By Evan Gurley
Proper training and maintenance ensures employee safety and can lengthen the life of your precast plant’s overhead cranes.
Overhead cranes are the workhorses that aid in increased productivity and growth for precasters across the country, but they attract little interest until they are inoperable or fail. However, statistics show there are inherent hazards that occur during normal work settings. A crane can be a very dangerous piece of equipment, and most injuries or even deaths from accidents can be attributed to several basic hazards.
Crane accidents are often a direct result of negligence or a lack of adequate operator training or experience. Overhead crane training is a key concern for industries that depend on such equipment, including the precast concrete industry.
The Occupational Safety and Health Administration estimates that 249 reported crane accidents from 1997-2007 cost the construction industry and general industry nearly $500 million, and that’s just the upfront costs. In addition, nearly 70% of the accidents could have been prevented by proper training and roughly 75% occurred during routine job activities that require specific training to prepare employees.
The owner/user must install, inspect, test, maintain and operate a crane or associated lifting equipment in accordance with the applicable volume of the American Society of Mechanical Engineers standard B30, OSHA regulations, National Fire Protection Association code 70, National Electric Code, and local regulations and laws. It is also the responsibility of the owner/user to require all personnel to read and comply with the instruction manuals furnished by the crane manufacturer or associated lifting equipment, and the applicable portions of the national safety requirements.
If the crane or associated lifting equipment is installed as part of a total lifting system, it is also the responsibility of the owner/user and associated personnel to comply with the applicable ASME B30 volumes that address the other equipment used in the system.
OSHA and ASME both require that crane operators are adequately trained to operate an overhead crane. While OSHA does not require operators be certified by a recognized and accredited organization, qualification training for individuals operating overhead cranes is required.
OSHA and ASME also both state that the individual must be designated, qualified, trained and capable to identify hazards and have the authorization to take corrective action if and when necessary.
Proper training is important
Overhead crane training gives equipment operators a solid foundation on health and safety standards, preventive maintenance and proper procedures for safely operating overhead cranes. Those supervising the use of cranes can greatly improve workplace safety by targeting the hazards that cause the most accidents. Basic training and hazard prevention measures can help eliminate these hazards. It is important to ensure the safety of all personnel who may be in the immediate areas where cranes are being operated, not just the riggers, signalers and operators.
Workplace safety involves more than complying with a few safety rules. Everyone must be involved, including management, supervisors and the production crew. All employees have specific safety responsibilities and must understand the responsibilities of their specific work areas. Hazards are the primary cause of most accidents, so hazard prevention is what brings about a safe workplace.
As it relates to cranes, a hazard is present in three forms:
- Dormant – an undetected hazard created either by design or crane use.
- Armed – a dormant hazard that has become armed and ready to cause harm during certain work circumstances.
- Active – an armed hazard triggered into action by the right combination of factors. At this point, it is too late to take any preventive action to escape injury or avoid death.
James Kehres, division sales manager of EMH in Valley City, Ohio, said the best hazard prevention practice precast plant employees can perform is to respect the dangers associated with overhead cranes.
“I’ve seen plant workers pick up loads and walk under a suspended load or see them walk into the danger zone, not realizing the danger they are putting themselves and others around them in,” he said.
Kehres stated training can help to instill that respect more, but challenges may arise.
“Precasters can absolutely train their employees in-house, but have to make sure training is extensive and in-depth,” he said. “From my experience, I’ve seen quite a bit of turnover in the precast concrete industry with overhead crane operators. This really makes it challenging for precasters to properly train workers as they continuously cycle in and out.”
Maximize your overhead crane use
Operators should perform daily inspections at the beginning of each shift. If any damage or malfunctions are noted during the daily inspections or during operation, the operator must advise the appointed person so corrective action can be taken. If corrective action has not been completed by the end of the shift, the crane must be tagged out with an “out of order” sign and the next shift operator must be told that corrective action is required.
Daily checks include:
Verify the crane or hoist is not tagged out.
Check the load block to ensure all sheaves are running freely and sheave covers/guards are in place.
Inspect the hook for the following:
- Safety latch (in place/operating correctly?)
- Is the hook bent or twisted?
- Has the throat opening increased?
