Machine Risk Assessment vs. Safeguarding Assessment? Start 2020 off on the right safety foot.

When it comes to accidents, manufacturing ranks second highest of all industries. That comes despite OSHA regulations and American National Standards Institute (ANSI) standards. A key culprit is unguarded hazardous machinery.

Year after year, OSHA issues thousands of citations and levies millions of dollars in fines for machine safeguarding violations in an attempt to prevent injuries and save lives OSHA 1910.212(a)(1) is the most common section citation, whereby “one or more methods of machine guarding shall be provided to protect the operator and other employees in the machine area from hazards” followed by OSHA 1910.212(a)(3)(ii) whereby “the point of operation of machines whose operation exposes an employee to injury shall be guarded.

Why the disregard?

Why is this so? Often facility safety managers are lulled into a false sense of security because a serious accident has not yet occurred or because accidents are rare in their facility. Other managers might wrongly suppose that their newly purchased machinery arrives fully compliant, not realizing that OEMs are typically concerned with new machinery price competitiveness, not necessarily guarding compliance. Still other managers may wrongly assume that older machines are “grandfathered in” before OSHA was formed.

For whatever reason, approximately HALF of industrial machinery has not been properly safeguarded.

That is the bad news.

The good news is there is a way to determine compliance through an assessment of the machinery on the plant floor, as outlined by ANSI B11.0. There are two types of assessments that reign supreme: the Risk Assessment and the Safeguarding Assessment. This article will address both methods and how they help an organization better protect the people operating the machines and reduce the risk at the facility.

Risk assessments should be conducted annually, including whenever a new machine is installed or a major change to an existing machine or production line has taken place. Additionally, in an ideal world, a pre- and post-assessment would be done to verify that the hazards identified in the assessment were properly mitigated.

Risk assessment

What a risk assessment is comprised of is outlined in ANSI B11 Series Standards for Industrial Machinery, ANSI/RIA R15.06-2012 Safety Standards for Industrial Robots, and the National Fire Protection Association (NFPA) 79-2015 Electrical Standard for Industrial Machinery.

The overarching goal of a task-based risk assessment is to identify hazards associated with machinery or robots. This requires an on-site visit by a risk assessment professional who audits and assigns each machine a risk rating based on three considerations: Severity of Injury, Exposure Frequency, and Avoidance Likelihood, which produces a Risk Level. Today’s risk assessment specialists use software-based tools that can make the process quicker than working through a pen-and-paper risk assessment form.

In advance of the facility visit and based upon project scope, the risk assessment specialist will need to review a comprehensive machine list and potentially other documentation such as: corporate safety standards, lockout/tagout (LOTO) procedures, electrical and mechanical drawings, floor-plan layout and equipment manuals.

The scope of assessing a piece of machinery for risk begins with reviewing its operational states with functionality tests performed to help identify potential hazards during machine start-up, cycle, and stopping. The risk assessment specialist may perform a Stop-Time Measurement (STM) test to determine the machine’s reaction time after receiving a stop signal to ensure proper safety distance of safeguarding devices. The specialist will also establish if a passerby or other employees in the area could be hurt if an incident occurs, in addition to the operator.

Along with assessing the production risks of the machine, the risk assessment specialist must analyze the tasks performed by the machine operator as they relate to interacting with the machine, loading and unloading materials, planned and unplanned maintenance methods, frequency of tool changes, and general housekeeping.

During the risk assessment, the specialist will photograph machines and generate a final hazard report documenting their assessment findings and risk levels. The hazardous findings of each machine are broken down into the following ranked classifications:

Critical: There is an imminent life-threatening or dismemberment hazard and immediate action is needed to reduce risk and improve operator safety
Mandatory: There is an imminent hazard that creates potential for injury and action is required to reduce risk, improve operator safety and to comply with OSHA/ANSI standards
Compliant: There is not a recognized hazard that creates potential for injury and no action is required.

Safeguarding assessment

While a risk assessment helps to identify a problem, it does not provide specific safety solutions nor cost estimates. For that, a safeguarding assessment is needed.

