Material Handling Safety in a Precast Plant

By Steve Wolszczenski

“Employee’s back fractured when struck by forklift.” “Employee killed when crushed by overturned towmotor.” “Employee killed when head crushed by gantry crane.”

These are just a few of the “Event Descriptions” found on OSHA’s website when viewing towmotor and crane accidents that resulted in OSHA investigations. Such equipment as various powered industrial lift trucks and cranes can be dangerous, yet they are necessities for precast concrete manufacturers. That’s why specific programs must be in place to ensure safe operation by employees, as well as to ensure compliance with applicable OSHA standards.

The movement of material within a precast plant occurs either manually or by utilizing machinery. Of course, manual lifting of concrete is limited by the extreme weight of the material (concrete weighs about 2 tons per yard of material). However, manual lifting or movement of work equipment and product components such as reinforcing wire and rebar, hand-held vibrators, forming panels, hand tools and wheelbarrows are also open invitations to injury for the precast workforce. Hernias, lumbar strains and other impairments can occur from overexertion in completing these tasks.

Precast manufacturing is a construction activity requiring high amounts of physical work. In order to mitigate the potential for these types of injuries, employers should have programs in place to properly train employees in work techniques that will reduce the risk of injury. These programs should not be limited to the proper mechanics of lifting, but should also account for administrative and engineering controls to prevent lifting injuries.

Administrative controls
Administrative controls could include maximum weights employees are permitted to manually lift as well as preferred methods for lifting and moving material with designated equipment. For instance, if an overhead crane is available to lift a heavy panel, but the crane is busy lifting other materials, employees may choose to lift the panel manually rather than wait for the crane to become available. It appears to be the quickest way to get the job done, but is it in the company’s best interest to risk employee injury to save a few minutes in waiting time? One serious back injury will answer this question.

The National Safety Council projects that the average back injury will cost more than $10,000 in direct medical expenses and replacement of an injured employee’s wages. In addition, indirect costs for replacement labor, loss of quality, loss of efficiency, etc., may be 2.5 times or greater than the direct costs associated with a work injury. Yes, the direct medical and wage replacement costs are insurable; however, future workers’ compensation premium increases more than recuperate this money for insurance companies over subsequent policy years.

Employees need management guidance in determining a company’s philosophy regarding how production and safety rate. If administrative controls are not determined and properly implemented, employees may decide that production takes top priority in all cases and take more short cuts than a company is willing to risk.

Engineering controls
The use of cranes and powered industrial trucks are examples of engineering controls. Other engineering controls may include the use of tables to elevate work to minimize bending, use of conveyors to move materials, or the design of push carts to carry materials from one area to another. Engineering controls can require a significant financial investment, but typically they will make a job more efficient – not to mention reduce injury potential to employees.

It would be relatively impossible to find a precast concrete manufacturer who hasn’t caught on to this principle to some degree. The use of overhead cranes and powered industrial trucks is a mainstay within the industry’s manufacturing process. Although this equipment makes work easier, it is dangerous and, consequently, creates other safety concerns that reach beyond conventional workplace hazards. Now, instead of being limited to back injuries, hernias and other strains, workers are exposed to the potential for more serious injuries – and possibly life threatening ones.

A lift involving an overhead crane, lifting chains and product containing lifting pins includes three distinctively different components that must all work together to ensure a successful lift. The weakest of these components determines the maximum weight that can be lifted. Therefore, developing a specialized program for proper use and maintenance of these components will help ensure the lift sequence isn’t compromised.

Of course, OSHA has recognized the need for safety guidance when utilizing this equipment and has developed requirements for Powered Industrial Trucks (29 CFR 1910.178), Overhead and Gantry Cranes (29 CFR 1910.179) and Slings (29 CFR 1910.184). Further, OSHA has enforced these standards during its inspections of precast plants as noted in the following:

OSHA citations issued to precast concrete manufacturers between October 2002 and September 2003
STANDARD # CITATIONS ISSUED DESCRIPTION
1910.178 50 Powered Industrial Trucks
1910.179 33 Overhead and Gantry Cranes
1910.184 15 Slings

OSHA standards
Developing programs to comply with these OSHA standards is a difficult task, but certainly a necessary one. Here is a summary of each standard.

Powered Industrial Truck Standard – OSHA 29CFR 1910.178. This standard applies to mobile, self-propelled trucks used to carry, push, pull, list, stack or tier materials. Excluded are vehicles used for earth moving and over-the-road hauling. Revised in 1999, this standard incorporates more specific requirements for operating, maintaining and inspecting this equipment than its previous version.

Variables such as employee training, employee evaluations, inspections and maintenance of the equipment must be incorporated into the program. The Plant Safety Guide issued by NPCA provides basic compliance program elements that can be adopted at your facility in establishing a site-specific program.

A key component of forklift compliance is to have an effective operator training program. OSHA requires that a company provide this training prior to operating the equipment, except that hands-on operation of the equipment may be performed where there is no danger to the operator or co-workers and the training is supervised by a person who has the knowledge, training and experience to train operators and evaluate their competence.

