Life Cycle Assessment


Life Cycle: Cradle to Grave
Consecutive and interlinked stages of a product system, from raw material acquisition or generation from natural resources to final disposal. (ISO 2006)

Life Cycle Thinking: What impacts?
Life Cycle Thinking is a mostly qualitative discussion to identify stages of the life cycle and/or the potential environmental impacts of greatest significance.

Life Cycle Assessment: How much?
LCA is a scientific method for analysis of the environmental impacts associated with the life cycle of a product. LCA is the compilation and evaluation of the inputs, outputs and the potential environmental impacts of a product system throughout its life cycle. (ISO 2006)

Life Cycle Assessment Methodology


The reasons for carrying out the study, intended application and intended audience

The functions of the product system or systems; the functional unit; the system boundary (cut off rules); impact assessment method and impact categories.

Inventory Analysis
Identify what happens at each stage along the life cycle for each  element of the system. What are the inputs and outputs for each thing that happens? How much of each material/component is involved?

Impact Assessment
The sum impact of the inputs and outputs.

Example: Plastic Water Bottle

1. Goal
This study in intended to compare the use of a reusable metal drinking container to a disposable plastic water bottle. This study will be used for educational purposes only as a tool to demonstrate Quantis Suite 2.0. This is an over-simplified study and is not intended to make any claims or be used in any decision making applications.

2. Scope
The functions of the containers are to contain a known amount of water.  Functional Unit (FU) = 1 year of 2.2 L per day (recommended daily intake for women) = 365 days, 2.2 L servings of water

System Boundary:
Study does not include impacts related to collecting, transporting and treating water. Does include weight of water during transport for plastic bottle.

Not accounting for recycling – assuming that both are incinerated at EOL. Data for this study has been indirectly acquired via 3rd party methods (the internet). Assuming that I wash my metal bottle every other day = 182 washes per year. Not including secondary packaging.

3. Inventory Analysis
First step is to understand how much of each component there is within the context of the Functional Unit:
FU = 365, 2.2 L servings of water

1 plastic bottle : 0.5 L
365*2.2 L = 803L
803 L/.5L = 1606 Plastic bottles

Plastic Inputs
1606 Plastic Bottles 14,775.2 g
1606 Plastic Films 16.06g
Ink 1.606g
0 Washes

Plastic Outputs
1606 bottles (assembly) 14791.26 g

1 Metal Bottle : 1 L of water

Metal Inputs
1 Metal Bottle 177.19g
1 Metal Cap 34.73g
1 Plastic Cap 11.34 g
182 Washes ((0.25 gal water) + (.01g/gal detergent))*182

Metal Outputs

1 Metal Bottle (assembly) 223.26g
Wastewater (0.25gal + 0.01g detergent)*182

Next – take the information from you process tree and create a table:

Plastic Bottle

Component Plastic Bottle Plastic Label Plastic Cap Ink
Amount/Unit 9.2 grams .01 grams .1 grams .001 grams
Core Material PET PET PET Chemicals
Raw Material Crude Oil Crude Oil Crude Oil Crude Oil, Pigment
Material Processing Oil Refining, Polymerization,
Pellet Production
Oil Refining, Polymerization,
Pellet Production
Oil Refining, Polymerization,
Pellet Production
Oil Refining,
Other Processes
Manufacturing Blow Molding Film Extrusion Injection Molding Printing
Use N/A
Distribution 524.65 km on truck (Portland, ME Bottling facility to NYC)
Payload-Distance (kgkm) .5 L H2O = 500 g water;
bottle assembly = 9.2+.01 g +500 g = 509.21 g = 0.50921 kg;,transport distance = 524.65 km; 0.50921 * 524.65 = 276.32 kgkm
EOL 9.21 g

Metal Bottle

Component Stainless Steel Bottle Plastic Cap
Amount/Unit 211.92 grams 11.34 grams
Core Material Stainless Steel Polypropelene
Raw Material Iron ore Crude Oil
Material Processing Mining,
Oil Refining, Polymerization,
Pellet Production
Manufacturing puck production
impact forming
Injection Molding
Use 1.82 g soap
45.5 g tap water
Distribution Ship from China to San Fran = 11187 km
Truck Sf to NYC = 4675.75 km
Payload-Distance (kgkm) Total assembly weight = 0.22326 kg;
Ship = 11187 km * 223.26 kg = 2497.60 kmkg
Truck = 4675.75 km * 0.22326 kg = 1043.90 kgkm
EOL 23.26 g

4. Impact Assessment
Once you have done all of this, you can log into Quantis!  Watch this tutorial video to remind you what to do. Quantis part starts at 54:00 and goes through this same example.

Quantis gives you the potential (not actual) environmental impacts.

Midpoint vs. Endpoint Methods:
Some impact assessment methodologies express results in midpoints while other use endpoints – and sometimes it is a combo. For example, ozone destroying agents are released into the atmosphere – we can measure their ozone depletion potential and compare that to something else, or we can measure that actual environmental Damage due to the Increase in UVB radiation.


Quantis Impact Assessment Method:
This frames out how quantis groups midpoint categories into more general damage categories – the 5th impact category that you will see in quantis is water – which is the grouping of the 3 water midpoint categories – so quantis’ impact assessment method expresses results in both midpoints and endpoints. We don’t have control in changing this in our limited version of the software but in the practitioner version, and other practitioner softwares, you can express results using various impact methods.

These are the units that Quantis (and many other tools) use to express impact.

Damage Category Units Comments
Human Health DALY Accounts for years lived disabled as well as life cut short.
Ecosystems PDF-m2-y The amount of species that can potentially be lost in a given area of land if it is occupied for other purposes, within a year.
Resources MJ Adds up different categories of energy.
Climate Change kg CO2 eq. Same method used by most GHG accounting programs.
Water m3 Counts the amount of water consumed. Does not show impact. Used for benchmarking only.

5. Interpretation
Your LCA results are just like a nutrition label – it gives you information about the potential impact of your product or system but does not tell you that it is healthy or not healthy. It is up to you, the designer, to use this information to optimize your design based on your prior research and personal values. Remember to look for opportunities to optimize in the following areas: Innovation, Materials, Processing and Manufacturing, Distribution and Packaging, Use, Optimized Lifetime, and End of Life.

LCA 9 LCA 10

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