- Check the bowl conditions
- Check the rotation of the hook
Inspect the wire rope to ensure it is lubricated and that none of the following conditions exist:
- Broken or cut strands
- Bird caging
- Core protrusion
- Crushed sections of rope
Inspect the following:
- Control device
- System conditions
- Bridge, trolley and hoist connections
- Mainline conductor bar system
- Operational functions
Periodic inspection items include:
- Structural members: Check for deformed, cracked, corroded or unsecured members.
- Signs and labels: Check for proper capacity labels, warning signs and load test.
- Connection points: Check for loose/broken bolts or rivets, cracked or insufficient welds.
- Sheaves and drums: Check for worn grooves, worn groove lands, sharp edges and cracks.
- Shafts, axles, wheels and couplings: Check for worn, cracked, bent or broken parts and check for loose/missing hardware.
- Brakes: Check for excessive wear and proper adjustment.
- Indicators and gauges: Check for load, wind and other indicators over their full range.
- Transmissions: Check for excessive wear of chain drive sprockets and excessive chain stretch.
- Electrical components: Check for loose wires and any evidence of overheating. Check that the door cover closes properly. Also, check all electrical apparatuses for signs of pitting or any deterioration.
- Covers and guards: Check that all covers and guards are in place, secured and undamaged.
- Bumpers and end stops: Check all bumpers and end stops for damage.
- Trolley and runway rails: Check rails and fastening devices for looseness, gaps, misalignment or wear.
- Runway structures: Check runway structure for proper anchors, loose bolted connections, corrosion, cracked or deformed members.
- Conductor system: Check alignment, fastening, splices, power feeds and conductor shoes for wear.
- Below-the-hook devices: Check for cracks or structural damage, check mechanical components for wear, alignment and missing/loose hardware.
Rigging selection is determined by the object being lifted and its weight. Rigging inspection items include:
- Check the load tag on the rigging to ensure it exceeds the capacity of the lift.
- Inspect rigging before use.
- Look for signs of wear, tear and other defects that could affect capacity. Examples could include kinks, bird caging, cuts, fatigue, rot, aging, deterioration, holes and more.
- Inspect all sockets, chokers, handles and other connections.
- Remove or repair defective slings.
Overhead crane operational safety tips
- Do not overload the crane or hoist. Make sure the combined weight of the lifter and load does not exceed the rated capacity of the crane or hoist.
- Refuse to make a lift if you are unsure of any issues.
- Do not proceed until all issues are resolved.
- Take instructions only from the person designated to give signals.
- Do not lift people and never ride the hoisting load.
- Make sure the sling is well balanced. Avoid tip loading and loading on hook latch.
- Avoid side pull or end pull and quick reversal operations.
- Make sure you take up slack slowly.
- To pick up a load, move the crane and hoist/hook directly above the load to eliminate the possibility of side loading and minimize load swing.
- Before lifting, ensure that everyone is clear of any pinch points or crush zones.
- When starting to lift the load, only lift a few inches off the ground to verify hoist brake is functioning properly before continuing with the lift.
- Make sure the rigging is in good condition and that safe rigging practices are applied.
- Ensure rigging is appropriate for the load size, shape and weight.
- Always maintain a clear view of the crane path so you can observe any obstacles or personnel in your path.
- Use one, continuous motion when traveling.
- Try not to start/stop as this will result in load swing.
- Do not lift loads over people. Stay out from under the load and make sure other people remain at a distance.
- Do not become distracted while traveling. If you need to speak with someone, cease operation of the crane.
- Never leave a suspended load unattended. If you must leave the area, lower the load to the ground first.
- Stay clear while moving a load. Do not allow the load to swing.
- When the crane is not in use, always raise the crane hook above head level.
OSHA recommended forms and documentation
- Maintenance log
- Frequent daily checklist
- OSHA crane inspection report
- Operator training questionnaire
In addition to daily inspections, OSHA also requires periodic inspections of overhead cranes. OSHA defines a periodic inspection as “a detailed visual and operational inspection whereby individual components are examined to determine their conditions.” The periodic inspection can be performed quarterly and is based on service, environmental and application factors as determined by a qualified person or as outlined in Table 1.
Cranes are useful and powerful tools that need to be treated with respect. Any mistake with a crane – small or large – can have serious consequences, including property damage, injury or loss of life. Knowing how to use the equipment properly and following established policies and procedures is critically important.
Evan Gurley is a technical services engineer with NPCA.