Overview
ISO 27850:2013 specifies test procedures and performance requirements for Falling-Object Protective Structures (FOPS) when fitted to agricultural and forestry tractors. It applies to tractors with at least two axles for pneumatic-tyred wheels or tracked tractors, and is not intended for forestry machinery as defined in ISO 6814. The standard harmonizes test methodology with OECD Code 10 and defines how FOPS must be prepared, tested, evaluated and documented.
Key topics and technical requirements
- Scope & definitions: Clarifies terms such as FOPS, ROPS, safety zone and agricultural tractor so test results are comparable across manufacturers and labs.
- Permissible tolerances: Measurement tolerances (distance ±5% of maximum deflection or ±1 mm; mass ±0.5%) for repeatable testing.
- Test preparation: Requirements for mounting the FOPS to the test bench or tractor chassis, and for removing removable cladding or brittle glazing that could artificially increase strength. If the same structure serves as ROPS, the FOPS test must be done first.
- Apparatus: Drop object is a solid steel or ductile-iron sphere (typical mass ~45 kg, contact diameter 200–250 mm). Equipment must allow raising and releasing the drop object and use a firm surface and means to detect penetration into the safety zone.
- Procedure: Specifies impact locations related to the vertical projection of the safety zone, with two cases for selecting drop points (centre-of-gravity or area of greatest projected surface). Instrumentation or a safety-zone template may be used to verify deflection.
- Performance & environmental checks: Acceptance conditions, cold-weather performance considerations (Annex A addresses brittle-fracture resistance at reduced temperatures) and prohibition of repairs during testing.
- Labelling and reporting: Labelling requirements and a standardized test report (Annex B) with a Maintenance Agency designation process (Annex C).
Applications and users
ISO 27850:2013 is used by:
- Tractor manufacturers and FOPS suppliers to design and validate overhead protection.
- Independent testing laboratories and certification bodies to carry out standardized drop tests and issue compliance reports.
- Safety engineers and compliance managers evaluating operator protection against falling objects in agriculture and forestry applications.
- Procurement specialists and fleet managers specifying safe equipment for farm and forestry operations.
Practical benefits include validated operator protection performance, consistent test records for certification, and clear guidance to manage cold-weather brittle fracture risks.
Related standards
Keywords: ISO 27850:2013, FOPS, falling-object protective structure, tractors for agriculture and forestry, drop test, safety zone, test procedures, performance requirements.