Choosing the Right PPE for Machinists

Workplace safety is a growing concern among workers in North America. According to Injury Facts®, preventable workplace deaths totaled 4,414 in 2017 in the U.S., the fourth year in a row this number has increased. And, for every worker lost, countless loved ones, co-workers, and friends are affected. According to the National Safety Council, a worker is injured on the job every 7 seconds. Under the OSH Act, employers have a responsibility to provide a safe workplace.

Hierarchy of Controls and PPE

Controlling exposures to occupational hazards is the fundamental method of protecting workers. Traditionally, a hierarchy of controls has been used as a means of determining how to implement feasible and effective controls. As defined by the National Institute for Occupational Safety and Health (NIOSH), it flows as follows:
• Elimination – Physically remove the hazard
• Substitution – Replace or reduce the hazard
• Engineering controls – Isolate people from the hazard
• Administrative controls – Change the way people work
• Personal protective equipment– Protect the worker with PPE

The Occupational Safety and Health Administration (OSHA) states that use of PPE – considered the last line of defense against worker injury – is acceptable when controls higher in the hierarchy don’t eliminate the hazard or are in development. Numerous types of PPE are available that are geared to work conditions and the part of the body that might be susceptible to a hazard. A broad range of safety products and services can help organizations effectively mitigate hazards in the workplace.

Developing a PPE Program

Diversity is the shopping cart of businesses throughout the world. The diversity of uses and needs for appropriate PPE can only be determined by PPE assessment that fully determines the risk factors of a particular job function with human involvement.

Quality assessment to determine if the exposure is presented as prescribed in OSHA’s Code of Federal Regulations (CFR), is a must. PPE suppliers are positioned in the marketplace to help make determinations relative to the selection of the proper PPE needed based on employer certifications. By understanding the work and the limitations of PPE, these suppliers can better identify the right equipment, predict the correct level of protection, and decide if the equipment meets the immediate level of need to help keep workers safe.

PPE for Machinists

PPE choices should be based on a PPE assessment that identifies the hazards of different machines that affect the operators. Many machinists commonly face hazards such as exposure to chemicals, liquids, oils, heat, sharp edges, moving parts, pinch points, punctures, welding sparks, noise, vibrations and flying debris – all of which should factor in the PPE assessment and selection process. Small injuries that occur frequently include lacerations from burrs or chips, bumping a sharp tool bit or insert while handling a part in the machine, dumping scrap in a bin, and unfolding a band saw blade. All of these injuries are preventable with the proper PPE.

Here are a few examples:

• Head protection – Bumping into objects/falling objects.
• Eye protection – Safety glasses/side shields (goggles for splashes and spatters)
• Face protection – Face shield with safety glasses and side shields (for splashes and spatters)
• Hand protection – Nitrile or other solvent-resistant glove based on an SDS review of the chemical
• Apron (plastic disposable) – Based on operation and an SDS review of the chemical
• Clothing in general – Rigid fabrics in good repair, FR rated as required
• Footwear – Steel toe boots or shoes
• Hearing protection – noise cancelling earmuffs (push to listen) based on recorded and documented decibels.

Gloves

The right glove selection depends upon the application. The OSHA CFR 1910.138 Hand Protection (a) General Requirements states: Employers shall select and require employees to use appropriate hand protection when employees’ hands are exposed to hazards such as those from skin absorption or harmful substances; severe cuts or lacerations; severe abrasions; punctures; chemical burns; thermal burns; and harmful temperature extremes. (b) Selection. Employers shall base the selection of the appropriate hand protection on an evaluation of the performance characteristics of the hand protection relative to the task(s) to be performed, conditions present, duration of use, and the hazards and potential hazards identified.

Chemicals and Liquids. Cleaning, wiping off, and degreasing machines expose workers to harsh chemicals. In addition, machine and metalworking fluids affect workers’ hands. Common applications include finishers polishing metal and workers cleaning machines after use. Coated fabric, rubber, plastic, or synthetic gloves are good solutions for standing up to chemicals and liquids. These gloves help protect against specific chemicals:
o Butyl rubber gloves: Nitric acid, sulfuric acid, hydrochloric acid, and peroxide
o Natural latex/rubber gloves: Water solutions or acids, alkalis, salts, and ketones
o Neoprene gloves: Hydraulic fluids, gasoline, alcohols, and organic acids
o Nitrile rubber gloves: Chlorinated solvents

Computer-Controlled Panels. Common applications include operators working around electronic metalworking equipment. Featherweight nylon, touchscreen, and mechanics gloves are good options for operating control panels.

Cutting Oils. Common applications include workers cleaning up work areas and maintenance workers around metalworking fluids. As with chemicals and liquids, nitrile gloves are a good choice for standing up to oils and are easy to dispose of after use.

Heat, Burns and Hot Objects. Machine parts and workpieces can get hot and machinists need protection when handling hot metal workpieces. Leather, welders, mechanics, and Kevlar® gloves offer protection from heat.

Material Handling. Transporting material onto the machine shop floor can rough up hands. Common applications include material movers handling heavy metal parts and machinists handling metal components that may have sharp edges and burrs.

Moving Rotary Parts. Machinists who are operating rotating machines should not wear gloves. If machinists are working with a CNC machine, a lathe, a knee mill, or a drill press, wearing gloves near a rotating spindle can spell disaster.

Pinch Points. Working on gears, chains, and pulleys puts machinists’ hands in immediate harm’s way. Common applications include CNC operators installing metalwork pieces, deburring metal, and handling machined parts with rough edges. Gloves that offer high dexterity, high cut resistance, and back-of-hand protection such as mechanics and impact gloves are recommended.

Puncture. Metal splinters, small metal chips, and burrs are found all over metal. Common applications include machinists handling metal scrap and punching operators handling metal burrs. High-rated ANSI puncture- and cut-resistant gloves are this hazard’s best choice.

Sharp Objects. Machine shop workers, such as milling operators, deal with sharp edges on workpieces, sharp metal chips, and cutting tools. ANSI A2 to A9 cut-resistant gloves are the best option to avoid cuts and lacerations.

Welding. Welders work around sharp metal and hot sparks. Welding, aluminized, and leather gloves are excellent hand protection choices for welders.

Eyewear

A PPE assessment should reflect the hazards such as flying debris and filings; chips; dust; molten metals; radiant light from welding, cutting and brazing, and splashing chemicals. All should bear the marking ANSI Z78.1.

Features and styles reflect the needs and the fit required of the wearer. It is appropriate for the employer to perform the assessment of the need and review the variety of styles available to fit each employee.

Rockford Systems offers a full line of PPE. Please call 1-800-922-7533 or email customerservice@rockfordsystems.com for more information.

Contributed by:
Brent Bryden, CEO for InterActive Safety Solutions, Inc., PO Box 457, Winnebago, IL 61088, 815-742-0513 www.interactivesafetysolutionsinc.com.

