A Guide to Calculation Methods for Determining Plastic Weight for the Federal Plastics Registry
The Three Calculation Methods
The Phase 1 guide of the Federal Plastics Registry describes three ways to calculate the weight of plastics you need to report. You can use any of them, but you must say in your report which one you used. Here's a simple breakdown:
1) Specific Component Identification
Definition: You determine how much plastic is in a single item by measuring its individual components or by using specific weight values provided by the supplier.
How you do it:
- Identify every plastic component that makes up the product.
- Measure the weight of each component or use verified weights from your supplier.
- Multiply those weights by your total number of items.
Examples:
Example 1: Measuring the Components Directly
A spray bottle is taken apart and weighed: the bottle is 22 grams, the trigger is 12 grams, and the tube is 2 grams. With 40,000 units placed on the market, these weights translate to 880 kg, 480 kg, and 80 kg of plastic reported.
Example 2: Using Supplier Material Percentages (Polo Shirt)
A polo shirt labeled as 50% polyester weighs 200 grams, meaning 100 grams is polyester. If 25,000 shirts are imported, this results in 2,500 kg of PET reported.
2) Average Bill of Materials (ABOM)
Definition: When you have many items that are nearly identical in design, size, or components, you can create one "average" plastic profile and apply it across the entire group. This reduces the need to measure every individual SKU.
How you do it:
- Take a few typical products (A, B, C), list their parts and weights.
- Average each plastic type across those products to get one “average” item.
- Multiply that average by your total number of items.
Example: A company sells a wide range of reusable plastic storage bins in different colours and with small size variations. The supplier is able to provide detailed component weights for only a few of these models. To streamline reporting, the company selects a representative sample of bins, measures their plastic content, and calculates an average plastic weight. This average is then applied to all similar bin SKUs sold during the year.
3) Fixed Factor Calculation
Definition: Use a pre-set factor (like a percent by weight, or kg per square metre) for a product, then multiply by how many you have. It's like saying “this kind of printer is 22.8% ABS plastic,” then using that percentage for every printer you report.
How you do it:
- Get the fixed factor (for example, “ABS is 22.8% of a printer” or “film weighs 0.0189 kg per m² based on thickness and density”).
- Multiply that factor by the number of items (and their weight or area/length, if needed).
Example: A printer weighing 10 kg x 22.8% ABS = 2.28 kg ABS per printer. Multiply by the number of printers sold.
When to Use Which?
- Specific Component Identification: best if you know the exact parts/weights of your items.
- ABOM: handy if you have many similar products and want one average to save time.
- Fixed Factor: useful when you don't know the detailed breakdown, but you do know a trusted percentage or ratio.
Note: the guide indicates you can use other methods provided they are reliable, documented, and capable of accurately determining the weight of plastic resins in products or packaging, as long as the chosen method is clearly identified and described in the FPR submission to ensure compliance with reporting requirements.