ROPS and FOPS

Mobile plant creates two particular ways to kill an operator who is otherwise doing nothing wrong. The machine can roll or tip onto its side or roof, and objects can fall from above onto the cabin. The two protective structures answer those two risks.

A roll over protective structure, or ROPS, is a frame designed to maintain a survivable space around the operator if the machine rolls. It absorbs energy by deforming in a controlled way, which is why a ROPS that has already been through a rollover has done its job and cannot be relied on a second time.

A falling object protective structure, or FOPS, is a guard over the operator's station designed to resist penetration by a falling object. On many machines the two are combined in a single cabin structure certified to both.

The critical detail, and the one most often missed, is that a ROPS only works if the operator stays inside the protected space. With the seatbelt unfastened an operator can be thrown against the structure or partly out of the cabin during a roll, and a frame cannot protect someone who is no longer behind it. Seatbelt use is part of the control, not an optional extra sitting alongside it.

Australia has adopted the international test standards directly. AS ISO 3471 covers roll over protective structures for earthmoving machinery and AS ISO 3449 covers falling object protective structures, both setting out laboratory tests and performance requirements. Older machines may be certified to the earlier AS 2294 series, and some machine categories sit under their own standards.

The plant risk assessment for a machine should record which protective structures it carries and the certification behind them, because that is the document the site works from.

Certification is by design and test, not by inspection on site. The structure is tested as a design, and the individual machine carries evidence that its structure complies. In practice that means documentary evidence should be available on site, usually a compliance plate on the structure plus the certificate or manufacturer documentation in the plant file.

The duty behind this sits in the plant provisions of the model work health and safety regulations, which require a person conducting a business or undertaking to manage the risks associated with plant, including rollover and falling objects. A hire agreement does not shift that duty. A builder using the machine still has to satisfy itself that the protection is present, certified and undamaged.

At mobilisation the practical test is short. Does the machine have the structure the task requires, is there paper to prove it, and has anything been done to that structure since it left the factory.

Falling object protection comes at two performance levels, and choosing the wrong one is a real exposure on demolition and excavation work.

Level 1. Protection against lighter falling objects such as bricks, small concrete blocks, hand tools and loose material. This is the level fitted to most general earthmoving machines and is adequate for ordinary construction tasks.

Level 2. Protection against heavy falling objects such as rock and trees. It is intended for work where substantial material can fall from height onto the cabin, including vertical rock excavation, tunnelling and underground work, forestry, and some demolition.

The choice is a risk assessment, not a preference. If the task can drop a heavy object onto the machine, Level 1 protection does not meet the risk even though the machine is technically fitted with FOPS.

This is also where supplementary guarding belongs. Demolition and scrap handling often need additional front and side guarding, screens or mesh to stop material entering the cabin from the side rather than from directly above, and that guarding has to be designed for the machine rather than fabricated on site.

Welding, drilling or modifying the structure. Mounting a beacon, an aerial, a camera bracket or a sunshade by drilling the frame can void the certification, because the structure was certified as it was tested. Attachments belong on the mounting points the manufacturer provided.

Repairing a damaged structure. A ROPS that has been in a rollover, or that is cracked or deformed, gets replaced rather than straightened and welded. Its energy absorption was designed in once.

Treating the seatbelt as a separate issue. The protective structure assumes a restrained operator. An unbelted operator in a certified machine is not protected.

Removing or folding protection to fit. Where a cabin or frame will not clear an opening, the answer is a different machine or a different method, not a removed structure.

Accepting plant without the evidence. Machines on dry hire arrive without plant files more often than anyone admits. Confirm the certification at mobilisation, record it in the plant register, and physically check the structure for cracks, previous repairs and missing bolts.

Assuming the standard decides the level. The standard describes how the structure was tested. Deciding whether this task needs Level 1 or Level 2 is the builder's risk assessment.