EU Machinery Regulation substantial modification

Article 3(16) defines substantial modification as a physical or digital change made after machinery or a related product has been placed on the market or put into service, where the change was not foreseen or planned by the manufacturer and affects safety by creating a new hazard or increasing an existing risk.

The threshold is not met just because machinery is repaired, serviced, or updated. The file should show whether the change affects compliance with the relevant essential health and safety requirements in Annex III and whether it requires one of the protective responses described in the Regulation.

The substantial-modification decision should be traceable to a risk assessment. Identify the hazards introduced by the modification, estimate and evaluate the changed risks, decide whether safeguards or information for use reduce the risks sufficiently, and verify that the modified machinery still meets the applicable Annex III EHSRs.

For machinery that is part of an assembly, document the affected boundary. Article 18 links the modifier's obligations to the affected machinery or related product, so the risk assessment should explain why any other machinery or related products in the assembly are unaffected.

If the change is a substantial modification, Article 18 treats the person carrying out it as the manufacturer for the affected machinery or related product. The modifier should then run the manufacturer obligations for that affected scope instead of closing the work as ordinary service or maintenance.

That means the modified machinery or related product needs a refreshed compliance file: applicable Annex III EHSRs, technical documentation, conformity assessment, EU declaration of conformity, CE marking, instructions, safety information, and records that explain the affected boundary.

The conformity assessment should be selected for the modified product, not copied from the original file without review. Article 25 distinguishes products outside Annex I, Annex I Part A products, and Annex I Part B products, with different routes depending on whether harmonised standards or common specifications cover all relevant EHSRs.

For Annex I Part A machinery or related products, plan for a conformity assessment route involving a notified body. For Annex I Part B, internal production control is available only where the modified product was designed and constructed according to harmonised standards or common specifications that cover all relevant EHSRs; otherwise, use the notified-body routes identified in Article 25. Products not listed in Annex I use internal production control.

The record should let a reviewer reconstruct the decision without knowing the project history. Keep both the threshold analysis and the resulting conformity work, including any conclusion that the change was not substantial.

For a substantial modification, retain the updated technical documentation and EU declaration of conformity for the required period and keep the release evidence aligned with the modified product identity. Where an assembly is only partly affected, keep the rationale for excluding unaffected machinery or related products from repeated tests or new documentation.