Convert Micrometres per Pascal Second to Gurley Seconds
Micrometres per Pascal Second and Gurley seconds are inversely related: s/100 mL = 127.0809506 ÷ µm/(Pa·s), so 1 µm/(Pa·s) = 127.0809506 s/100 mL.
Also searched as micrometres per pascal second to s/100 mL, micrometres per pascal second in s/100 mL, micrometres per pascal second into Gurley seconds, micrometre per pascal second to s/100 mL, micrometre per pascal second in Gurley seconds, micrometre per pascal second into Gurley second, micrometre per pascal second to Gurley second, micrometre per pascal second to Gurley seconds converter and micrometers per pascal second to Gurley seconds.
1 µm/(Pa·s) = 127.0809506 s/100 mL
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk micrometre per pascal second to Gurley second converter to paste a column from Excel.
How to Convert Micrometre per Pascal Second to Gurley Second
- s/100 mL = 127.0809506 ÷ µm/(Pa·s)
- µm/(Pa·s) = 127.0809506 ÷ s/100 mL
- Example: convert 1 µm/(Pa·s) to s/100 mL: 127.0809506 ÷ 1 = 127.0809506 s/100 mL
Reference conditions. 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 = 127.0809505655 ÷ µm/(Pa·s)
Derivation from SI units:
- Air permeance P = flow per unit area per unit pressure difference = 10⁻⁶ m/(Pa·s) (ISO 5636-1).
- 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 = 127.0809505655 ÷ µm/(Pa·s) (a higher µm/(Pa·s) means a lower s/100 mL)
One unit is a measured value, so the factor is approximate. Micrometre per Pascal Second definition: micrometre per pascal second; Gurley Second definition: Gurley second.
Worked examples
- A paper of 1 µm/(Pa·s) reads 127.0809506 s/100 mL.
127.0809506 ÷ 1 = 127.0809506 s/100 mL - An open sheet of 50 µm/(Pa·s) reads 2.541619011 s/100 mL.
127.0809506 ÷ 50 = 2.541619011 s/100 mL
Micrometre per Pascal Second to Gurley Second conversion table
| Micrometres per Pascal Second (µm/(Pa·s)) | Gurley Seconds (s/100 mL) |
|---|---|
| 0.01 µm/(Pa·s) | 12708.09506 s/100 mL |
| 0.1 µm/(Pa·s) | 1270.809506 s/100 mL |
| 0.5 µm/(Pa·s) | 254.1619011 s/100 mL |
| 1 µm/(Pa·s) | 127.0809506 s/100 mL |
| 2 µm/(Pa·s) | 63.54047528 s/100 mL |
| 5 µm/(Pa·s) | 25.41619011 s/100 mL |
| 10 µm/(Pa·s) | 12.70809506 s/100 mL |
| 20 µm/(Pa·s) | 6.354047528 s/100 mL |
| 50 µm/(Pa·s) | 2.541619011 s/100 mL |
| 100 µm/(Pa·s) | 1.270809506 s/100 mL |
Where it's used
Permeance values in µm/(Pa·s) from specifications and ISO 5636 reports are converted to Gurley seconds for mills and customers that test with a Gurley densometer. Divide 127.08 by the permeance.
Micrometre per Pascal Second to other air permeance units
| Conversion | 1 µm/(Pa·s) equals |
|---|---|
| micrometre per pascal second to Gurley second | 127.0809506 s/100 mL |
| micrometre per pascal second to Frazier | 0.02460629921 cfm/ft² @125 Pa |
| micrometre per pascal second to Bendtsen | 88.2 mL/min (Bendtsen) |
| micrometre per pascal second to millimetre per second at 100 Pa | 0.1 mm/s @100 Pa |
| micrometre per pascal second to millimetre per second at 200 Pa | 0.2 mm/s @200 Pa |
Frequently asked questions
What Gurley is 1 µm/(Pa·s)?
127.0809506 s/100 mL; the Gurley method covers roughly 0.1 to 100 µm/(Pa·s).
What is the formula for micrometres per pascal second to Gurley seconds?
s/100 mL = 127.0809506 ÷ µm/(Pa·s). The two systems are inversely related, so divide the constant by the value; do not multiply. For example, 127.0809506 ÷ 1 = 127.0809506 s/100 mL.
Why does a higher µm/(Pa·s) give a lower s/100 mL?
Gurley Seconds counts length per unit mass (an indirect system), while micrometres per pascal second counts mass per unit length (a direct system). A finer yarn has a higher indirect number and a lower direct number.
Is the µm/(Pa·s) to s/100 mL conversion exact?
Not exactly. 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
- ISO 5636 Paper and board — Determination of air permeance (Part 3: Bendtsen method; Part 5: Gurley method), International Organization for Standardization , Part 1, definition of air permeance.
- 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 Micrometres per Pascal Second to Gurley Seconds. Retrieved October 29, 2026, from https://scientificconverters.com/air-permeance/micrometers-per-pascal-second-to-gurley-seconds/
IEEE
Scientific Converters, "Convert Micrometres per Pascal Second to Gurley Seconds," scientificconverters.com. Accessed: Oct. 29, 2026. [Online]. Available: https://scientificconverters.com/air-permeance/micrometers-per-pascal-second-to-gurley-seconds/