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Circularity or safety in second life products? Here’s how to achieve both

Sponsored: The growing prevalence of second life products achieves circular objectives, but there may be safety risks inherent with refurbished products. We’ll explore some of the risks and propose best practices for verifying the safety of second life products.


UL engineer from the company’s renewable energy office in Pamplona on a site visit to a wind farm in Spain; Source: UL.

This article is sponsored by UL.

Circularity is a life-cycle approach to sustainability in product design that is gaining momentum worldwide. Circular business models maximize the use of limited natural resources, reduce reliance on the take/make/waste economy and, in many cases, reap cost savings for businesses. 

However, in the race to achieve the critically important attribute of circularity, companies run the risk of sidelining other important criteria such as safety and performance. 

As we enter new territory for circularity with the expansion of second-life products and materials, it’s important to keep a watchful eye on safety. For example, does recycled plastic maintain integrity and performance in an end product? Do refurbished electronics meet fire and shock risk requirements the same as new electronics? Do reconditioned medical devices or molded-case circuit breakers offer the same performance as new? 

Harmonization of circularity, safety and performance standards is critical to achieving a more sustainable and safe economy. Evaluating circular products for all of these criteria helps ensure long-term viability of new circular approaches, protects consumers and other end users, and reduces risk associated with achieving circularity. What’s more, validations of the performance, quality and circularity attributes of products and materials can provide the evidence needed to confront myths and misunderstandings about these products and encourage widespread adoption of remanufactured or other second life or "like new" products.

Assessing the safety risks of second life products

While single-attribute sustainability claims such as recycled content are helpful in creating the ecosystem in which recycling markets can operate more effectively, circularity is broader and aims to optimize resources by circulating products and/or components in a way that ensures materials are used at their highest value for the longest time possible. 

Several business models support circularity, but of particular focus in this article are product life extensions, by which companies extend the life of products through remanufacturing, upgrade, technical assessment or remarketing. This method is highly effective for maximizing the value and life of products and reduces the need for virgin materials as well as carbon emissions associated with production and distribution of new products. 

For example, according to a study titled "The Remanufacturing Industry" by Robert T. Lund, funded by the Argonne National Laboratory, remanufactured products conserve the equivalent to 400 trillion British Thermal Units (BTUs) of energy annually, which translates into the energy used to power 6 million passenger cars each year. It also represents a significant revenue stream for many companies, with some estimates that $60 billion of remanufactured goods are sold each year in the U.S. alone. 

However, some risks are inherent with this type of product life extension.

  • Component failure: In the case of refurbished electrical products, consumer electronics, appliances and other electrical distribution devices, if components such as batteries or semiconductors are not properly tested and recertified, they may present a fire and/or shock risk. Refurbished products are only as safe and reliable as their individual components. Faulty components have a cascading effect, ultimately yielding faulty second life products.
  • Material degradation: Recycled plastics must be managed to ensure essential performance is not degraded. They may have a high accumulation of substances of concern, making them unacceptable for reuse in items such as food packaging or medical devices. While circularity encourages the use of recycled materials, they should not compromise the safety of products.  
  • Materials unqualified or poorly qualified for reuse: Certain equipment may not be reconditioned per U.S. National Fire Protection Association 70 National Electrical Code, 2020. These include certain fire prevention or protection equipment that provides ground-fault circuit-interrupter protection for personnel, equipment that provides arc-fault circuit-interrupter protection or equipment that provides ground-fault protection. 
  • Unqualified repair: If trained, qualified personnel are not repairing products, performance and safety failures may result. Verification of the qualifications of repair personnel is essential to safety.

But it’s also important to consider the lived life of that product. The Guide Information for Electrical Equipment for Use in Ordinary Locations (Category AALZ), found on, summarizes UL's position that "when a product bearing a UL Mark is modified or rebuilt (including being refurbished, remanufactured, reconditioned or renovated) after it leaves the factory where the UL Mark was applied, UL does not know if the product continues to meet the applicable requirements unless the modification or rebuilding has been specifically investigated by UL." (Registration for Product iQ is free; register today at key question is: does this product perform as well and operate as safely as a new product?

Achieving circularity and safety

While circularity is becoming embedded into business practices of sustainability-minded companies, there is often a lack of awareness of the possible safety risks described above. Depending on the type of product, regulations may call for testing and assessment. However, for items such as electrical equipment, automobiles, building products and furniture, there is often little awareness among manufacturers and end users of potential risks. 

For companies in any industry, here are some steps toward achieving both circularity and safety.

  • Design with second life in mind: In their book "Remanufacturing in the Circular Economy: Operations, Engineering and Logistics," authors Brian Hilton and Michael Thurston offer three principles for designing for remanufacturing: designing to create value, protect and preserve value and easily and cost effectively recover value.
  • Assess the risk and the value: A little planning can go a long way toward understanding the potential risks associated with second life products, alongside the potential upside value of your business and customers. Some internet research can reveal potential pitfalls based on news stories of failed products. Review regulations applicable to new products to identify safety aspects that may pose a risk for products built some years ago. 
  • Search for standards: As circularity comes of age, increasingly industries and respected organizations are developing standards for second life products. Some examples include the National Fire Protection Association’s NFPA 70, the National Electrical Code, to address practical safeguarding of persons and property from hazards arising from the use of electricity. UL 1974, Standard for Evaluation for Repurposing Batteries, was published in 2018 and designed to support safe and reliable repurposing of electric vehicle (EV) batteries for other uses, such as in the electrical infrastructure. And, UL is integrating UL validated recycled content information, per UL ECVP 2809, Environmental Claim Validation Procedure for Recycled Content, into Prospector and UL's Yellow Card program that provides third-party certification about the quality, safety and performance of plastic products. By following these standards, you can help your company incorporate best practices for refurbished products.
  • Achieve transparency: Today’s complex environment calls for transparency that paves the way to knowledge and, ultimately, trust. Third party testing for safety, performance and sustainability demonstrates your company’s commitment to safety, performance and sustainability and provides documentation that offers vital visibility.
  • Build capabilities: As more industries adopt circular economic models, their leading companies, associations and educational channels will need to work to grow industry knowledge of risks, develop standards and promote validation services for new technologies, products and product categories.

Success story from UL 

In an effort to promote confidence in the safety of refurbished products and to increase transparency, UL has established programs for the safe and sustainable rebuilding of many categories of products. We are committed to supporting circularity on a secure foundation of safety.

As an example, consider the growing number of wind turbine farms installed over the last two decades.

These wind turbines have an average lifespan of 20 years. As the equipment nears end of life, many parties become interested in assessing continued safe and reliable operation. 

UL developed a standard to determine if it would be possible to safely extend the life of turbines. UL 4134, the Standard for Safety for Lifetime Extension of Wind Turbines, employs a science-based approach to test and validate the safety and performance of equipment to extend the life of these large, costly assets. The requirements take into account the external conditions of use for the specific turbine, operational characteristics and turbine information. This data is used to calculate the remaining useful life and set the stage for physical inspections and risk analysis, allowing the turbines to continue to operate rather than being decommissioned and replaced with new turbines. This allows for extension of life through reasonable repair.

Looking ahead

As we continue to shift from a take/make/waste to circular business models, we will need to make a number of shifts across business, government, investors and society at large. Among the lessons learned during the pandemic, we know that human health and safety remain a priority and should be top of mind as we investigate new methods for bringing circular products to market. Second life products have the potential to dramatically reduce use of precious natural resources and divert waste from the landfill; ensuring their safety and “like new” performance is one of the new safety imperatives of our time, and in turn will help encourage adoption.

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