High-Piled Plastic Storage in an Existing ESFR Warehouse
A 12,000 ft² warehouse with a 24-foot ceiling and an existing ESFR sprinkler system is leased to a new tenant. The previous tenant stored Class II commodity on racks 12 feet high. The new tenant plans to store Group A plastic in double-wall corrugated boxes on single-row racks 18 feet high, with 8-foot aisles and 6-inch longitudinal flue spaces. The sprinkler system has 165°F ESFR heads at 24-inch spacing, a 6-inch riser, and a placard showing a design pressure of 50 psi. The tenant has no storage layout drawing. The building has smoke and heat vents, but the fusible links are painted. The tenant wants to move in next week. You are conducting a pre-occupancy inspection. The building is 120 feet by 100 feet.
1. Determine the commodity classification and the key sprinkler-design questions you must answer before allowing the storage.
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Group A plastic in corrugated boxes is a high-challenge commodity, not Class II. The existing ESFR system may be capable, but the placard alone is not a design review. You need the original design basis, hydraulic calculations, head listing and temperature, minimum and maximum storage height, aisle width, flue spaces, and ceiling/deflector clearance. With 18-foot storage under a 24-foot ceiling, verify that the ESFR deflector clearance and storage height are within the listing. Verify that the 8-foot aisles and 6-inch longitudinal flues match the design. Also check that the 165°F heads are appropriate and not obstructed. Because ESFR systems are sensitive to storage arrangement, a change from Class II to Group A plastic is a material change that requires engineering review, not just a field walk.
2. List the field deficiencies visible in the setup and explain why each matters.
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Visible deficiencies include painted fusible links on smoke and heat vents, which make them inoperable; no storage layout drawing, which prevents verification of commodity, height, aisle, and flue spaces; a placard that does not prove compatibility with the new commodity; and planned 18-foot racks that may block sprinkler spray or violate clearance. Also look for damaged heads, storage in aisles, missing rack labels, and clearance to electrical panels. Each matters because ESFR performance depends on unobstructed discharge, correct clearance, and maintained flue spaces. A painted link is a direct impairment. Document with photos and measurements.
3. What enforcement action is appropriate and what must the tenant submit?
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Do not approve occupancy. Issue a correction notice requiring removal or replacement of vent links; a scaled storage plan showing commodity, rack type, height, aisles, and flues; a design professional's or sprinkler contractor's written verification that the ESFR system is designed for Group A plastic at the proposed height; and hydraulic calculations if not available. Require a permit for any sprinkler modification. Re-inspect after corrections and verify the placard matches the design. If the tenant occupies before approval, consider a fire watch or limit storage. Only after the system is documented, field-verified, and any impairments corrected should you recommend occupancy.