An employer must certify that operators have been trained and evaluated on each piece of equipment the employees will operate. This certification must include the operator’s name, date of training, date of evaluation and identity of the person(s) performing the evaluation. Be certain to document training through the use of sign-in sheets, quizzes, evaluation checklists and license cards. At a minimum, training should include those items listed in the following:

Items to include in training program

• Refueling or recharging procedures
• How to complete preoperational inspections
• Proper loading protocol
• Proper traveling protocol
• Procedures for removing unsafe equipment from service
• Lift truck rated capacities and limitations
• Lift truck stability concepts

Refresher training is required when an employee is seen operating the truck in an unsafe manner; an employee has an accident or near miss; evaluation indicates a need or deficiency; or the workplace and/or equipment changes. At a minimum, refresher training must be completed every three years and must include an evaluation of the operator’s ability to safely operate the equipment.

Other components of a Powered Industrial Truck program include pre-operational equipment inspections prior to each shift and provisions for proper maintenance of the equipment to ensure it is in safe operating condition.

Overhead and Gantry Cranes – OSHA 29 CFR 1910.179.
This standard establishes requirements for inspections, maintenance, lifting and handling loads and other physical crane construction requirements. In essence, an employer who utilizes overhead and/or gantry cranes must make sure there are procedures in place to prevent lifting failures. Such procedures required by the OSHA standard include daily visual operator inspections of the components on a crane. These daily inspections include checking the hoisting ropes, load hooks, limit switches and the hoisting, bridge and trolley brakes.

When checking hoisting ropes, look for obvious defects such as kinks, cuts or unstranding. Make certain the rope is spooling properly on the hoist drum and that the rope is running freely through the running sheaves. Damage to the rope can occur when it is not running through properly.

Load hooks should also be checked for cracks, gouges or bending. A frequent problem with load hooks is damage or employee removal of the safety latch that closes the throat opening of a hook to ensure loads do not accidentally slide off the hook.

Slowly and carefully move the load block to the upper limit switch on the crane in a safe and clear area. If the switch does not work, immediately remove the crane from service. This switch’s function is to prevent raising a load too high and running the load block into the hoist drum. This would cause a failure in the lift, causing a load to fall and putting any employee in the vicinity into grave danger.

An operational check is also required of the braking systems. For instance, lift a load a few inches off the ground to determine if the hoist brake will hold. If any braking mechanism is found to be questionable or not working, immediately remove the crane from service and prevent further use until it is repaired.

Other checks that an operator should perform include observing the crane motions to make sure the crane responds properly to the pendant or remote functions. Make certain the controls are labeled as to function and that they do not stick. If any unusual noises or vibrations are found, this could indicate serious wear or maladjustment and the crane should be taken out of service.

Periodic inspections should be conducted that get more in depth than daily inspections, and in this case must be documented. Dependent on how hard the crane is used and how harsh the environment is, this inspection must be conducted every one to 12 months. Your crane service company or manufacturer can help you determine how frequently these inspections should be conducted. In fact, the crane service company will have the expertise to complete the inspections for you. This type of inspection requires an in-depth knowledge of the equipment and should be conducted only by qualified technicians with the proper training. At a minimum, an inspection utilizing an outside crane service company should be completed annually. Even then, a monthly or quarterly internally documented inspection is recommended.

Operators should be trained in how to control the crane, proper rigging, how to move a load and how to inspect the crane, as well as where the disconnect is located. The crane capacity must be clearly marked on the crane in order for operators to make proper judgments in what can safely be lifted.

Slings – OSHA STANDARD 29 CFR 1910.184. There are many types of slings including chain, wire rope, and synthetic and wire mesh. The most common sling used in the precast industry is the chain. Of course, not all chains are suitable for lifting – be sure to use lifting-grade chains only. As with a crane safety program, an important element in developing a sling program is implementing the proper inspection program.

Due to the repeated use and the harsh environment lifting chains are exposed to, chain links, master links and hooks can wear or become damaged. When a chain fails, it is sudden and without warning. Therefore, OSHA requires a daily visual inspection of slings and all fastenings. In addition, based on conditions and use, a periodic inspection must be performed and documented on all slings. Check chains for excessive wear at all bearing points between links and where the load sits on the hook. If 10 percent of the overall original thickness is worn, the chain must be removed from service.

Check the throat opening for twisting or stretching. If the throat opening has increased by 15 percent over the original opening, the chain must be removed from service. Also look for elongation of the chain and individual links, nicks, gouges, cracks, twisting, deformities and signs of heat damage. An alloy chain must be permanently removed from service if exposed to more than 600 degrees Fahrenheit.

Employee training is another critical component in developing a sling program. All slings must have a rated capacity tag on the chain. This capacity is the maximum amount the chain can lift and is based on a 90 degree angle between the chain and the load. Whenever this angle becomes less than 90 degrees to the load, the capacity of the chain is reduced. No load should be lifted with a chain-to-load angle of less than 30 degrees. Employees should be instructed in the concepts of how load angles affect the chain capacity as well as how to properly attach a chain sling to a load. Train employees in the type of slings that will be used, whether the slings are two-legged, three-legged or quad-type.

Tying it all together
As mentioned earlier, the maximum weight that can be lifted safely is determined by the weakest link within the lift sequence. A failure of any one component, whether a single chain link, a hydraulic line on a forklift or an employee who has made a bad decision, can result in an unsuccessful lift and can cause serious injury to employees as well as damage to product. The NPCA Guide to Plant Safety includes programs that can be adopted and made specific to a precast plant in order to establish a compliant program for both powered industrial trucks and cranes. Other resources include insurance loss control representatives, equipment vendors and service companies.

Steve Wolszczenski is Safety Director at Terre Hill Concrete Products Inc. and Chair of NPCA’s Safety, Health & Environmental Committee.