From December NZ Manufacturer

-Troy Coyle,CEO,HERA

Across the infrastructure and construction sectors, material passports are emerging as a promising tool for enabling circularity. They’re often described as a “bank of materials,” and I understand why (in fact HERA even describes them this way).

After all, they catalogue the materials embedded within a building so they can be withdrawn at the end of life and reused elsewhere.

The more I’ve worked with the concept, the more I’ve found that the banking analogy falls short. In fact, my own conceptualisation has shifted quite significantly: I now see material passports as closer in spirit to a donor organ registry than to a passport or financial ledger.

This is because for reuse to work in construction, it’s not enough to know what materials exist. We also need to understand which components are actually compatible with which future projects- this makes it much like donors and recipients in medical systems.

This compatibility challenge is where I believe the next evolution of thinking must occur.

 Why the “Material Bank” analogy isn’t enough

Material passports are often framed as banks because they identify valuable materials for future “withdrawal.” The logic is sound: buildings act as repositories of steel, timber, concrete elements, glass, fixtures, and systems that shouldn’t be lost to landfill or downcycling.

However, in a bank, all currency of the same denomination is interchangeable. One dollar equals another dollar. Construction materials are not interchangeable in this way.

Two steel beams of the same nominal specification may have vastly different histories, including different loading conditions, different environments, different coatings, different compliance requirements.

Their future use potential can vary dramatically.

This is where the financial metaphor starts to break down for me.

 Why I think the organ donor registry analogy fits better

In my view, material passports need to function more like a donor registry. That is, a system not just for recording available assets, but for matching them intelligently with viable recipients.

Consider how organ donation works:

• not every organ is suitable for every recipient;
• condition, history, compatibility and timing all matter; and
• A central system is required to evaluate, match, and facilitate exchanges.

Construction has similar dynamics.

A component removed from one building cannot simply be “withdrawn” from the material bank and dropped into another project. It needs to be compatible: structurally, dimensionally, chemically, and in terms of code compliance.

The receiving building must have the right “physiology” for the component to integrate safely and effectively.

Seeing material passports through this lens highlights why our current framing is incomplete.

Compatibility: The missing piece in current circularity thinking

In my view, an over-focus on simply calatologuing materials does not go far enough. If we truly want reuse at scale, we need systems that can evaluate:

• load history and fatigue;
• mechanical and chemical properties;
• end-of-life condition and deterioration;
• certifications and inspection histories;
• environmental exposure;
• dimensional fit and assembly logic;
• compliance with contemporary codes and performance standards; AND
• Ease of disassembly and compatibility with the new design.

This is not a simple “what materials are in this building?” exercise. It’s a “which materials are suitable for which buildings?” challenge.

That’s donor registry territory.

It also puts a focus on ensuring compatibility through design.

 Designing buildings as future donors and preparing buildings to be donees

If we adopt the donor analogy, our approach to design also changes.

Buildings should be created in a way that maximises the future “donatability” of their materials. That means:

• designing for disassembly;
• standardising elements where practical;
• documenting load paths and structural utilisation;
• creating digital twins that track changes across life; and
• specifying materials with reuse pathways already in mind.

In addition, the recipient buildings would need to be specifically designed and prepared to receive donated elements. This perspective reinforces that circularity isn’t just an end-of-life task it’s a design philosophy.

 Why this Mmtters for infrastructure policy

For infrastructure, where material volumes and lifespans are significant, this shift in thinking could reshape procurement and regulation. I believe we will eventually see:

• mandated material passports for public assets;
• national or trans-Tasman material matching registries;
• certified testing protocols for reused components; and
• incentives for incorporating donor materials in new builds.

All of these require us to think beyond banking models and toward compatibility-based models.

 Reframing the future of material passports

In articulating my own view, I’ve found the organ donor registry analogy helps reveal what’s missing in our current material passport frameworks: the recognition that reuse requires more than information. It requires compatibility.

It requires matching and preparation. It requires systems that ensure the right components find the right projects at the right time.

Material passports are a critical foundation but without compatibility-matching, they remain incomplete.

If the construction and infrastructure is serious about circularity, resilience and carbon reduction, I believe it’s time we stop thinking of material passports as mere banks, and start seeing them as part of a sophisticated donor ecosystem.

A system that ensures every viable material has the chance for a meaningful second life.