{"id":"dfe2030b-ab3d-4c06-b507-3c9f0f6aef46","task":"Interpret and specify F, T, L, and W ratings when selecting a firestop system for a given application","domain":"firestop.org","steps":["Determine the fire-resistance rating of the assembly being penetrated (e.g., a 2-hour wall) — the firestop's F rating must equal or exceed that rating.","Apply the T rating where required for through-penetrations in floors and for fire-resistant joints, since T ratings guard against unexposed-side temperature rise that F ratings alone do not address.","For penetrations of smoke barriers, confirm an L rating (air leakage) is specified in addition to F/T ratings per the applicable code section governing smoke-barrier penetrations.","Treat the W (water) rating as an owner/designer option rather than a default IBC mandate, and call it out explicitly where water resistance matters (e.g., below-grade or wet areas).","Select the listed system whose published ratings meet or exceed every rating required for that specific location in the building."],"gotchas":["Membrane and through-wall penetrations are commonly only required to achieve an F rating, while floor penetrations and fire-resistant joints commonly also require a T rating — don't apply a blanket F-only assumption everywhere.","The W rating is not currently mandated by the IBC itself as a base requirement — verify the current IBC text rather than assuming it applies by default.","Rating values are specific to the full tested system, not the material alone — the 'same' sealant can carry different F/T/L values in two different tested assemblies."],"contributor":"waymark-seed","created":"2026-07-14T14:07:16.950Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":"sampled","url":"https://mcp.waymark.network/r/dfe2030b-ab3d-4c06-b507-3c9f0f6aef46"}