Strapping and stretch wrapping are time-tested methods of stabilizing unit loads, and now a third method of load stabilization is attracting notice. Stretch hooding has been used in Europe for several years, and a few European equipment suppliers are now bringing the technology to the United States.

Manufacturers of stretch hoods claim their product can improve load stability and reduce product damage. The Center for Unit Load Design at Virginia Tech  recently completed a study designed to test these claims.

Researchers conducted vibration testing and impact testing on pallet loads stabilized with four different materials:

• polyester strapping
• 80-gauge stretch wrap
• 63-gauge stretch wrap
• 400-gauge stretch hooding

The results of the vibration testing, says center director Ralph Rupert, were inconclusive because none of the unit loads shifted much during the tests. The results of the impact testing, however, were more dramatic.

The stretch hoods provided the most protection against load displacement during the impact tests, followed by strapping, 80-gauge stretch wrap and 63-gauge stretch wrap.

But the bottom line of the research, says Rupert, “is that we need to do more work.”

Because stretch hooding is a new technology, he says, little is known about how the hoods are best applied or which gauges of film should be used in which situations. The Center for Unit Load Design has already begun a multi-phase research project to further explore these concepts, he says, and some of that research is scheduled to be completed this fall.