FM Global DS 8-3: Rubber Tire Storage Summary

Tyres are among the toughest fuels in warehouse fires. Rubber and its additives release a great deal of heat; the ring shape of a tyre creates chimneys with airflow inside the stack; and burning rubber decomposes into an ignitable oil that runs across the floor. The result is a fire that grows quickly, produces dense toxic smoke and takes hours, sometimes days, to put out. FM Global DS 8-3 Rubber Tire Storage sets building, sprinkler and outdoor storage rules around this specific behaviour.

Scope

The data sheet covers storage of new and used car, light commercial, truck and off-road tyres. Indoor storage (solid piles, pallets or portable racks, fixed racks) and outdoor tyre yards are dealt with separately. Tyres are not assessed within the Class 1–4 and plastics classification of DS 8-1, but in their own data sheet with their own design tables — a clear statement that tyres cannot be protected as a generic "plastic commodity".

Fire Behaviour and Storage Arrangement

How severe a tyre fire becomes depends largely on how the tyres are stacked. The basic arrangements are:

Burning tyres decompose into an ignitable liquid (pyrolytic oil). It can run across the floor to form a pool fire and, carried by firewater, create a serious environmental pollution risk.

Key Loss-Prevention Principles

1. Sprinkler design follows arrangement, height and ceiling

Sprinkler design is selected from the data sheet tables by storage arrangement, storage height, ceiling height and tyre type. Tyre storage tends to need a higher density, a larger design area and a longer duration than general commodities. ESFR protection is possible for some arrangements; others require in-rack sprinklers. For an arrangement or height not in the tables, the design should not be borrowed from "a nearby row"; instead, change the arrangement to one the data sheet covers. Use the current revision for design values.

2. Limit the storage area

Limiting the tyre storage area within one fire area sets an upper bound on the loss if the sprinklers fail. Fire walls, aisle widths and distances between storage blocks serve this purpose. Wide aisles also give the fire service access for manual firefighting.

3. Water supply and duration

Tyre fires last a long time and consume a great deal of water. The supply must cover the hose allowance and prolonged manual firefighting in addition to the sprinkler design duration. A supply relying on a single pump and tank should be assessed separately for reliability against this kind of hazard.

4. Drainage and the environment

Collecting and containing pyrolytic oil and contaminated firewater limits both fire spread and environmental harm. Planning drainage, firewater retention and sewer connections for the fire scenario also ties in with local environmental law.

5. Outdoor storage

In outdoor tyre yards the key measures are limiting the size and height of each pile, adequate clear space between piles and between piles and buildings, fire service access roads, hydrant coverage and control of ignition sources (hot work, waste burning, trespass). An outdoor tyre pile fire can burn for weeks, so separation matters more than extinguishing capacity.

6. Operating discipline

Forklift charging areas, hot work and electrical panels inside the warehouse should be kept away from tyre stacks. Stack heights not exceeding the design value, clear aisles and the required clearance below sprinklers are checked regularly.

How It Differs from NFPA 13 and EN 12845

NFPA 13 also separates tyre storage from the general commodity classes and gives its own protection criteria, which used to sit in a separate NFPA standard. European rules such as EN 12845 and CEA 4001 place tyres within their storage categories; check the current edition for the category and height limits. The FM difference lies in tying the design directly to stack arrangement and orientation, limiting ESFR and in-rack options to combinations backed by FM fire tests, and putting weight on separation rules for outdoor storage.

Practical Checklist

• Tyre type (car, truck, off-road) and new/used status are identified.
• Stack arrangement (on-side, on-tread, laced, pallet, rack) and height are defined.
• Sprinkler design comes from an exact combination in the data sheet tables.
• In-rack sprinklers are provided where required.
• Storage area per fire area and aisle widths are limited.
• The water supply covers sprinklers, hose and prolonged manual firefighting.
• Drainage and containment for pyrolytic oil and firewater are planned.
• Outdoors: pile size, separation distances and fire service access are provided.
• Stack height and clearance below sprinklers are checked regularly.

Frequently Asked Questions

Can tyres be classified as a plastic commodity?

Not for FM. Tyres are protected under DS 8-3 with their own tables; a general plastic commodity design may not cope with how tyres burn.

Can ESFR sprinklers protect a tyre warehouse?

Yes, where the data sheet provides for specific stack arrangements, storage heights and ceiling heights. Outside those combinations ESFR may not be suitable.

Why does pyrolytic oil matter?

Burning rubber decomposes into an ignitable liquid. It flows across the floor, enlarges the fire and pollutes the surroundings with the firewater, so drainage and containment must be planned.

Can the online calculators be used for a tyre warehouse?

The ESFR suitability checker and fire water tank sizing tools help with preliminary sizing, but final criteria for tyre storage must come from the DS 8-3 tables.

What matters most in outdoor tyre yards?

Limiting pile size and leaving adequate distance between piles and buildings. Outdoor fires last so long that separation matters more than extinguishing capacity.

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