For many years, excavators unlike most other items of earthmoving and construction equipment have been exempted from the requirement to have a ROPS (roll over protection structure), for a number of reasons.

20072010WhyTheISOExcavatorRopsStandardHasBeen-(1).jpgHowever, that has all changed with the recent publication of ISO 12117-2: 2008 which sets out laboratory tests and performance requirements for protective structures on excavators weighing between 6 tonnes and 50 tonnes. Mini excavators up to 6 tonnes have had an ISO ROPS standard for a number of years.

According to Chris Moroz, Komatsu Australia's national business manager, construction, there are a number of reasons why excavators have not traditionally been fitted with ROPS cabs and cabins.

"For a start, the structural design of an excavator has made it quite a challenge to develop a strong enough 'platform' on which to mount a ROPS, and which is able to withstand the forces on a cab and its supporting platform in the event of a rollover.

"It's not like a dozer or truck, where the cabin sits on the main body of the machine, and simply has to be robust enough to withstand the weight of the machine if it rolls over.

"Komatsu along with some other suppliers has carried out a lot of R&D work to come up with a platform and cabin structure that can meet the high safety requirements of a ROPS standard."

Other reasons for a lack of an excavator ROPS standard include long-standing industry attitudes.

"For many years, it was felt that due to the nature of their work, and their limited load-and-carry duties, excavators were at fairly limited risk of roll over," Moroz said.

"In addition, the consensus was that the boom and arm helped protect against a rollover in the first place and that if one did occur, the boom acted to give some protection to the cab and operator.

"However, with excavators increasingly used on steep sites and rough terrain, and with an ever-growing range of attachments, the risks of rollover have been increasing.

"At Komatsu, we certainly felt the latest advances in design and materials technology meant an excavator ROPS was feasible, and we were very proud to play a major role in the development of a new standard," he said.

Further information (Australia): Komatsu Australia, ph 1300 KOMATSU (1300 566 287),,

Further information (New Zealand): Komatsu Australia NZ Branch, ph 0800 KOMATSU (0800 566 287),,