Several of the dangers of an industrial workplace setting seem obvious. At an energy-from-waste conversion or feedstock preparation site, these hazards can include shredding machinery, high-temperature combustion units and large mobile material handling machines capable of crushing someone walking nearby.
Less obvious sources of danger, but of a type that causes severe injuries in workplace settings each year, are the conveyors that quietly transport materials from one area of a plant to another.
Agencies such as the Occupational Safety and Health Administration (OSHA) and trade groups such as the Institute of Scrap Recycling Industries Inc. (ISRI) have gathered records of such incidents, and fortunately also have advice to offer on how to keep employees safe from the unseen dangers posed by conveyor systems.
The conveyors that move material up, down and through an industrial facility are powered by motors that will not stop unless directly instructed to do so. Unfortunately, this becomes all too clear to hundreds of people each year who have an article of clothing, jewelry or their own hair or fingers caught up in a conveyor.
Even though a conveyor may not be moving that fast, the forces driving it forward may be considerable. Adding to the danger, the nearest stop button or kill switch may be out of reach of the victim, especially if the victim already has one hand caught in a conveyor dragging the victim away from the nearest such switch.
In a presentation given at a regional ISRI event in 2013, Dave Guyton of Hustler Conveyor Co., O’Fallon, Missouri, noted that “powered conveyors were the primary source of injury in 23 workplace fatalities in the past eight years.”
According to the Bureau of Labor Statistics (BLS) and its “Table of fatal occupational injuries by event or exposure,” both in 2013 and 2014 more than 100 Americans died in the workplace when they were “caught in running equipment and machinery,” many of these being conveyors.
Fatal conveyor incidents in recent years have occurred in warehouses, coal mines, quarries, automotive plants and also at recycling plants. A 2014 conveyor-related fatality at an Illinois scrap yard involved an employee who entered a shredding chamber to clean it out while a nearby conveyor continued to run. The employee’s arm got caught in the conveyor and produced injuries that proved fatal.
In addition to fatal injuries, conveyor accidents can cause severe injuries, including amputations or partial amputations that, while not fatal, can be life-altering for the victim and traumatizing for the co-workers who witness them.
Postaccident investigations can reveal shortcomings including failing to shut off power and placing inadequate machine guarding. Each of these circumstances can cause OSHA and other agencies to issue fines.
Safety experts also increasingly look to the intangibles of awareness and a workplace safety culture as critical aspects that can keep conveyors useful while preventing them from being harmful.
START TO FINISH
Conveyor safety awareness begins before an employee enters a work zone and even before a conveyor system is powered on, according to the “Recommended Industry Safety Practices” for conveyors adopted by ISRI in 2008.
The list of practices includes a pre-operation inspection routine intended to spot potential hazards and familiarize employees with the workings of a conveyor system. “At the beginning of each shift, and periodically thereafter as necessary, the conveyor and its surrounding area must be inspected for hazards, and where hazards exist they must remove them,” ISRI recommends.
The inspection fits into ISRI’s wider precaution that “the conveyor operator must be fully aware of the equipment’s surroundings before initiating startup,” according to the ISRI document.
Accounting for the exact location of workers likely to come into contact with the conveyor is another crucial step. “All personnel must be accounted for and verified to be out of harm’s way,” says ISRI. “Visual and audible alarms must be sounded prior to startup, and the alarms must give adequate warning to allow someone who might have wandered into danger to remove himself from danger.”
As indicated by the Illinois scrap yard incident, maintenance procedures, as with startup, can be another source of heightened danger. ISRI recommends “strict adherence to lock-out/tag-out protocols be enforced whenever a machine guard is removed or when maintenance work is being performed.”
Lock-out/tag-out procedures are defined by OSHA as “the practices and procedures necessary to disable machinery or equipment, thereby preventing the release of hazardous energy while employees perform servicing and maintenance activities.”
In his presentation, Guyton remarked the person who conducts the lock-out/tag-out procedure is critical.
Such procedures should be performed by “authorized individuals—a knowledgeable individual to whom the authority and responsibility to perform a specific assignment has been given by the employer,” said Guyton.
While conveyors are running, emergency shutdown buttons or switches can be the last life line available to someone snagged by a moving conveyor. “ISRI recommends that such emergency shut-off devices be readily accessible from any point along the length of the conveyor, and not require movement to a specific button for activation,” the trade group says in its best practices document.
Preventing those snags from happening is the function of guarding—sheet or gridded metal that makes it difficult for inadvertent contact between a person and a conveyor to occur. “All rollers, pulleys, rotating shafts, pinch points, nip points and other moving parts must be guarded in such a way that contact with such parts is physically impossible,” writes ISRI, adding an exception for overhead conveyors of a height of seven feet or greater above the nearest pedestrian walkway.
Pinch points and nip points are areas where two different conveyor surfaces or rollers meet, creating a space where loose clothing, hair or fingers can theoretically be caught up in the mechanism.
Efforts to meet the highest fabrication and installation safety standards may only be effective if combined with companion educational and workplace culture efforts, according to workplace safety advisors.
RULES AND REMINDERS
While metal guarding may help prevent some conveyor snags, so can attention to worker attire. “A common mechanism of injury involves loose clothing being snagged by moving machinery parts, which then pull the workers into the machinery,” writes ISRI. “Loose clothing or jewelry is prohibited for wear within six feet of a conveyor, unless the conveyor is shut down or locked out.”
Other workplace rules recommended by ISRI include:
- workers must never touch/reach across a moving conveyor belt;
- workers must never stand or walk upon a conveyor belt unless the conveyor mechanism is shut down and locked out;
- workers must never exceed a conveyor’s load capacity;
- workers must never be beyond the reach of the emergency stop mechanism; and
- workers must remain vigilant of the movement of others and shut the conveyor down when anyone wanders into danger.
Awareness and attention to such rules requires training, notes ISRI. “Prior to being exposed to the potential hazards posed by conveyors, employees must be trained on the specific safety requirements of their positions,” the group recommends. “The training must be presented in a language they understand and the effectiveness of the training should be affirmed through some combination of apprenticeship, observation and on-the-job reinforcement.”
While one might think it would go without saying, workers may need to be reminded that conveyors are not to be treated as amusement park rides. “Lack of common sense, horseplay, and taking short cuts contribute to accidents,” said Guyton in his presentation. “There have been incidents of people being injured while being transported on powered belt conveyors and getting loose clothing and long hair caught in the system.”
Guyton says the culture and training aspects can play an enormous role in preventing conveyor-related accidents. “The single most important factor in the prevention of accidents is a proper attitude toward safety,” he told his ISRI audience. “It requires only a little effort to think about possible accidents and how to prevent them. The habit of anticipating potential accidents and how to prevent them automatically prevents many of them from occurring.”