Why Machine Guards Are Essential In The Workplace
October 3, 2019
By: Aric Asplund
The heavy equipment used to build our communities and the machines that drive manufacturing at high rates of speed are also listed in the top 10 leading causes of workplace injury by the U.S. Bureau of Labor Statistics. In the construction industry, caught-in equipment or compressed by equipment or objects accounted for 5.1 percent of the worker fatalities in 2017. In manufacturing, being caught in or compressed by the actions of mechanical equipment or energized objects in motion "accounted for approximately 18,000 amputations, lacerations, crushing injuries, abrasions, and over 800 deaths per year", according to EHS.
The inherent dangers of mechanical components like gears, belts, flywheels, and chains along with the operating hazards associated with groups of production equipment used every day in manufacturing across the nation, are very real. Some of the most dangerous machines are used in metal shearing and stamping operations, in plants that use hydraulic or pneumatic presses, and within injection molding processes that are used in the plastics industry.
When machine operating dangers exist, OSHA requires manufacturers to use machine guards that can prevent workers from being struck by, drawn into, or crushed by the machines they operate. If employers are complacent about machine operating risks and the necessary steps required to prevent contact between body parts and the moving parts of equipment, the potential for serious or fatal injury will increase.
What is Machine Guarding?
Machine guarding places a barrier or other feature is on or around machinery to prevent or limit contact between workers and hazardous conditions. This includes equipment that expels material such as metal chips or flying sparks. In these cases, struck by accidents can be reduced with a machine shield to contain the material or energy and protect the worker from injury.
When it comes to safeguarding your workers from the dangers of mechanical or energized machinery, safety experts suggest paying close attention to the following three areas:
- Point of Operation - Safeguarding the position where the worker performs their duties in relation to machine hazards
- Power Transmission Apparatus - Safeguarding against the release of mechanically or electrically generated energy
- Other Moving Parts - Safeguarding against actions or motions due to moving parts (cutting, rotating, punching)
There are many ways to place safeguards between workers and machines. The most common examples of machine guards include:
- Fixed Guards and Shields permanently attached to equipment to prevent inadvertent contact with moving parts
- Electromechanical Interlocks that will shut off power to disengage equipment before a worker can be injured
- Light Curtains Systems that can sense when an operator passes a predetermined danger limit
- Electrical Interlocks will disallow power to operate when a worker has disengaged another safety measure
- Pressure Sensitive Mats wired into the machine's control system will stop the equipment if stepped on
- Fixed Perimeter Guarding prevents workers from walking into a dangerous area such as robotics operations
OSHA Machine Guarding Requirements
You will find OSHA's machine safeguards standards in 29 CFR 1910 Subpart O, Machinery and Machine Guarding. These guidelines cover machine-related hazards in the workplace and the actions employers can take to protect workers. OSHA outlines the types of equipment motions that are most common to worker injury or fatality. These include rotating, reciprocating and transverse motions, along with equipment actions such as cutting, punching, shearing, and bending. Even when these motions are smooth and/or the actions are slow, it doesn't take long for a loose sleeve or a dangling neck badge to be irreversibly taken up in a rotating gear.
When these types of machine motion and/or actions are present in the workplace, OSHA requires the company to install one or more machine safeguards that protect workers and meet minimum safety requirements:
- To prevent contact with hands, arms or any other part of a worker’s body and dangerous moving parts.
- To secure unsafe areas with safety devices that cannot be easily removed or tampered with.
- Provide protection from crushing injuries due to falling objects, including objects that can fall into moving parts.
- A safeguard should present no new hazards such as jagged edges or pointed projections.
- There should be no interference that could impede a worker from performing their job comfortably.
- If possible, maintenance on the machine should be performed without removing the safeguard.
A particular note of clarity is often made by OSHA concerning nip points - as it presents a particularly subtle hazard that can be devastating. You will find nip points are common on machines that have rotating gears and those that feed stock into equipment by way of conveyance rollers. A nip point is that intermeshing point where the mechanical gears or rollers meet. A pinch point is created at that location and a part of the worker's body or clothing can be drawn into the mechanism resulting in severed, crushed, or mangled body parts. Guards are a standard requirement on moving machinery that has nip points, and are typically a part of the manufacturer's machine design.
Other Ways to Protect Employees
Workers can experience significant injuries when they are unintentionally entangled in the machines they operate. Regular machine maintenance, workplace practices training, and a set dress code for machine operators can go a long way in preventing injuries that can range from serious bruising to amputations.
No Long Hair, Jewelry, and Dangling Work Badges
Consider an employee with long hair that bends slightly over the work piece while operating a high-speed lathe. Imagine an employee wearing a bracelet or a ring that snags on a fast-moving food processing line. A tie, an unbuttoned jacket, an un-tucked shirt - all these can become caught in the moving parts of machinery, incredibly fast and with devastating results.
Any facility with moving equipment must have firm workplace practices that address 'caught-in or caught-between hazards'. Anything that hangs loosely from a worker while operating equipment that moves will present a hazard. In addition to worker training and firm penalties when workplace safety rules are broken, you can keep your workers reminded of moving equipment risks by posting safety signs.
Replace Loose Clothing with Uniforms
Protective personal equipment or PPE in manufacturing, construction, and refineries serve multiple purposes. Workplace uniforms not only protect the worker's skin from the chemicals, dirt, grime, and biological hazards found in these environments, they also solve the problem with loose clothing that can cause injury. Examples include:
- Baggy or too long pants can cause a trip or fall into equipment
- A loose shirt or sleeve can catch on fire near hot surfaces or flames
- Loose sleeves and hanging shirt tails can get caught in moving machines
- Drawstrings on sweatshirts and sweatpants can be drawn into rotating machines
- Neck ties, neck jewelry, or neck badges can cause choking or strangulation injuries
Consider workplace uniforms that are fire-retardant, have cuffed or fitted sleeves, and are made with a breathable fabric and fit comfortably. If uniforms are not used, then proper industrial and construction attire should be stressed. Insist that all shirts be tucked in and all arm sleeves secured at the wrist.
Cotton, denim, or khaki fabrics are most comfortable and will wick moisture from the worker's body to keep them cooler throughout the day. Pants should be straight-legged and without extra leg pouches/pockets along the side. Finally, the proper foot protection, gloves, and safety goggles should be mandated for all workplaces where machine hazards exist.
The OSHA Machine Guarding eTool
OSHA provides a Machine Guarding e-tool where you can drill down to discover common machinery used in manufacturing that can cause caught-in hazards to employees. This tool can also help with selecting the right safety devices or machine guards to reduce the possibility of injury in the workplace. In addition to machine guards, equipment safety devices can provide another level of protection for your workers. These include:
- Trip Wires
- Two-Hand Controls
- Presence-sensing Devices
- Optical (Photo-electric) Instruments
- Hold Back or Pull Back Restraints
- Safety Gates
When machines are not properly guarded with built-in barriers, employers can use these safety devices to help control access to machinery or eliminate machine operations when a safety protocol has been violated.
For a wide selection of industrial and manufacturing uniforms and other personal protective equipment (PPE), visit International Enviroguard for more information.