Overview
ISO 3208:1974 specifies a test method and required apparatus for evaluating protrusions inside passenger cars - controls, knobs, levers and other internal devices - to determine how significant they are and whether they will retract, compress, or become detached when subjected to force. The standard defines the test headform and piston geometry, measurement ranges and basic calibration and test procedures. It also defines the Reference Zone (head-impact zone) inside the vehicle where these tests apply.
Key topics and technical requirements
- Test apparatus
- Hemispherical headform: 165 mm diameter.
- Flat-ended sliding piston: 50 mm diameter fitted inside the headform to contact protrusions.
- Force application and measurement system with a scale 0–50 daN and accuracy 0.5 daN.
- Angle measurement device for the application direction: 0°–90° with ±1° accuracy.
- Protrusion measurement
- Protrusion scale with at least 30 mm range, graduated in 0.5 mm increments; device retains maximum reading.
- Procedure: headform contacts surrounding material with force ≤ 2 daN, piston advanced to contact protrusion and reading taken.
- Force testing
- Continuous progressive force is applied to check that before reaching the reference load the protrusion retracts, compresses or becomes detached to below the reference protrusion value.
- Multiple closely spaced controls that sit within the headform recess are treated as a single protrusion; total compressive force must not exceed the reference force.
- Calibration
- Protrusion scale zeroed with piston on flat surface; verify with a 10 mm gauge block.
- Force scale checked using known forces (example checks at 30 and 40 daN specified).
- Reference Zone (Annex)
- Defines the head-impact zone relative to a seat “H point”, steering control envelope and instrument panel geometry. Includes procedures for determining contact points with the adjustable headform (pivot-to-top dimensions 736–840 mm).
Applications and who uses it
ISO 3208 is aimed at:
- Vehicle manufacturers and interior design engineers assessing occupant safety and ergonomics.
- Component suppliers (controls, knobs, switches) verifying mechanical behavior under impact or loading.
- Test laboratories and homologation bodies performing interior safety evaluations for type approval or certification.
- Ergonomics and safety engineers developing compliant dashboard and cockpit layouts.
Keywords: ISO 3208, protrusions inside passenger cars, headform test, sliding piston, protrusion test, vehicle interior safety, reference zone.
Related standards
- ISO 48 - Vulcanized rubbers: determination of hardness (referenced for material hardness requirements).
- Relevant vehicle approval and interior safety regulations (see annex references to ECE documents for related approval procedures).