Bye-Bye Boomers: What Retiring Machinists Mean to Plant Safety

Within the next decade approximately 2.7 million Baby Boomers (1946-1964) will retire, thereby ensuring that tens of thousands of positions will become available without a ready supply of American workers to fill them. Statistics paint an especially gloomy picture for the manufacturing sector, and the resulting widening of the skills gap as young replaces old.

Compared to the rest of the economy, the impact on manufacturing of this generational shift is over sized because of two reasons: One, despite increased efforts by colleges and vocational schools to train new manufacturing workers, available jobs still outpace qualified employees. And two, the existing manufacturing workforce is considerably older than the national employee average of 42 years. Currently, the average age of highly-skilled manufacturing employees is 56, and nearly a third of all manufacturing professionals are over 50. As they retire, knowledge goes out the door with them.

What are the implications of these trends for your plant’s productivity? How will it impact employee safety? What can you do to transfer knowledge from one generation to the next?

SAFETY KNOWLEDGE GAP
Besides having less experience operating machinery correctly, workers new to the job are often unsure about their safety rights and responsibilities, or might feel uncomfortable speaking out about a potential hazard. They may also not have the proper training, so they underestimate the risks involved with operating high-speed machinery. A recent survey of machinists in North America exposed that 70 percent could not recall receiving any formal training when they first hired on.

Equally troubling, the Millennials (1980-1996), who are replacing Baby Boomers, are more apt to job hop — 90 percent expect to stay in a job for less than three years, leaving manufacturers with heightened turnover and a badly depleted knowledge base, especially when it comes to safety.

Given all this, it probably comes as little surprise that employees under the age of 25 are twice as likely to visit the emergency room for an occupational injury than those over 25. The dangers facing younger workers underscore the critical importance of machine safeguarding. The lathe, press or saw on the plant floor considered “safe” solely on the basis of being accident free for many years is no guarantee that modern safety standards are being met. Seasoned machinists may have developed workarounds that prevented accidents. Worse yet, the machinist may have covered up small accidents they’d suffered, considering an occasional nick or scratch simply part of the job. Your “safe” machine may be the most dangerous on the floor.

Step One: Safeguarding
Faced with the wave of Baby Boomer retirements, many manufacturers are trying to hold on to their older workers, persuade some to return after retirement or recruit those retired from other companies. Unfortunately, these steps only postpone the inevitable. A more successful, long-term answer is having your plant’s machinery subject to a thorough risk assessment process.

A risk assessment draws on the expertise and experience of an outside company to identify machine hazards before they cause accidents. Over the course of the assessment, detailed information is collected concerning each machine, its operator and the process it is tied to. Hazardous areas are pinpointed on the machine with a risk level assigned to each potential danger. Evaluating this risk level helps determine if further safeguarding methods should be applied to the machine to make it safe. If a risk is not tolerable, safeguarding measures need to be applied that will reduce the risk to an acceptable level that is in accordance with national, regional and local regulations. The risk assessor should also accurately identify all costs associated with the final project. After installing safeguards, a follow-up assessment will be conducted to verify that risk levels have been reduced to a code-compliant, tolerable level that will not threaten the safety of less experienced employees.

Step Two: Transferring Tribal Knowledge

Retirees won’t leave behind every bit of knowledge they’ve gained over the years, but capturing a majority of the important nuggets will be beneficial down the road. Your organization needs to find ways of capturing this “tribal” knowledge before the machinist hangs up their hat and heads for the white sandy beaches of retirement. One common way of doing so is implementing a structured mentoring program pairing young workers with senior people who are technically expert in complex machinery. Along with face-to-face training on the machinery, the experienced worker is there to answer questions about operating procedures that are unclear or not understood, and to help the young worker learn the ropes of a new job. Recognizing hazards and learning safe work practices must be central part of mentoring programs so make sure they are given equal billing with productivity during conversations. Mentors can also play an important role in informing young workers of their OSHA rights to a safe workplace, as well as the right to refuse unsafe work. Once retired, the mentor can return on a part-time or as needed basis to continue training new hires.

TRAINING
While older machinists certainly have the experience and technical knowledge, they may not know how to teach because they aren’t professional trainers or they can’t communicate effectively with a younger generation. Others may feel that training is an additional obligation that has been hoisted upon them when they are already crunched for time.

Hiring an outside firm to teach young employees about machine safety overcomes those problems. Rockford Systems offers Machine Safeguarding Seminars at its Rockford Systems Training Center in Rockford, Illinois. The popular 2.5-day seminars combine classroom discussion with live demonstrations on fifteen machines set up to give the hands-on experience that new employees need. Once the seminar is complete, the employee will be enable to interpret the OSHA 29 CFR 1910 and ANSI B11 Series Standards as they relate to their specific machine applications and production requirements, perhaps better than the retired operator they are replacing.

AGAIN, IMPORTANCE OF RISK ASSESSMENTS & SAFEGUARDING
A perfect storm has formed, making it increasingly difficult for manufacturers to find and train labor. The retirement of the Baby Boom generation only makes matters more challenging. To ensure plant productivity and safety needs are continuously met despite retirements, take proactive steps by conducting a risk assessment of machines, work to promote the transfer of knowledge, and install code-compliant safeguarding equipment.

The good old days? Not for machine operators.

History of U.S. Machine Safeguarding

When manufacturing moved from small shops to factories during the Industrial Revolution, inexperienced, often very young workers were confronted with a confusing jumble of moving belts, pulleys and gears. While pre-industrial craftsmen faced risks from kilns and hand tools, industrialization introduced massive steam engines and fast-moving machines. Adults and children, some as young as four years old, operated unprotected machinery 12-16 hours a day under conditions unheard of today, with many losing their lives.

Safeguarding History

In America the use of labor saving machines was driven by a regulatory climate that discouraged employer’s interest in safety. As a result, manufacturers at the time developed machinery that was both highly productive and very dangerous. Overworked American factory workers in the 1900s faced life with missing limbs, damaged vision and hearing, lung infections, and severe burn injuries.

Child Worker Injury

Workers who were injured might sue employers for damages, yet winning proved difficult. If employers could show that the worker had assumed the risk, acted carelessly or had been injured by the actions of a fellow employee, courts would usually deny liability. Only about half of all workers fatally injured recovered anything and their average compensation amounted to only half a year’s pay. Because employee accidents were so cheap, industrial machinery was developed with little reference to safeguarding.

Not unexpectedly, reports from state labor bureaus were full of tragedies that struck the unlucky. These reports spurred the budding labor movement to call for factory safety. In 1877, Massachusetts passed the Nation’s first factory inspection law. It required guarding of belts, shafts and gears, protection on elevators, and adequate fire exits. Its passage prompted a flurry of state factory acts. By 1890, nine states provided for factory inspectors, 13 required machine safeguarding, and 21 made limited provision for health hazards.

