How are tiedown working load limits calculated under 49 CFR 393.108?

Short answer

The working load limit (WLL) of a tiedown is calculated as the lowest working load limit of any of its components, or the working load limit of the anchor points to which it is attached, whichever is less. The WLL can be determined using the manufacturer's markings or the tables in 49 CFR 393.108.

The rule says

"The working load limit (WLL) of a tiedown, associated connector or attachment mechanism is the lowest working load limit of any of its components (including tensioner), or the working load limit of the anchor points to which it is attached, whichever is less." (49 CFR 393.108(a))

In plain English

In practice, this means that the WLL of a tiedown is the minimum strength of any part of the tiedown system, including the tiedown itself, the connectors, and the anchor points. If any part of the system is weaker than the others, it can compromise the entire system and lead to cargo shifting or falling off the vehicle.

What to do

• Check the manufacturer's markings on the tiedown for the working load limit.
• Use the tables in 49 CFR 393.108 to determine the WLL if the manufacturer's markings are not available.
• Ensure that the aggregate working load limit of all tiedowns used to secure an article or group of articles is at least one-half times the weight of the article or group of articles.
• Regularly inspect tiedowns and anchor points to ensure they are in good condition and not damaged.