Life Cycle Assessment: an Introduction to Concepts and Applications

What is a Life Cycle Analysis?

A life cycle analysis (LCA) is an internationally accepted methodology (e.g. AS/NZA ISO 14044:2006, ISO 14040 (2006) and ISO 14044 (2006)) for analysing the environmental impacts of a process, product or activity along its “life cycle”. This type of analysis encompasses the extraction of raw materials, manufacturing of a finished product, maintenance and performance in service and the subsequent disposal or recycling of the item at the end of its service life and can be referred to as “Cradle-to-Grave”.

They have become more popular as manufacturers seek to improve their sustainability and supply more environmentally friendly products. They also allow informed decisions to be made when comparing two products, processes or services on the basis of their environmental impact.

The environmental impact of an LCA may be calculated on the basis of mass of CO2 produced per unit mass of product.

Cradle-to-Gate and Embodied Energy

A true LCA takes into account all the inputs and outputs throughout the entire life of a product or service, including energy and materials inputs and environmental releases.

Some manufacturers have employed other types of analysis claiming to be LCA’s, which fall short of the mark. One such example is cradle-to-gate, a partial LCA which is effectively the extraction of raw materials and manufacturing of a finished item. It does not take into account how the material/component performs in service, nor does it consider disposal at the end of its service life or even transport to the consumer. They are sometimes used as the basis of an Environmental Product Declaration (EPD).

The embodied energy of a product is the energy tied up in its manufacture and delivery to the building site. It differs from an LCA in that it does not take into account operational effects and disposal.

Another partial LCA type is gate-to-gate, which essentially evaluates the production process. It only takes into account the processing of raw materials into a product and the emissions from that process.

Another variant is a cradle-to-cradle assessment where the disposal step is a recycling process. An example is the recycling of glass bottles.

(Image from Thinkstock)

What is an LCA Used for?

Manufacturers typically use LCA’s to reduce the environmental impact of their products by examining the inputs and outputs of their products, with the aim of producing a more environmentally friendly product. They might achieve this by implementing a more efficient production process or simply by sourcing raw materials from locations closer to the production facility.

A 2006 survey of LCA practitioners found that LCA’s were used for supporting business strategy and R&D, to improve process design, education and for labelling and product declarations.

Stages of an LCA

An LCA consists of 4 basic stages:

  • Goal and scope definition – define and describe the product, process or activity in question. Define the boundaries and environmental effects to be assessed and the purpose of the study
  • Inventory analysis – identify and quantify energy and materials inputs and outputs e.g. raw materials required, energy required for production processes, waste and by-products, emissions, materials that can be recycled etc
  • Impact assessment – assess the potential impacts on the environment and population of energy, materials, emissions etc. based on the inventory analysis
  • Improvement analyses – with a clear picture of the items involved (inventory analysis) and impact assessment, evaluate the results obtained to identify areas where improvements can be made. Once tested with a positive outcome implement these changes to improve sustainability

The major processes that need to be evaluated in an LCA study are raw material acquisition, materials manufacture, production, use/reuse/maintenance and waste management.

Advantages and Disadvantages

One of the advantages of an LCA is that it can include the production or consumption of resources like energy or carbon emissions regardless of where the process may be located or if changed from one form to another.

An LCA also provides a complete picture of the product, process or service i.e. while a small change may appear to bring environmental benefits, it may actually create more carbon emissions downstream, negating its overall benefit. A cradle-to-grace allows the manufacturer to evaluate any change in the production timeline.

Some of LCA’s weaknesses include:

  • They are very specific and often cannot be transposed across to similar operations
  • Sometimes inventory data is difficult to obtain and best estimates need to be used. This is being addressed by the Life Cycle Inventory (LCI) program that improves access to high quality life cycle data
  • Pulling together data can be time consuming and costly
  • They do not necessarily determine which product or process performs the best or is the most cost effective, so may need to be used as a component of a more comprehensive study

Case Study – Clay Bricks

The Australian brick industry undertook a total LCA to help them compete against other recently developed building materials and systems. Their detailed analysis took into account all inputs from beneficiation of raw materials, energy required to fire the bricks, transportation to the building site and the subsequent disposal and recycling of bricks at the end of a life of the house.

As the performance of a brick on the performance of a house did not correlate, they went a step further and compared the performance of various walling systems (e.g. cavity brick, brick veneer and lightweight construction) on the energy efficiency of the house. Studies were carried out using full-scale housing modules taking into account the other materials used in the construction of a house such as mortar and a 50 year service life. In doing so they created an entire LCA with a holistic approach that demonstrated a more realistic sustainability model.

Their research showed that a cavity brick construction was the most sustainable design. The heavy weight construction (high thermal mass) helped to regulate the internal temperature of the building more so than lighter weight designs. This reduced the need to artificial heating and cooling and hence energy consumption during the life of the home, resulting in lower greenhouse gas emissions. The fact that bricks can be recycled or disposed of easily, as they are inert, also added to a positive LCA outcome.



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