1. What is LCA?
LCA stands for Life Cycle Assessment. In simple terms, LCA studies the environmental impact of a product or service across different life cycle stages.
It can help answer questions such as:
- Which stage causes the highest environmental impact?
- Which materials or processes are most important?
- How does one product compare with another?
- Where can improvements be made?
- What data is needed for product environmental reporting?
2. Why LCA matters
LCA helps companies avoid looking at only one part of a product. For example, a product may look environmentally friendly during use, but may have high impacts during raw material extraction or manufacturing.
Product improvement
Hotspot identification
Product carbon footprint work
Environmental product declarations
Customer sustainability requests
Eco-design decisions
Supplier and material comparison
Climate and resource efficiency strategies
3. The four main phases of LCA
ISO 14040 and ISO 14044 describe LCA through four connected phases.
Goal and scope definition
This defines why the study is being done and what will be studied, including the purpose, intended use, audience, product system, functional unit, system boundary, allocation approach, impact categories, data quality needs, assumptions, limitations, and need for critical review if relevant.
Life Cycle Inventory, LCI
This phase collects input and output data such as raw materials, energy, water, fuels, chemicals, packaging, transport, products, co-products, waste, and emissions to air, water, or soil.
Life Cycle Impact Assessment, LCIA
This phase converts inventory data into environmental impact results, such as climate change, acidification, eutrophication, resource use, water use, ozone depletion, toxicity, ecotoxicity, and particulate matter.
Interpretation
This phase explains the results, identifies important stages and processes, checks data completeness and assumptions, and connects recommendations back to the goal and scope.
For example, greenhouse gas emissions such as CO2, methane, and nitrous oxide can be converted into climate change impact, usually expressed as kg CO2 equivalent.
4. Important LCA concepts
Functional unit
The functional unit is the reference unit of the study. It defines what function is being assessed, such as 1 kg of product, 1 liter of beverage delivered, or 1,000 hand drying events.
Reference flow
The reference flow is the amount of product needed to deliver the functional unit. For 1,000 hand drying events, it could be the number of paper towels or the amount of electric dryer use needed.
System boundary
The system boundary defines which life cycle stages, processes, materials, transport steps, waste treatment steps, and small excluded inputs are included in the LCA.
Product system
A product system is the full set of connected processes that deliver the product function, from raw material extraction through production, use, reuse, recycling, waste treatment, and final disposal.
Unit process
A unit process is one smaller process inside the product system, such as melting metal, producing plastic granulate, truck transport, electricity generation, packaging production, or waste incineration.
Allocation
Allocation is used when one process produces more than one product or function. It decides how inputs and outputs are divided between products and should be explained transparently.
5. Boundaries and product carbon footprint
Cradle-to-gate
Cradle-to-gate covers the life cycle from raw material extraction to the factory gate. It usually includes raw materials, upstream production, transport to the production site, and manufacturing. It usually excludes product use, maintenance, and end-of-life.
Cradle-to-grave
Cradle-to-grave covers the full life cycle, including raw materials, production, transport, use phase, maintenance, end-of-life, recycling, or disposal.
Cradle-to-cradle
Cradle-to-cradle focuses on circular systems where materials are recovered and used again through reuse, recycling, material recovery, or closed-loop systems.
Product Carbon Footprint, PCF
A Product Carbon Footprint focuses on climate change impact. It usually measures greenhouse gas emissions across a product life cycle and reports them as CO2 equivalent.
PCF is related to LCA, but it focuses mainly on climate change, while a full LCA can include many environmental impact categories.
6. What data companies should collect first
Product information
- Product name, function, and weight
- Bill of materials
- Production volume
- Packaging details
- Expected lifetime and use scenario, if relevant
Process data
- Energy, fuel, and water use
- Material inputs and chemicals
- Scrap, waste, and production losses
- Measured emissions, if available
- Recycling rates
Transport data
- Supplier locations
- Transport distances
- Transport modes
- Inbound and outbound logistics
End-of-life data
- Reuse and recycling
- Incineration and landfill
- Waste treatment route
- Recovery assumptions
Background data
- Electricity mix
- Fuel emission factors
- Material, transport, and waste treatment datasets
- Database sources
Data quality
- Time period, geography, and technology
- Completeness and representativeness
- Consistency and data sources
- Uncertainty and assumptions
7. Critical review
A critical review may be needed when LCA results are used for public comparative claims. It helps check whether the study methods, data, interpretation, and reporting are suitable for the stated goal.
Important note
This guide is for general educational purposes only. It does not provide legal, audit, certification, verification, product declaration, or official LCA compliance advice. Companies should confirm their LCA approach with qualified LCA, sustainability, audit, legal, or verification professionals.
References and disclaimer
This guide was prepared using ISO 14040:2006 and ISO 14044:2006 documents reviewed for EcoGradeX, together with official ISO source information.
Main references include:
- ISO 14040:2006 - Environmental management - Life cycle assessment - Principles and framework
- ISO 14044:2006 - Environmental management - Life cycle assessment - Requirements and guidelines
The reference documents were used to simplify and structure the guide content for general educational understanding. They should not be treated as legal, audit, certification, verification, or official compliance advice.