Tyres sit outside the commodity classes as a special storage type with their own rules. They are slow to ignite, but once developed they produce very high heat, dense smoke and a fire load that is hard to extinguish.
Quick reference
| Item | Value |
|---|---|
| Commodity type | Special commodity: rubber tyres |
| Storage arrangements | On-side, on-tread, laced, palletised or portable rack, fixed rack |
| Governing variables | Arrangement, storage height, ceiling height, aisle width |
| FM Global | DS 8-3 Rubber Tire Storage |
| Typical protection | Ceiling sprinklers (dedicated criteria); ESFR in some arrangements; in-rack where needed |
What it is
Under this heading NFPA 13 deals with the storage of pneumatic tyres for cars, lorries, buses, aircraft, trailers, farm and construction equipment. Tyres are not protected using the Class I–IV or plastics tables, but to dedicated criteria defined by storage arrangement and height. Rubber and carbon black burn with high energy, and the toroidal shape of a tyre creates voids in the pile that water cannot reach.
Typical examples
- Tyre dealers and distribution centres
- Finished goods stores at tyre plants
- Spare tyre stores for fleets and bus operators
- Casing stores at retread plants
How packaging and plastics change the class
For tyres, the storage arrangement rather than a class is decisive. On-side storage stacks tyres like towers; on-tread storage stands them side by side. Laced storage interlocks tyres at an angle and behaves differently as a flue. Tyres on pallets or portable racks are assessed separately. When the arrangement changes in the same building, for example from on-side to laced, the required protection changes too. Stretch film or plastic wrapping on tyres adds fire load.
Protection approach
NFPA 13 gives ceiling sprinkler criteria and water supply requirements for tyre storage according to arrangement and height, and permits ESFR sprinklers in some arrangements. Because tyre fires can burn for a long time, water supply duration and hose allowance are treated differently from general storage; read the values from the edition in force. At greater heights ceiling sprinklers struggle to control the fire, so in-rack sprinklers or a limit on storage height come into play. Aisle width and pile size also affect fire spread.
FM Global equivalent
FM Global covers tyre storage in a separate data sheet, DS 8-3 Rubber Tire Storage. FM's arrangement definitions and protection tables differ from NFPA, and on FM-approved sites that sheet governs. For the general commodity framework see DS 8-1.
The commodity class depends on what goes into the warehouse today. The commodity and storage arrangement assumed in the design report should be recorded in writing and rechecked whenever operations change. For the overall framework see NFPA 13 commodity classification, and for a quick check on whether ESFR can be used, the ESFR suitability checker.
Common site mistakes
- Designing tyres to the Group A plastics tables; tyres have their own criteria.
- Missing a change in storage arrangement (on-side, on-tread, laced) over time.
- Stacking above the height limit used in the sprinkler design.
- Blocking aisles with tyre piles and shortening the path for fire spread.
- Calculating water supply duration with general storage values.
Frequently Asked Questions
What commodity class is a tyre warehouse?
Tyres are not classed within Class I–IV or the plastics groups; NFPA 13 gives them dedicated criteria based on storage arrangement and height.
Can ESFR be used for tyre storage?
Yes, for certain arrangements and heights. Suitability must be checked against the standard for arrangement, ceiling height and obstructions.
Why are tyre fires so hard to extinguish?
Rubber burns with high energy, melts and flows, and the voids inside tyres stop water reaching the burning surface. Early intervention at sufficient density is therefore critical.
SprinkCalc — Fire Sprinkler Design Across Three Standards
SprinkCalc covers hazard classification, design density and area, K-factor selection, water demand and hydraulic calculations for NFPA 13, FM Global and BS EN 12845 in a single iOS app, and exports a professional PDF report.
Download SprinkCalc on the App StoreNFPA 13, Standard for the Installation of Sprinkler Systems (current edition) · FM Global Property Loss Prevention Data Sheets (FM Global DS 8-3). This page summarises the definitions in our own words; for design densities, areas and height limits the edition in force and the decision of the authority having jurisdiction govern.