Flame-retardant (FST) 3D printing materials are formulated to meet fire, smoke, and toxicity standards required in aircraft interiors, rail, and public transit. They self-extinguish, produce minimal smoke, and release low toxicity when exposed to flame. The leading options are ULTEM (PEI), FR nylon, and FR polycarbonate. Here is where each applies.
Key Takeaways
- FST = Flame, Smoke, Toxicity — the safety triad for transit interiors.
- Relevant standards include UL 94 V-0 and aerospace FAR 25.853.
- Top materials: ULTEM 9085 (PEI), FR nylon, FR polycarbonate.
- Used in aircraft cabins, rail interiors, and electrical enclosures.
- Certification documentation matters — work with a quality-certified bureau.
What do FST ratings mean?
A flame-retardant material self-extinguishes rather than sustaining a flame (e.g., UL 94 V-0). Smoke and toxicity ratings limit how much smoke and how many toxic gases a burning part releases — critical in enclosed cabins where evacuation time depends on visibility and air quality. Aerospace adds FAR 25.853 burn-test requirements for cabin materials.
Which FST material should you use?
| Material | Strength | Use case |
|---|---|---|
| ULTEM 9085 (PEI) | Aerospace-grade FST | Aircraft cabin parts, ducting |
| FR nylon | Durable, V-0 | Rail/transit functional parts |
| FR polycarbonate | Tough, transparent options | Electrical enclosures, covers |
Where are FST parts required?
Aircraft interiors, train and metro cabins, bus interiors, and electrical enclosures where fire safety codes apply. For aerospace specifically, ULTEM 9085 is the workhorse — see ULTEM 9085 vs 1010 and our aerospace 3D printing guide.
Frequently Asked Questions
Can you provide burn-test documentation?
We work with certified material grades and can advise on the documentation your application requires under ISO 9001 quality processes.
Is FR nylon as strong as standard nylon?
Close, with flame-retardant additives; we''ll match the grade to your load and safety needs. Get a quote.