Construction Truck Crane 2009Presentation Transcript
Construction Truck Crane Safety John Newquist August 2009
Most Likely Accidents
Crane Buckles the Ground
Crush in Swing radius
Two employees had finished loading a trench box onto the bed of a truck crane.
The deceased was in the process of securing the trench box with a chain when the boom contacted a 7620 volt power line, causing him to be electrocuted.
On May 12, 2008
Crane used to lift and move a hub and spindle assembly of a rear axle (approximately 7,500 lbs),
As the employee was lifting the unit, the hub and spindle separated, causing the spindle to fall from the crane and striking the employee in the upper region of his body.
The truck crane onsite was staged above an unleaded tank.
The crane broke through the asphalt below the right rear outrigger.
This resulted in the crane leaning to the side and the telescoping boom to fatally strike the spotter on the walkway.
June 22, 2006
Crane was loaded beyond the rated capacity.
44,775 pound reel of cable
Maximum rated load for the crane was 14,000lbs.
Crane fell over toward the load side, crushing the crane cab against the lowboy trailer and fatally injuring the operator.
January 28, 2004,
Caught between counterweight and fixed object.
If the counterweight extends beyond the crane turntable, precautions must be taken such as marking or barricading the swing radius.
May 31, 2005
Employee #1 was dismounting from a truck crane, when he slipped and fell, catching his left foot between the outrigger and the curb. Employee #1 sustained a compound fracture of his left ankle.
Accidents Cranes cannot swim.
Accidents Even though people may not get hurt in some crane tipping accidents, the property damage costs can be expensive.
Accidents Cranes tipping accidents can be prevented by ensuring the crane is level, lifting within capacity, and proper outrigger padding is used.
Accidents Many accidents occur because the crane buckles the hollow space or soft ground underneath it.
Accidents Water affects the soil compressive strength. Manufacturer specified padding/cribbing must be used.
Powerline distance is 10 feet for voltages under 50kV. It increases as voltages go up.
Placement of loads or materials under near lines is a common scenario that precedes a powerline contact.
Inspect the area under the power lines to ensure nothing is stored underneath them.
Many companies mark off spots/approach distance on ground
Spotters are another option
This crane had hit the powerline.
1926.550(g) has extensive rules to follow when lifting people.
It must be a last option.
Aerial lifts can often be used in lieu of a personnel platform.
No one should be under loads when lifting.
This will require good communication.
Lifting steel beams into an obstructed area is very hazardous.
Taglines and good communication is necessary.
No standard definition in ANSI B30.5
Many use load exceeds 75% of load chart for crane, multiple cranes will lift object, or special hoisting / rigging equipment will be utilized.
Many use detailed critical lifting checklists with calculations and review by multiple people.
Many accidents occur to failure of rigging and not understanding how the configurations and angles of the hitches used affect capacity. A rigging class should be taken by anyone inspecting cranes and rigging.
A flagger is needed to land material on high roofs because the operator cannot see where the load is going.
Fall Protection for the landing operation needs to be provided.
Most cranes when lifting on outriggers will lift the crane’s wheels off ground
The photo shows on partially off for two wheels. It probably is not level.
Boom angle indicator
Boom angle indicator are necessary to verify the correct load chart angle is used.
It is required to be readable from the operators cab.
Boom Length Indicator
The load chart to the right has different capacities depending on the length of boom used.
The operator should be able to show you the length of boom extended on telescoping booms
Wire rope should wrap evenly on the drum.
Is the Crane Level?
If the crane is not level, the load charts will not work.
All cranes should have a leveling device like a bubble indicator.
The headache ball should be in the center of the crane if level in all directions.
Crane Load Chart
Many Factors affect the ability to lift.
Jib or no job.
Outriggers extended or not
Length of Boom
An operator should be able to explain his last lift on the chart.
Capacities can differ depending on lifting from the front, side, or rear.
Sheaves are sized for a certain size wire rope.
A Sheave gauge as shown can show wear.
Wire Rope should be in good shape. The crane standards and manufacturers have guidance on how many broken wires are allowed on a wire rope lay.
Nearly all manufacturers prohibit the metal pad being placed on the ground directly.
There is no universal pad/cribbing requirement so manufacturer manual must be referenced.
Leaking Hydraulic is a problem.
Mark or watch the spot to see if it actually leaking vs. wet from spilled fluid.
Outriggers not fully extended.
The on wheels/tire chart would have to be used if they cannot extend the full distances.
Many times a crane used on a roadway cannot extend the outriggers fully.
Slab/similar items stuck flat to ground can create a suction effect on cranes that adds additional weight beyond the weight of the item being lifted.
A load moment Indicator will be needed.
Load Moment Indicator
Load Moment Indicator tells the operator the weight the crane perceives that is being lifted.
It can tell length of boom extended and angle of the boom.
What is the daily pre-inspection?
When was the thorough inspection?
Where are the inspection records?
What is the qualification of the person conduction inspections?
Are they following the recommended inspection criteria set by the manufacturer?
There are annual and monthly inspections requirements.
How long as an operator of this specific crane?
What training did he/she receive?
Who does the inspection before use?
Is the operator a contractor?
How often does a crane have to be inspected? __________
Name way to tell if the crane is level? _______________________
A 7200 volt line requires ____ feet of clearance from truck crane?
Name three issues to be inspected for out riggers. ________, _________, _________________.
Name one way to prevent getting hit by the counterweight on an truck crane? ____________
Managing Mobile Cranes Hazard Workbook from www.buildsafe.org
Handbook of Rigging
http://www.bcacs.ca/ for idea on operator certification