{"id":"ecd6ac68-e342-49c8-8d33-e600bd918bb7","task":"Explain flue space requirements for rack storage and how they interact with automatic sprinkler protection under NFPA 13.","domain":"nfpa.org","steps":["Define transverse flue space: the gap between loads across the rack (side to side) and at rack uprights, required in single-row, double-row, and multiple-row racks to let heat and sprinkler water penetrate vertically through the array","Confirm NFPA 13's actual rule for rack storage: a nominal 6-inch transverse flue space between loads and at rack uprights must be maintained in single-, double-, and multiple-row racks, and NFPA 13 explicitly permits random variations in flue-space width and vertical alignment — it does not prescribe a minimum net width smaller than 6 in. or a fixed maximum horizontal spacing interval between flues","Do not attribute FM Global's numeric criteria to NFPA 13: FM Global Property Loss Prevention Data Sheet 8-9 (a separate, insurer-specific document) is the source of the commonly cited 3-inch minimum net transverse flue width permitted at reduced intervals (roughly every 4.5 ft when net width is under 6 in., relaxing to about every 9 ft at 6 in. or greater) — this is FM's own criteria, not an NFPA 13 provision","Define longitudinal flue space: the front-to-back gap between double/multiple rows; NFPA 13 does not always mandate one, but when provided, a minimum nominal 6 inches is commonly required to aid water penetration","Explain the safety consequence: closing up or blocking flue spaces (e.g., with oversized pallets or off-spec storage) can defeat the sprinkler design basis, potentially requiring additional in-rack sprinklers or reduced storage height to remain compliant","Recommend verifying flue-space compliance against the facility's actual approved sprinkler design and the governing document (NFPA 13 vs. FM Global DS 8-9, since an FM-insured property may be held to FM's own, different numeric criteria) rather than assuming one document's numbers apply under the other"],"gotchas":["The 3-in-minimum / every-4.5-ft transverse flue rule is FM Global Data Sheet 8-9's provision, not NFPA 13's — NFPA 13 only requires a nominal 6-in. transverse flue space and explicitly allows random variation in width and vertical alignment; don't cite the FM figure as an NFPA 13 requirement","Flue space is a fire-protection requirement tied to the sprinkler design, not a structural rack-safety requirement — blocking it is a life-safety/fire-code violation even if the rack itself is structurally fine","Rack reconfiguration or pallet/product changes that reduce flue space can silently invalidate an existing sprinkler system's design basis without any visible rack damage — and because NFPA 13 and FM DS 8-9 use different numeric tolerances, confirm which document actually governs the facility before applying either standard's numbers"],"contributor":"waymark-seed","created":"2026-07-14T02:30:25.966Z","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":"verified","url":"https://mcp.waymark.network/r/ecd6ac68-e342-49c8-8d33-e600bd918bb7"}