Overview
ISO/TS 28924:2007 - "Agricultural machinery - Guards for moving parts of power transmission - Guard opening without tool" - defines safety requirements and verification methods for guards that can be opened without a tool on agricultural machines. It applies to self‑propelled ride‑on machines and mounted, semi‑mounted or trailed implements used in agriculture, and it specifies the information manufacturers must provide on safe working practices and residual risks. This Type‑C technical specification (per ISO 12100‑1) focuses on guarding moving parts of power transmission to reduce mechanical hazards such as crushing, shearing, entanglement and drawing‑in.
Key topics and technical requirements
- Scope and applicability: Guards that open without a tool for power transmission parts on specified agricultural machines. Not applicable to tractors, aircraft, air‑cushion vehicles or lawn and garden equipment.
- Design principles: Guards must consider operator risk, machine function and secondary hazards (drainage, debris accumulation, interference with material handling) and allow normal operation and service to be readily carried out (Clauses 4.1–4.4).
- Fixed and movable guarding: Use location, safety distance or fixed guarding; where access is required, guards should remain attached (hinges or tethers) to prevent loss during maintenance (Clause 4.5).
- Opening without tool: Guards that can be opened without a tool still must protect against access to moving parts and comply with strength and sizing rules. Mesh/grille openings must respect distance-to-opening relationships per ISO 13852.
- Residual motion indicators: If machine elements continue to rotate after power is disengaged, provide visible or audible rotation evidence or a suitable safety sign on access doors/guards (Clause 4.6, 6.2).
- Strength and verification: Guard strength to comply with ISO 4254‑1 (Clause 4.7). Verification procedures and inspections are specified (see Table 1).
- Information for use: Operator’s manual must include warnings about significant residual risks, control measures and training requirements (Clause 6.1). Annex A lists significant hazards relevant to these guards.
Practical applications and users
Who benefits from ISO/TS 28924:
- OEMs and agricultural machinery designers specifying and integrating guards into new machines.
- Safety engineers and compliance officers conducting risk assessments and conformity checks.
- Maintenance teams and technical writers preparing operator manuals, service instructions and safety signage.
- Procurement and QA staff creating specifications and acceptance criteria for guards and retrofits.
Practical uses include design guidance, verification checklists, user information requirements, and establishing safe maintenance procedures.
Related standards
- ISO 4254‑1 - Agricultural machinery - Safety - General requirements (strength and safety principles)
- ISO 13852 - Safety of machinery - Safety distances to prevent upper limb access
- ISO 12100‑1 - Safety of machinery - Basic concepts and methodology
Keywords: ISO/TS 28924, guards for moving parts, agricultural machinery safety, power transmission guards, guard opening without tool, operator manual, residual risks.