Regulatory Compliance Guide for Wire Rope Tiedowns on Legal Weight Trucks For
Packages Weighing Greater Than 5,000 Pounds Containing Radioactive Materials
The Transportation Technologies Group at Oak Ridge National Laboratory has supported DOE
in the development of a Topical Regulatory Compliance Guide (RCG) to provide guidance on
wire-rope-type package tiedowns. While it was developed for larger packages (e.g., those
weighing 5,000 pounds or greater and which are designed to transport radioactive material
in normal commerce), the Guide may also be used to provide information on how to secure
many types of heavy packages to the bed of a semi-trailer. The RCG does not address those
cases in which the trailer has been designed for a specific package and utilizes non-wire
rope tiedowns. Radioactive material packagings with proper tiedowns are not expected to
come off their transport vehicle under low-impact accident conditions, but are expected to
be released if the g forces in the cables exceed the design values used. Thus, the RCG
provides an effective way to encourage and ensure uniform implementation of regulatory
requirements applicable to tiedowns. Often shippers depend upon a carrier to properly
secure packages to their trailers using methods that meet federal and state tiedown
requirements. While reliance on the carrier's actions may be legal in most instances,
mandating tiedown requirements with the carrier would be a business practice which could
enhance package retention during normal transport conditions. In addition, shippers using
exclusive-use vehicles for larger packages of radioactive materials are frequently
required to provide the tiedown system to the transport vehicle.
This RCG provides a method for defining an appropriate tiedown system through the use
of the Tiedown Stress Calculation Program (TSCP). A diskette containing a copy of the TSCP
is included with the RCG. The TSCP calculates, based on user-specified inputs, specific
information on size, length, and tiedown angles of wire ropes that will safely withstand
specific g forces that might be generated in a given accident situation. The RCG also
includes the User's Guide, for system requirements, program installation, and program
operation. This guide will help ensure uniform implementation of applicable regulatory
requirements; however, the TSCP is provided for informational purposes only and the user
is responsible for assuring adequacy for a particular purpose.
Future plans include modifying the program to address additional tiedown devices (e.g.,
chains, nylon straps) and other vehicles (e.g., cargo aircraft and rail cars). The extent
of the development and maintenance of the TSCP will depend upon feedback from the users.
Steps are also being taken to convert the RCG and its companion TSCP into an American
National Standards Institute standard (ANSI-N14.31).
For information on the Regulatory Compliance Guide, please contact Paul Singley at 865-576-2068.