Safeguarding HistoryOn the national level, Congress passed a federal employers’ liability law in 1908 that made it more expensive for companies to have a machine accident on their books. Thanks to the new law, worker injuries that once cost companies $200 to resolve now cost almost $2,000. In 1910, the state of New York created a workmen’s compensation law that forced companies to automatically compensate for workplace injuries, eliminating the need for families to take corporations to court. By 1921, 43 more states had followed New York’s lead and established their own compensation laws. Compensation laws and other liability costs suddenly made workplace injuries an expensive proposition for many employers.

What followed was a slow but steady increase in machine safeguarding. Manufacturing companies began to work to create safer production equipment, and managers began getting tasked with identifying machine dangers.

In 1913, the U.S. Bureau of Labor Statistics documented approximately 23,000 industrial deaths among a workforce of 38 million — a rate of about 61 deaths per 100,000 workers. Although the reporting system has changed over the years, the figure dropped to 37 deaths per 100,000 workers by 1933 and 3.5 per 100,000 full-time-equivalent workers in 2010. A major contributor to the trend in fewer deaths was machine safeguarding.

Safeguarding HistoryAfter WWII accidents declined as powerful labor unions played an increasingly important role in worker safety. Personnel Protective Equipment (PPE) became a requirement with gloves, masks and aprons given to workers. Posters were hung throughout the plant floor reminding workers of their responsibility to think and act in a safe manner. Basic guards and safety mats became common features around industrial machinery. Also, the American Standards Association published its “Safety Code for Mechanical Power Transmission Apparatus” in the 1940s. Very similar to OSHA 1910.218 it was written to serve as a guide for machine manufacturers in guarding systems. The National Safety Council found that the injury frequency rate dropped from 15 injuries per 100 full-time workers in 1941 to 9 in 1950. By 1956, it reached a decade low of 6 per 100 workers. As impressive as those numbers were, the on-the-job death toll in the 1950s remained a stubborn 13,000-16,000 workers annually.

Nixon Signs OSH ACTIn the 1960s economic expansion again led to rising injury rates with 14,000 workers dying each year. An additional 2.2 million workers were injured on the job. Resulting political pressures led Congress to establish the Occupational Safety and Health Administration (OSHA) in 1970. On December 29, 1970, President Richard Nixon signed into law the Williams-Steiger Occupational Safety and Health Act (OSH Act), which gave the Federal Government the authority to set and enforce safety and health standards for most of the country’s workers. This act was the result of a hard fought legislative battle that began in 1968 when President Lyndon Johnson unsuccessfully sought a similar measure.

In the House, Representative William A. Steiger worked for passage of his bill by saying: “In the last 25 years, more than 400,000 Americans were killed by work-related accidents and disease, and close to 50 million more suffered disabling injuries on the job. Not only has this resulted in incalculable pain and suffering for workers and their families, but such injuries have cost billions of dollars in lost wages and production.”

Machine Safeguarding AssessmentsWhen the agency opened for business in April 1971, OSHA covered 56 million workers at 3.5 million workplaces. Today, 105 million private-sector workers and employers at 6.9 million sites look to OSHA for guidance on workplace safety and health issues.

Safeguarding technology and requirements have come a long way since the industrial revolution. Advanced light curtains, interlocked guards, laser-guided systems and presence sensors are now commonplace. Despite this progress, the lack of machine guarding has been named to OSHA’S Top 10 Most Cited Violations List virtually every year since the list began. In 2018 OSHA handed out nearly 2,000 violations to companies for failing to have machines and equipment adequately guarded, underscoring how much work there is left to do.

In many respects, we take today’s focus on machine safety for granted. However, by reviewing history we can see how it has benefited society by radically reducing accidents and deaths.

Safeguarding History

Minimize Conveyor Injury Risks with Safeguarding

While conveyor belts are integral facets of the distribution process and most warehouses could not function without them, they also pose the potential to cause serious injuries and sometimes even fatalities. In fact, the U.S. Department of Labor, Bureau of Labor Statistics has reported that over 40 workplace fatalities a year are the result of conveyor accidents, along with 9,000 injuries.

While in motion, conveyor systems have inherent and obvious dangers. Belts continuously move at speeds up to 600 feet per minute or 10 feet per second. There are many pinch-points within their machinery, any of which could cause an injury to a worker. Common employee injuries incurred working with conveyors include arm and hand amputations, finger lacerations, burns, scrapes and broken bones. Even when employees are being careful, accidents can happen. It’s easy for loose clothing, jewelry or hair to get trapped in conveyor belts. If workers aren’t paying attention, they could get caught in the machine.

Every conveyor belt injury in a warehouse is costly, affecting worker morale, availability of trained labor, lost production, and increased overhead due to insurance premiums, along with mountains of paperwork, lawsuits and possible fines from government regulatory agencies. Conveyor belt injuries account for nearly 25% of all workers’ compensation claims. Safeguarding conveyors protects employees from injuries, and companies from potential financial ruin.

Safeguarding Conveyors
Safety considerations for conveyor design are detailed in ASME B20.1-2018: Safety Standard For Conveyors And Related Equipment.

ASME B20.1-2018 applies to the design, construction, installation, maintenance, inspection, and operation of conveyors and conveying systems in relation to hazards. The conveyors covered can be bulk material, package, or unit-handling types installed for permanent, temporary, or portable operation. OSHA has also issued its own standard 1926.555(s)(1), General Conveyor Safety Requirements. In many cases, local municipalities and equipment manufacturers will require standards above and beyond ASME and OSHA be met.

Because conveyor designs vary, each conveyor should be evaluated to determine what primary safeguarding methods and energy control practices are required. For instance, a chain conveyor introduces the hazards of nip points when a chain contacts a sprocket. As a result, the primary safeguarding method would be enclosing the moving chains. If this isn’t possible, barrier guards can be installed around moving points so that nip and shear points can be eliminated by a guard. Secondary guarding options would include safeguarding by distance or the use of awareness devices.

Rather than concentrate on specific details of unique conveyor designs, for the purpose of this article, we are going to look only at three basic requirements of conveyor safeguarding: emergency stops, guards and motor starters.

Emergency Stops: The only conveyors that don’t require emergency stops or “e-stops” are ones mounted more than eight feet above the working surface, since those are guarded by their elevation, a situation called “guarded by location.” Conveyors that are accessible to operators must be equipped with e-stops.

conveyor belt safeguarding
 
According to both ASME B20.1-2018, remotely and automatically controlled conveyors where operator stations are not manned or beyond contact shall be furnished with emergency stop buttons, pull cords, safety-rated limit switches or similar emergency stop devices. As a general rule of thumb an operator should be able to stop any conveyor within his or her line of sight by activating the nearest emergency stop. ASME also requires that all emergency stop circuits should fail in the event of a power loss to the emergency stop circuit. Employees must be familiar with the location and function of e-stops to allow them to make fast decisions on using them. E-stop training should be provided to all employees regarding where they are located, when to use them, and how to access them.