During the safeguarding assessment, a specialist will visit the site and conduct an intensive audit of each machine and identify compliance in five guarding areas: safeguards, controls, disconnects, starters and covers. The safeguarding specialist may request copies of electrical, pneumatic or hydraulic schematics, operator manuals and ask for control panel access so that engineers can review the control circuit for electrical compatibility of any proposed safeguarding solutions and to verify reliability of the control circuit to determine the interfacing requirements of suggested equipment. Then the safeguarding specialist will focus on risk reduction using this basic methodology:

– Eliminate Access — A good safeguarding system eliminates the possibility of the operator or other workers placing parts of their bodies near hazardous moving parts.
Reduction in Exposure — A machine safeguard should not be able to be removed, bypassed or tampered with by the operator. To minimize risk exposure, all guards and devices must be securely mounted at the point-of-operation and durable enough to withstand industrial environments, vandalism and heavy usage.
– Create No New Hazards — A safeguard defeats its own purpose if it creates a hazard of its own such as a shear point, a jagged edge, or an unfinished surface which can cause a laceration. The edges of guards, for instance, should be rolled or bolted in such a way that they eliminate sharp edges.
– Create No Interference — Any safeguard which impedes a worker from performing a job quickly and comfortably might soon be overridden or disregarded. Proper safeguarding can actually enhance efficiency since it can relieve the worker’s apprehensions about injury.
– Allow Safe Lubrication — Locating oil reservoirs outside the guard, with a line leading to the lubrication point, will reduce the need for the worker to enter the hazardous area.
Administrative Controls — Without administrative oversight and supervisory control, a machine safeguarding program will fail. Training is key to establishing a safety culture. Operators need to trained to follow the Standard Operating Procedures provided by the machine manufacturer in order to reduce hazards and related risks.

Uncovering gaps in protection

Unlike a risk assessment, a safeguarding assessment recognizes both the problem and the solution. A final compliance report and safeguarding project proposal is issued to facility management which identifies deficiencies or gaps where each machine is not in compliance with current or specified regulations and standards. When not in compliance, the proposal offers standard and customized safeguarding solutions, along with associated costs and timelines to help bring machines into compliance and reduce risk. Each proposed solution is carefully weighed against factors such as risk-reduction benefit, productivity, technological feasibility, economic impact, and maintainability.

In this way, a machine safeguarding assessment follows the OSHA/ANSI approach to controlling machine hazards: eliminate the hazard by design; or control the hazard by guarding, posted warnings, personal protective equipment, and employee training.

Risk reduction strategies

When evaluating risk reduction solutions to address identified hazards, consider each machine and its unique risks. Three basic methods are available.
– Eliminating or reducing risks to a “tolerable” level by installing a new, inherently safe machine. Please note that what constitutes “tolerable” to one company is not necessarily tolerable to another.
– Installing the necessary safeguarding equipment on an existing machine to minimize risks that cannot be eliminated. Fixed enclosing guards, protective devices such as light curtains, palm buttons or presence sensing mats, and training on the safe working methods of the machine are all necessary to reduce injury risks.
– Changing the production process to eliminate the hazard. Perhaps the operator performs actions that increase his exposure to serious hazards? Or recent changes upstream have created a more dangerous environment? Even a small change in procedures can make for a safer, more efficient operation.

Conclusion

Both risk assessments and/or the safeguarding assessments are critical first steps in any machine or robot safeguarding project as outlined in ANSI B11 Series Standards for Metalworking, OSHA 1910.212 General Requirements, ANSI/RIA R15.06-2012 Safety Standards for Industrial Robots and NFPA 79. These standards pave the way for risk-reduction measures that are both effective and economical. Machine risk assessments provide a comprehensive hazard analysis with a risk ranking; machine safeguarding assessments identify safeguarding solutions and provide cost estimates for implementation. Which one is right for an organization depends upon the specific needs of the organization, the organization’s objectives, desired outputs and risk levels.

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I, COBOT

I, COBOT: The Rise of Industrial Robotics and the Need for Employee Safeguarding

In general, OSHA’s view on robot safety is that if the employer is meeting the requirements of ANSI/RIA R15.06, the manufacturer has no issues.

Tech executive and billionaire entrepreneur Elon Musk recently took to Twitter calling for the regulation of robots and Artificial Intelligence (AI), saying their potential, if left to develop unchecked, threatens human existence. Google, Facebook, Amazon, IBM, and Microsoft joined in with their own dire forecasts and have jointly set up the consortium “Partnership on AI to Benefit People and Society” to prevent a robotic future that looks not unlike the “Terminator” movie series. National media heightened panic by broadcasting a video released by a cybersecurity firm in which a hacked industrial robot suddenly begins laughing in an evil, maniacal way and uses a screwdriver to repeatedly stab a tomato. The video demonstrated how major security flaws make robots dangerous, if not deadly.

