Convert Frazier (cfm/ft²) to Gurley Seconds
Frazier (cfm/ft²) and Gurley seconds are inversely related: s/100 mL = 3.126991894 ÷ cfm/ft² @125 Pa, so 5 cfm/ft² @125 Pa = 0.6253983788 s/100 mL.
Also searched as Frazier to Gurley, cfm/ft2 to Gurley seconds and air permeability to Gurley.
1 cfm/ft² @125 Pa = 3.126991894 s/100 mL
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk Frazier to Gurley second converter to paste a column from Excel.
How to Convert Frazier (cfm/ft²) to Gurley Second
- s/100 mL = 3.126991894 ÷ cfm/ft² @125 Pa
- cfm/ft² @125 Pa = 3.126991894 ÷ s/100 mL
- Example: convert 5 cfm/ft² @125 Pa to s/100 mL: 3.126991894 ÷ 5 = 0.6253983788 s/100 mL
Reference conditions. cfm/ft² @125 Pa: Measured at 125 Pa (0.5 inH₂O) as in ASTM D737; assumes flow proportional to pressure difference. s/100 mL: 100 mL through 6.45 cm² (1 in²) at 1.22 kPa (TAPPI T 460, ISO 5636-5); assumes air flow proportional to pressure difference.
Formula
s/100 mL = 3.126991893836 ÷ cfm/ft² @125 Pa
Derivation from SI units:
- 1 cfm/ft² = 0.00508 m/s; at 125 Pa that is 0.00508 ÷ 125 = 4.064 × 10⁻⁵ m/(Pa·s) = 40.64 µm/(Pa·s).
- Gurley t = seconds for 100 mL of air through 6.45 cm² at 1.22 kPa, so P = 100 mL ÷ (6.45 cm² × 1.22 kPa × t) ≈ 127.08 ÷ t µm/(Pa·s).
- Solving for s/100 mL: s/100 mL = 3.126991893836 ÷ cfm/ft² @125 Pa (a higher cfm/ft² @125 Pa means a lower s/100 mL)
One unit is a measured value, so the factor is approximate. Frazier (cfm/ft²) definition: Frazier (cfm/ft² at 125 Pa); Gurley Second definition: Gurley second.
Worked examples
- A filter medium of 5 cfm/ft² @125 Pa is about 0.6253983788 s/100 mL.
3.126991894 ÷ 5 = 0.6253983788 s/100 mL - A dense fabric of 0.5 cfm/ft² @125 Pa is about 6.253983788 s/100 mL.
3.126991894 ÷ 0.5 = 6.253983788 s/100 mL
Frazier (cfm/ft²) to Gurley Second conversion table
| Frazier (cfm/ft²) (cfm/ft² @125 Pa) | Gurley Seconds (s/100 mL) |
|---|---|
| 0.5 cfm/ft² @125 Pa | 6.253983788 s/100 mL |
| 1 cfm/ft² @125 Pa | 3.126991894 s/100 mL |
| 2 cfm/ft² @125 Pa | 1.563495947 s/100 mL |
| 5 cfm/ft² @125 Pa | 0.6253983788 s/100 mL |
| 10 cfm/ft² @125 Pa | 0.3126991894 s/100 mL |
| 20 cfm/ft² @125 Pa | 0.1563495947 s/100 mL |
| 50 cfm/ft² @125 Pa | 0.06253983788 s/100 mL |
| 100 cfm/ft² @125 Pa | 0.03126991894 s/100 mL |
| 200 cfm/ft² @125 Pa | 0.01563495947 s/100 mL |
| 500 cfm/ft² @125 Pa | 0.006253983788 s/100 mL |
Where it's used
Frazier air-permeability values in cfm/ft² are converted to Gurley seconds to compare filter media and fabrics with paper specifications. Gurley ≈ 3.127 ÷ Frazier.
Frazier (cfm/ft²) to other air permeance units
| Conversion | 1 cfm/ft² @125 Pa equals |
|---|---|
| Frazier to Gurley second | 3.126991894 s/100 mL |
| Frazier to micrometre per pascal second | 40.64 µm/(Pa·s) |
| Frazier to Bendtsen | 3584.448 mL/min (Bendtsen) |
| Frazier to millimetre per second at 100 Pa | 4.064 mm/s @100 Pa |
| Frazier to millimetre per second at 200 Pa | 8.128 mm/s @200 Pa |
Frequently asked questions
How many Gurley seconds is 1 cfm/ft²?
About 3.126991894 s/100 mL; denser materials read more seconds.
What is the formula for Frazier (cfm/ft² at 125 Pa) to Gurley seconds?
s/100 mL = 3.126991894 ÷ cfm/ft² @125 Pa. The two systems are inversely related, so divide the constant by the value; do not multiply. For example, 3.126991894 ÷ 5 = 0.6253983788 s/100 mL.
Why does a higher cfm/ft² @125 Pa give a lower s/100 mL?
Gurley Seconds counts length per unit mass (an indirect system), while Frazier (cfm/ft² at 125 Pa) counts mass per unit length (a direct system). A finer yarn has a higher indirect number and a lower direct number.
Is the cfm/ft² @125 Pa to s/100 mL conversion exact?
Not exactly. The Frazier (cfm/ft² at 125 Pa) is a measured value (Measured at 125 Pa (0.5 inH₂O) as in ASTM D737; assumes flow proportional to pressure difference.). The Gurley second is a measured value (100 mL through 6.45 cm² (1 in²) at 1.22 kPa (TAPPI T 460, ISO 5636-5); assumes air flow proportional to pressure difference.). Results are good to about 5 significant figures.
Sources
- ASTM D737 Standard Test Method for Air Permeability of Textile Fabrics, ASTM International .
- ISO 5636 Paper and board — Determination of air permeance (Part 3: Bendtsen method; Part 5: Gurley method), International Organization for Standardization , Part 5, Gurley method.
- TAPPI T 460 om-21 Air resistance of paper (Gurley method), TAPPI .
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Convert Frazier (cfm/ft²) to Gurley Seconds. Retrieved October 29, 2026, from https://scientificconverters.com/air-permeance/frazier-to-gurley-seconds/
IEEE
Scientific Converters, "Convert Frazier (cfm/ft²) to Gurley Seconds," scientificconverters.com. Accessed: Oct. 29, 2026. [Online]. Available: https://scientificconverters.com/air-permeance/frazier-to-gurley-seconds/