Quick answer: Layer FR for winter in three parts: a cotton, wool or FR base layer, an FR mid layer (hoodie or insulated vest), and an FR coat or bibs on top. Anything worn over FR must be FR, nothing meltable goes next to skin, and arc ratings of separate garments don't add up.
| Temp | Base | Mid | Outer |
|---|---|---|---|
| 40–55°F | Cotton or FR tee | FR work shirt | FR hoodie |
| 20–40°F | FR base layer | FR shirt + FR vest | FR duck coat |
| Below 20°F | FR base layer | FR shirt + FR fleece | Insulated FR coat, bibs, balaclava |
FAQ
Can I wear thermals under FR?
Cotton or wool, yes. Polyester or polypropylene, no: they can melt. An FR base layer is safest.
Can I wear a regular coat over FR?
No. NFPA 70E requires outer layers over arc-rated clothing to be arc-rated. Try the Carhartt FR Quick Duck Coat.
Do layers raise my arc rating?
Only a layer system tested together carries a combined rating. See the FR rating guide.
Hoodie or quarter-zip?
Some sites ban hoods. Go up one size, not more, to layer.