Is all this just media hyperbole, or are robots really that hazardous to our collective health? Are productivity-driven manufacturers unknowingly putting employees at risk by placing robots on the plant floor? What kind of safeguarding is required? Should robots be regulated, as Elon Musk believes?

‘Dumb’ Machines vs. Cobots
Until now, the robots used in manufacturing have mostly been “dumb” robots—that is, room-sized, programmed machinery engineered to perform repetitive tasks that are dirty, dangerous, or just plain dull. Typical applications would include welding, assembly, material handling, and packaging. Although these machines are very large and certainly have enough power to cause injuries, the instances of employees actually being injured by robots is relatively rare. In fact, during the past three decades, robots have accounted for only 33 workplace deaths and injuries in the United States, according to data from the Occupational Safety and Health Administration (OSHA).

So, you might ask, why the sudden uproar when there are already 1.6 million industrial robots in use worldwide? Most of the clamor behind calls for regulation stems from a new generation of robots called “cobots” (collaborative robots) that are revolutionizing the way people work. Unlike standard industrial robots, which generally work in cages, cobots have much more autonomy and freedom to move on their own, featuring near “human” capabilities and traits such as sensing, dexterity, memory, and trainability.

The trouble is, in order for cobots to work productively, they must escape from their cages and work side by side with people. This introduces the potential for far more injuries. In the past, most injuries or deaths happened when humans who were maintaining the robots made an error or violated the safety barriers, such as by entering a cage. Many safety experts fear that since the cage has been all but eliminated with cobots, employee injuries are certain to rise.

Because cobots work alongside people, their manufacturers have added basic safety protections in order to prevent accidents. For instance, some cobots feature sensors so that when a person is nearby, the cobot will slow down or stop whatever function it is performing. Others have a display screen that cues those who are nearby about what the cobot is focusing on and planning to do next. Are these an adequate substitute for proven safeguarding equipment? Only time will tell.

There is another, more perilous problem with robots in general: Robots are basically computers equipped with arms, legs, or wheels. As such, robots are susceptible to being hacked. But unlike with a desktop computer, when a robot is hacked it has the ability to move around. For instance, a disgruntled ex-employee could hack into a robot and re-program it to harm people and destroy property. The more functionality, intelligence, and power a robot has, the bigger its potential threat.

Types of Injuries
OSHA lists four types of accidents resulting from robot use in the Technical Manual “Industrial Robots and Robot System Safety” (Section IV: Chapter 4).
1. Impact or collision accidents. Unpredicted movements, component malfunctions, or unpredicted program changes related to the robot’s arm or peripheral equipment could result in contact accidents.
2. Crushing and trapping accidents. A worker’s limb or other body part can be trapped between a robot’s arm and other peripheral equipment, or the individual may be physically driven into and crushed by other peripheral equipment.
3. Mechanical part accidents. The breakdown of the robot’s drive components, tooling or end-effector, peripheral equipment, or its power source is a mechanical accident. The release of parts, failure of gripper mechanism, or the failure of end-effector power tools (e.g., grinding wheels, buffing wheels, deburring tools, power screwdrivers, and nut runners) are a few types of mechanical failures.
4. Other accidents. Other accidents can result from working with robots. Equipment that supplies robot power and control represents potential electrical and pressurized fluid hazards. Ruptured hydraulic lines could create dangerous high-pressure cutting streams or whipping hose hazards. Environmental accidents from arc flash, metal spatter, dust, electromagnetic, or radio-frequency interference also can occur. In addition, equipment and power cables on the floor present tripping hazards.

Robot Safety Regulations
Robots in the workplace are generally associated with machine tools or process equipment. Robots are machines, and as such, must be safeguarded in ways similar to those presented for any hazardous remotely controlled machine, falling under the OSHA General Duty Clause (5)(a)(1), which requires employers provide a safe and healthful workplace free from recognized hazards likely to cause death or serious physical harm. Also applicable are OSHA 1910.212 (a)(1) “Types of Guarding” and 1910.212 (a)(3)(ii) “The point of operation of machines whose operation exposes an employee to injury shall be guarded.”