As for restart, OSHA requires that “emergency stop switches shall be arranged so that the conveyor cannot be started again until the actuating stop switch has been reset to running or ‘on’ position.” ASME goes further, requiring that the starting device be locked out or tagged before any attempt is made to remove the cause of the stoppage. Besides having the activated emergency stop switch or pull cord reset, an audible warning signal must be sounded immediately before starting up the conveyor.

Depending upon the size of the conveyor, multiple start buttons may need to be activated. Modern conveyors may feature a Human Machine Interface (HMI) that allows operators to remotely identify the location of the tripped emergency stop on a display. Once the local emergency stop has been reset, the system can be remotely restarted via the HMI.

Finally, e-stops should never be modified for any reason by unqualified personnel. Monitor e-stops to ensure employees have not misused, modified, or disconnected them.

Guards: ASME B20.1-2018 requires conveyor with accessible nip points on spools and pulleys be guarded to prevent contact by a worker, and that a conveyor have guards or sideboards to prevent material from falling from the conveyor into areas occupied by workers if the falling material presents a hazard of impact injury or burn. Barriers, enclosures, grating, fences, or other obstructions that prevent physical contact with conveyor components are considered to be guards. When the guard is used as the primary safeguarding method, a guard opening scale can be used to ensure no employee cannot reach under, over, around, or through the guard. Any openings created by the guards must be checked for compliance with ANSI/CSA safety standards. Hand railing is not acceptable to limit access to a pinch point as it can be breached easily.

Most serious accidents and fatalities involving conveyors result from inadequate guarding. Guards are sometimes removed by plant employees for maintenance purposes, or because they obstruct an employee’s access doing work, exposing sharp machinery, gears, chains, and moving parts that are extremely dangerous. To help ensure worker safety, lock out conveyors when in service, and operate equipment only when all approved covers and guards have been reinstalled.

Lockout/Tagout: Conveyors are widely thought to not require a lockout/tagout procedure, which is incorrect. According to the OSHA 29 CFR 1910.147, OSHA expects that all equipment with more than one energy source, including energy that can be locked and energy that must be dissipated manually, must require a machine-specific procedure. Conveyors have both electrical energy and kinetic energy. Additionally, adjacent equipment feeding the conveyor can cause a hazard if still running during conveyor service. According to OSHA data, workers who operate conveyors, packaging equipment and printing presses experience the highest number of accidents associated with lockout/tagout failures.

Lockout / tagout
 
Whenever a conveyor is under repair or maintenance, it must be stopped with power sources locked out and tagged out. Exceptions may be given to conveyors that need power for testing or making minor adjustments. For more about “alternative LOTO measures” consult ANSI/ASSE Z244.1 for expanded guidance beyond OSHA’s regulatory limitation to tasks that are “routine, repetitive and integral to production operations”. Following the Hierarchy of Control model, ANSI/ASSE Z244.1 provides detailed guidance on if, when, and how a range of alternative control methods can be applied to result in equal or improved protection for people performing specific tasks.

When it comes to conveyor service, maintenance work should only be carried out by fully trained, highly qualified professionals. These professionals will ensure proper lockout/tagout procedures are followed, and to block or disengage all power sources to the conveyor — electrical, hydraulic, air and gravity. Keep in mind that even the best trained technicians are occasionally injured by a conveyor. Untrained staff should never attempt a conveyor system repair.

As with any industrial equipment, conveyors are capable of causing grave injuries if not safeguarded according to established standards. However, it is equally important that employees working around conveyor systems are trained regarding potential hazards. Constant vigilance and a safeguarded conveyor are vital to keeping your warehouse and facility safe.

Valve Safety Trains Require Regular Inspections, Maintenance and Training

Thermal processes are used to alter the physical, and sometimes chemical, properties of a material or coating. Two common examples of thermal processing would be high-temperature operations such as heat treating, and low-temperature operations, for instance drying or baking. Heat treating involves the use of heating or chilling, normally to extreme temperatures, to modify a material’s physical properties — making it harder or softer, for example. Many industries use baking, drying or other lower temperature heating processes to modify aspects of a material or coating. Additionally, facilities may have incinerators for oxidizing pollutants, or air heaters for tempering climate air. Applications for thermal processing are virtually endless.

At the heart of all thermal processes is a valve safety train. These fuel-delivery devices maintain consistent conditions of gasses into furnaces, ovens, dryers and boilers, among others, making them crucial in assuring safe ignition, operation and shutdown. Equally important, they keep gas out of the system whenever equipment is cycled or shut off.

Valve safety trains are critical to the operation of combustion systems. Despite being used daily in thousands of industrial facilities, awareness on their purpose and function may be dangerously absent because on-site training is minimal or informal. To many employees on the plant floor this series of valves, piping, wires and switches is simply too complex to take the time to understand. What is known can be dangerously misunderstood.

A valve safety train isn’t a single piece of equipment. Instead, it has many components including regulators, in-line strainers (“sediment traps”), safety shut-off valves (SSOV), manual valves (MV), pressure switches, and test fittings logically linked to a burner management system. Flame-sensing components make sure that flames are present when they are supposed to be, and not at a wrong time. Other components may consist of leak-test systems, gauges and pilot gas controls. At a minimum there are two crucial gas pressure switches in a valve safety train, one for low pressure and one for high pressure. The low gas pressure switch ensures the minimum gas pressure necessary to operate is present. As you would assume, it will shut off fuel to the burner if the gas pressure is below the setpoint. The high gas pressure switch ensures an excessive pressure is not present. It too will shut off fuel if the gas pressure is too high. Both switches must be proven safe to permit operation. Additionally, there will be an air pressure switch to ensure sufficient airflow is present to support burner operation. Some systems have supplementary pressure switches, such as a valve-proving pressure switch. Switches such as these are typically used to enhance safety or provide other safety aspects specific to that application’s needs. A multitude of sensors within the valve safety train — pressure switches, flame detectors, position indicators — and isolation and relief valves work together in concert to prevent accidents.

Valve safety trains must be compliant with all applicable local and national codes, standards, and insurance requirements. The most common of these for North America are NFPA, NEMA, CSA, UL, FM. Annual testing and preventive maintenance are not only an NPFA requirement, but also oftentimes required by insurance agencies, equipment manufacturers, and national standards, including ANSI, ASME, and NEC.

