05 Aug Misconceptions about F1 Ratings for Outdoor Plastics Applications
Posted at 09:54h
in News Article
The F1 rating, as defined by UL 746C, is often misunderstood. It’s an important benchmark for plastics used in outdoor environments, but not all F1-rated materials are created equal. Just because a grade carries a listing doesn’t mean it will succeed in your application.
Let’s clear up a few common misconceptions:
- Misconception #1: “F1 means it’ll last 10+ years outdoors.”
- Reality: F1-rated materials are tested using accelerated weathering methods (like Xenon Arc or UV Fluorescent) over ~1,000 hours—roughly simulating 1 to 3 years of outdoor exposure depending on climate and material chemistry. Long-term performance still relies on the specific formulation, stabilizers, and part design. PART AND APPLICATION-SPECIFIC TESTING IS ALWAYS RECOMMENDED.
- Misconception #2: “All grades of PC, or PC blends, are F1.”
- Reality: Only specific, tested, and UL-certified grades hold an F1 rating. Just because a material family (e.g., PC) is “outdoor capable” doesn’t mean every grade within it includes a UL listing.
- Misconception #3: “F1 is all I need to worry about.”
- Reality: F1 doesn’t guarantee performance. It indicates basic durability in both UV and moisture conditions, but temperature extremes, chemicals, and mechanical abuse still need to be considered.
What about F2?
F2 means the material has passed testing for either UV or moisture, but not both. It’s more limited in outdoor use and should only be considered when one exposure type is minimal or controlled.
Bottom Line:
- F1 = dual-tested for UV + water exposure
- F2 = only one of those exposures
When specifying materials for outdoor use, don’t just rely on a box checked in a datasheet. Ask: what was tested, how long, and under what conditions? Reach out to PolySource with questions.