An Overview

Few human activities, including packaging, leave the environment untouched, despite their net benefits. Yet the main pathways to minimize the impact of human activities on the environment are evident: First and foremost, use renewable resources to provide for future needs and new uses; use no more than necessary; process natural resources with as little environmental burden as possible; reuse or recycle the products whenever possible. Relegate as little of the product into the waste stream as possible by finding other uses, recycling the product's components, or extracting renewable energy or compost from it. And finally, manage the waste streams to minimize the impact of the waste itself upon the environment.

Successfully achieving continuously better sustainable outcomes in our society requires achieving those goals in a manner that is economically sustainable, as well. To endure, economic methods must be employed to produce sustainable outcomes. Research focused on extending the range of sustainable choices must be part of any integrated approach.

Maximize Use of Renewable Resources

In the flexible packaging arena, multiwall packaging uniquely relies on paper, a renewable resource for almost all of its construction. The paper supplied to the US producers of multiwall packaging comes overwhelmingly from a renewable resource base, supplied sustainably from woodlands managed under the principles and practices of the Sustainable Forestry Initiative or similar programs, such as Canada's national sustainable forest management standard promoted by the Forest Products Association of Canada.

Other materials such as coatings, starches, adhesives, films and inks used in the construction of multiwall sacks, while a significantly smaller portion of the finished product, may also be entirely or largely based upon renewable resources. Examples include corn- or potato- based starches and soy-based water soluble inks. Today, while most films are not made from renewable materials, research is underway to develop alternatives made from renewable materials that meet performance requirements economically. And work is also underway to develop renewable fiber-based barrier materials that provide adequate grease resistance while being repulpable in today's commercial paper recycling operations.

Users of paper multiwall sacks may want to communicate to their consumers about the renewability of their packaging. To facilitate this, PSSMA has developed a Renewable Resource logo which may be printed on sacks made of renewable resources. For an image of this label and to learn about the criteria for using it on packaging, please visit our Renewable Resources Logo page. PSSMA invites paper multiwall sack users to talk with their suppliers concerning details of using the logo on their packaging.

Use No More Material Than Necessary

Because it conforms so closely to the volume of material being packaged, multiwall packaging meets this measure of sustainability by design. No overpackaging is needed, as multiwall packaging meets both transport and go-to-market needs.

In addition though, driven primarily by advances in papermaking technology over time, the amount of fiber needed to package the same volume of product has decreased substantially. This improvement has occurred in both the thickness, or basis weight (weight/unit area), of the paper used and in the number of plies needed to achieve necessary performance features. Illustrative of the tradeoffs between packaging material alternatives, it is this very strength characteristic of virgin sack kraft paper that enables the use of less fiber that also renders impracticable the inclusion of substantial amounts of less long and strong recycled fibers for multiwall sack paper construction.

Process Raw Materials with Minimum Environmental Burden

The environmental burden associated with construction of multiwall sacks is almost always much less than that associated with producing the materials from which the sacks are constructed. Because this is generally the case with converting operations relative to primary raw material extraction and processing operations, most of the current efforts to quantify sustainability factors for packaging are concentrated on primary manufacturing operations.

Almost all of the paper used in the production of multiwall packaging in the US today comes from mills that are committed to the Workplace Safety of the American Forest & Paper Association (AF&PA), the national trade association of the US forest products industry. These companies report biennially on progress made to improve environmental performance. Highlights of the 2006 Report include:

• 99.2% reduction of chlorine compound release since 1988
• Sulfur dioxide emissions reduction of 11.6% since 2002
• Nitrogen oxide emissions reduction of 9.6% since 2002
• 97% reuse of solid wastes at wood products facilities
• 11% reduction in fossil fuel use per ton of product since 2002; 52%

  reduction since 1972.

Renewable Energy & Cogeneration

The forest products industry leads all other industries in the use of renewable energy, with 60% of the total energy used by AF&PA member mills generated from renewable biofuels. According to the US Department of Energy, pulp and paper mills produced 75% of the biomass-based fuel generated by the US industrial sector in 2003. Also, the forest products industry which supplies the kraft and other papers used in multiwall sack construction is a leader in the production and use of more efficient co-generated electricity. Not only does cogeneration at pulp and paper mills take advantage of renewable energy sources, it squeezes out energy remaining in the exhaust steam for manufacturing and heating processes, rather than wasting it to cooling towers as happens with conventional electricity production.

Greenhouse Gases

Estimates of net carbon dioxide and other greenhouse gas emissions associated with production of packaging materials are of heightened interest today, even though the methods for developing statistically meaningful averages across a range of variables such as mining, extraction, forest cycle maturity and landfill management practices are still being refined. An early important analysis of this subject was published by the National Council For Air and Stream Improvement (NCASI) in February 2007 . This report quantifies the greenhouse gas emissions and carbon sequestration occurring in the major value adding steps of the forest products industry. It indicates that the greenhouse gas emissions that occur throughout the forest products industry's value chain are largely offset by sequestration of carbon in sustainably managed forest and forest products. Further, the report suggests factors that point to continued improvement in the industry's carbon and greenhouse gas profile over time.

The Bottom Line

Many factors contribute toward improved sustainability of multiwall packaging. Chief among them is the use of a renewable resource base, coupled with advances that allow multiwall converters to use less input materials to achieve equivalent packaging performance. Using paper and other materials that have been manufactured with minimum environmental burdens also help producers of multiwall packaging to make more sustainable products.

Finally, by relying upon paper as the primary bag construction material, customers and consumers can depend upon multiwall packaging to provide flexible packaging solutions where greenhouse gas emissions are largely offset by carbon sequestered in sustainably managed forests and forest products.

For more information
Paper Shipping Sack Manufacturers' Association
5050 Blue Church Road
Coopersburg, PA 18036
Phone: 610-282-6845;
Fax: 610-282-6921
www.pssma.org