Almost any printed component destined for the inside of a train carriage, aircraft cabin, naval vessel or armoured vehicle interior must meet specific flame, smoke and toxicity requirements. The relevant standards (UL94, FAR 25.853, EN 45545, ISO 5658, AS 7240) are demanding and unforgiving, and standard FDM filaments do not meet them.
Flame-retardant FDM filaments are a deliberate sub-category, formulated either with intrinsic flame-retardant chemistry or with additives that achieve the required performance. Material selection in this space is unforgiving. The wrong material in the wrong application is not just a performance problem; it is a regulatory and safety failure that nobody wants on their record.
UL94 V-0: the common reference
UL94 V-0 is the most commonly cited FR rating in industrial AM. It requires that a vertical specimen self-extinguish within 10 seconds after a flame source is removed, with no flaming drips that ignite a cotton indicator below. V-0 is a baseline, not a complete specification. Application-specific standards typically include V-0 plus additional requirements for smoke density, heat release rate, and toxic gas emission. Confirm the full applicable specification before assuming V-0 is sufficient for your platform.
Sample thickness matters too. UL94 is a small-coupon test; thicker sections may behave differently in a fire scenario, and very thin sections sometimes fail tests that the bulk material passes comfortably. Specify thickness in the project documentation, not just the material grade.
A V-0 logo on a datasheet is the start of the conversation, not the end of it.
Global3D materials engineering
FR filament categories at a glance
The current FR-rated FDM material landscape, available in part through OzFDM, looks broadly like this. Match the material to the temperature envelope and the structural demand of your part, not the other way around.
V-0 PETG: general transport interior, low temperature service
V-0 ABS: interior duty with slight temperature gain over PETG
V-0 PA: structural FR applications, engineering thermoplastic envelope
PEI (Ultem): aerospace and high-performance, inherently flame retardant
PEEK: extreme environments, premium cost, premium performance
The certification reality
A V-0 rating on a material datasheet is not a certification of your printed part. Real-world certification requires testing the actual production parts, in their as-printed condition, against the applicable standard. Some FR additives are diminished by print processing; some print parameters affect FR performance more than the datasheet suggests. For applications that require certification, particularly rail and aviation, the path involves selecting a certified grade, printing to a documented recipe, and witness-testing production batches under a controlled change regime.
Document the recipe alongside the certification artefacts. Nozzle temperature, bed temperature, layer height, infill pattern and density, perimeter count and post-processing steps all influence how a part behaves in the test rig. Recipes change quietly when machines age, so re-witness any locked configuration at sensible intervals.
Key takeaways
Standard FDM filaments will not pass rail, aviation or naval interior tests
V-0 PETG and V-0 ABS cover most general transport interior work
PEI and PEEK are the inherent-FR options for the hardest envelopes
Always certify the part as-printed, not just the material