Handling with Care
Posted on 01/09/2017 by IED
Handling steel threaded drill casings and cylindrical drill rods can result in serious accidents, despite the wearing of anti-crush gloves. A new award-winning solution may be the antidote
Site investigation services contractor Structural Soils (an RSK company, with teams based in Bristol, Glasgow, Castleford and Hemel Hempstead) was recently named the winner of two awards: Ground Investigation Project with a Geotechnical Value of over £500k and the Health and Safety Award at the 2017 Ground Engineering Awards. The former was a joint win with design, engineering and project management consultancy Atkins; management consulting services company Arup; and client Horizon Nuclear Power.
Structural Soils’ Health and Safety Award win is well worth looking at in some detail. This was for its manual handling solution – a one-piece plastic, lightweight, adaptive, one-size-fits-all tool. The technology enables operators to lift any dimension and length of metal casing without having to place their hands or forearms in the hollow steel tube. It enables two people to lift the casing securely, thereby removing the risk of contact with potentially sharp threads, and with correct posture while walking across uneven ground. The tool is made out of one piece of plastic without moving parts, so is simple to use and has little to go wrong. The way the tool is lifted causes its jaws to tilt, thereby locking the casing in place while being carried.
“We identified the need to find a solution to a long-term manual handling issue in the drilling part of the business,” comments Structural Soils drilling manager for the south Nick Reichelt. “Carrying casing was responsible for most minor and occasionally more serious hand injuries. Staff engagement was critical in designing and evolving the optimum tool for the job, which all our crews now use. An additional benefit of using the tool is that it naturally imparts a better posture for carrying, thereby helping to alleviate another cause of injuries on-site.”
In 2015, it became apparent from analysis of near miss and minor accident reports that a significant number of minor injuries were being incurred by staff who were handling steel threaded drill casings and cylindrical drill rods, despite the wearing of anti-crush gloves. “Conventionally, this equipment is stacked either on trestles, trailers or the ground during transportation and storage before use,” explains Reichelt. “It is normal for two individuals to lift the equipment, one either end, each grabbing one end by inserting part of their hands into the tube.
Injuries were being incurred by cuts from sharp threads or burrs, or by crushing when tubes rolled against one another or the side of the trestle during a lift. We realised the need to develop a system to eliminate these injuries,” he adds.In early 2016, a hand safety stand-down campaign was rolled out to focus all staff on the risks related to injuring hands and fingers/thumbs.
This campaign resulted in a surge of reporting of near misses, minor plaster non first-aider treatment and ongoing discussion relating to the difficulties with handling down hole equipment.
The actual number of handling injuries was higher than recorded in the reporting figures for 2015, but enabled the rapid assessment of the main root causes – intrinsically sharp and difficult to handle equipment.
“Lacerations and crush soft issues and minor fracture injuries were the most commonly recorded issue on site,” adds Reichelt. “Improved glove selections were rolled out, but the pinch points, metal shards, and number of reported back injuries while carrying down hole kit continued to rise; an engineered solution was urgently required.”
Structural Soils’ drilling department set about finding a resolution to this increasing amount of hand injuries, especially in relation to drill casings and rods, often transported to site in stillages delivered to the work site by lorry or trailers. “Something was needed that separated the operator’s hand from direct contact with the drill tool. The solution needed to be simple, robust and ideally without moving parts, as the drill tools are often coated in thick mud, which might impinge moving parts. Various models were considered before the simplest grip handle tool was considered for development,” he continues.”
A wooden prototype was built in the in-house workshop from heavy-duty marine plywood and discussed with end users. Modifications were made to increase the depth of the handle fingers grips and tested with an individual wearing heavy duty gloves to ensure the PPE use did not compromise the design. The slot for the casing threads was deepened and the angle steepened to improve the grip – black version below.
“When the wooden prototypes were tested, feedback from the team of end users was that these handles had immediately improved their posture by enabling the casing to be carried by personnel of different heights with less back strain potential, as the casing was in a suitable height position to keep the back straight and did not increase strain on the lower back areas.
“Early designs were discussed with our in-house CAD Team, measurements taken and a technical drawing created suitable for submission to the machining subcontractor. After discussions with some of the health and safety team, along with the drillers’ feedback of the original prototype, it was decided that six possible designs would be put forward for testing to work out the most ergonomic design, as well as the safest, incorporating some minor changes to each to try to dial in a final design. The drawing shown was sent out to various staff members for comments and two final designs decided.”
Wood was clearly not durable enough to survive protracted time in the wet and abrasive conditions of site. A selection of materials were considered from which to form the next generation. Metal was considered too heavy and uncomfortable, so plastic was adopted.
A subcontractor was selected – CAM Machine, based in Clevedon, near Bristol. Following face-to-face discussions, they were enthusiastic about involvement in a research and development project, and understood that large-scale orders were a way off. But, if the trials proved successful, these were likely to have a wide potential for procurement within the ground investigation industry.“The manufacturer added value before the design was sent for machine production by making suggestions about material suitability, thickness, wear potential and ease of machining,” states Reichelt. “They initially ran a single batch of both of the below designs and subjected them to basic destructive testing. The preferred design at the time, the preferable one, had to be abandoned and the reserve design pushed forward, as the hand grip area, although more ergonomic to remove the hand from, pushed the limitations of the base material too far and caused it to snap with minimal loading.
“Being completely enclosed added extra rigidity to the casing handle, increasing its breaking strain by 70 per cent.”After the theoretical design process, 10 sets of the V1 casing grip were made. Initial feedback from a short trial with end users proved promising, but this version was found to have some limitations:
The jaw sometimes slipping, as these were only a tight fit on one type of drill casing
Nylon, being self-lubricating, increased this slippage
The handle area was small for large hands wearing gloves
V2 was produced shortly after, with some changes. The jaw design now had larger teeth over a greater distance, with the jaw tapering toward the rear. Hand grip was increased.
V3 was then developed, following further feedback from the end users:
Some form of protection for the upper area was required in case of lifting casings from stacks, stopping risk of entrapment when holding the handles
The jaw was rethought, as the previous handles could still slip. Instead of relying on teeth to grip the casing, the upper area of the jaw was changed to curve by 4 degrees along the jaw area. This pushes the casing down in to the toothed lower jaw, resulting in a gripped and pinched action. That action is increased by twisting the grips onto the casing
THE END GAME
Since those three versions, a V4, wih a rounded and knurled top handle to add further comfort and grip, is undergoing production.“End user feedback has been key in the development of these casing grips,” says Reichelt. “First, to ensure they are effective and, secondly, to engage with the end users and embrace their experience in using the casing grips.”
The goal, he confirmed, is to roll out V4 later this year and to supply these to subcontractors working for Structural Soils before distributing them across a much wider user base.”