By Claude Goguen, P.E., LEED AP
Odds are good that one day, you will be bidding on a project and the bid documents will contain a request for an Environmental Product Declaration. At that point, you will frantically type EPD into Google as you begin to scramble to assemble the information or you will breathe a sigh of relief as you include your product’s EPD with your bid. NPCA and industry partners PCI, CPCI and ACPA are partnering to develop the first North American precast concrete Product Category Rule. The public comment period has just ended and the third party review is about to begin. What does this mean to you? The PCR being finalized will guide you in creating that EPD. However, you will need one more three-letter acronym, a Life Cycle Assessment or LCA.
Sustainability, at its core, is a simple concept. In the context of precast concrete manufacturing, it means producing high-quality, durable products in a safe and environmentally conscious manner while employing efficient use of raw materials, energy and water. In the context of a building or infrastructure project, the two meanings are similar. It’s about minimizing or even eliminating the environmental impact of the end product, whether it is a four-story multi-family unit or a two-compartment precast concrete septic tank. But how do we define this impact?
Imagine you’re a designer and you have two choices of wood doors for your building. One is made of pine from Michigan while the other is made of Burmese Redwood from the forests of Southeast Asia. Your immediate assumption may be that the pine doors would have less of an impact due to the proximity of the raw materials. Surely, the energy and emissions associated with shipping the materials from the other side of the world would make the redwood a poor choice in terms of sustainability. However, what if the redwood doors have an expected life of 30 years with practically no maintenance, while the pine doors will last 15 years with periodic maintenance? On top of that, the redwood doors can be recycled while the pine doors are landfill bound. Now the obvious choice is not so obvious. Instead of looking at one aspect of the product, you must look at all aspects involved including raw material extraction, manufacturing, transportation, durability and final disposal. A true measure of a product’s environmental impact must consider its entire life cycle. This is the essence of a LCA.
LCA is defined as a technique used to assess the environmental aspects and potential impacts associated with a product. An LCA can help you:
• Compile an inventory of relevant energy and material inputs and environmental releases
• Evaluate the potential environmental impacts associated with identified inputs and releases
• Interpret the results to help decision-makers make a more informed decision.
Therefore, let’s assume you want to conduct an LCA on a particular line of precast concrete products. First, you use the PCR as a guideline since it sets the system boundaries on how the LCA should be performed. The evaluation of the product will be conducted from its cradle, which is the stage where raw materials are extracted or produced. It continues all the way through the manufacturing process, shipping, installation, use and finally to its grave, where final disposal of the product takes place. That’s why you will often hear the term cradle to grave. There is also the term cradle to cradle, which is used when the product can be recycled into a new product.
The LCA process begins with a Life Cycle Inventory. This is the process of quantifying energy and raw material requirements, atmospheric emissions, waterborne emissions, solid wastes and other releases for the entire life cycle of your product. The different phases include:
1. Raw materials acquisition. The life cycle of a product begins with the removal of raw materials and energy sources from the earth. In the case of precast, extraction of limestone for cement and processing of steel for rebar would also be considered. In addition, transportation of these materials from the point of acquisition to the point of processing is also included in this stage.
2. Manufacturing. Raw materials are transformed into a product and then that product is then delivered to the consumer. In the case of precast, this stage includes the forming, reinforcing, batching, consolidation and curing processes. The energy used to heat, cool and light the plant buildings would also be considered. As the product is moved to the yard and then eventually onto a truck for delivery, the fuel consumed and the resulting emissions for all these operations are included.
3. Use/Maintenance. This stage involves the consumer’s actual use and maintenance of the product. This includes energy and emissions during installation. The use phase for precast concrete products is generally not considered since they do not consume energy while in use and do not generate environmental waste. Maintenance is very minimal depending on the type of product so at times this may also be minimal or null.
4. Recycle or waste management. When the product is no longer needed to fulfill its purpose, it will need to be disposed or recycled. Any energy, waste or emissions during these operations are considered.
You may choose to have an LCA done specifically for your products. This would not only enable you to proceed in creating a product-specific EPD, but it would also reveal the nature and scale of environmental impacts specific to your product and operations. Armed with this knowledge, you can then make adjustments to address areas that significantly contribute to those impacts. NPCA and other industry partners had a general industry LCA conducted on underground products with a final report issued in 2010. This report can be viewed online at precast.org. For more information on LCA, go to the EPA website which contains a thorough examination of the process.
If you have any questions about this or any other sustainability related topic, please contact Claude Goguen, Director of Sustainability and Technical Education at [email protected] or (800) 366-7731.
Claude Goguen, P.E., LEED AP, is NPCA’s director of Sustainability and Technical Education.