Struck by object: attempt to clear pipe blockage ended in death of piling-rig operator.June 2007

A high-risk operation to clear a blockage in a concrete pump went wrong, resulting in the death of a 63-year-old construction worker, Chester Crown Court heard recently.

Peter Roberts was working for Dawson Wam Ltd, of Bedfordshire, on the site of a glass bottle manufacturing facility in Elton, Chester, when the incident occurred in May 2004. Dawson Wam was constructing 7500 piles as part of the foundations at the site. The process involved drilling a hole into the ground with the auger (the corkscrew-like boring bit) of a piling rig, pumping concrete into the hole as the auger was withdrawn, and finally inserting reinforcement bars.

The court heard that concrete being delivered to Mr Roberts' rig remained in the flexible rubber hose and began to harden, forming a blockage. After other attempts to clear it failed, it was decided to try using compressed air. The flexible hose was broken up into individual sections, at least two of which were blown out with the compressed air without their ends being restrained. As the last section was being unblocked the end of the hose whipped upwards and struck Mr Roberts on the head. He died from his injuries four days later.

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Sitting on 25 April, Chester Crown Court fined Dawson Wam Ltd [pounds sterling]75,000 after it pleaded guilty to breaching section 2(1) of HSWA 1974 by failing to ensure the health and safety of its employees. It also ordered the company to pay [pounds sterling]34,425 in costs to the HSE, which took the case on the basis of Dawson Wam's failure to ensure provision and maintenance of safe systems of work.

Said inspector Robert Hodkinson: "Cleaning out, or unblocking piling rigs and associated equipment--such as concrete pumps and pipework--with compressed air is a very high-risk activity and should therefore have been formally assessed. While no charges were brought directly in relation to selecting compressed air as a method for this particular operation, a safer alternative to clean out such equipment would be to use water. Indeed, the British Concrete Pumping Group Code of Practice states that using compressed air to clean out a pipeline should only be done when there is no practical alternative."

In mitigation, Dawson Wam offered its previous good safety record and its full cooperation with the HSE investigation. Since the incident, it has reviewed its procedures for cleaning and unblocking rigs and associated equipment, and has drawn up a comprehensive risk assessment and safe system of work.

Concluded inspector Hodkinson: "I recommend that all piling companies and others who use concrete pumps and associated equipment reassess their cleaning and unblocking operations to ensure that they have safe systems of work in place, and that employees carrying out such activities have received clear instruction and training."