Overview
ISO 5636-5:2013 specifies the Gurley method for determining the air permeance of paper and board using a Gurley air-resistance tester (Gurley apparatus). The standard applies to papers and boards with air permeances in the medium range (0.1 µm/(Pa·s) to 100 µm/(Pa·s)) and is unsuitable for rough-surfaced materials that cannot be securely clamped. ISO 5636-5:2013 also defines how to report air resistance (Gurley) and includes calibration and precision guidance.
Key topics and requirements
- Scope and applicability: Designed for medium-range air permeance testing of paper and board; not suitable for highly rough surfaces.
- Test principle: Air pressure produced by a weighted inner cylinder forces air through a test piece; the time for a set volume of air to pass is measured.
- Apparatus: Gurley apparatus with inner/outer cylinders, clamping plates and a rubber gasket defining the measurement area. Sealing fluid and timer/stopwatch are required.
- Measurement area and volume: The method uses a nominal 100 ml air volume per measurement (timed) and a standardized measurement area (gasket-defined).
- Test pieces and conditioning: Samples prepared and conditioned per ISO 186 (sampling) and ISO 187 (conditioning). Minimum of 10 test pieces (both sides) is required for typical reporting.
- Clamping and leakage control: Controlled clamping force is recommended (nominally 180 ± 30 N) to avoid surface leakage and improve repeatability.
- Procedure and timing: Time the passage of 100 ml (typically by timing two consecutive 50 ml graduations) to 0.1 s accuracy; avoid vibration during testing.
- Calculation and reporting: Air permeance P is calculated from the measured time (standard formula in the standard) and reported to three significant figures; air resistance reported in seconds (Gurley) to two significant figures.
- Calibration and precision: Calibrate per manufacturer instructions or Annex A of the standard; Annex C provides informative precision data.
Applications and who uses it
- Quality control and specification testing in paper mills and converting operations.
- R&D and product development for printing papers, packaging papers, and functional papers where breathability or barrier properties matter.
- Suppliers and purchasers requiring a standardized test for air permeance/air resistance comparisons.
- Laboratories performing routine compliance testing or comparative performance evaluation for ink absorption, coating, and filtration candidate materials.
Related standards
- ISO 5636 (other parts): Part 3 (Bendtsen method), Part 4 (Sheffield method), Part 6 (Oken method - in preparation).
- Normative references cited: ISO 186 (sampling), ISO 187 (conditioning), ISO 48 (rubber hardness) and others.
Keywords: ISO 5636-5, Gurley method, air permeance, Gurley apparatus, air resistance, paper and board testing, ISO 187, ISO 186.