Machine Guard Makeover: A Sound Guarding and Lockout/Tagout Program Helps Control Hazards

This article is based on a webinar by the Grain Handling Safety Coalition as part of the Stand Up for Grain Safety Week, April 13-17, 2020. The presenter was Dr. Aaron Yoder, associate professor of environmental, agricultural, and occupational health at the University of Nebraska Medical Center, Omaha (402-559-4000). The webinar can be viewed for free at www.grainnet.com/yoder.

A variety of potential machine hazards are present in grain handling. Proper machine guarding practices, together with an effective energy control program (lockout/tagout), can help control these hazards.

Machine Hazards Overview

Machine hazards occur at a point of operation (where materials are being pulled in), point of transmission apparatus (belts, chains, pulleys, rotating shafts, etc.) and moving parts (reciprocating, rotating, transverse movements, feed mechanisms, or auxiliary parts). Anything that moves and could cause injury must be guarded.

Determine the hazards and where they exist in your facility. What needs to be guarded, what should be guarded, and what needs to be avoided? Some examples of hazards include:

Pinch points – Belts, chains, pulleys.

Wrap points – Power takeoff (PTO)shafts, which are among the oldest and most common hazards.

Pull-in points – Conveyors, feed rolls, feed chambers, grinders, and harvest equipment. These are often among the least guarded points, because these areas have to allow the product into the machine.

Shear points – Augers and blades. They are difficult to guard other than by distance, because the material has to go into the equipment.

Crush points – Drawbars on tractors and truck beds going up and down.

Burn points – Mufflers, engines, pipes, and fluids like fuel, oils, and chemicals.

Free-wheeling parts – For example, conveyors cannot bring rotational force to a sudden stop and continue to move after power has been turned off.

Stored energy – Unexpected and uncontrollably released pressurized systems, mechanical, hydraulic, pneumatic, gravitational, capacitors, springs, and flywheels.

Thrown objects – Rotating fan or knife blades to grind or chop material, such as a rotary mower.

Guarding Principles

The purpose of guarding is to protect the operator and others from hazards created by normal machine operation.

Any machine part, function, or process that might cause injury must be safeguarded both for the operation of the machine while it’s being used and for unintended contact. Hazards must be controlled or eliminated.

Preventing Hazards

• Train employees to ID hazards.

• Learn methods of machine guarding.

• Learn the regulatory requirements.

• Identify and categorize mechanical hazards.

• Note locations.

• Match hazards with safeguards and facility uses.

• Upgrade machine guards not meeting requirements.

• Ensure new equipment has appropriate guards.

Of particular concern are unintended contacts that often catch us off guard and injure us. Guards should prevent contact, be difficult to remove, protect from falling objects, not create new hazards, not interfere with job performance, not have to be removed to lubricate machinery, provide easy access for maintenance, and protect a person from being able to get around, under, through, or over a machine.

GHSC_Presenter_Slides2-28.jpg#asset:214987


Types of Guards

• Fixed – Permanent and requires a tool to remove. This is the first and best option.

• Six-sided – Top, bottom, front, back, left, right.

• Interlocked – Mechanism disengages power from machine.

• Adjustable/self-adjusting – The operator adjusts, and the guard is attached; partially guarded while operating, material pushes through the point of operation (table saws).

• Other guarding devices – Pressure sensors, which interrupt the operation cycle or prevents area entry; location/distance, which prevent access to a hazard with a physical barrier at the point of operation.

The opening size for grates/guards that prevent access to a hazard is governed by Occupational Safety and Health Association (OSHA) Standard 1910.217(o). The opening size is determined by the distance of the worker from the hazard. The farther away the hazard, the larger the opening can be. The grate/guard should prevent reaching the equipment with a body part or tool.


Ensure guards are in place, and use lockout/tagout before any service or maintenance. Guarding and lockout/tagout will prevent the majority of machine injuries.


Preventing Hazards

• Train employees to recognize hazards.

• Learn methods of machine guarding.

• Learn regulatory requirements.

• Identify and categorize mechanical hazards.

• Match hazards with safeguards and facility uses.

• Upgrade machine guards that do not meet requirements.

• Ensure new equipment has appropriate guards.

Answer these questions:

• What is the task?

• What is the machine/equipment?

• What is the machine/equipment doing?

• How and where do people interact with the machine?

• Where should the guard be installed?

• What type of guard would work best?

• What can be done to improve the situation?

• What else should you consider (i.e., blocking a walkway)?


Any machine part, function, or process that might cause injury must be safeguarded both for the operation of the machine while it’s being used and for unintended contact.


Successful Strategies

• The best guarding is on new equipment, fixed, and according to manufacturer recommendations.

• On old grain handling equipment, fabricate guards according to current designs and regulations.

• Interlock features installed at the feed end of equipment prevents hand access.

• Replace broken sections. Newer guarding also can protect against machinery noise.

Best Practices

• Not wearing loose clothing around machines.

• Waiting for machines to completely stop.

• Never stepping over a running PTO.

• Never reaching over machines that are operating – take the time to walk around them.

Ensure guards are in place, and use lockout/tagout before any service or maintenance. Guarding and lockout/tagout will prevent the majority of machine injuries.

More info. