Plastic (polyethylene, polypropylene, PVC) raw material (pellets/granules) burns at very high HRR (1,000 MJ/kg). LyondellBasell, BASF, SABIC and Petkim warehouses use ESFR K=25.2 (K360) sprinklers worldwide. 12 m pile height, 75 psi nozzle pressure and 12-sprinkler design area are the critical criteria.
Plastic Group Classification
- Group A plastic: PE, PP, PS, PVC, ABS
- Group B plastic: butadiene, acrylonitrile
- Group C plastic: rigid PVC
- Elastomer: Group A equivalent
- Expanded (EPS): worst - rapid burn
ESFR K=25.2 System
- K-factor: 25.2 (SI) / K360 (US)
- Nozzle pressure: 75 psi (5.2 bar)
- Flow per nozzle: 725 L/min
- Design area: 12 sprinkler open
- Total flow: 12 x 725 = 8,700 L/min
- Hose allowance: 500 gpm (1,900 L/min)
Pile Design
- Max pile: 12.2 m (40 ft) NFPA 13 limit
- Aisle width: 2.4 m (8 ft) min
- Arrangement: solid pile or rack
- Flue space: 150 mm transverse, 75 mm longitudinal
- Ceiling height: 13.7 m (45 ft)
Alternative Protection
- In-rack sprinkler: K=14 level spray
- CMSA K=16.8: lower pressure, legacy
- High-expansion foam: special design required
- Cartoned storage: Class IV commodity
- Open shelving: ESFR may suffice
Required Infrastructure
- Pump: 12,000 L/min @ 9 bar
- Tank: 60 min x 12,000 = 720 m3
- Riser: DN200-250
- Zone valve: split into 4 zones
- Detection: sprinkler + smoke vent
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Sources & Further Reading
NFPA 13, FM DS 8-9, FM DS 8-1, Viking ESFR-25, Tyco ESFR. NFPA 13 Sprinkler standard.