TS ISO 22095-2

TS ISO 22095-2 is the second part of the chain of custody framework for mass balance, setting out requirements and guidance for applying the mass balance model and for attributing specified characteristics to material or product flows within that model. In general technical terms, mass balance is used where physically mixed or transformed inputs cannot always be kept separate, but traceability still needs to be maintained through a structured accounting relationship across the supply chain.

How the mass balance model is positioned

This standard provides requirements and guidelines for the ISO 22095 mass balance model. As a general concept, mass balance allows defined attributes to be allocated through a process system even when the physical output is not fully separable by attribute. The key idea is not that every unit of product is physically identical in origin, but that inputs, conversions and outputs are accounted for consistently within defined system boundaries.

Topics the document addresses

• distinctions from controlled blending and book and claim models
• general requirements for organizations operating a mass balance chain of custody
• system boundaries including geography and time
• conversion factors and the rolling average percentage method
• the credit method, transparency, communication and claims

The document also helps clarify when material or product flows can be treated within a mass balance system and how declared characteristics should be communicated. In practice, such systems are widely used in complex supply chains such as agriculture, bio-based feedstocks, chemicals and converted products, where sustainability-related or other defined characteristics need to be tracked without complete physical segregation. By aligning terminology and methodological boundaries, TS ISO 22095-2 supports more consistent and comparable declarations across organizations.