Fire rated plastic pallets

Why the sprinkler cares

Sprinkler design assumes a certain fire load per stack. Plastic burns differently from wood, and the ICC Building Safety Journal notes that unlisted plastic pallets can change the commodity classification a sprinkler system has to meet. That can mean a pallet purchase that triggers a sprinkler upgrade.

A fire listing is how a maker shows that a specific model behaves in a test. Two standards come up: FM 4996, a classification from FM Approvals, and UL 2335, a fire test standard for storage pallets. Each is a test the pallet either passes or does not, and the result is held by that model.

How to ask

• Is this exact model listed, by name, to FM 4996 or UL 2335?
• What is the listing number and the date?
• What stack height and arrangement does it cover?
• Does colour or recycled content change the listing?

The pages

A stack worked out

Take a stackable rated 25,000 lb static. The bottom pallet carries the pallets above it, so with each loaded pallet weighing 2,077 lb it can hold 12 above, a stack of 13. With 6,119 lb per pallet it can hold 4 above. This is a ceiling on a flat floor for a still stack, not a promise for a stack that moves or waits.

Questions to put to the maker

• How is the pallet marked so an inspector can match it to the document?
• Does the listing cover the pallet with its deck pattern, open or closed?
• Which arrangement was tested: height, spacing and the load on it?
• Does your insurer name a specific classification?
• Does the classification apply once the pallet is loaded and wrapped?
• Does the document name a limit on storage height?
• What is the name of the testing body on the document, and what is the date?
• Is the listing current, and is there a date when it expires?
• Who in your own building reads the sprinkler design, and have they seen the document?
• Is the document a classification, a test report or a catalogue line?

From the dock

• Plastic pallets burn differently from wood, and the design that protects one may not protect the other.
• Colour is not a marker of fire performance; read the moulded model name and match it to the paper.
• A listing covers the pallet as tested: height, spacing and arrangement matter as much as the material.
• A pallet added to a stack at the last minute is the one nobody classified; set a rule for new stock.
• A fire listing says nothing about food contact, and food approval says nothing about fire.
• Insurers sometimes ask for a listing by name; a note that says "fire retardant" is not the same thing.
• Inspections happen on a schedule you do not control; keep the documents where the inspector can find them.
• Ask your insurer which standard they use before asking a maker for a listing to that standard.
• Keep a dated record of each listing document; they are revised and withdrawn over time.

Words on this page

Beam span

The open gap between two rack beams. The longer the span, the lower the load the pallet can carry across it.

UL

Underwriters Laboratories, a safety testing body that publishes fire test standards, including one for storage pallets.

Open deck

A deck with slots or a grid, which drains water, sheds dust and weighs less than a solid one.

Edge rack

A rack arrangement where the pallet rests on the edges of the beams. It is the common test case for a racking rating.

Commodity class

A fire-protection category for stored goods and their pallets, used to design sprinkler systems.

FM Approvals

A testing and certification body whose classifications insurers and sprinkler designers read.

HDPE

High-density polyethylene, a tough resin used in many plastic pallets, valued for strength against its weight.

Polypropylene

Another common pallet resin, lighter and stiffer than some others, with its own behaviour in the cold.