FM 4996 explained for pallet buyers

Three things to ask for

• The model name and revision the classification applies to.
• The approval listing, with a number and a date.
• The storage arrangement the classification covers: rack, block, height.

An FM classification is a statement about a tested pallet. It is held by a manufacturer for a model. The classification for one plastic pallet does not pass to a lookalike from another maker.

What the sprinkler designer does with it

The designer uses the classification to treat the stack under a commodity class and a protection scheme. The buyer's job is to hand the designer the listing, not to interpret it. If the pallet changes, the paper changes.

A stack worked out

Take a stackable rated 20,000 lb static. The bottom pallet carries the pallets above it, so with each loaded pallet weighing 3,013 lb it can hold 6 above, a stack of 7. With 7,055 lb per pallet it can hold 2 above. This is a ceiling on a flat floor for a still stack, not a promise for a stack that moves or waits.

A buyer's checklist for an FM classification

1. Write down the pallet's exact model name and the maker's name.
2. Ask for the classification document, not a catalogue line.
3. Check that the document names the same model, in the same colour, with the same recycled content.
4. Note the date, and ask the maker whether it has been renewed since.
5. Give the document to the sprinkler designer and the insurer, and keep a copy with the purchase record.

A note on this page

In practice, the classification matters most to whoever designs the sprinklers. Give that person the document and the pallet model, then let them confirm the arrangement before pallets are stacked, not afterwards on the day of an audit.

Questions to put to the maker

• Does the document name a limit on storage height?
• Which arrangement was tested: height, spacing and the load on it?
• Does the listing cover the pallet with its deck pattern, open or closed?
• How is the pallet marked so an inspector can match it to the document?
• What is the name of the testing body on the document, and what is the date?
• Is a different model offered with a listing, and what does it cost in weight or rating?
• Does the classification apply once the pallet is loaded and wrapped?
• Does the maker hold a listing for this exact model, or only for a family of models?

From the dock

• Plastic pallets burn differently from wood, and the design that protects one may not protect the other.
• A listing covers the pallet as tested: height, spacing and arrangement matter as much as the material.
• Ask your insurer which standard they use before asking a maker for a listing to that standard.
• Inspections happen on a schedule you do not control; keep the documents where the inspector can find them.
• A pallet added to a stack at the last minute is the one nobody classified; set a rule for new stock.
• Fire design changes with ceiling height and commodity; the same pallet can be fine in one building and not another.
• Mixing listed and unlisted pallets in one aisle undoes the point of listing the ones that are.

Words on this page

Commodity class

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

Open deck

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

UL

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

Closed deck

A solid deck that keeps small items and torn bags from falling through and wipes clean on top.

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.

Racking load

The weight a pallet holds when it rests on two rack beams with an open gap between them. It is usually the lowest rating and only exists for pallets built for racks.

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.