Material Flow Analysis


Material Flow Analysis (MFA) is a methodology for investigating metabolism by quantifying and visualizing the flows and stocks of systems. MFA is tool commonly used in Industrial Ecology, Life Cycle Assessment, and urban metabolism. For examples of how it is used, check out over 60 samples on our MFA Diagrams blog.

MFA  of Plato Wood processing in The Netherlands

Our methodology


System modeling

Formal MFA graphic language for built ecology case in Germany

To rigorously quantify flows in a scientific manner, the standard MFA methodology uses four fundamental building blocks.


Good: Goods are materials within a MFA that are the contents of the flows.


Flow / Flux: Flows are directed pathways of goods.  A flow is expressed in [unit]/[time], e.g kg/year, ml/sec, kWh/min. A flux is expressed in [unit]/{[time][area]}, e.g. crop yield per year per hectare, rainfall per year per square meter.


Process: Processes can be physical processors, e.g. a factory, an engine, or activities, e.g. running, consumption. Within a process, a Stock is the accumulation of goods.


System: The system is the set of material flows, stocks, and processes within a temporal frame and a spatial or virtual boundary.  Spatial boundaries include a region, a municipal incinerator, a private household, a factory, a farm.  Virtual boundaries can be used to include processes affecting the analysis from outside of a spatial boundary, for example emissions from electricity feeding into the grid.


With these building blocks, any system can be constructed. Once the flows are known, data collection is undertaken to fill in values that will be used in analysis.

Analysis and quantification

Screenshot of STAN 2.5 (subSTance flow ANalysis)

The completed system model and known data (mass flows, stocks, concentrations, transfer coefficients) is used to calculate unknown quantities with specialized software that can take into account fluctuations in quantity. The data is then exported to visualize the complete system.


3D Sankey visualization of a closed-loop residential project

Our visualizations use Sankey diagram arrow styles to graphically display the relative flow quantity. Beyond these attention-grabbing flowcharts, additional layers of meaning can be added, including 3D elements (as shown above), icons, infographic elements, and spatial elements.


Nels Nelson, Symoto, Draft for online system modelling tool, 2011 Symoto (system modelling tool) is an online application for modelling systems and structuring data about consumption in cities so that one person can directly benefit from another’s research. This allows users to quickly build a community of knowledge and information about how cities are performing with regards to water, energy, material and CO2.