Determine code equivalence between drywall grid ceiling systems and standard acoustical tee grid

Steps

1. Recognize gypsum-board ('drywall') ceilings hung on a concealed grid are a distinct product category from acoustical tile/lay-in tee grid covered by ASTM C636 — drywall grid systems achieve code recognition primarily through an ICC-ES Evaluation Service Report (ESR), not C636 alone.
2. Confirm the specific ESR number referenced for the drywall grid product in hand, and check its current validity/renewal date directly on icc-es.org rather than relying on a possibly outdated cached PDF.
3. Verify the main-tee/cross-tee structural classification (e.g., 'heavy duty' load classification per ASTM C635) and base-metal specification (commonly cold-formed steel with a specified hot-dip galvanized coating designation) match what the ESR actually lists as tested.
4. For fire-resistance-rated drywall-grid assemblies, confirm the specific rating claimed is listed in the ESR's assembly table, and that field gypsum-board attachment (screw pattern) follows the applicable IBC chapter referenced by the report.
5. Don't assume an ESR issued for one manufacturer's drywall grid product applies to a different manufacturer's system, even if visually similar.