Moving materials and heavy equipment to and from a worksite is serious business and it pays to be knowledgeable and vigilant.
A LOADED QUESTION
“Are we securing this cargo correctly?” It’s a question that’s asked every day across the country. But securing cargo, particularly heavy cargo and construction equipment on open-deck, hydraulic, spread axle, tank hauler, lowbed, flat bed, gooseneck, and ultra-heavy capacity trailers can challenge the expertise of even the most seasoned professionals.
Fleets, vehicle operators, and others responsible for securing a payload, must stay well informed and keep up-to-date with federal regulations and how these apply to each vehicle’s individual cargo. They must also possess a basic understanding of their cargo’s shape, weight, geometric form, and how physical forces will act on the load once it is in motion.
LAWS OF THE LAND
Fleets and professional drivers must have a strong working knowledge of federal regulations. In North America, the official regulations are governed by two key entities. In the United States, the Federal Motor Carrier Safety Administration (FMCSA) establishes the regulations. In Canada, the regulations are set forth by the National Safety Code Standard 10 – Cargo Securement (NSC 10).
The FMCSA is an agency in the United States Department of Transportation (USDOT) that regulates the American trucking industry as a whole. The agency provides information regarding safety as required by the Federal Motor Carrier Safety Regulations Parts 392 and 393. The Drivers-Handbook on Cargo-Securement by the FMCSA also classifies different commodities and stipulates the standards for proper securement of these specific load types. These are:
- Dressed Lumber & similar building products
- Metal Coils
- Paper Rolls
- Concrete Pipe-loaded Crosswise on a Platform-vehicle
- Intermodal Containers
- Automobiles, Vans and Light Trucks
- Heavy Vehicles, as well as Equipment & Machinery
- Flattened or Crushed Vehicles
- Roll-on/ Roll-off Hook-Lift Containers
- Large Boulders
FMCSA regulations are informed by standards published by The Web Sling and Tie Down Association (WSTDA), regarding recommended standard specification for load securement devices, including synthetic web tie downs, winches used with web tie downs, and load binders used with chain tie downs. The WSTDA standards detail definitions, construction, testing procedures, operating practices for tie downs, winches, and load binders. The National Association of Chain Manufacturers (NACM) writes the standards for steel chain used for load securement.
LAWS OF PHYSICS
Physical forces begin to act upon cargo as soon as it’s on the move. The surface conditions and the mechanical action and movement of the trailer begins to be transferred to its cargo. To keep cargo stable and in its proper position, one must comprehend the basic forces that can cause a payload to shift, tip, slide, and otherwise become unstable.
The gravitational force, most commonly referred to as “g-force” or “g” is the most important part of the equation. One g is basically equal to something’s weight here on earth and first knowing the weight of one’s cargo is necessary to understand performance criteria for the breaking strength and related working load limit (WLL) of tie down assemblies (including chains, wire rope, steel strapping, synthetic webbing, and cordage) and other attachments or fastening devices used to secure articles of cargo. All such devices are manufactured to include clearly marked information on WLL and these must remain legible for a tie down assemblies to remain in service.
According to FMCSA regulations for performance criteria, cargo securement devices and systems must be capable of withstanding the following three forces, applied separately:
- 0.8 g (or 80% of the weight of the cargo) deceleration in the forward direction
- 0.5 g (or 50% of the weight of the cargo) acceleration in the rearward direction
- 0.5 g (or 50% of the weight of the cargo) acceleration in a lateral direction
Securement systems must provide a downward force equivalent to at least 20% of the weight of the article of cargo if the article is not fully contained within the structure of a vehicle.
WSTDA has established the design factor of tie down straps as 3:1 or a WLL of 1/3 of the tie down strap’s breaking strength. For chains, the design factor is 4:1 or a WLL of 1/4 of the chain’s breaking strength.
The combined ratings of all the straps or chains must equal at least one-half the load’s total weight. If the load is 80,000 lbs, the aggregate WLL of all the tie-downs together must equal at least 40,000 lbs.
Along with FMCSA guideline, one should ensure that these four critical conditions are met:
- The cargo should be fully contained and supported by the flatbed structure and should be restrained from any horizontal or vertical movement.
- The cargo should be fully restrained from shifting or tipping over by the trucks structure and blocking implements of adequate strength.
- The cargo should be completely immobilized by appropriately applied tie-downs so it can withstand the required g-forces in all directions.
- Consideration should be given to the angle from the horizontal tie down to its anchor point on the trailer, as this affects the downward pressure. The lower the angle, the less pressure and friction against the load. This may result in the need for additional tie downs.
ANGLING FOR SUCCESS
Often overlooked, the angle of a tie down assembly can significantly decrease the amount of downward pressure exerted on a load, reducing friction between tiers of stacked cargo, and ultimately, against the deck. As an example, at a 30-degree angle, a tie down may only be able to exert 50% of its effective downward pressure, which under certain circumstances may allow some cargo, including sheeted materials to slide or become unstable.
Unfortunately, the noted angle factors assume equal tension on all parts of the tie down assembly, but in reality, tie down tension varies from side-to-side due to friction on the cargo. So, the effective downward pressure impact on actual load securement is compounded.
In all cases, chains and straps face limits on cuts, breaks, and other defects as defined in a Defect Classification Table in the CVSA guidelines. Inspectors use the Out of Service Guideline when examining a vehicle’s cargo securement. It’s wise to make chain and strap inspection a part of any cargo securement application process.
Cargo can be expertly secured at the outset of transit, but once it’s moving, everything can and will change. Per FMCSA 392.9 Inspection of Cargo, Cargo Securement Devices and Systems, drivers are required to inspect cargo before driving the vehicle and no more than 49.7 miles from where the cargo is loaded.
Periodic Inspection of Cargo Securement Devices and Systems is mandatory when:
- There is a change of duty status for the driver.
- The vehicle has been driven more than 3 hours.
- The vehicle has been driven for 149.129 miles.
Be in compliance! When in doubt, visit the Federal Motor Carrier Safety Administration website at www.fmcsa.dot.gov for the most up to date regulations in the U.S. and Canadian Council of Motor Transport Administrators in Canada at ccmta.ca/en/.
About the Author:
Troy Geisler is the vice president of salRalph Abato has been an active member of the Web Sling and Tie Down Association (WSTDA) for more than three decades. He currently serves as vice chair of the Technical Resource Committee, has previously served as vice president of the Association, as technical chairman of both Tie Down and Sling committees. He continues to serve on WSTDA’s Board of Directors. Abato is also president/managing director, Doleco USA. For more about Doleco USA, and its DoNova PowerLift Chain Slings and PowerLash Textile Lashing Chain and Tie Down System, visit www.doleco-usa.com.
Modern Contractor Solutions, August 2022
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