Hypermarket Racks: NFPA 13 ESFR K25.2 (K360), Class IV Commodities

Hypermarkets and large retail chains come with rack warehouses in addition to 10,000–20,000 m² of sales floor. Racks are typically 10–14 m high and hold Class III–IV commodities. On most projects NFPA 13 ESFR (early suppression fast-response) sprinklers are chosen: within the table limits, K25.2 (K360) sprinklers largely eliminate the need for in-rack sprinklers. ESFR, however, is limited to 12.2 m (40 ft) of storage under a 13.7 m (45 ft) ceiling; racks taller than 12.2 m need a different solution.

Commodity Classes (NFPA 13 Section 20.4)

• Class I: Noncombustible products such as metal and glass, on pallets, in single-layer corrugated cartons or shrink-wrapped
• Class II: Noncombustible products in wooden crates/boxes or multiple-layered corrugated cartons
• Class III: Products of wood, paper, natural fibers (textiles) and Group C plastics
• Class IV: Products made of Group B plastics or containing roughly 5–15% by weight of Group A plastics
• Group A plastics: For example expanded polystyrene (EPS); high fire load

ESFR Design

• K25.2 (K360): From Q = K√P, 150 gpm (570 L/min) is reached at about 36 psi (2.5 bar); the actual minimum pressure is read from Table 23.3.1
• K14.0 (K200) pendent: 50 psi (3.4 bar) minimum operating pressure
• Maximum storage height: 40 ft (12.2 m)
• Ceiling height: 45 ft (13.7 m) maximum
• 12 sprinklers: Calculated over the 12 hydraulically most demanding sprinklers

Pump Calculation

• Total flow: 12 × 570 L/min ≈ 6,800 L/min (1,800 gpm)
• Hose allowance: 250 gpm (950 L/min) per NFPA 13 Table 20.15.2.6
• Duration: 60 min
• Tank: (6,800 + 950) × 60 ≈ 465 m³ (122,800 gal)
• Pump: 7,750 L/min (2,000 gpm), 15 bar (218 psi)

In-Rack Alternative

• Face sprinklers: At every third tier
• Transverse flue: Nominal 6 in (150 mm) between loads and at rack uprights (NFPA 13 20.6.2.2)
• Longitudinal flue: Not required in double-row racks up to 25 ft (7.6 m); nominal 6 in (150 mm) above 25 ft (NFPA 13 20.6.2.1.1–20.6.2.1.2)
• Plastic commodities: Face and longitudinal in-rack sprinklers may be required
• Class I–III: Ceiling-only ESFR is sufficient; no in-rack sprinklers needed

Examples from Turkey

• Hypermarket chains: ESFR installed in many stores
• Wholesale retail logistics: An 80,000 m² warehouse
• Chain-store regional warehouses: ESFR K25.2 (K360) as the standard solution
• E-commerce logistics centers: Warehouses on the scale of 50,000 m²

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