Breathability & Waterproof Rating Calculator

For ePTFE / PU / non-fluorinated waterproof breathable vent membranes · free tool by Mimoyin Technology

Breathability → Waterproof
Waterproof → Breathability
Breathability is measured as total air flow through a Ø10 mm orifice at 7 kPa differential pressure — the manufacturer's standard test method.

Material comparison (measured data)

PropertyePTFEPU filmNon-fluorinated film
Max waterproof rating2 – 50 m1 – 2 m1 – 2 m
Breathability range*200 – 12,000 ml/minmid bandnarrow band
Sound attenuation≤ 1 dB0.5 – 1.5 dB6 – 10 dB
Continuous temp. range-40 ~ +260 °Clower ceiling**-40 ~ +120 °C
Typical useoutdoor / automotive / acoustic ventsconsumer water-repellentcost-sensitive general
* Breathability measured @ Ø10 mm orifice @ 7 kPa. ** PU film upper temperature limit is lower than ePTFE in factory testing and does not reach +260 °C.

How to read the trade-off

For ePTFE, breathability and waterproofing move in opposite directions:

Breathability bandEst. waterproofBest fit
Low 200 – 1,000 ml/min50 – 30 mdeep-water / high-IP sealed enclosures
Mid 1,000 – 5,000 ml/min30 – 2 mautomotive sensors, outdoor electronics
High 5,000 – 12,000 ml/min10 – 1 macoustic vents, wearables needing max airflow
Custom per spec: Mimoyin supplies ePTFE membrane by customer drawing / requirement — we do not sell fixed SKU parts. Final breathability and waterproof values depend on pore structure, thickness and lamination, and must be confirmed by sampling and testing against your enclosure.

Frequently asked questions

What does "ml/min @ Ø10 mm orifice @ 7 kPa" mean?

It is the standard breathability test: total air flow (ml per minute) passing through a 10 mm diameter orifice under a 7 kPa pressure differential. Higher ml/min = more air-permeable = "breathable".

Can I convert breathability directly to an IP rating?

Indirectly. Breathability sets the waterproof ceiling (see trade-off table). Map the resulting water-column height to IP67 (1 m / 30 min) or IP68 (continuous immersion) per IEC 60529. The calculator gives the water-column estimate; IP grading also depends on enclosure sealing.

Why is ePTFE better than PU or non-fluorinated film?

ePTFE reaches 2–50 m waterproof with ≤1 dB sound loss and -40~+260 °C range, while PU / non-fluorinated films are limited to ~1–2 m waterproof and narrower temperature or acoustic windows.

Do you sell standard membrane parts?

No. Mimoyin is an ePTFE membrane material supplier; we match film to your drawing and test it (custom per spec). Contact us with your enclosure requirements.