ASTM D7611: The Möbius Loop Versus an Equilateral Triangle

ASTM International has published a brochure (purchase required) that proudly states, "ASTM D7611 now uses a solid equilateral triangle symbol surrounding a numeral from 1 to 7 that defines the resin type used in the product's packaging." The brochure shows you the revised symbols.

 Rolande Hall

Much of the rest of the world uses arrows shaped like a triangle, as shown in ISO 11469. The table in figure 1 shows the new ASTM symbols alongside those currently in use.

The Australian Plastics and Chemical Industries Association says about the system used there:

The Plastics Identification Code continues to be one of the most successful and enduring Product Stewardship programs run by industry. The simple, effective "1 to 7" numbering system identifies the resin composition of plastic containers (and other items intended for recycling). This voluntary coding system has been a key element in the successful collection, recovery and management of used plastics in Australia.

New Zealand uses the same system. Plastics New Zealand "encourages all companies in the plastics industry to clearly label their plastic products," according to the organization's website. "This means using the number in the chasing arrows as well as the letters on all rigid and flexible packaging and all homeware, engineered, construction and agricultural plastics."


You can read about similar requirements in the UK, Ireland, and elsewhere.

I have not read a copy of the new standard itself, but I am left wondering how a committee consensus was achieved for changing the symbol from the universally adopted set of three bent arrows to a solid equilateral triangle. Perhaps there was a resurrection of the unwarranted concern over the vague similarity to the triangular Möbius loop recycling symbol.

Manufacturers around the world have voluntarily labelled their plastic products with the three bent arrows so that the materials used can be easily identified for reuse and recycling. Think of the introductory cost of a new symbol. Every mould used worldwide for marking plastic products and packaging would need modification.

If some manufacturers start to use this newly revised ASTM standard, only time will tell how well it will be understood and what problems a lack of understanding will cause. Meanwhile, the medical device industry might be well advised to ignore this new symbol. If it were to be used on our products at this time, MDMs would probably need to explain its meaning in the information supplied by the manufacturer with the product.

What do you think? Comment below, and take this week's poll to tell us what your company will do as a result of the ASTM D7611 revision.

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Rolande Hall, FIMMM Pkg Prof

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