaster adds 1/2 hour to the fire resistance rating of the assembly.

What aggregates are used in Ernest Maier CMU?

Ernest Maier and Parker Block CMU use quarried stone along with expanded shale and/or pumice as primary aggregates. These lightweight aggregates contribute to the unit's thermal resistance properties.

How do I choose the right CMU for a 2-hour fire rating?

Several block options meet a 2-hour rating, including 4x8x16 C-145 units at 100 percent solid and 6x8x16 C-90 units at 64 percent solid. Review the equivalent thickness values in the chart above and confirm selection with your project architect or structural engineer.

Where can I order fire-rated CMU from Ernest Maier?

See our e-store or contact Ernest Maier directly for availability and pricing. Stock varies by location, and specialty or high-solid units may require advance ordering for large projects.