Understanding of fuel-fired equipment, especially the valve safety train, is necessary to prevent explosions, injuries and property damage. The truth is, although valve safety trains are required to be check regularly, they are rarely inspected, especially when maintenance budgets are cut. And while codes require training, they offer very little in terms of specific directions.

Don’t wait for a near-miss or accident to inspect and/or upgrade your valve safety train. For more information on Rockford Systems Combustion Safety Solutions, please visit or call 1-800-922-7533.

Please read our extensive set of Combustion Safety Questions & Answers HERE.

Please read our Combustion Safety press release HERE.

Evaluating the Machine Guarding ROI

Insurance studies indicate machine safeguarding provides an excellent opportunity for businesses to reduce bottom-line operating costs by eliminating both the direct and indirect costs of accidents.

Consider this:According to the 2018 Liberty Mutual Workplace Safety Index, serious, non-fatal workplace injuries amounted to nearly $60 billion in direct U.S. worker compensation costs. This translates into more than one billion dollars a week spent by businesses on injuries. Another study, this one conducted by Colorado State University, set the total direct and indirect cost of workplace injuries at $128 billion. For its part, the National Safety Council (NSC) set the total cost to society of occupational injuries and deaths at $151.1 billion.

So how does an organization evaluate the machine guarding return on investment (ROI)?

DIRECT COSTS

First off, what are the direct costs of an accident? These refer to out-of-pocket expenses like hospital and medical bills, but may also include the loss of a worker’s time because of the accident, the lost productivity by the machine involved in the accident being idled or requiring repairs, as well as the other machines further down the production line being shut down. Direct costs continue to cascade throughout the company with overtime required to make up the lost productivity or new workers who need to be hired and trained.

The NSC estimates that cost per medically consulted injury, counting wage losses, medical expenses, administrative expenses and other direct employer costs, to be $32,000. This varies greatly by cause and nature of the injury, and which part of the body is impacted. For example, the average cost per worker compensation claims involving an amputation runs $95,204, while a crushing accident is $57,519. These two sorts of injuries are mentioned here because they are both very common in machinery-related accidents. The NSC also reports that an employee death resulting from an accident costs the company on average $1.2 million. Total medical cost to society annually from occupational injuries and deaths is $33.8 billion.

INDIRECT COSTS
Analysis reveals that the actual total cost of an accident ranges from four to ten times the direct cost stated by an insurance company once indirect costs are factored in. Indirect costs can include such things as workplace disruptions, loss of productivity, and increased insurance premiums. And of course, there are litigation and lawyer fees. Here, the sky is the limit. Lawsuits resulting from employee injuries or death, especially those involving a lack of machine safeguarding, often result in multi-million dollar settlements or verdicts. Investments targeted for company growth may need to be diverted to cover the costs of these settlements, putting the future of the company in jeopardy.

While it is not calculated as an indirect cost, a poor safety record can make the difference between a company winning or losing bids, especially with government contracts. A plant with a singularly bad reputation for safety may also find itself unable to attract qualified workers or may have to pay wages well above market value to do so. Also, if the machine is locked out for investigation or until the safeguarding deficiency is abated, the company may need to outsource the work at a much higher cost. It’s also possible that the work is so specialized that it’s impossible to outsource and therefore the company loses the business.

MANAGEMENT OPINIONS ON SAFETY
A poll by Liberty Mutual Group insurance showed that the majority of executives surveyed (61%) reported that for every one dollar spent on safety, three dollars is saved. Nearly all (95%) said workplace safety had a positive effect on financial performance. OSHA estimates a 6:1 ratio for saved dollars for every one dollar invested in safety, twice Liberty Mutual’s 3:1 ratio.

Of course, if a company could be guaranteed a huge return on their safety investment, more than half the machines in the U.S. today would not be operating unprotected. Convincing upper management to commit tens of thousands of dollars on machine safeguarding when a return may not be seen for years can be a hard sell. In this situation, safety professionals can stress that although cost savings are a motivator, safety’s biggest ROI comes in the form of human capital. Money savings from fewer injuries, increased productivity, and higher morale are all additional benefits.

Safeguarding press brakes without sacrificing productivity

Technology advances can keep the operator safe and the press brake running

Even though the U.S. has some very strict machine guarding regulations, the U.S. Department of Labor reports that press brake operators in this country suffer more than 350 amputations per year—and these are only the reported injuries. The question is why?

For one, by their design, press brakes are very dangerous machines, much more so without proper safeguarding equipment. Injuries result because of unguarded access to the point of operation at the front of the machine and the operator’s ability to reach around the safety device to get to the point of operation at the side or back of the machine. Also, the back-gauge system creates pinch points and poses a risk to the operator with its hazardous motion. Although rare, operators also can experience blunt force trauma after being struck by ejected materials.

But perhaps the greatest threat linked to running press brakes is having the operator’s hand trapped between the part being bent and the frame of the machine (see Figure 1). If the force is great enough or the part is sharp enough, impalement or an amputation can occur.

Another factor contributing to the dangers of press brakes is the metal fabricator’s failure to perform an upfront risk assessment. This type of assessment is the critical first step in any safeguarding project and, unfortunately, seldom completed. An overall risk assessment considers hazard severity, frequency of exposure, and probability of injury, as suggested by ANSI B11.0-2015. Risk or machine safeguarding assessments should be done before commissioning any new machinery, after upgrading existing machinery, after changing the work area, and after any accident or serious incident.

Yet another dynamic contributing to press brake injuries is lack of press brake maintenance, in particular testing safety devices to ensure they are working properly and in the correct position. An unmaintained press brake, especially one with damaged tooling, can put both the machine and operator at risk for serious injury.

All of these issues can be addressed in a few moments. It is time well spent to ensure that the machine is safe to operate. Having said that, not all shops will commit to that type of preparedness and maintenance. So it’s not a question of if an operator will get hurt by a press brake; it’s a question of when.

What Are the Safety Standards?
The Occupational Safety and Health Administration (OSHA) does not specifically address mechanical or hydraulic press brakes, but the machines are commonly cited under the general duty clause 1910.212, which covers failure to provide adequate protection for plant employees from known machine hazards. Most commonly, the industry follows the ANSI standard for press brakes, ANSI B11.3, for safeguarding method guidance and then ANSI B11.19 for design criteria.

The original B11.3 standard was approved in 1973 and revised in 1982 and again in 2002. The current 2012 standard, ANSI B11.2-2012, includes the new topics of close proximity point of operation, active opto-electronic protective devices (AOPD), and a safeguarding means called safe speed.

Safe speed is protection for the operator when safeguarding is not provided by a light curtain, such as after the optical system is muted for the bending operation to occur. Safe speed must be monitored automatically, so the press brake ram does not exceed 10 mm/s and for the machine closing movement to be stopped if this limit is exceeded. To insert these new safe speed requirements into B11.3, the committee drew on experience with this requirement in Europe and its corresponding EN 12622 standard.

