ISO 8084:2003 establishes a laboratory test method and performance requirements for operator protective structures (OPS) on self-propelled forestry machines. It is applicable to mobile forestry machines defined in ISO 6814 engaged in felling, processing, forwarding and skidding. The OPS are designed to provide reasonable protection from objects otherwise able to pierce, such as saplings, branches, broken winch lines and poking hazards in forestry work, but not from small, thrown objects such as chain teeth. Those OPS meeting the performance criteria will not provide complete operator protection under all conceivable circumstances, but are expected to minimize the possibility of operator injury in normal operational situations.