Safety Bulletins

Chainshot incident

NRW Shared Learning

Key learning following a Serious Incident Review.

What happened?

The near miss incident happened on a NRW direct production thinning coupe, involving a harvester operator contracted by NRW to undertake harvesting operations. The harvester operator was not injured and did not suffer ill health as a consequence of the serious near miss.

The harvester operator described hearing a sudden ‘thud’ noise against the cab and saw a crack in the windscreen. The harvester operator was unsure whether the cracked windscreen was caused by debris flying up towards the cab or by chainshot. The harvester operator made the decision to stop work to investigate further. On checking the saw box and inspecting the chain, it was found that there were three teeth missing from the chain. The harvester operator then returned to the cab to inspect the windscreen but could not find any evidence of the cab having been penetrated by the chainshot.

The harvester operator was processing a tree with the saw pointing directly towards the cab, due to restricted manoeuvrability of the harvester head in the thinning racks and also the need to process directly in front of the cab to create brash mats as he was progressing through the racks. Upon inspection of the saw box, there was no chainshot guard/protection device fitted. The harvester operator believed that the chain catcher was in fact the chainshot guard/protection device.

This chainshot incident happened due to the chain breaking and fragments (three teeth) of the chain being ejected towards the cab. It is presumed given that the saw was pointing directly at the cab, that the ejection was from the tip of the chain bar.

Had the machine been fitted with a chainshot guard/protection device this would have been effective in reducing the production of whip and therefore chainshot. However, it has also been identified that there was still a level of risk of ejection of chain pieces due to the processing direction towards the cab. Both the chainshot guard/protection device and processing direction are required to effectively control this risk.

The contractor has had a chainshot protection device retrospectively fitted at an approximate cost of £150.

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Documents to download

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