Does Safeguarding Hinder Productivity?
A widespread misconception in the industry is that safeguarding a press brake prevents or hinders employees from making production quotas. However, an Aberdeen Group research study (“Integrated Safety Systems: Ensuring Safety and Operational Productivity”) concluded that companies that have taken steps to invest in safeguarding not only improve plant safety, but realize superior operational performance and overall equipment effectiveness (OEE). The 20 percent of best-in-class companies that had the highest OEE also had the lowest safety incident rate. The top companies typically had an OEE on average of 90 percent and an injury incident rate of 0.05 percent, while the bottom 20 percent of companies had an OEE of 76 percent and an injury frequency rate of 3 percent, which is 60 times higher. Top manufacturers were also able to achieve a 2 percent unscheduled asset downtime rate, versus a 14 percent rate for the laggard group in the study.

Figure 1
When it comes to older bending machinery, nothing really acts as a barrier between the press brake and the machine’s operator.

What makes these statistics possible is modern safeguarding tools. Some of these options are awareness and barrier guards, light curtains, two-hand controls, and laser AOPD.

First, however, a word or two about retrofitting. When retrofitting older machines, installers must take great caution to ensure that the new technology does not decrease the safety of the machine or add new hazards. Sometimes an older machine simply cannot be brought up to today’s standards. At that point the installer must evaluate the situation and ensure the full machine installation becomes safer overall than its original state with the new safeguarding. If not, he needs to step back and consider the options. ANSI B11.3-2012 gives direction on this topic.

Awareness Barrier. The backs of press brakes cannot be left wide open. Two hazards often lurk here: reaching the dies from the back and the possibility of a multi-axis back gauge moving and creating pinch points. As to exactly what is required on the back of equipment often depends on local OSHA interpretation. At the very least, an awareness barrier, like a railing, chain, or cable with a “danger” or “warning” sign complete with pictographs, not just verbiage, should be installed. Awareness barriers are bare-minimum methods in reducing risk.

Barrier Guards. Although not versatile, barrier guards on the ends of most press brakes are effective when used in conjunction with other safeguarding devices (see Figure 2). They also can be used to mount/support light curtains, adding to their value. Barriers can have openings for material to be fed into the die area, but do not allow for hands into that area.

Barrier guards reduce the risk of the operator getting his hands pinched when he reaches between the punch and die from either side of the press brake or reaches between the back-gauge system and tool. By OSHA’s definition, a guard must prevent people from reaching over, under, through, or around it. Guards must meet one of two measurement scales—the OSHA guard opening scale or the ANSI/CSA guard opening scale—to ensure that a small hand can’t reach far enough through any opening to get hurt.

Barrier guards can be fixed or interlocked. The interlocked design prevents misuse and is required to be either electrically interlocked or fixed in place using a fastener that requires a tool for removal. They’re often hinged or sliding to allow easy access to the point of operation for machine setup (access to limit switches or other levers and dials), tool change, or maintenance tasks.

Light Curtains. These safeguarding tools have been around since the mid-1950s. They consist of a vertically mounted transmitter and receiver with closely spaced beams of laser creating a flat sensing field. When fingers, hands, or arms reach through that sensing field, the press cycle is prevented or stopped to avoid operator injury.

One of the reasons that press brakes make a good application for light curtains is that they can be stopped midcycle very quickly. Hydraulic press brakes stop quickly if maintained properly. Mechanical press brakes may not. Air clutch machines have reasonable stop times, but mechanical friction clutch (MFC) machines are known for stopping very slowly. Quite often light curtains can’t be used on MFC press brakes because the safety distance can end up being 2 to 3 feet.

Like any safeguarding device, light curtains should be “function-tested” before every operating shift to ensure that they are continuing to provide protection. Make/model-specific function-test procedures are usually available on each light curtain manufacturer’s website.

Two-Hand Controls. These controls are considered a safer means of cycling a press than a footswitch because both hands must be in a safe position to use them. When a press is cycled with a footswitch, hands can be anywhere. It’s possible to use a two-hand control as a safeguarding device as well during press brake operation.

Figure 2
The barriers on the side of this press brake have light curtains attached to them, providing the press brake operator with two layers of protection.

Most operations require that the part be held when bending, so two-hand control is rarely used to cycle a press brake or used as the point-of-operation safeguard. The part would have to be fixtured and supported by a backgauge to use a two-hand control.

Laser AOPD. The newest entry into the press brake safety category is the laser AOPD (see Figure 3). Inclusion of laser AOPD technology in the B11.3-2012 is a welcome addition to the standard that now gives press brake manufacturers, dealers, and users a clear guideline to implementing this technology safely for retrofit applications (B11.3 subclause 8.8.7 —Close Proximity Point of Operation AOPD Safeguarding Device).

It is important to note here that AOPDs are an acceptable method of safeguarding hydraulic press brakes only per ANSI B11.3 and also following most manufacturers’ specifications.

A unique feature of AOPDs is that they are designed to be mounted with zero safety distance, unlike light curtains that must be mounted at a calculated safety distance (see Figure 4), as outlined in ANSI B11.3. Safe speed safeguarding is based on a ram speed of 10 mm/s or less, providing that speed is carefully monitored. Again, this new method of protection can be applied only to hydraulic press brakes (and potentially servo-drive press brakes). Because of their close proximity point of operation, AOPD systems are best-suited for applications such as box bending, bending with flanges, or where light curtain effectiveness is diminished due to excessive blanking or muting.

Press brakes are very dangerous machines, much more so without proper safeguarding equipment. When safeguarding equipment is engineered, installed, and operated correctly, it provides positive, business-enhancing benefits while mitigating risks and reducing insurance and energy costs. Metal fabricators also should recognize the payback of reducing costs associated with accidents, medical expenses, and regulatory noncompliance.

For more information about safeguarding press brakes, please contact us at 1-800-922-7533.

Ten Most Reported Worker’s Compensation Injuries

Last year in America 2.9 million employees (U.S Bureau of Labor Statistics) suffered a workplace injury from which they never recover, at a cost to business of nearly $60 billion (Liberty Mutual Insurance). These statistics are staggering. To help gain a better perspective on the realities of workplace danger, we have compiled a list of the ten most reported worker’s compensation injuries, as reported by a leading insurance company.

By raising awareness of these dangers, we hope we can help you identify hazards in your workplace and take measures to control the risks preferably by eliminating them – but if that is not possible, by reducing them as far as possible.

1. Overexertion– These are injuries due to excessive physical effort such as lifting, pulling, pushing, turning, wielding, holding, carrying or throwing. The Liberty Mutual Workplace Safety Index, which is compiled using Bureau of Labor Statistics (BLS) data, workers’ compensation claims reported to the National Academy of Social Insurance and compensation benefits paid by Liberty Mutual, indicates that overexertion accounts for more than 25 percent of direct workers’ compensation costs paid out annually.

