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New guidelines on deadly excavations

New guidance on excavation safety will be made available a year and a half after a geotechnical firm was convicted of corporate manslaughter when a trial pit collapsed on an employee.

The Health and Safety Executive (HSE) told NCE it will produce a new industry publication giving updated advice on safety rules and best practice surrounding excavations, to be published by July 2012 at the earliest.

The publication is pertinent in the wake of Cotswold Geotechnical Holdings’ conviction in February this year of the corporate manslaughter of junior geotechnical engineer Alexander Wright, who died in a 3.8m deep unsupported trial pit.

Much of the trial centred on the question of whether pits deeper than 1.2m should be supported or battered back.

However, the HSE said the decision to produce new guidance was taken “some time ago” and was not influenced by the corporate manslaughter trial.

The document is being produced by HSE together with the Construction Plant-hire Association (CPA). The new publication will address technological advances in construction equipment and legislation such as the Construction, Design and Management Regulations 2007.

The Executive’s previous guidance book on excavations, HSG 185, is out of print and will not be reissued because it predates these developments. “Simply re-issuing was not appropriate,” said a HSE spokesman. 

ICE guidance says trial pits over 1.2m deep must be reinforced by “timbering or other support”, or else should not be entered by employees when alone on site.

However, HSE told NCE that the 1.2m rule appears in “prescriptive” regulations from 1966 but not in newer regulations published in 1996 and 2007, which are − like most modern health and safety legislation − “goal setting, not prescriptive”.

HSE said: “For some activities and materials [or] ground conditions, danger might arise from excavations less than 1.2m deep and in other exceptional circumstances excavations exceeding such a depth may not present potential danger. 

“Specific works should be assessed by someone who is competent to assess the risk and determine what controls are needed.”

Readers' comments (6)

  • I don't agree that 1.2 m (4 feet in old money) should be even contemplated as an acceptable threshold. The only predictable thing about soil (even some rock) is its unpredictability so any narrow excavation in which it is easy and/or likely for someone to duck their head below the top (e.g. a geotechnical engineer taking samples) is potentially highly dangerous. In my company we specify 500mm as the depth below which shoring/battering etc is mandatory – and the decision for excavating up to 500mm without support must be initially, and continuously, justified via a risk assessment.

    As an aside it's always intrigued me how the participants on Time Team get away without supporting their deep trial pits. Anyone know..?

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  • As a wartime baby, I'm now a bit too long in the tooth to come over all macho but, to be fair to the old rules, I think they were about right: they said no-one should enter an excavation deeper than 1.2 metres when alone on a site. Quite right too.

    However, I see nothing wrong with people entering much deeper excavations when operating from the bucket of a digger in the same trench. I've done it many times - once involving a cave-in but no damage done (apart from to my nerves and a pair of jeans). As long as someone is around to dig you out, just do it. The critical factor is NOT ON YOUR OWN.

    Bruce Denness

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  • Please completely disregard Bob's advice. I can't believe that his post made it past the moderators.

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  • Nick -- it seems that the HSE agrees with you that 1.2m is too deep to be safe in many ground types, as the historic '1.2m rule' doesn't appear in its modern regulations.

    From my understanding, the idea nowadays is that companies are free to either define their own rule on what is a safe depth -- as your company has done -- or to make a judgment on each individual excavation depending on the circumstances and ground conditions in each case, which is perhaps what happens on Time Team digs.

    However, the Cotswolds Geotechnical Holdings corporate manslaughter trial showed that those individual judgments are sometimes not carried out or enforced properly -- so, would it be better for the HSE to impose a strict rule on the industry again? I'd be interested to hear opinions on this.

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  • Bruce -- from what I have heard this is indeed common practice at some companies. However, one company known to have done it is Cotswold Geotechnical Holdings, the company convicted in February of corporate manslaughter because of its failure to enforce a proper safety policy. Food for thought, perhaps!

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  • Keith Nicholls

    I pray that Bruce, or more likely a junior employee of his, isn't next to be killed in this completely avoidable manner. Man riding in buckets is both stupid and illegal.

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