Various techniques are available to prevent employee exposure to the hazards that can be imposed by robots. The most common technique is through the installation of perimeter guarding with interlocked gates. A critical parameter relates to the manner in which the interlocks function. Of major concern is whether the computer program, control circuit, or the primary power circuit is interrupted when an interlock is activated. The various industry standards should be investigated for guidance; however, it is generally accepted that the primary motor power to the robot should be interrupted by the interlock.

In general, OSHA’s view on robot safety is that if the employer is meeting the requirements of ANSI/RIA R15.06, Industrial Robots and Robot Systems—Safety Requirements, then the manufacturer has no issues. For guidance on how to select and integrate safeguarding into robot systems, refer to the Robotic Industries Association’s Technical Report: RIA TR R15.06-2014 for Industrial Robots and Robot Systems—Safety
Requirements and Safeguarding.

Published by the American National Standards Institute (ANSI) and Robotic Industries Association (RIA), ANSI/RIA R15.06 is a consensus standard to provide guidance on the proper use of the safety features embedded into robots, as well as how to safely integrate robots into factories and work areas. The latest revision of the standard, ANSI/RIA R15.06-2012, references for the first time ISO 10218-1 & 2 to make it compliant with international standards already in place in Europe. Part 1 of ISO 10218 details the robot itself; Part 2 addresses the responsibilities of the integrator.

There are also new requirements in ANSI/RIA R15.06-2012 for collaborative robots; in this case, ISO 10218 and the ISO/TS 15066 Technical Specification. This standard clarifies the four types of collaboration: Safety Monitored Stop, Hand Guiding, Speed & Separation Monitoring, and Power & Force Limiting. ISO/TS 15066 holds key information, including guidance on maximum allowable speeds and minimum protective distances, along with a formula for establishing the protective separation distance and data to verify threshold limit values for power and force limiting to prevent pain or discomfort on the part of the operator.

The requirement for risk assessments is one of the biggest changes in the new RIA standard. The integrator, or the end user if they are performing the job of an integrator, now must conduct a risk assessment of each robotic system and summarize ways to mitigate against these risks. This may involve procedures and training, incorporating required machine safeguarding, and basic safety management. Risk assessments calculate the potential severity of an injury, the operator’s exposure to the hazard, and the difficulty in avoiding the hazard to arrive at a specific risk level ranging from negligible to very high.

In the future, as cobot use rapidly expands throughout industry, regulation of this technology will grow more focused and specific. Consider this: Although cobots currently represent only 3 percent of all industrial robots sold, they are projected to account for 34 percent of the industrial robots sold by 2025, a market that itself is set to triple in size and dollar volume over that period.

Conclusion
The next 10 years will be pivotal for American manufacturing, and success largely depends on companies’ ability to navigate the transition from traditional manufacturing to Industry 4.0-style automation and the widespread use of robots. While few people have as dire a view as Elon Musk on the subject, it is critical that employee safety is not lost in the excitement as we shepherd robots out of their cages to work hand in hand with humans.

Playing It Safe With Robotics

OVERVIEW

Robotics is a growing field as more and more companies are incorporating industrial automation into their production processes. In just the first nine months of 2016, 23,985 robots were ordered from North American companies, many of which require machine guarding equipment to maximize productivity and safety. Robots are used for replacing humans who were performing unsafe, hazardous, highly repetitive, and unpleasant tasks. They are utilized to accomplish many different types of application functions such as material handling, assembly, arc welding, resistance welding, machine tool load/unload functions, painting/spraying, etc.

POTENTIAL HAZARDS
Studies indicate that many robot injuries occurring in robotic automation typically occur during non-routine operating conditions, such as programming, maintenance, repair, testing, setup, or adjustment when the worker may temporarily be within the robot’s working envelope.

Non-Safeguarded Robots
Non-Safeguarded Robots

As stated by OSHA, mechanical hazards might include workers colliding with equipment, being crushed, or trapped by equipment, or being injured by falling equipment components. For example, a worker could collide with the robot’s arm or peripheral equipment as a result of unpredictable movements, component malfunctions, or random program changes. The worker could be injured by being trapped between the robot’s arm and other peripheral equipment or being crushed by peripheral equipment as a result of being impacted by the robot into this equipment.

