Flatbed load securement rules, explained with the regulations

Flatbed securement is the part of the job where the rules are specific and the consequences are serious. Get it wrong and you risk the load, an out-of-service order and other people on the road. This guide puts the federal rules in plain words, with the section numbers so you can check the source yourself. The regulations themselves are short; read them once.

The core rules (49 CFR 393, Subpart I)

Performance. Your securement system has to hold the cargo against set forces without going over the working load limit (WLL) of the devices: 0.435 g forward, 0.5 g rearward and 0.25 g sideways, plus a downward force of at least 20% of the cargo weight for cargo not fully contained in the trailer (393.102). In practice, you meet this by following the specific rules below.

Devices in good order. Tiedowns with cuts, cracks or other damage that reduces their strength are not allowed, knots are not allowed, and each tiedown must be attached so it cannot come loose in transit (393.104).

Edge protection. Required whenever a tiedown would be subject to abrasion or cutting, and the protector itself has to resist abrasion, cutting and crushing (393.104(f)(4)). Edge protectors are cheap compared with a cut strap or a cargo claim.

Rolling cargo. Anything likely to roll must be restrained with chocks, wedges, a cradle or similar (393.106(c)).

How many tiedowns: the count rule (393.110)

For an article not blocked against forward movement by a headerboard, bulkhead or other cargo (393.110):

If the article is blocked at the front, the minimum is one tiedown for every 10 ft of length or fraction of 10 ft. Cargo that needs special methods, like heavy machinery, follows its own section instead.

EXAMPLE. A single 22 ft steel beam, not blocked, weighing 9,000 lb. The first 10 ft needs 2 tiedowns. The next 12 ft is one full 10 ft plus a 2 ft fraction, so add 2. Minimum: 4 tiedowns.

Working load limits: the weight rule (393.106(d))

The count is only half the test. The WLL of all tiedowns on an article or group of articles must add up to at least half the cargo weight (393.106(d)). How each tiedown counts:

• Over the cargo and attached to the opposite side of the trailer: full WLL.
• Over the cargo and back to the same side: half its WLL.
• From the trailer to an anchor point on the cargo: half its WLL per end section.

Use the WLL marked on the strap or chain. If it is unmarked, use the default table in 393.108. A few common defaults:

Unmarked welded chain is treated as the lowest grade (grade 30) in the table, and a tiedown assembly is only as strong as its weakest part, including the winch or binder and the anchor point.

EXAMPLE, continued. The 9,000 lb beam needs at least 4,500 lb of aggregate WLL. Four 4 in straps over the top to the opposite rail count 4,000 lb each, 16,000 lb total. Both tests pass: count (4) and WLL (16,000 ≥ 4,500). Our load securement calculator runs both checks for any load.

Commodity-specific rules

Some freight has extra rules on top of the general ones. The ones flatbed carriers meet most:

• Metal coils, 5,000 lb or more (393.120): the method depends on whether the eye faces up, sideways or front to back. Eyes crosswise need a tiedown through the eye against forward movement and another against rearward movement, and crossing them in an X is prohibited.
• Dressed lumber and similar building products (393.118): bundled lumber, plywood and gypsum board. Bundles sit side by side in contact, and multi-tier loads use one of four approved methods, such as stakes plus top-tier tiedowns or tiedowns over each tier.
• Heavy vehicles, equipment and machinery (393.130): wheeled or tracked units of 10,000 lb or more need at least four tiedowns placed as close as practicable to the front and rear, accessory equipment such as hydraulic shovels must be fully lowered and secured, and articulated machines must be kept from articulating.
• Logs, paper rolls, concrete pipe, intermodal containers, automobiles, flattened cars, roll-on containers and boulders each have their own sections from 393.116 to 393.136.

When a commodity rule applies, it takes precedence over the general rules where they differ.

Inspections and common violations

You must inspect the cargo and securement within the first 50 miles, then again whenever you have driven 3 hours or 150 miles or change duty status, whichever comes first (392.9). Straps stretch and loads settle, especially in rain and heat.

Roadside inspectors use the Commercial Vehicle Safety Alliance's (CVSA) out-of-service criteria. Securement problems that commonly lead to trouble include:

• Too few tiedowns for the article length.
• WLL total under half the cargo weight.
• Loose, damaged or knotted tiedowns.
• Missing edge protection where a strap is being cut.
• Coils or machinery not secured to their specific rules.

Load securement equipment for flatbed

A working flatbed securement kit usually includes 4 in ratchet straps and winches, grade 70 chain with binders, edge and corner protectors, coil racks, wood dunnage and chocks, plus a few spare straps. For frequent hauling, buy straps and chains with clear WLL labels from a known maker; unlabeled gear drops to the lowest default WLL and wears out fastest.

Securement questions are also why brokers ask about experience on high-value loads. See how to vet flatbed freight brokers, where to find freight on flatbed load boards, and how lease-on flatbed companies handle training. For the freight itself, see flatbed loads.