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Aggregate Working Load Limit
What is the Aggregate Working Load Limit?
The sum of the working load limits of each device used to secure an article on a vehicle is called the aggregate working load limit.
How do you calculate Aggregate Working Load Limit for tiedowns?
To calculate Aggregate Working Load limit, add together:
- 50% of the WLL of each end section of a tiedown that is attached to an anchor point.
- 50% of the WLL of each end section that is attached to the cargo
Sample 1: Aggregate Working Load Limit
Example:
50% of A
+ 50% of B
+ 50% of C
+ 50% of D
+ 50% of E
+ 50% of F
+ 50% of G
+ 50% of H
= Aggregate Working Load Limit
Sample 2: Aggregate Working Load Limit
Example:
50% of A
+ 50% of B
+ 50% of C
+ 50% of D
= Aggregate Working Load Limit
How much should the Aggregate Working Load Limit be?
The aggregate working load limit of any securement system must be at least 50% of the weight of the cargo being secured.
Inspection Requirements
The driver is responsible for the following cargo securement inspection activities:
-
Inspect Cargo and Securing devices:
- Pre-Trip: Yes
- Within first 50 mi: Yes
- When duty status of driver changes: Yes
- At 3 hour intervals or every 150 mi, whichever is first: Yes
-
Inform Carrier if Packaging is Not Adequate:
- Pre-Trip: Yes
- Within first 50 mi: No
- When duty status of driver changes: No
- At 3 hour intervals or every 150 mi, whichever is first: No
-
Adjust Cargo and/or Securing devices:
- Pre-Trip: As necessary
- Within first 50 mi: As necessary
- When duty status of driver changes: As necessary
- At 3 hour intervals or every 150 mi, whichever is first: As necessary
-
Add Additional Securing devices:
- Pre-Trip: As necessary
- Within first 50 mi: As necessary
- When duty status of driver changes: As necessary
- At 3 hour intervals or every 150 mi, whichever is first: As necessary
Note: The inspection rules do not apply to the driver of a sealed commercial motor vehicle who has been ordered not to open it to inspect its cargo or to the driver of a commercial motor vehicle that has been loaded in a manner that makes inspection of its cargo impracticable.
Driver inspection checklist:
Pre-Trip
- Make sure that cargo is properly distributed and adequately secured (in other words, according to the Standard).
- Make sure that all securement equipment and vehicle structures are in good working order and used consistent with their capability.
- Stow vehicle equipment.
- Make sure that nothing obscures front and side views or interferes with the ability to drive the vehicle or respond in an emergency.
-
Inform carrier if packaging is not adequate. For example:
- Banding is loose or not symmetrical on package.
- Banding attachment device(s) are inefficient.
- Wrapping is broken or ineffective.
- Pallets are broken.
Periodic inspections during transit:
- Inspect cargo and securing devices.
- Adjust cargo or load securement devices as necessary to ensure that cargo cannot shift on or within, or fall from, the commercial motor vehicle.
- As necessary, add more securing devices.
Law enforcement inspections
Law enforcement is responsible for roadside inspections in accordance with federal, state, or provincial laws.
Related Cargo Securement Terms That Every Driver Should Know:
-
Cab shield:
A vertical barrier placed directly behind the cab of a tractor to protect the cab in the event cargo should shift forward.
-
Dunnage bag:
An inflatable bag intended to fill otherwise empty space between articles of cargo, or between articles of cargo and the wall of the vehicle.
-
Container Chassis Vehicle:
A vehicle especially built and fitted with locking devices for the transport of intermodal containers.
Multiple-Choice Questions:
The Aggregate Working Load Limit should, at minimum, be:
- Determined by the shipper.
- 100% of the weight of the cargo.
- 80% of the weight of the cargo.
- 50% of the weight of the cargo.
How much should the Aggregate Working Load Limit be?
The aggregate working load limit of any securement system must be at least 50% of the weight of the cargo being secured.
A container chassis vehicle is defined as:
- A vehicle especially built and fitted with locking devices for the transport of intermodal containers.
- A structure, device, or another substantial article placed against an article to prevent it from tipping that may also prevent it from shifting.
- A reusable, transportable enclosure that is especially designed with integral locking devices that secure it to a container chassis trailer to facilitate the efficient and bulk shipping and transfer of goods by, or between various modes of transport, such as highway, rail, sea, and air.
- A specialized container, primarily used to contain and transport materials in the waste, recycling, construction/demolition, and scrap industries, which are used in conjunction with specialized vehicles, in which the container isloaded and unloaded onto a tilt frame body by an articulating hook-arm.
Container Chassis Vehicle:
A vehicle especially built and fitted with locking devices for the transport of intermodal containers.
What is a cab shield?
- A vertical barrier across the front of the deck of a vehicle to prevent forward movement of cargo.
- A structure, device, or another substantial article placed against or around an article to prevent horizontal movement of the article.
- The depression formed between two cylindrical articles when they are laid with their eyes horizontal and parallel against each other.
- A vertical barrier placed directly behind the cab of a tractor to protect the cab in the event cargo should shift forward.
What is the Aggregate WLL of the securement system for a load secured with 7 tiedowns: 3 rated at WLL of 4,000 lbs, 2 at 6,500, and 1 at 8,000?
- 33,000 lbs
- 10,000 lbs
- 8,250 lbs
- 16,500 lbs
How do you calculate Aggregate Working Load Limit for tiedowns?
To calculate Aggregate Working Load limit, add together:
- 50% of the WLL of each end section of a tiedown that is attached to an anchor point.
- 50% of the WLL of each end section that is attached to the cargo
A dunnage bag is:
- A structure, device, or another substantial article placed against or around an article to prevent horizontal movement of the article.
- A transverse load bearing structural component, particularly a part of a log bunk.
- An inflatable bag intended to fill otherwise empty space between articles of cargo, or between articles of cargo and the wall of the vehicle.
- A waterproof sheet used to cover cargo.
Dunnage bag:
An inflatable bag intended to fill otherwise empty space between articles of cargo, or between articles of cargo and the wall of the vehicle.
As part of their pre-trip cargo securement inspection, drivers should:
- All of these apply.
- Inform carrier of any inadequate packaging.
- Make sure cargo is properly secured.
- Check for anything that will obscure their vision.
Driver inspection checklist:
Pre-Trip
- Make sure that cargo is properly distributed and adequately secured (in other words, according to the Standard).
- Make sure that all securement equipment and vehicle structures are in good working order and used consistent with their capability.
- Stow vehicle equipment.
- Make sure that nothing obscures front and side views or interferes with the ability to drive the vehicle or respond in an emergency.
-
Inform carrier if packaging is not adequate. For example:
- Banding is loose or not symmetrical on package.
- Banding attachment device(s) are inefficient.
- Wrapping is broken or ineffective.
- Pallets are broken.
Who is responsible for inspecting securing devices and cargo within the first 50 miles?
- Your Moms.
- The D.O.T.
- The shipper.
- The driver.
Inspect Cargo and Securing devices:
- Pre-Trip: Yes
- Within first 50 mi: Yes
- When duty status of driver changes: Yes
- At 3 hour intervals or every 150 mi, whichever is first: Yes
Complete!
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