Mechanical hazards also can result from the mechanical failure of components associated with the robot or its power source, drive components, tooling or end-effector, and/or peripheral equipment. The failure of gripper mechanisms with resultant release of parts, or the failure of end-effector power tools such as grinding wheels, buffing wheels, deburring tools, power screwdrivers, and nut runners are a few of the possibilities.

Non-Safeguarded Robot
Non-Safeguarded Robot

Human errors can result in hazards both to personnel and equipment. Errors in programming, interfacing peripheral equipment, connecting input/output sensors, can all result in unpredictable movement or action by the robot which can result in personnel injury or equipment breakage.

Human errors in judgment frequently result from incorrectly activating the teach pendant or control panel. The greatest human judgment error results from becoming so familiar with the robot’s redundant motions that personnel are too trusting in assuming the nature of these motions and place themselves in hazardous positions while programming or performing maintenance within the robot’s work envelope.

SAFEGUARDING AUTOMATION CELLS

Robots in the workplace are generally associated with the machine tools or process equipment. Robots are machines, and as such, must be safeguarded in ways similar to those presented for any hazardous remotely controlled machine, falling under the general duty clause or OSHA 1910.212(a)(1) or 1910.212(a)(3)ii.  Refer to https://www.osha.gov/SLTC/robotics/standards.html and OSHA’s compliance directive on robotics STD 01-12-002 at https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=DIRECTIVES&p_id=170 for more information.

Robotics Packaging Cell Courtesy: Banner Engineering
Robotics Packaging Cell
Courtesy: Banner Engineering

Various techniques are available to prevent employee exposure to the hazards which can be imposed by robots. The most common technique is through the installation of perimeter guarding with interlocked gates. A critical parameter relates to the manner in which the interlocks function. Of major concern is whether the computer program, control circuit, or the primary power circuit, is interrupted when an interlock is activated. The various industry standards should be investigated for guidance; however, it is generally accepted that the primary motor power to the robot should be interrupted by the interlock.

Although ANSI standards are guidelines, many U.S. industry experts experts agree that ANSI standards provide the best guidelines for safeguarding machinery that doesn’t have a vertical OSHA requirement.
ANSI/RIA R15.06-2012 is the most recent U.S. Standard on Industrial Robots, which requires that perimeter guards contain the robot automation. These guards are required to have a 12-inch sweep and a 60-inch height (ANSI/RIA R15.06-1999). However, CSA 2003 cite best practices at a 6-inch (.15m) sweep and a 72-inch (1.8m) height.

When a robot is to be used in a workplace, the employer should accomplish a comprehensive operational safety/health hazard analysis and then devise and implement an effective safeguarding system which is fully responsive to the situation. In general, the scale of the automation cell will drive the scale of the safeguarding. (Various effective safeguarding techniques are described in ANSI B11.19-2010.)

ROCKFORD SYSTEMS CAN HELP
During Rockford Systems Onsite Risk Assessments and Onsite Machine Surveys, we find one of the most common problems with robotics is the failure to accurately calculate safety distances, typically used in regard to the installation of safety mats. Robots make rapid and wide-reaching moves. The goal is to stop a robot before it can hurt someone.

Robotics Palletizer and Stretch Wrapper Cell Courtesy: Banner Engineering
Robotics Palletizer and Stretch Wrapper Cell
Courtesy: Banner Engineering

Any robot that moves more that 10 inches per second must be safeguarded adequately. Safe distance is determined by the following Robotics Industry Associations (RIA) formula with the following parameters:

DS= 63 inches per second (IPS) X(TS+ TC+ TR) + DPF
DPF= 1.2 m (48 in.)

Where:
DS= minimum safe distance
TS= stopping time of device
TC= worst stopping time of control system
TR= response time of safeguarding device including interface
DPF= maximum travel distance toward a hazard once someone has entered the field

 

So the total horizontal space to be protected is 48 in. plus 63 IPS, multiplied by the total time delay between detection of a person in the protected area and the actual time it takes for the robot to stop.

It’s imperative that the automation cell and all aspects of machine use be identified and considered when selecting and implementing a robotics safeguarding. Ultimately, the best type of protective measure will be the device or system that provides maximum protection, with minimal impact on normal machine operation.

Please call 1-800-922-7533 or visit www.rockfordsystems.com for more information.