EN 12845 Annex G — Nonwoven Synthetic Fabric Storage

Nonwoven synthetic fabric — nappies, hygiene products, insulation, automotive trim — is treated as Group A plastic under Annex G. The fire is fast, the material melts and drips, and the chimney effect is real. Standard storage design is inadequate; ESFR and specific precautions are required.

A hygiene products logistics warehouse held PP and PET nonwoven in bales, racked five tiers to about 9 m, protected by standard OH3. The producer had classified the goods as "textile" and declared OH3 to the insurer. The first year passed without incident. In the second, a forklift nicked a bale, fibre dust collected in the tear, and after a month friction and static ignited it. The sprinklers operated in 14 s, but the PP bale burned at the surface, melted and dripped onto the tiers below. Sprinkler water could not cool the melt, and the fire grew to 1500 m² within eight minutes. Annex G requires ESFR for nonwoven; classifying it as OH3 is a dangerous reading.

Types of synthetic fabric

Type	Application	Calorific value (MJ/kg)	Class
Polypropylene (PP) nonwoven	Nappies, hygiene products, masks	46	Group A plastic
PET nonwoven	Automotive trim, insulation	22	Group A plastic
Polyethylene (PE) film	Packaging film	46	Group A plastic
Acrylic fibre bales	Carpet, furniture fabric	32	Group A plastic
Natural fibre (cotton bales)	Textile raw material	16	Textile HHS
Wool bales	Textile	20	Textile HHS

Annex G design densities

Storage height	Design	Area	Duration
≤ 3 m	12.5 mm/min, ceiling only	360 m²	90 min
3–5 m	16.5 mm/min plus in-rack every 2.5 m	360 m²	90 min
5–9 m (racked)	ESFR K360 at 5.2 bar	12 sprinklers	60 min
Above 9 m	ESFR K360 at 5.2 bar plus in-rack	12 plus every 3 m	60 min

Fire behaviour in detail

• Low ignition temperature (PP around 340 °C, PET around 480 °C)
• Very low melting point (PP 165 °C, PET 250 °C) — melting comes before ignition
• Molten plastic drips to the floor and ignites the tier below
• Burning rate: roughly 0.3–0.5 m of height per minute
• Flame height reaches two to three times the stack diameter
• Dense black smoke, with rapid loss of visibility
• Hydrogen cyanide and aldehyde emissions — toxic

Field error — fibre dust from hygiene product bales

In nonwoven production, small PP fibre fragments separate from the bale surface and accumulate as dust. In one logistics warehouse, six months of fibre dust built up on the floor and rack tops, creating an airborne ignition risk. Forklift movement generated static and a dust deflagration followed. The sprinklers extinguished the fire, but the deflagration itself caused damage. The precautions are monthly floor cleaning, anti-static forklift tyres, earthing, and at least four air changes per hour.

Acrylic fibre bales

A compressed acrylic bale (250–400 kg, roughly 1.2 × 0.8 × 1 m) burns at the surface; flame cannot penetrate quickly into the compacted interior. That is both an advantage and a problem: the fire area grows slowly, but once a bale is alight it will burn for six to twelve hours and sprinklers will not finish it — the fire service has to break the bale apart. Annex G therefore specifies for acrylic:

• 12.5 mm/min over 360 m²
• An extended duration of 120 min
• Stack height no more than 4 m
• 1.5 m aisles between stacks
• Forklift access channels of at least 3.5 m for fire service access

ESFR as the solution

Above 5 m, ESFR is the only practical design for synthetic storage:

• K360 (25 mm) at 5.2 bar — fast response, rapid suppression
• Spacing 3 × 3 m, coverage no more than 9 m²
• Deflector 0.15–0.4 m below the ceiling
• Roof slope no more than 5 %
• Limited skylight and venting area
• Strict obstruction rules — racking itself may count as an obstruction
• EN 12845-2:2024 Annex P gives the detail

Passive measures

• Metal grating beneath stacks, to limit the spread of molten drips
• Concrete floor with a defined fall, to direct sprinkler water
• Absolute ban on smoking, heaters and other ignition sources
• Forklift battery charging at least 8 m away, in a separate room
• Anti-static flooring, to prevent charge building on PP bales
• Monthly floor cleaning to prevent dust accumulation
• A hot work permit system for welding and grinding
• Trained staff, with a drill every six months

Mixed stacks of bales and timber pallets

In practice, bales sit on timber pallets. Timber pallets carry a high fire load in their own right, so a mixed stack is designed on the worst category:

• Plastic pallet under a synthetic bale: ESFR required
• Timber pallet under a synthetic bale: in-rack plus 16.5 mm/min
• Bales wrapped in cartons: higher fire load, so one category up
• Bales in polyethylene stretch film: increased dripping risk, so ESFR recommended

Comparison with NFPA 13 and FM Global

NFPA 13 covers nonwoven synthetic fabric under Group A plastics, where ESFR is generally the standard. FM Global's commodity classification data sheet places synthetic fabric in the highest category of highly combustible plastic. Major international hygiene product manufacturers build their logistics facilities to NFPA 13 with that data sheet.

Turkish regulation and local practice

BYKHY's bulk storage provisions give no separate class for nonwoven, so insurers interpret it against Annex G or the FM Global data sheet. ESFR design is standard in Turkey's hygiene product logistics hubs, while OH3 is still encountered in domestic manufacturers' warehouses and an upgrade is usually required after an audit.

Quick check list

• The product is categorised as PP, PET, PE or acrylic.
• Storage height measured.
• ESFR planned above 5 m.
• In-rack plus 16.5 mm/min between 3 and 5 m.
• Protection beneath the stack against molten drips.
• Anti-static flooring and earthing in place.
• Monthly floor cleaning against dust accumulation.
• Forklift charging in a separate room.
• Mixed stacks designed on the worst case.
• Toxic smoke assessed in the evacuation strategy.

Frequently Asked Questions

Is nonwoven fabric a textile or a plastic for design purposes?

A plastic. PP and PET nonwoven are assessed as Group A plastics, not as textiles. Classifying a nonwoven store as OH3 is one of the more dangerous misreadings in practice.

Why do acrylic bales need a longer duration?

Because a compressed bale burns at the surface for six to twelve hours and sprinklers cannot finish it. Annex G extends the design duration to 120 min and limits stacks to 4 m.

What makes fibre dust a separate hazard?

Fibre fragments accumulate on floors and rack tops, and forklift-generated static can trigger a dust deflagration — a fire the sprinklers extinguish only after the explosion has already done damage.

At what height is ESFR required?

Above 5 m for racked synthetic storage: K360 at 5.2 bar with twelve design heads, and additional in-rack lines above 9 m.

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