Calcuatling the Sustainability of Alumninium Packaging

Since we manufacture a variety of containers in different sizes, using different metals and glass, and serving different markets, along with ends, vacuum closures and crowns, we developed a set of conversion factors to transform these container and closure production volumes into 12oz. (Ø211) aluminum beverage can equivalent volumes, or “units.” This modification more accurately represents our efforts to conserve raw material use and reduce emissions over time. 

In our previous Sustainability Reports, we used a three-factor conversion to recast our entire production into a standard 12 oz. aluminum beverage can.  In those reports, the conversion of Type of Metal was used to convert steel beverage cans into the standard aluminum material type. Since our 2013 Sustainability Report, Crown’s production of steel beverage cans has been reduced and is no longer material to our overall production. Therefore, we no longer need to include this conversion. Starting with our 2017 report, Crown will use a two-factor conversion to represent our entire production into standard 12 oz. aluminum beverage can units. 

Our 2017 report will also be the first summary to include glass bottle production. For the purpose of calculating standard production units, glass bottles will only factor in the container capacity, as the bottles manufactured by Crown are solely for the purpose of bottling beverages.  For emission data in this report, glass bottle manufacturing is separated from metal manufacturing. This separation is consistent with other multi-material packaging companies and allows the different manufacturing process to be evaluated separately.

The two conversion factors we are still employing are explained in more detail below.

  1. Product functional requirements: This factor adjusts for the fact that different market applications (e.g. beverage cans, food cans and aerosol cans) use different amounts of metal for the same sized can due to very different performance requirements such as pressure performance. These values were determined by comparing the amount of metal required for an approximately 355ml container across different applications. For beverage cans, the value is 1.0; for food cans, the value is 1.5; and for aerosol containers, the value is 2.0.
  2. Container capacity (fluid volume): We used three different approaches to correct for the extra raw materials required for different sized containers/closures:
  • For a 2-piece container, we used the weight of different sized containers. This is because height changes have a relatively smaller impact on metal utilization for such containers, as the thinnest part of the container is expanded or reduced to change size, with little change to the top and bottom of the containers.
  • For draw/redraw and 3-piece containers, we simply used the volumetric capacity of the container to determine the conversion factor.
  • For our metal (vacuum) closures, we determined the correction factor directly from the weight of the closure derived from our cut edge and thickness data.

Some illustrative examples, representing some of our more significant production volumes, are provided below:

  • A single 16oz. (Ø211) aluminum beverage container would be converted into 1.33 standard "units."
  • A Ø300 x 409 steel food can would be converted into 2.685 standard "units" (1.79 due to volume times 1.5 due to the functionality).
  • A Ø57x164 aerosol can would be converted into 2.36 standard "units" (1.18 due to volume times 2.0 due to the functionality).
  • A single 8oz glass bottle container would converted into 0.67 standard “units.”

The functionality factor was validated by comparing typical weights as per example:

Container Size Brim-full Gauge Weight (g) Ratio
3-piece food can 65x112 355 0.14 body / 0.17 NEO 32.14 1.48
3-piece aerosol can 65/60/63x112 355 0.20 body / 0.30 bottom 44.86 2.07


Given the large range of containers we produce, we needed to make some simplifying assumptions. In all cases, these assumptions will not have a material effect on the outcome.

  1. For every 2-piece container, we produce one end and for every 3-piece container, we produce two ends. This is a very good approximation as it is very nearly the case, but is not exactly true in all circumstances.
  2. We have eliminated the number of unit containers sold data from our Specialty Packaging Business Unit as it represents < 5% of our total revenues. We have done this since the types and volumes of products in this business segment vary greatly, from very small ~10 milliliter containers to 20 liter containers, and because the product mix can vary dramatically from year-to-year.

In recognition that this normalization methodology is unfamiliar to those outside of Crown, we have obtained third-party validation for the approach. Unlike previous reports, this report brings our environmental reporting in line with CDP protocols. The report includes environmental data from our specialty packaging plants and our CMB Engineering equipment and tooling division.  Although the energy and emissions data from these plants is included in the report, production from these plants were not included (as stated above). Assets gained from the acquisition of Mivisa Envases, SAU and EMPAQUE in 2014 and 2015 are also included in this report.