Scope
Tiedown criteria applies to the devices used in securing loads
to commercial motor vehicles.
Definitions of tiedown assemblies and working load limit (WLL) ratings
Tiedown Materials
Synthetic Webbing. Synthetic webbing (nylon or polyester) tiedown
strap assemblies come in a variety of types and sizes. The most
common webbing width for securing loads on commercial vehicles are:
| |
2 Inch (50mm) |
3 Inch (75mm) |
4 Inch (100mm) |
Fittings or Attachments
Devices used with or in tiedowns for purposes of attachment or tightening.
This includes:
|
a.
b.
c.
d.
e.
|
Hooks
Ratchets
Triangles or D-Rings
Winches
Sewn Loops |
Anchor Point
The location on a vehicle where a tiedown is attached. If the anchor
point is inadequate to support the load rating of the tiedown system,
then the load rating of the tiedown will be limited to the strength
rating of the anchor point.
Minimum Breaking Strength
The minimum straight tensile load or force at which the product
fails to support the load.
Working Load Limit (WLL) Load Rating
The WLL load rating is the maximum load which may be applied:
Web tiedown WLL rating is a maximum of 1/3 of the minimum breaking
strength of the assembly.
Method of Applying Working Load Limit (Based only on weight)
The aggregate static WLL of the tiedown assemblies used to secure
an article against movement in any direction must be equal to at
least (.5) times the weight of the article.
| |
NT = (Load) (.5)
WLL
NT = Number of tiedowns
Load = Weight of load to be secured
WLL = Working Load Limit of tiedowns
|
Synthetic Webbing*
Labels or Tags
Identification: Web tiedown assemblies will be identified with a
label within 18 inches (46 cm) from one end of the assembly.
Minimum information required on label:
|
|
Manufacturer or trademark of final assembler
Working Load Limit (WLL) in pounds and kilograms. |
* Note: Webbing used as a component of a tiedown assembly must
conform to the requirements of the 1998 edition of the Recommended
Standard Specification for Synthetic Webbing Tiedowns of the Web
Sling & Tiedown Association. Copies of these specifications
may be secured by writing to:
|
Web Sling & Tiedown Association,
Inc.
710 East Ogden Ave. - Suite 600
Naperville, IL 60563
|
Marking of Fittings
Fittings designed to be detached from tiedown assembly shall be
marked with:
|
a.
|
"Working Load Limit" in pounds or kilograms. |
Manufacturers' identification shall be on all fittings for web
tiedowns, except wire forms.
Repairs
Synthetic Webbing
Webbing used in tiedown assemblies shall not be repaired or spliced.
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