Riggers rig up loads to be moved by crane, erect structural steel for buildings under construction, erect precast concrete panels used for walls of buildings and noise walls along freeways, and erect/dismantle cranes. Duties include examining objects to be moved, estimating their weight, size, weight distribution / centre of gravity and deciding on the type and arrangement of equipment such as slings, chains and other grappling devices required to move them safely.
The Rigger attaches the hoisting equipment to the load using hooks, bolts, coupling and clamping devices, and communicates with and directs the crane operator, as well as providing some manual guidance of the load as it is lifted and then lowered into position by the crane. Communication includes use of hand signals, whistles or two-way radios.
Duties include the inspection of chains, slings, ropes, cables, hooks and lifting gear for damage and wear and reporting defects.
When erecting steel, vertical columns are craned into position, guided by and then fastened by the Rigger onto metal studs using a rattle gun, or welded onto plates by a boilermaker. Horizontal components are craned into position, manually guided and then fastened by the Rigger, working from booms and scissor lifts, using large bolts and tools including rattle guns and large sockets and spanners (up to 80mm).
The lighter-weight horizontal components, such as ‘purlins’ and struts used to tie the structure together, may be craned in bulk onto the rafters and then manually spaced and positioned by the Rigger. The Riggers typically work in pairs at either end of the horizontal components when spacing, positioning and fastening them.