Plycem USA (8170-2180:0503)
This is a material class, not a wall or roof assembly listing. Listing 8170-2180:0503.
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Allura 4/4 and 5/4 fiber-cement trims are listed as ignition-resistant materials, with thicknesses that differ from their size labels.
Under Plycem listing 8170-2180:0503, the 4/4 trim is 3/4 inch thick; the 5/4 trim is 1 inch thick. Preserve each pairing when selecting trim. Reading the fractional label as the stated thickness would select a different dimension from the one OSFM describes.
The handbook identifies ASTM E84 with an extended 20-minute test. That duration belongs to the material test protocol, not a fire-resistance period for a completed wall. Construction details come from Plycem's instructions and product data sheets, as OSFM directs. Confirm the exact Allura trim listing through GOVmotus and carry both the trim label and its corresponding thickness into the specification. This is the trim listing, with its own dimensions, rather than a general listing for all Plycem cladding.