Challenging tandem lift takes down horticultural chimney stacks

Hird has carried out a tandem lift with two mobile cranes to remove chimney stacks at a large horticultural centre.

The business had to take down the stacks as part of an upgrade of the boiler system used to heat plant growing areas.

Hird was commissioned to plan and implement the lift by the horticultural engineering company that was project managing the boiler improvement.

The Hull-based company deployed its 100t Grove GMK4100L crane and 60t Liebherr LTM1060 3.1 crane to work together to carry out the lifts.

grove_gmk4100l_hird_mobile_crane — **100t Grove GMK4100L**

Liebherr-LTM1060-3.1-hird-mobile-crane — **60t Liebherr LTM1060 3.1 crane**

One chimney stack needed to be reduced by five metres. The other 12m stack was being removed, out through the boiler room roof, in its entirety.

Crane placement important

Hird Technical Manager Jason Timmins, the Appointed Person, said: “For the stack reduction lift, the Grove took the load and the Liebherr lifted a basket for an operative to cut the chimney.

“The tip height of the Grove mobile crane had to be substantially higher than the Liebherr to ensure there was enough clearance for them to work together safely.

stack tandem lift - boiler system upgrade - hird

“This made the placement of the cranes particularly important, an issue complicated by an overhead telephone wire that crossed the site and had to be avoided.”

This resulted in a maximum radius for the Liebherr of 30 metres while the Grove worked at a maximum radius of 22m.

The lifting operation also had to take account of the need to allow vehicle movements around the site while the work was underway.

The lifts had been postponed due to high winds. On the day they took place the wind was light and weather conditions excellent.

Tighter wind restrictions

Jason Timmins said: “This was particularly useful because there are tighter wind restrictions for lifting a personnel basket.

“Also, the chimney being completely removed had to be lifted through a narrow aperture in a roof that contained asbestos.”

With both lifts, the cranes were used in tandem to lay down the chimneys, one of which weighed 400kg and the other 1,200kg, both less than had been planned for, based on data supplied by the client.

The lifts were completed in one day in accordance with the lift plan and with no incident reported.

Jason Timmins said: “The project demonstrated Hird’s capability on planning and implementing a complex lift with precisely the right equipment and expertise.”