Sterling Anthony, Product Packaging Expert

When justified by a product’s size and/or weight, hand holes (also known as access holes) are designed into corrugated boxes to facilitate safe manual handling.  Examples of such products include wide-screen televisions, printers, windows, patio doors, automotive body replacement parts, and multi-packs of non-durable products sold by big-box stores.

The selection of corrugated boxes with hand holes as a means of packaging requires application-specific knowledge.  While hand holes may seem simple, the misconception that these features are merely a matter of die-cutting openings into a blank contributes to numerous accounts of user injuries as the result of packaging failures each year.  These incidents may introduce manufacturers and retailers to potential vulnerabilities, such as personal injury and product liability claims.

The following discussion introduces a selection of the major variables and considerations associated with designing or selecting corrugated boxes for a specific, intended purpose.  For additional information on this subject, the ASTM D6804-02 Standard Guide for Hand Hole Design in Corrugated Boxes is a recommended resource.

Board: Corrugated paperboard is an engineered structure with a strength-to-weight ratio that makes it unrivaled for box construction.  Still, additional decisions remain in regard to the board and its properties.  

Should the material be single-walled, double-walled, or triple-walled?  

For the types of large and/or heavy products previously mentioned, double-wall paperboard should be the default choice.  Single-wall might not embody the required strength, and if triple-wall strength is required, the load is likely best suited for mechanical handling.

What type(s) of flute will be used between facing sheets?  

With double-walled paperboard, using the same type of fluting between sheets can cause the arches to align on top of another, weakening the structure.  When different flutes are used, their heights and number-per-linear unit create a staggered alignment that is more resistant to forces.  Beyond that, additional combinations (A/B, A/C, B/C, etc.) each yield a distinct board thickness with properties that differ depending on the placements of the flutes selected in the outer or inner layers.

Does the selected paperboard consist of virgin or recycled fibers?  

Sustainability considerations aside, there’s no denying that virgin fibers are stronger than recycled.  If the required measure-of-safety only can be met with virgin, then so be it.  This judgement certainly applies to the liners and should be applied to the flutes as well.

Should the Mullen Burst Test or Edge Crush Test be used to evaluate durability?

The Mullen Burst Test indicates resistance to rough handling, while the Edge Crush Test indicates resistance to compression, or stacking.  Hand holes factor into which test is designated on the box maker’s certificate because the removal of material can result in a weaker box.  In turn, the test score cited on the box maker’s certificate should compensate for material removed to create the hand holes.

Box style:  The regular slotted container (RSC) is the most popular style due to its efficient use of corrugated board.  When an RSC has hand holes, they are located on the end panels.  Other styles, such as tall and long boxes, are known to have hand holes on the end panels and side panels.  For any box style, hand holes present two major concerns: how the bottom is secured and where the hand holes are located.

When a box is lifted via hand holes, the weight of the contents is supported by the bottom of the box.  The bottom will give if not adequately secured, potentially resulting in damage to any contents that fell through and personal injury.  Even when the bottom is adequately secured, if there is not enough board between the location of the hand holes and the top of the panel, the board may rupture from the force of lifting, likely causing the handler to drop that end of the box. The location of the hand holes is used to determine the amount of material that should be provided between the hand holes and the panel’s top score line.

Hand hole size and shape:  As previously mentioned, hand holes weaken a box due to the materials that are removed from the board.  The size and shape of the hand holes offer varied trade-offs between function and practicality.  Ergonomic considerations often pertain to the size of hand that should be accommodated.  Are users likely to be wearing gloves, or using bare hands?

The above excerpt is from an article originally published by Packaging World that has been used with the author’s permission.  Read the full article here.

Sterling Anthony, Product Packaging Expert with DJS Associates, Inc., can be reached via email at experts@forensicDJS.com or via phone at 215-659-2010.

Categories: Product Liability | Product Packaging Expert | Sterling Anthony

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