Paper Mills: NFPA 13 OH2, Roll Paper Storage, Dryer Section and Pulp Mill Protection

A paper mill brings several different fire scenarios together in one plant: roll paper stacks up to 8 m high, dryer sections 50–100 m long, and pulping and bleaching areas under the same roof. One of the critical figures on site is the K_st of cellulose dust, around 150, and dry paper rolls carry a very high fire load. In these plants the NFPA 13 Ordinary Hazard Group 2 (OH2) classification applies, together with the NFPA 13 roll paper provisions and FM Global Data Sheet 8-21 for roll paper storage.

Paper Fire Load

• Paper: Heat of combustion about 15 MJ/kg
• Roll density: 600–800 kg/m³
• 6 m stack: 6 m × 600–800 kg/m³ × 15 MJ/kg ≈ 54,000–72,000 MJ/m² of stack footprint
• Classification: Paper and pulp mills are OH2 per NFPA 13 A.4.3.3.2
• Flame spread: Class A interior finish in corridors

ESFR for Roll Paper Storage

• ESFR K25.2 (K360): Per NFPA 13 Table 23.6, maximum storage height 30 ft (9.1 m) for heavyweight paper only (25 ft / 7.6 m for mediumweight; not applicable to tissue), in buildings up to 45 ft (13.7 m)
• Design: 12 sprinklers; minimum pressure 50 psi (3.4 bar) for K25.2 (K360) in a 45 ft (13.7 m) building
• Flue space: 150 mm transverse
• In-rack sprinklers: Mandatory for horizontal storage
• FM DS 8-21: The data sheet for roll paper storage (FM DS 8-1 is commodity classification and refers roll paper to DS 8-21)

Dryer Section

• Steam drum: 10 bar, 180 °C operating temperature
• Sprinklers: Two lines, under the hood and above the belt
• Broke: Combustible paper waste and a constant fire risk
• Hood: Sprinkler layout under the arched hood ceiling is critical
• Felt: Wool and fabric blend, highly combustible

Pulp Mill and Bleaching

• Black liquor: Burned in the recovery boiler
• ClO₂ plant: Toxic gas hazard under NFPA 55
• Lime kiln: 1,000 °C, a permanent hot surface
• Turpentine: Class IB flammable liquid (low flash point)
• Sprinkler density: OH2: 0.20 gpm/ft² (8.1 mm/min) over 1,500 ft² (140 m²) (NFPA 13 Table 19.2.3.1.1)

Turkish Paper Mills

• A large mill, now closed: The largest paper mill of its time
• A large production plant: 1.5 million tonnes a year of production capacity
• Packaging paper plant: Mainly packaging paper lines
• A paper mill fire: Still a reference case in the industry
• Tissue lines: Toilet tissue and paper towel production

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