2. Slips – Slipping accidents are the second leading cause of workers’ compensation claims and the top cause of workplace injuries for workers 55 and older, as reported by the National Flooring Safety Institute. In a hard fall, a worker may sustain injuries to the knee or ankle, wrist or elbow, back or shoulder, hip or head. Employers need safety guidelines to ensure spills are promptly cleaned and no debris is present which can be dangerous.

3. Falling – In 2013, 595 workers died in elevated falls, and 47,120 were injured badly enough to require days off of work. A worker doesn’t have to fall from a high level to suffer fatal injuries. While half of all fatal falls in 2016 occurred from 20 feet or lower, 11% were from less than 6 feet. Not surprisingly, construction workers are most at risk for fatal falls from height – more than seven times the rate of other industries. These types of accidents can be reduced by the use of proper personal protection gear, training and employee diligence.

4. Bodily Reaction– Coming in at number four are reaction injuries caused by slipping and tripping without falling, often leading to muscle injuries, body trauma, and a variety of other medical issues. Although these injuries may sound non-serious, insurance companies paid out $3.89 billion in workers’ compensation in 2016 for bodily reaction incidences (Liberty Mutual Insurance).

5. Falling Object Injuries – There are more than 50,000 “struck by falling object” injuries every year in the United States, says the Bureau of Labor Statistics. That’s one injury caused by a dropped object every 10 minutes. How serious is the danger? Consider this: an eight-pound wrench dropped 200 feet would hit with a force of 2,833 pounds per square inch – the equivalent of a small car hitting a one-square-inch area. Proper personal protection gear usage, such as a hard hat, can be instrumental in keeping the employee safe.

6. Distracted Walking Injuries – They may seem funny in slapstick comedies, but distracted walking injuries in the workplace were recently labeled a “significant safety threat” by the National Safety Council. These injuries occur when a person accidentally runs into walls, doors, cabinets, glass windows, tables, chairs or other people. Head, knee, neck, and foot injuries are common results. As with distracted driving accidents, it is difficult to track the number of occupational injuries caused by distracted walking, since workers might be reluctant to admit they were looking down at their cell phones when they were injured.

7. Vehicle Accidents – Accidents are common in workplace environments using cranes, trailers and trucks. According to the Bureau of Labor Statistics more than 1,700 deaths a year result from occupational transportation incidents. Employee Safe Driver training courses are likely to reduce vehicle accidents that may injure employees. Managers are required to conduct routine vehicle maintenance to ensure vehicles are operating safely and properly.

8. Machinery Accidents – Machines used in the workplace are often operated without safety guards and devices, exposing their operators and others to serious injury. Common injuries involve clothing or hair becoming caught in moving parts. Many of the amputations that occur on machinery can be prevented by updating machines with appropriate safeguarding. Electrical updates for magnetic motor-starters, main power disconnects, and emergency-stops, also help to prevent injury. OSHA regulations and ANSI safety standards spell out safety modifications that can prevent needless accidents. Learn more about how Rockford Systems, a leader in machine safeguarding, will help you create a safer workplace with their extensive line of innovative safeguarding solutions.

9. Repetitive Motion Injuries – Thousands of employees suffer from injuries that occur gradually and make it difficult to do daily tasks, such as typing, twisting wires, using hand tools, or bending over to lift objects. These are called repetitive motion injuries and strain muscles and tendons. Over time it will lead to back pain, lumbar injuries, tendonitis, bursitis, vision problems, or carpal tunnel syndrome. Repetitive motion injuries may be temporary or permanent. Employee training and the use of proper ergonomic tools can help keep these incidents low.

10. Workplace Violence – According to OSHA, workplace violence is any act or threat of physical violence, harassment, intimidation, or other threatening disruptive behavior that occurs at the work site. It ranges from threats and verbal abuse to physical assaults and even homicide. Nearly 2 million American workers report having been victims of workplace violence each year. Unfortunately, many more cases go unreported. Workplace violence employee training and employee diligence in watching out for suspicious activities can help keep these incidents at bay. One of the best protections employers can offer their workers is to establish a zero-tolerance policy toward workplace violence.

Workplace injuries can leave the lives of employees and their families shattered. Employers have legal obligations to ensure a safe workplace for their employees – and also for anyone else who may visit the workplace such as customers, contractors and members of the public.

Work Safety Topics

Did you know that June is National Safety Month? Rockford Systems has partnered with the National Safety Council to promote safety to our valued customers!

Nearly 13,000 American workers are injured each day, and each injury is preventable. Here are some of the safety topics NSC is focusing on.

Fatigue
Adults need seven to nine hours of sleep each day to reach peak performance, but nearly one-third report averaging less than six hours. The effects of fatigue are far-reaching and can have an adverse impact in all areas of our lives.
· Safety performance decreases as employees become tired
· You are three times more likely to be in a car crash if you are fatigued
· Chronic sleep-deprivation causes depression, obesity, cardiovascular disease and other illnesses

Drugs at Work
Drug use at work is a safety topic that is gaining attention. Lost time, job turnover, re-training and healthcare costs are three of the primary implications of drug use regularly confronted by employers. The typical worker with a substance use disorder misses about two work weeks (10.5 days) for illness, injury or reasons other than vacations and holidays.
· Workers with substance use disorders miss 50% more days than their peers, averaging 14.8 days a year
· Workers with pain medication use disorders miss nearly three times as many days – 29 days
· Workers in recovery who report receiving substance use treatment miss the fewest days of any group – 9.5

Driving
Many employers have adopted safe driving policies that include bans on cell phone while driving and on the job. NSC has created a Safe Driving Kit with materials to build leadership support for a cell phone policy and tools to communicate with employees.

Workplace Violence
Every year, 2 million American workers report having been victims of workplace violence. This violence fits into four categories: criminal intent, customer/client, worker-on-worker and personal relationship (most involving women).
The deadliest situations involve an active shooter.

Every organization needs to address workplace violence through policy, training and the development of emergency action plans. While there is no way to predict an attack, you can be aware of warning signals that might signal future violence.

Slips, Trips and Falls
You might be surprised to learn that falls account for the third-highest total unintentional deaths every year in the United States. Fatalities as a result of falls are surpassed only by poisoning (including deaths from drugs and medicines) and motor vehicle crashes.

Fall safety should be a top priority. Construction workers are at the most risk for fatal falls from height, but falls can happen anywhere, and it is important to recognize potential hazards, both on the job and off. Plan ahead and use the right equipment.

Ergonomics and Overexertion
Overexertion causes 35% of all work-related injuries and is the No. 1 reason for lost work days. Regular exercise, stretching and strength training can prevent injury. Likewise, ergonomic assessments can ward off ergonomics injuries, often caused by excessive lifting, lowering, pushing, pulling, reaching or stretching.

