CFM | Definition
Acronym for Cubic Feet per Minute
CFM is a measure of wind permeability ain fabric. 0 CFM is complete wind proofness.
Here’s an outline for the practical application of these numbers:
- 60 CMF – about what an average fleece material is rated; the wind will go right through this.
- 20 CFM – wind-resistant.
- 10 to 5 CFM – very wind-resistant; what most softshells are rated.
- 1 CFM or less – considered windproof.
- 0 CFM – completely windproof; no wind at all will get through and therefore you will experience no convective heat loss.