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How to do a product life cycle assessment: 9 expert tips from Dr. Karpagam Subramanian

April 28, 2022
Data & transparency

For the last blog in our LCA series, we speak with one of our senior LCA analysts, Dr. Karpagam Subramanian, PhD in Environmental and Social Sustainability, to understand how brands can get started on LCA and learn from her experience of working with partner brands like PANGAIA, thredUP and BAM Bamboo Clothing on impact assessments. In addition, Dr. Karpagam Subramanian shares 9 practical tips for brands to make the best use of life cycle analysis.


How can brands prepare for conducting an LCA? What are the “good-to-know” tips?

Tip 1: Have a clear understanding of why you want to conduct an LCA as well as the four key stages used in LCA methodology.

Functional unit (FU) is the core of LCA, which provides a reference to normalize all the input and output data collected from different life cycle stages. When brands want to compare products, a common FU should be determined that can ideally be related to the amount of product needed to perform that function. For example, when comparing reusable clothing with conventional clothing, possible FUs can be one average use of a garment or one year of a garment usage by a consumer. Impact per kilogram of apparel production or impact per use of a 1 kilogram of apparel are possible FU considerations for cradle-to-gate or cradle-to-grave analysis.

Tip 2: Robust data is the key.

Collect data for all the input and output flows and make it relatable to the functional unit selected. Construct a flow diagram of the whole process, so the analysis can be more transparent. Focus on unit processes and think about the details you wish to cover. For example, fiber cultivation involves irrigation, seeds, machinery (fuel used), transportation of workers, so you need to first determine which of these factors will be included in the LCA modeling and gather data accordingly. For gathering data, identifying and checking the sources from which relevant data can be collected will help conduct the LCA. Finally, it is important to ensure the gathered data can be related to the functional unit by the LCA practitioners later. For instance, for a FU of 1 kilogram of finished garment, all the inventory items like electricity, chemicals, steam have to be computed for producing 1 kg of finished apparel. 

What are the most common challenges for brands to get started on LCA? Can you share your advice on overcoming such challenges please?

To get started, data availability and accuracy is the main challenge faced by brands. Lack of understanding in the following areas could be another challenge.

  • Accurate data is the key to derive reliable conclusions from an LCA study
  • How to relate the data collection from different life cycle stages to the product or the process being analyzed
  • How LCA can help understand the impacts that the product makes on the ecosystem

Common data collection techniques include developing questionnaires, surveys or checklists, and communicating it to the organizations and stakeholders involved in the textile supply chain. Stakeholders from the brands can also directly visit such organizations. During such company visits, some additional activities like further estimation, re-calculations, and various examinations and measurements related to the activity data can be carried out.

Tip 3: Primarily, brands have to start focusing on techniques and tools to collect data from end to end.

Traceability, transparency and stakeholder commitment is the key. Brands have to focus on making their suppliers better understand the need to limit the footprint of their products, and how tracing the manufacturing of their products can help them understand the environmental impacts they create, and finally make all the stakeholders of its supply chains responsible, accountable and involved in data collection.

Tip 4: Collecting and exchanging data between brands and their suppliers should not be carried out as a separate step or phase to enable LCA modeling, but should be made a regular exercise.

Brands have to take up the responsibility to ensure that the data exchanged is secure, auditable but not corrupted or mishandled. Such data can then be analyzed real-time, by environmental specialists or external consultants like Green Story to identify impacts. This real-time data can also be used by brands for various other purposes such as ESG reporting, sustainability reporting that comply with GRI standards, or overall stakeholder engagement (i.e. communication with consumers and investors).

Tip 5: Brands can also consider investing in secure technologies like IoT-Blockchain integrated platforms, supply chain analytics to name a few.

Visibility, transparency and distribution network that these data analytics provide helps brands to detect risks faster, track performance of suppliers, trace the issues at source.

Tip 6: When using LCA to evaluate circular business models, consumer responses (i.e. consumer behaviors and habits towards second-hand clothing) play a key role in determining environmental impacts. Surveys have to be administered for this purpose.

What is the best approach for brands to interpreting, communicating and reporting LCA results? How can brands make the best use of the impact assessment?

Comparative LCAs showcase products’ positive impacts at two levels: (1) impact savings of one brand’s garment, in contrast to a garment made from a conventional or alternate fibre that is sourced and processed from multiple locations across the globe; (2) impact savings of one brand’s garment made from a sustainable fibre in contrast to a garment made from conventional fibres of identical supply chains. The comparative LCA results also allow companies to decide if their choice of shifting to sustainable fiber like cellulosic fibers or any other potential intervention (i.e. use of renewable energy source) is actually resulting in any impact reduction.

In addition, the impact savings data such as GHG emissions, energy and water used, derived from LCA, can be used to provide a basis for sustainability reporting that comply with GRI standards.

Tip 7: Hotspot analysis, based on per stage impact calculation, can help the brands identify suppliers, locations, transport means, chemicals and fibers that need attention, set quantifiable goals for them and monitor their progress closely to mitigate impacts.

For example, shift fiber processing locations to reduce emissions, use energy efficient spinning technology, keep a check on water-intensive drying processes and irrigation techniques, and ensure wastewater treatment wherever applicable, etc.

Brands that have set corporate goals like zero water wastage or zero fossil fuel usage can use LCA results to identify the supply chains that currently contribute the least towards water and energy usage, which would accelerate the probability of achieving their goals at a faster pace. Internally, these results can be used to set measurable goals and most importantly, should be monitored at regular time intervals with accurate data from involved stakeholders and should be validated with LCA iteratively.

Tip 8: It is important to note that LCA results are very specific to the specific product defined using a FU within a specific system boundary.

The inputs cannot be simply changed and results cannot be proportionally calculated. The models have to be rerun for those specific changes Also, certain sets of variables need to remain consistent throughout to enable comparison.

Tip 9: Communicate your LCA results with consumers in an authentic, credible and easy-to-understand way. 

The impact metrics, otherwise known as impact savings, that Green Story provides are based on three key impact categories: climate change, energy demand and blue water consumption. The results of these positive impacts are derived from comparative LCAs, which enable brands to validate the sustainable product claims backed up with credible data. Communicating these numbers to the customers not only gives the brands a competitive advantage, but also makes the customers feel good.

Are you interested to learn more about how to communicate LCA results? Or, do you have questions about starting an LCA study? Green Story has helped 150+ brands gain accurate life cycle analysis data of their products and guided them through LCA studies. Besides life cycle assessment, our Know Your Impact solution visualizes brands’ impact with relatable metrics and shows their audience the positive impact they make when choosing sustainable products. Get in touch with us here!