How do we use, determine and calculate component weights?
Among the data we collect from our customers, the weights of products and components are fundamental to the analyses we carry out. But what happens when these weights are not mentioned?
Why are weights necessary data in our analyses?
This information is used in three calculations:
- Life cycle analysis (LCA) requires the weights of products and their components in order to determine the quantities of materials used at each stage of production.
- Claims concerning the presence of recycled materials and plastic microfibre emissions are mandatory under the AGEC law and are calculated on the basis of the quantities of synthetic or recycled materials present in the products analysed.
- The traceability score also takes into account the weight of the components. It is weighted according to the presence of each component in the product analysed.
However, sometimes information is missing when the data is retrieved. This is why we have determined reference weights for products and components.
How were the reference weights determined?
The reference weights for the products were determined in two ways:
- Firstly, where ADEME provided a weight, this was taken into account.
- Where this was not the case, we carried out research to determine the average weights for each of these product categories.
As far as component weights are concerned, we carried out a study in conjunction with our customers to ensure that we obtained average weights for all components and products. You can find these components' weights here.
How are the weights of the components on my product calculated?
When we receive weights, it can happen that the sum of the component weights is not equal to the weight of the product, or that not all the weights have been entered.
There are two types of component weight:
- Fixed: for example, buttons, because their weight always has the same order of magnitude depending on the product.
- Variable: other components such as linings or main materials have variable weights (expressed as percentages) because their weight depends on the GSM of the material.
If a value is missing when the data is imported, the weight entered by the garment maker is used. If they have not answered this question, then the reference weight is used. Finally, if the value does not exist (for example a sole for a shoe would never exist on a T-shirt), a default value of 5% of the product weight is used.
The component weights are then cross-multiplication to ensure that the sum of the component weights is equal to the product weight.
For example :
For a shirt with three components: main fabric, buttons and collar with a weight of 200g.
The weight of the buttons was entered during data collection and weighs 5 grams. We will therefore consider this weight. The main material would be 85% of the product weight and the collar 2% of the product weight.
We therefore have :
Buttons = 5 grams
Main material = 85% x 200 = 170 grams > >Buttons = 5 grams
Collar = 2% x 200 = 4 gram
This makes a total of 179 grams, which gives the following final weight for each component:
Buttons: 5.59g
Main material: 189.94g
Collar: 4.47g
These values are not absolute truths for all the calculations made, but these estimates enable us to obtain results that are more representative of reality when information is missing from the data sent to Fairly Made®. This is why the weights are regularly updated using the data sent during the data collection phases, which makes it possible to add value to the actual data given during the data collection phases.