Industrial lifting equipment supplier Hoist & Winch was approached to provide a comprehensive and robustly tested lifting solution for a specialist marine subcontractor. This reservoir application required the transfer of three large-diameter pumping station pipes – each weighing 30 tons – across the reservoir waters and up the inclined slope of its dam wall.
This hire equipment project required a triple-aspect approach. Firstly, to move each pipe across the water, Hoist & Winch supplied, installed, commissioned, load-tested and LOLER-certified two air-powered chain hoists offering 20-ton safe working load (SWL). The company proposed a pair of JDN top-hook suspension air hoists, each with its own load chain collector box, air service unit and air supply hoses. The hoist units are each controlled by an individually connected, heavy-duty, air-powered pendant control. They were fixed to the customer’s free-standing fixed gantries on two fabricated floating pontoons (20t SWL), which Hoist & Winch also had to load-test and LOLER-certify.
Secondly, Hoist & Winch was tasked with providing a similar package of services for a large-capacity hydraulic winch system. The company recommended a 12t SWL floor-mounted hydraulic winch with wire rope, diesel-powered hydraulic power unit, joystick control stand and interconnecting hoses. The winch was required to pull each pipe up the inclined slope of the reservoir’s dam wall in conjunction with two rail-mounted traveling gantries (20t SWL) fabricated by the customer.
Lastly, the customer wanted Hoist & Winch to supply four 15t SWL manual chain blocks. The Tiger top-hook suspension type manual chain blocks proposed by Hoist & Winch would support each pipe from the rail-mounted traveling gantries following transfer from the air hoists in readiness for winching up the slope of the dam wall.
Hoist & Winch technical support experts partnered closely with the main contractor’s civil and mechanical engineers throughout this safety-critical project, with strict approval procedures in place.
Load testing of the two air hoists and their supporting gantries was facilitated by a 20t/25t skid-mounted dynamic proof-test load. Working closely with the marine subcontractor’s dive team, the test weights were initially positioned on the reservoir bed.
Dynamic load testing of the hydraulic winch took place in two stages, firstly using an interim site test load comprising lighter concrete components, which also required winching up the reservoir’s dam wall. A further dynamic test was performed on the day of winching the first pipe. This activity was closely monitored to check all aspects of the winching system installation as work proceeded. Indeed, Hoist & Winch was tasked with operating the winch for the full duration of the first pipe lift up the dam wall slope while maintaining constant radio communication with the overall lift supervisor. As the night time closed in the very precise lifting operation had to continue and so the work was completed under floodlights.
Work continued under floodlights with Hoist & Winch operating the winch while maintaining constant radio communication. © Hoist & Winch
Hoist & Winch also provided various other aspects of technical consultancy, including guidance on lifting equipment legislation, lifting operation planning/management, the specification and procurement of a portable diesel-powered compressor, and operator handover training.
