Quick answer: Layer FR for winter in three parts: a base layer of cotton, wool or FR knit, an FR mid layer (hoodie, quarter-zip or insulated vest), and an FR outer layer (insulated coat or bib overalls). Everything worn over your FR must be FR too, and nothing meltable goes next to your skin. Arc ratings of separate garments can't be added together.
Winter FR Layering by Temperature
| Conditions | Base layer | Mid layer | Outer layer | Extras |
|---|---|---|---|---|
| Cool mornings, 40–55°F | Cotton or FR tee | FR work shirt | FR hoodie or quarter-zip | None |
| Cold, 20–40°F | FR base layer, long sleeve | FR shirt plus FR hoodie or insulated vest | FR duck or canvas coat | FR beanie or neck cover |
| Hard cold, below 20°F or high wind | FR base layer top | FR shirt plus FR fleece or hoodie | Insulated FR coat and insulated FR bibs | FR balaclava, warm glove liners |
Three Rules for Layering FR
- The outside layer has to be FR. A regular coat or hoodie over FR can catch and keep burning. NFPA 70E requires outer layers worn over arc-rated clothing, like jackets and rainwear, to be arc-rated too.
- Nothing meltable next to skin. Polyester, nylon, polypropylene, acetate and spandex can melt into a burn. Cotton and wool underlayers are allowed under FR; FR knit base layers are better.
- Don't add up ratings. A CAT 2 shirt under a CAT 2 jacket is not CAT 4. Only a layered system tested together carries a combined arc rating.
What Crews Tell Us
Go up one size on a hoodie or coat that goes over a heavy shirt, not more; loose fabric hangs up on equipment. Some sites ban hoods, so check before you buy a hoodie and switch to a quarter-zip or FR balaclava if yours does. Cover your neck: wind down the collar is what makes a cold day on the lease miserable.
Winter FR Layering FAQ
Can I wear thermal underwear under FR clothing?
Cotton or wool thermals, yes. Polyester or polypropylene thermals, no: they can melt under heat that passes through the FR layer. An FR base layer is the safest choice.
Can I wear a regular Carhartt coat over my FR?
No. Only FR coats belong on top of FR. Carhartt makes FR versions, like the FR Full Swing Quick Duck Coat.
Do layers raise my arc rating?
Layers usually protect better than one garment, but the combined rating only counts if the layer system was tested together. Wear what your hazard assessment calls for as your outer FR. See our FR rating guide and FR vs AR clothing.
Are insulated FR bibs worth it?
For all-day work below freezing, yes. Bibs keep your lower back covered when you bend, where a coat rides up. See Carhartt FR Quick Duck lined bibs.
Can my company cover winter FR?
Yes. Our company FR programs can add hoodies, coats and bibs to each worker's allowance.
Winter FR Gear
FR hoodies and sweatshirts, FR jackets, vests and bibs, FR shirts, FR jeans and pants, FR balaclava, men's FR and women's FR. Try layers on at our store, 3000 W 3rd St, Elk City, OK.