FM Global DS 8-1: Commodity Classification — Class 1 to 4 and Plastics

The first step in warehouse sprinkler design is commodity classification: what is stored, and what fire load does it represent? FM Global DS 8-1 assigns every commodity to Class 1 to 4 or to a plastic category. The DS 8-9 sprinkler design follows directly from that classification.

Class Definitions

• Noncombustible: unpackaged noncombustible goods such as glass, metal and cement. No sprinkler requirement from the commodity itself.
• Class 1: noncombustible product on a combustible pallet or in light packaging. Low fire load.
• Class 2: similar to Class 1 but with heavier corrugated packaging. Moderate fire load.
• Class 3: combustible product such as timber, paper and natural fibre textiles, plus packaging. High fire load.
• Class 4: Class 3 with a limited proportion of Group A plastic. Very high fire load.
• Group A unexpanded plastics: PE, PVC, PP, ABS and nylon — most modern consumer product.
• Group A expanded plastics: foams such as EPS, EPP and urethane — the highest fire load.

Worked Examples

Commodity	Class
Glass bottles, palletised	Class 1
Canned food in heavy cartons	Class 2
Timber furniture	Class 3
Baled cotton textiles	Class 3
Computers and electronics with plastic housings	Class 4
Plastic buckets and toys	Group A plastic
Foam mattresses, EPS packaging	Expanded plastic
Finished rubber tyres	Group A (see DS 8-3)
Paper rolls	Class 3 (see DS 8-21)
Empty timber pallets	Class 4 (see DS 8-24)

Mixed Storage

A warehouse holds more than one commodity. The FM rule is that the highest class governs — even a modest proportion of Group A plastic by volume escalates the whole zone.

• Sprinkler design follows the hardest commodity in the zone
• Separation requires either a genuinely clear aisle of at least 1.8 m, or a fire wall
• If the aisle is inadequate, a single hazard class applies across the area

The Effect of Packaging

• Cardboard cartons: Class 2 to 3 depending on board weight
• Plastic containers: lift the class by one or two steps
• Timber pallets: add fire load in their own right
• Plastic pallets: Group A plastic, with a very high fire load
• Stretch wrap: a thin film that does not change the class

The Link into DS 8-9

• Class 1 and 2: low demand, ceiling-only sprinklers generally sufficient
• Class 3 and 4: ESFR or CMSA with in-rack sprinklers, depending on storage height
• Group A plastics: designed more severely than Class 4, with ESFR K360 and in-rack as the norm
• Expanded plastics: the hardest case, with ESFR K480 and in-rack sprinklers at every level

Quick Checklist

• All commodities listed and classified
• Governing class established for mixed storage
• Packaging effects, including plastic containers and pallets, accounted for
• Special commodity data sheets consulted where applicable
• Classification carried through into the DS 8-9 sprinkler design

Frequently Asked Questions

Why does commodity classification matter more than anything else in warehouse design?

Because it sets everything downstream: density, duration, K-factor, whether in-rack sprinklers are needed, tank volume and pump size. A single step in class can multiply the water demand, so an error at this first stage invalidates the whole design regardless of how carefully the hydraulics are calculated.

What is the difference between Class 4 and Group A plastics?

Class 4 is a combustible commodity with a limited proportion of Group A plastic. Once the plastic content rises beyond that limit, the commodity is treated as Group A plastic in its own right, which is designed more severely than Class 4 because polymers release far more heat and burn faster.

Does packaging really change the classification?

Substantially. The same product in a plastic container can sit one or two classes higher than in a cardboard carton, and a plastic pallet adds Group A plastic beneath every unit load. Packaging and pallet decisions made for logistics reasons therefore have direct fire protection and capital cost consequences.

How is a mixed commodity warehouse classified?

The highest class present governs the whole zone unless the commodities are genuinely separated by an adequate clear aisle or a fire wall. Because aisles in operating warehouses are rarely clear, most mixed sites end up designed to the governing class, which is why identifying that class early matters so much.

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