Overview
ISO 4022:2018 specifies a laboratory method for determining the fluid permeability of permeable sintered metal materials whose porosity is deliberately continuous or interconnecting. The standard defines how to measure the pressure drop and volumetric flow rate of a test fluid through a sintered metal test piece and how to express permeability in terms of the viscous and inertia permeability coefficients (see Annex A). It excludes very long, small-diameter hollow cylindrical specimens where axial pressure drop along the bore may be significant.
Key topics and technical requirements
- Scope and definitions: clear terms for permeability, test area, thickness, pressure drop, velocity, density and apparatus correction.
- Principle: pass a fluid of known viscosity and density through the sample and measure pressure drop and volume flow rate to derive permeability coefficients.
- Test-piece preparation: remove liquids, oil and grease (use solvent extraction per ISO 2738) and dry the specimen before gas testing.
- Apparatus: two main fixtures are described:
- Guard ring test head for flat sheets - minimizes side leakage by pressurizing a surrounding guard ring; O‑ring seals and appropriate porting required.
- Jig for hollow cylindrical test pieces - clamps cylinders axially and measures outward radial flow; seals must ensure leak‑free clamping.
- Test fluids: gases are generally preferred (clean, dry); liquids only by agreement when permeability relative to a specific liquid is needed (see Annex B).
- Measurements: thickness and test area, pressure upstream/downstream, volumetric flow rate, mean temperature and fluid density/viscosity, and apparatus correction (pressure difference with no sample).
- Results: calculation of viscous and inertia permeability coefficients, reporting of mean flow rate, densities/viscosities and final permeability values. Test report requirements are specified.
Applications and who uses this standard
ISO 4022:2018 is applicable to organizations and professionals involved with:
- Powder metallurgy and sintered metal manufacturers (quality control and R&D)
- Industrial filter and porous component designers (fuel filters, oil filters, breather elements)
- Laboratory testing houses and materials characterization labs
- Component suppliers specifying permeability for hydraulic, pneumatic or filtration performance
- Researchers studying flow through porous metals and engineers validating computational models
Using ISO 4022 ensures repeatable, comparable permeability data for product specification, acceptance testing and performance verification.
Related standards
- ISO 2738 - referenced for specimen preparation: determination of density, oil content and open porosity of sintered metal materials.
- Annex A (informative) explains fluid flow models through porous materials; Annex B (informative) discusses test fluid selection.
Keywords: ISO 4022:2018, permeable sintered metal materials, fluid permeability, viscous permeability coefficient, inertia permeability coefficient, permeability testing, guard ring test head, hollow cylindrical test pieces.