Struck by Objects
While employers are responsible for providing a safe work environment, employees can take steps to protect themselves at work. Paying attention is vitally important for those operating machinery as well as those working around power tools and motor vehicles.

Source: National Safety Council

Avoiding Pinch-Point Injuries on Riveters and Welders

Pinching your finger in a door can be painful but certainly not life threatening. Pinch-point injuries involving industrial machinery are another story, one that rarely has a happy ending.

What is a pinch point?
A pinch point is “any point at which it is possible for a person or part of a person’s body to be caught between moving parts of a machine, or between the moving and stationary parts of a machine, or between material and any part of the machine,” according to OSHA. A pinch point can be located anywhere on a machine, including the point of operation. If any part of the worker’s body, typically hands or fingers, occupies that space during the pinching movement, there is a high probability of injury, such as fractures, amputations, contusions, lacerations or even death. Pinch-point hazard injuries can occur on a variety of different machine types, ranging from large hydraulic presses to small specialized machines, such as riveters and welders.

Hand safety regulation
There are several important U.S. hand protection standards designed to help employers keep workers’ hands safe at work: ANSI/ISEA 105-2011, American National Standard for Hand Protection Selection Criteria, and OSHA’s 29 CFR 1910.138.

Physical Barriers: Eliminate the hazard by ensuring proper machine guarding is in place or keeping your hands away from pinch point hand injury and prevention altogether.

Awareness: Pay attention to where your hands are around any moving parts or any objects that have the potential to move. Do not place your hands where you cannot see them.

Spot Welding
Personal Protective Equipment (PPE): Make sure you are always wearing your safety gear and inspect it before each use. Although the last line of defense against a pinch point injury, PPE (proper gloves, footwear) is a necessity to ensure others notice your position and your extremities are protected. Make sure clothing is properly fitted as to not get caught in machinery, moving parts, items that open/close, etc.

Properly block any equipment or parts where stored energy could be released. OSHA defines stored energy as hazardous energy sources including electrical, mechanical, hydraulic, pneumatic, chemical, thermal or other sources in machines and equipment that can be hazardous to workers. During the servicing and maintenance of machines and equipment, unexpected startup or release of stored energy could cause injury to employees. Lockout-tagout procedures need to be put into place to control hazardous energy and prevent unexpected start up.

Properly installed physical barriers or machine guards can help prevent workers from reaching into, through, over, under or around the pinch point.

Riveters & welders
We will be looking at “Good, Better, Best” approaches to safeguarding two machine types that present unavoidable pinch-point hazards – spot welders and pneumatic riveters. It is important to appreciate the magnitude of force between spot welding electrodes or riveting tips.

Spot welders require high forces between the moving electrodes ranging from a few hundred pounds to several thousand pounds. Because the force is concentrated on a small contact surface, the pounds per square foot can be extremely high. For example, a fairly typical electrode of 800 pounds with an electrode that has a ¼ inch diameter contact face will deliver 16,306 pounds per square foot. This is easily enough to severely crush or amputate a finger. Similarly, pneumatic riveting machines produce several thousand pounds of force concentrated on small-diameter mandrils. A typical rivet force of 2,000 pounds will deliver over 40,000 pounds per square inch.

Two-hand control and light curtains can be used to safeguard riveters and welders capable of stopping on the down-stroke (hazardous portion of the cycle, creates the pinch point).

Good: Drop-probe devices
Drop-probes provide economical, simple to understand and use, reliable protection for the operator. Drop-probe devices function by allowing a sensing probe to drop by gravity around the point-of-operation hazard of a riveter or welder prior to each intended machine cycle. The sensing probe cycle is initiated when the foot switch is pressed. If the sensing probe encounters the operator’s fingers and fails to drop past a preset position, the machine will not complete the cycle until the obstruction is cleared and the cycle is re-initiated.

Drop-probe devices can be used on machines that run in an automatic mode, but they only provide risk reduction for the first stroke.

The drawbacks of traditional drop-probe devices are:
– Stroke adjustment is limited to 1-5/16 inches.
– Uses a 50-percent duty rotary solenoid. It needs an equal amount of work time vs. rest time, so it’s not an ideal solution for high-volume welding or riveting applications.

Better: Adjustable stroke drop-probes
Identical in most ways to standard drop-probes, adjustable models offer an externally adjustable stroke, via a clamp collar, typically from 0 to 4.0 inches to accommodate any fixture, tooling, or changes in the profile of the workpieces.

Advantages of this device are:
– Longer stroke adjustment (4-½ inches versus 1-5/16 inches).
– Uses an air cylinder to move the drop probe, which is better suited for high-volume applications.

Best: Continuity monitoring
The most unique and highly effective guarding device measures electrical continuity between the two electrodes to verify they are actually touching the part to be welded, or in the case of a riveter, continuity between the upper and lower mandrils. If anything, such as the operator’s finger, blocks the movement of the electrode, the system will not detect continuity. In other words, it must detect metal between the copper tips or riveting mandrils rather than a finger.

When the foot pedal is closed, the electrodes are close under low force (50 pounds or less).
– If continuity is detected within a customer-set maximum detect time, the air pressure rises to the full welding or riveting level and the process runs through completion.
– If continuity is not detected within this maximum time, low pressure will be released and the electrode or mandril returns to the fully open position.

The continuity signal in a spot welder is picked up from wires on the welding transformer secondary pads, eliminating the need for wire connections at the electrodes. For riveters the sensing wires are connected to the frame of the rivet machine and the electrically-isolated lower tooling holder. In both cases the system will fail safe (lock out) if either of the pick-up wires is disconnected or if they are shorted together.

Rockford Systems offers the Unitrol SOFT TOUCH Pinch-Point Safety System that is the first and only fully passive safeguarding equipment designed to prevent a pneumatic riveter, welder or other small machine from applying full force if it detects fingers in the machine’s point-of-operation area. SOFT TOUCH measures electrical continuity between electrodes to verify they are actually touching the part to be welded — and not the operator’s fingers. If anything other than metal is present between the electrodes, their sensors will not detect continuity and the electrodes will open automatically. This simple step prevents the machine from delivering high-pressure riveting or welding force onto the operator’s fingers.

Conclusion

Pinch-point injuries are common and employers have an obligation to keep worker’s hands safe from pinch-point hazards. As outlined by ANSI B.11, task-based risk assessments are the critical first step in any safety evaluation and can identify hazards, such as pinch-point hazards. Risk-control factors, such as machine guarding, proper training and awareness of hand locations, and lockout tagout procedures, all help prevent pinch-point injuries. Devices, such as SOFT TOUCH, are the best method of safeguarding against pinch-point injuries as it features a 100% passive, fail safe method of detecting continuity.