Legal Limits

Avatar photo

T here’s a chain or a strap every eight feet or so, the boomers are all secured, and the chains are so tight a fiddler could play a tune on them. Nothing’s even close to coming loose. Still, the creeper-cop is writing you up for an improperly secured load. What gives?

There’s this little section of most provincial load-securement regulations, you see, that outlines in muddy language the precise number of tie-downs required to keep your cargo where it belongs. It’s not enough to simply throw a few chains or straps over the load and hope for the best. For example, the January 2000 edition of the Insurance Corporation of British Columbia’s load-security handbook states, “The aggregate safe working load of the tie-downs must not be less than the weight of the load secured.” Ontario’s handbook says pretty much the same thing: “Tie-downs used to secure loads shall have an aggregate working load limit equal to the weight of the articles being secured.” The text of the American regulation is a little less concise, but makes the same point.

How the heck are you supposed to know the aggregate working load limit of your tie-downs? Chains, straps, binders, boomers, even grab hooks all have limits to what they can do. The manufacturers use a prescribed formula to rate the working load limit (WLL) of their products; they also mark each device to indicate its rated strength. You’ll usually find the manufacturer’s rating stamped into every few links of a chain and embossed onto a grab-hook or the handle of a binder.

It’s also sewn or stenciled onto the webbing of a strap. The term “tie-down,” by the way, refers to the complete assembly: consisting of a chain or strap, its grab hooks, and the binder used to cinch it tight.

The inspectors look for those rating indicators when trying to determine the WLL for each tie-down assembly, and when tallying up the sum of the WWLs for all the tie-down assemblies used to secure a piece of cargo.

The total is called the aggregate working load limit (AWLL). This can also be referred to as the Rated Load Value (RLV), the Safe Working Load (SWL), or the Resultant Safe Working Load (RSWL).

Here’s where it gets a bit tricky. A chain secured to the trailer and running once over the cargo and fastened again to some point on the trailer with a binder, counts as two separate tie-downs. That same chain fastened this time to the trailer with a binder and then directly to a tie-down point on the cargo, counts as only one tie-down. A single chain counts as two tie-downs when both ends are secured to the trailer, but as a single tie-down when secured directly from the cargo to the trailer. There’s some important fine print to consider here as well. We’ll deal with that in a moment.

Here’s an example: four chains with binders were used to secure a 33,000-pound electrical transformer to a trailer. Each was attached to a tie-down point on the transformer, and then secured to the trailer. The WLL of each tie-down was 4700 pounds. In this case, each chain/hook/binder assembly counts as a single tie-down assembly, so the inspector calculated the total, or aggregate working load limit of the four assemblies, which equaled 18,800 pounds (4 x 4700 = 18,800). The driver had a shortfall in his AWLL of 14,200 pounds (33,000 – 18,800 = 14,200).

Had the driver looped each of the same four chains over the transformer and secured it to the trailer in the usual fashion, he would have had an aggregate WLL of 37,600 pounds (8 x 4700 = 37,600). That’s more than enough to secure the transformer according to the regulations. In order to meet the requirements using the first method, the driver would have needed three more chains and binders with a WLL of at least 4700 pounds.

While the process for determining whether cargo is properly secured isn’t terribly complicated, drivers often get into hot water because they’re using insufficient, under-rated or damaged tie-down devices.

The Weakest Link:

Heard that expression before? If you’re using a binder rated at 5400 pounds to secure a chain with a WWL of 4700 pounds, but one of the grab hooks rated at only 3900 pounds, the whole assembly is really no better than its weakest element: in this case, the grab hook. Inspectors rate the entire tie-down assembly according to the lowest WLL of any of its components.

If a tie-down assembly consists of a length of 5/16 Grade-7 chain with a WLL of 4700 pounds, a binder rated at 5400 pounds and a 5/16 HT grab-hook with a WLL of 3900 pounds, then the entire assembly will have a WLL of only 3900 pounds.

Here’s an example: a marine container and its contents weighing 42,800 pounds was secured on a flatdeck by two chains, each wrapped through the lower ends of the container at the front and rear, and two four-inch cargo straps (5000-pound WLL each) slung over the container at even intervals. The two straps provided an AWLL of 20,000 pounds, but one of the two chains was stamped “PC-3” and had a WLL of only 1900 pounds. The other, along with the binders and hooks, was rated at 4700 pounds.

