Tower Cranes

Tower cranes stand over high-rise and large commercial sites for months. The most dangerous phases are erection, climbing (jumping) and dismantling, and high winds.

• Construction

Parts of a tower crane

• Base and foundation: a large concrete footing or a structure the crane is tied to.
• Mast (tower): stacked lattice sections. On climbing cranes, new sections are added as the building rises.
• Slewing unit and cab: lets the top of the crane rotate.
• Jib: the working arm with the trolley and hook. Luffing-jib cranes raise and lower the jib instead of moving a trolley.
• Counter-jib and counterweights: balance the jib and load.

Key safety points

• Erecting, climbing and dismantling follow the manufacturer’s procedures under a qualified A/D director, with a pre-erection inspection of all parts.
• Foundations and ties are engineered by a qualified person.
• Wind: operations stop at the manufacturer’s wind limit. When out of service, the crane is left to weathervane (slew freely) per the manufacturer.
• Operators are certified for tower cranes; access to the cab is by ladder with fall protection.
• Communication is usually by dedicated radio with a qualified signal person.
• Multiple cranes need anti-collision planning or systems.

Inspections

• Pre-erection inspection of all components before assembly
• Inspection by a qualified person after erection and before use
• Shift inspections by the operator or a competent person
• Monthly and annual inspections, with documentation
• Inspection after high winds, a lightning strike, overload or any event that could damage the crane

Climbing (jumping) the crane

Raising a tower crane by adding mast sections is one of the riskiest operations on site. The top of the crane is temporarily supported by a climbing frame, and the crane must be balanced and not lifting loads. Follow the manufacturer’s procedure exactly, with a qualified crew, in low wind, and keep everyone not involved out of the area.

Cities and neighbors

Some cities and states license tower crane operators and riggers separately and require permits, engineering reviews and notice before erection. Cranes on neighboring sites may overlap; their operators and contractors must coordinate. Swinging loads over occupied buildings, sidewalks and streets is often restricted.

Working under a tower crane

• Know when loads are flying overhead. Many sites use horns or lights.
• Stay out of marked load paths and landing zones.
• Keep material on decks secured so the wind can’t lift it.
• Watch for ice falling from the jib and mast in winter.
• Never walk under a suspended load, and use tag lines to control loads at landing zones.
• Riggers and signal persons must be qualified. See Rigging Basics and Crane Hand Signals.

For the operator

• Climb to the cab with fall protection, rested and fit for duty. Long climbs are tiring
• Check the weather forecast and wind readings on the anemometer
• Test limit switches, brakes and load moment indicator before lifting
• Confirm radio channel and signal person for each lift
• Leave the crane in weathervane (free-slew) mode with the hook raised when going out of service
• Get down during lightning storms

Last updated: October 1, 2026