A life cycle inventory is one of the four stages of a life cycle assessment. This is a system for assessing and measuring the environmental effects of the production process for a product or service. The goal is to measure those effects which are specifically caused by the product or service and would not exist without it.
There are internationally agreed standards for life cycle assessments. These are set down as part of a series of ISO standards numbered 14040 to 14049. The idea is to make sure different organizations use the same method for the assessment. This gives the results credibility and makes it easier to compare both different products and different companies.
There are four stages to the life cycle assessment process. The first is to decide what will be covered and what the goal of the assessment is. The second is the life cycle inventory. The third stage is to assess the results of the inventory in the form of objective figures. The final stage, which is more subjective, is to interpret these results and decide what, if any, corrective action needs to be taken.
The life cycle inventory is therefore the “meat” of the assessment and involves the gathering of all the relevant data. This usually covers every stage of a product’s production process, from the mining of any raw materials right through to the disposal of the product once the consumer has finished using it. As well as the production of the product, the data will also cover elements such as the packaging and the transportation of both the components and the finished product.
There are a wide variety of environmental factors which can be measured for each stage of the production process. They are usually measured as quantities of a particular substance. These include input substances: the natural resources used to produce the product or services. They also include output substances, such as chemical by-products or waste material.
The sheer quantity of data which must be collected in a life cycle inventory means that most firms will use dedicated software to carry out the task. Such software often gives users flexibility to tailor the inventory to their particular circumstances, but also makes it easier to compare results in a consistent format. The most popular software is a range of packages sold under the GaBi brand.
There are several optional factors which can be introduced to make the life cycle inventory more accurate. These can include taking account of environmental resource savings, such as when burning waste material can generate power which would otherwise have required coal or gas burning. The assessment can also be extended to take account of effects which occur outside of the product’s life cycle, such as when waste material is sold to another firm to recycle into a different use.