The inspector noted that the straps and chains were used in such a way as to give the driver credit for eight tie-down assemblies, but the AWLL of the two chains was only 13,200 pounds. The combined AWLL for all the securement devices was only 33,200 pounds-a shortfall of 9600 pounds.

It’s obviously pretty important for a driver to understand the correct method of using the tie-down devices to achieve the maximum WLL for the assembly.

It’s equally important for the driver to understand how the rating of the equipment affects the AWLL. But that’s still not quite enough. The inspectors need to see the rating stamp on the tie-down gear, and if they can’t find a stamp, they’ll down rate the device to a default rating for the size of chain or strapping.

Default Ratings

All proper tie-down equipment is stamped with the manufacturer’s WLL rating. If the inspector is unable to determine what the rating is, either because the rating stamp can’t be found or it’s unreadable, he’ll rate the tie-down at the lowest rating (Grade 3) for that size of chain.

A driver might assume he’s using a piece of 5/16 Grade-7 chain with a WLL of 4700 pounds, but if the inspector is obliged to down-rate the assembly to the default rating of a Grade-3 chain, the maximum WLL would be only 1900 pounds. That would have a considerable impact on the AWLL of all the tie-downs.

The same applies to webbed straps. If the WLL rating can’t be identified, a four-inch, 5000-pound WLL strap will be down-rated to a default rating of 1000 pound-per-inch of width, or 4000 pounds. Here’s where it gets really brutal. Both strap and chain are subject to damage through normal use.

When an inspector discovers a damaged chain, he’ll discount it completely from the AWLL-just like it wasn’t even there. Since a single chain can be counted as two tie-downs if used properly, a damaged 5/16 Grade-7 chain (4700-pound WLL) could strip as much as 9400 pounds from the aggregate WLL of your tie-downs. Ouch!

The same applies to webbed straps. The entire assembly will not be counted if 25% or more of the lap-portion stitching, used to secure a web to the D-ring or flat hook, are missing. Knotted, spliced, severely worn, or repaired straps won’t count either. Any cuts, burns, abrasions, or holes totaling more than 3/8 of an inch in a two-inch strap, 5/8 on a three-inch strap, or 3/4 on a four-inch strap will disqualify it as well. That means any cut or cuts totaling 3/4 of an inch over the entire length of the strap.

It pays to know what you’re doing in the flatdeck business, because not knowing can really cost you a bundle. Take a little time to inspect your chains, binders, and grab hooks for the proper stamps and ratings.

Check for damage while you’re at it, and make darned sure you’re using equipment that’s rated for the job. And from a compliance perspective, make sure the rating stamps on your gear are readable.

That’s what the creeper cops are going to look at first.

A New Standard:

Load-securement regulations are perhaps the most complex of all the laws truck operators have to comply with. There are local-level interpretations, numerous cargo-specific requirements that vary across jurisdictions, and some cargoes that simply defy definition.

The picture should clear up soon. The North American Cargo Securement Standard, almost 10 years in the making, is expected to become law in the United States and Canada later this year. The proposed standard (available from the Canadian Council of Motor Transport Administrators at 613/736-1003, or online at sets mandates for anchor points, tie-downs, friction, blocking, and special commodities like dressed lumber and metal coils.

The expectation is that most Canadian provinces and U.S. states will adopt the final proposal “by reference,” a legal manoeuvre designed to bypass the time-consuming and costly need to officially introduce an identical regulation and process it through each jurisdiction’s government. With uniform rules should come more uniform enforcement across North America. Also in the works is a comprehensive training program for drivers and driver-trainers, and a detailed booklet describing all the securement methods.

It might take a bit of getting used to, but at least every jurisdiction will be required to comply with the same set of standards. That’s got to be a step in the right direction.

Avatar photo

Jim Park was a CDL driver and owner-operator from 1978 until 1998, when he began his second career as a trucking journalist. During that career transition, he hosted an overnight radio show on a Hamilton, Ontario radio station and later went on to anchor the trucking news in SiriusXM's Road Dog Trucking channel. Jim is a regular contributor to Today's Trucking and, and produces Focus On and On the Spot test drive videos.

Have your say

This is a moderated forum. Comments will no longer be published unless they are accompanied by a first and last name and a verifiable email address. (Today's Trucking will not publish or share the email address.) Profane language and content deemed to be libelous, racist, or threatening in nature will not be published under any circumstances.