For cylindrical filter cartridges, ISO 3724 defines the specification designations and tolerances. The sections below describe the scope, the properties it leaves to companion standards, and the equivalent designations across standards bodies.
ISO 3724 — Scope
ISO 3724 specifies the designation system, dimensions and tolerances of cylindrical filter cartridges — mesh count or nominal opening, wire diameter and the permissible aperture deviations. Alloy chemistry, mechanical testing and delivery condition are governed by separate documents in the same standards family.
Tolerance Classes
ISO 3724 defines tolerance limits on the average aperture and on the maximum single aperture, tightening as the aperture gets finer. For test-sieve duty the tighter ISO 3310-1 tolerances apply instead of the general cloth tolerances — specify sieve grade explicitly if the mesh will be used for particle-size analysis.
Specifications Defined by ISO 3724
| Outer diameter (mm) | Length (mm) | Micron rating (u00b5m) | End connection | Reference standard |
|---|---|---|---|---|
| 25 | 100 | 25 / 50 / 100 | Plain ends | ISO 2941 collapse-tested |
| 40 | 150 | 10 / 25 / 50 / 100 | Plain or threaded | ISO 2941 collapse-tested |
| 50 | 250 | 10 / 25 / 50 / 100 | M20 / G1/2 fitting | ISO 2941 collapse-tested |
| 65 | 250 | 5 / 10 / 25 / 50 | DOE gasket | ISO 2941 collapse-tested |
| 65 | 500 | 5 / 10 / 25 / 50 | DOE / 222 / 226 | ISO 2941 collapse-tested |
| 65 | 750 | 5 / 10 / 25 / 50 | DOE / 222 / 226 | ISO 2941 collapse-tested |
Equivalent Standards
Where direct equivalents exist (ISO ↔ ASTM ↔ DIN), they are listed on the parent Cylindrical Filter Cartridges page. Confirm against the specification table on this page — nominally equivalent documents can differ in tolerance limits.
Companion Standards
ISO 3724 controls the geometry of cylindrical filter cartridges. Companions frequently cited alongside it: ISO 565 / ASTM E11 (test-sieve aperture series), ISO 3310-1 (test sieves of metal wire cloth), ISO 4783 (selection of wire and aperture combinations), ISO 9044 (industrial woven wire cloth), and ISO 2941 (collapse/burst rating for finished filter elements).
