V0 Flame Retardant Filaments: where they are mandatory and how to choose them
, by Strato3D, 5 min reading time
The V0 (UL 94) class is the highest self-extinguishing standard for 3D printing: the material stops burning within 10 seconds. Find out where it is mandatory, which materials to choose, and how to purchase them directly from Strato3D.
If you've ever tried to print a component intended for an electrical panel, an industrial drone, or a solar panel module, you've probably encountered a request like: "it must be V0". This is not a client's whim: in many production and regulatory contexts, the V0 flame retardant requirement according to the UL 94 standard is simply mandatory.
In this technical guide, we will answer all these questions, with precise data, real application examples, and a comparison of the main available materials.
What is UL 94 classification and what does V0 mean?
UL 94 is the international standard issued by Underwriters Laboratories to evaluate the flammability of plastic materials. For 3D printing, the most relevant classes are:
| UL 94 Class | Flame Behavior | Typical Applications |
|---|---|---|
| HB | Slow burning; not self-extinguishing | Non-critical prototypes |
| V2 | Self-extinguishing within 30 s; may drip | Appliances, common components |
| V1 | Self-extinguishing within 30 s; no dripping | Connectors, electrical enclosures |
| V0 | Self-extinguishing within 10 s; no dripping; no igniting particles | Aerospace, energy, industrial safety |
The V0 class is the most restrictive: the sample must stop burning within 10 seconds after each of the two flame applications, without releasing drips or glowing particles.
Where V0 filaments are mandatory by law or standard
1. Electronics and low voltage (LVD Directive 2014/35/EU)
The European Low Voltage Directive requires that components exposed to the risk of overheating or electrical arcing be made of materials that limit fire propagation. For enclosures, fuse holders, and mounting plates, the minimum class recommended by IEC 62368-1 is V1, but many manufacturers specify V0 for added safety.
2. Aerospace and defense (FAR 25.853)
For non-structural components on board aircraft, FAA/EASA regulations require compliance with FAR 25.853 testing. In practice, manufacturers printing 3D parts for aerospace use aim for materials with V0 certification or higher (5VA/5VB).
3. Construction and systems (EN 13501)
For materials installed in buildings, EN 13501-1 defines classes from A1 (non-combustible) to F. For applications in escape routes or technical rooms, the specification often requires V0 materials. The Italian Ministerial Decree of August 3, 2015 (Italian Fire Prevention Code) implicitly refers to these classes.
4. Electric mobility and energy storage (IEC 62133)
Battery packs for electric vehicles, e-bikes, and UPS systems require that casings and separators resist flame propagation in the event of thermal runaway. V0 is the practical requirement for any printed enclosure near lithium cells.
5. Railway (EN 45545-2)
The EN 45545-2 standard classifies materials into categories HL1, HL2, HL3. For interior finishes in HL2 and HL3 classes, polymeric materials must pass LOI and smoke tests that practically correspond to or exceed V0.
Which materials offer V0 performance in FDM/FFF printing
| Material | UL 94 Class | HDT Temp. (°C) | Notes |
|---|---|---|---|
| PA6-FR / PA12-FR (Flame-retardant Nylon) | V0 @ 1.6 mm | 150–180 | Excellent mechanical strength; dry before use |
| PC-FR (Flame-retardant Polycarbonate) | V0 @ 1.6 mm | 110–130 | High rigidity; prints at 260–280°C |
| ABS-FR (halogen-free) | V0 @ 1.6 mm | 85–100 | Reduced warping compared to standard ABS |
| PETG-FR | V0 @ 1.6 mm (some formulations) | 70–80 | Excellent for electronic covers |
| PEI / ULTEM (AM9085) | V0 (+ 5VA >3 mm) | 170–220 | Aerospace standard; hotend >300°C |
| PEEK-FR | V0 @ 3 mm | >250 | Extreme performance; high price |
How to optimize printing V0 flame-retardant filaments
- Hotend temperature: PA-FR and PC-FR require 260–290°C; use all-metal hotends.
- Mandatory drying: PA-FR absorbs up to 3% humidity; dry at 80°C for 6–8 hours before use.
- Heated bed: PC-FR requires 90–110°C; ABS-FR works at 70–90°C.
- Enclosed chamber: for PC-FR and PA-FR drastically reduces warping.
- Reduced cooling: fan at 20–40% for PA; almost off for PC.
Real application cases
| Application | Sector | Standard | Recommended Material |
|---|---|---|---|
| Relay and fuse enclosure | Industrial electronics | IEC 62368-1 | PC-FR or PA6-FR |
| Aircraft wiring clip | Aerospace | FAR 25.853 | PEI/ULTEM or PA12-FR |
| LV junction boxes | Plant engineering | CEI 23-48 | ABS-FR or PC-FR |
| E-bike battery pack cover | Electric mobility | IEC 62133 | PC-FR or PETG-FR V0 |
| Train cabin panels | Railway | EN 45545-2 | PC-FR or PEI |
How to verify if a filament is truly V0
- Ask for the complete UL 94 report with tested thickness, date, and laboratory — not just the technical data sheet.
- Verify that at least 5 samples were tested (UL 94 protocol requirement).
- Check the LOI (Limiting Oxygen Index): values >28% indicate good flame resistance.
- Ask if the material is halogen-free: brominated retardants are prohibited in many ROHS applications.
- Beware of bright colors: they can dilute the concentration of the flame retardant additive.
How to purchase V0 flame-retardant filaments from Strato3D
⚠️ We only sell special technical filaments — V0 flame-retardant, food contact, medical, PEEK, PEI — directly.
This is because every project has different needs: thicknesses to certify, variable quantities, technical data sheets to match the CE file. We evaluate the right material for your specific application together.
FAQ
Do V0 filaments cost much more?
Yes, on average 30–60% more than their standard counterparts. The cost is justified when the component needs to pass regulatory audits: redoing it in the wrong material after a failed test costs much more.
Can I print V0 filaments with any printer?
It depends. ABS-FR and PETG-FR are compatible with most FDM printers with all-metal hotends. PC-FR and PA-FR require 260–290°C and an enclosed chamber. PEI/ULTEM requires a specialized hotend >300°C.
Is an object printed in V0 flame-retardant in every situation?
No. The classification refers to flat samples in standardized tests. For certified applications, the finished part in its real geometry must be tested separately.
Does the print parameter influence the V0 classification?
Yes. Low infill or excessive cooling create voids that alter flame behavior. For certified applications, print with >40% infill and conservative parameters.
Does Strato3D offer third-party printing with V0 filaments?
Yes. Contact us to evaluate geometry, material, and quantity together.
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