Freight class for wooden crates

What freight class is

Freight class is a number the carrier assigns to a shipment so that very different goods can be priced on one scale. The classification system is the NMFC, published by the Commercial Freight Classification Audit Council. It rates freight on several characteristics, including density, how easily it is stowed, how easily it is handled, and its liability for damage or theft.

For many commodities, density is the characteristic that moves the class most. A dense item pays a lower class than a light, bulky one. For other commodities the NMFC assigns a class by item, and density may not apply. That is why the right starting point is the commodity description, not a rule of thumb about crates.

How a crate changes density

Density is weight divided by volume, using the shipment's outside dimensions. A machine on its own might be compact and heavy. Once crated, the shipment's volume is the crate's volume, which is larger than the machine's, and its weight is the machine plus the crate's tare. Volume usually grows faster than weight, so density falls.

A lower density can move a shipment into a higher class bracket for commodities rated by density. We do not assert class numbers for crates in this guide, because the class belongs to the commodity and packaging as the carrier finds them. What we can do is give you accurate crated dimensions and weight so the carrier's figure and yours agree.

What goes on the bill of lading

The bill of lading is the shipping contract and the document the carrier uses to rate the freight. Entries on it that do not match the freight on the dock are the single most common cause of reclassification and reweigh charges.

Always list the crated dimensions and the gross weight, not the bare load's. Describe the commodity accurately, and state the packaging type. If you ship several crates, list each handling unit with its own dimensions.

• Outside length, width and height of each crate in inches.
• Gross weight of each crate in pounds, including the load and the crate.
• Number of handling units, with the packaging type named as crate or skid.
• A plain commodity description that matches the NMFC item you are rating under.
• Special handling notes: do not stack, this side up, liftgate needed.

Steps to rate a crated load

Work through the steps in this order. The quote input we need from you is the first two, and the rest is for your traffic manager or your carrier.

1. 01
   Get the crate dimensions

   Use the outside dimensions from the crate spec, rounded up to the next inch, because carriers round up when they cube a shipment.

2. 02
   Get the gross weight

   Add the crate's tare to the load's weight, or weigh the finished crate on a calibrated scale before pickup.

3. 03
   Calculate density

   Divide gross weight by cubic feet. Cubic feet is length times width times height in inches, divided by 1,728.

4. 04
   Find the NMFC item

   Match your commodity and packaging to the NMFC item. The item and its rules set the class, or the density brackets under it.

5. 05
   Confirm with the carrier

   Send the dimensions, weight and item description to the carrier and ask them to confirm the class in writing before pickup.

A worked example

Take an example machine of 2,000 lb on a bare skid measuring 48 x 40 x 36 in. Its volume is 48 x 40 x 36, divided by 1,728, or 40 cubic feet. At 2,000 lb, that is 50 lb per cubic foot. These are example figures, not a quote for any real load.

Now crate it. Suppose the crate measures 56 x 48 x 46 in and the gross weight rises to 2,350 lb. The volume is about 71.5 cubic feet, so the density is about 33 lb per cubic foot. The shipment is less dense than the bare load, though it weighs more. Whether that moves the class depends on the commodity and its NMFC density brackets, which the carrier will read.

Keeping class from surprising you

Most class disputes come from weights and dimensions that were estimated and not measured. Weigh the finished crate when you can, and compare the carrier's inspection with the bill of lading before you sign for the delivery receipt. If the carrier reclassifies, ask for the inspection record with the dimensions they used.

On repeat shipments, keep the crate spec and the final weights and dimensions on file with your traffic desk. We keep the crate spec on file on our side, so a repeat order is built to the same size, and your bill of lading can carry the same figures each time.

Why classification disputes happen

Carriers keep inspection and weighing crews at terminals, and they compare what they measure with the bill of lading. A mismatch triggers an adjustment, and the adjustment can arrive as an invoice weeks after delivery. Common culprits are crates measured at the panel instead of the widest overhang, skids whose lifting handles stick out, and weights taken from a catalogue instead of a scale.

The cure is documentation. Keep the crate spec, scale tickets, dimensioned photographs and the signed bill of lading together. If your traffic desk rates by software, enter the rounded outside dimensions and let the system calculate density. A carrier that sees consistent, verifiable numbers on repeat shipments is less likely to open an argument every time.

Mixed loads and multiple crates

When one machine ships in several crates, each handling unit is measured separately and the carrier may rate the shipment on the combined cube and weight, or on each piece, depending on its tariff. A tall narrow crate beside a short wide one can produce a different result from the same freight consolidated. Ask the carrier how it rates multi-piece shipments before deciding how to split a load.

Shrink-wrapping two crates together or strapping one on top of another changes the measured dimensions and the stability of the stack. Do it only if the carrier agrees and the lower crate was built to bear the weight. Otherwise ship each crate as its own handling unit and mark every one clearly.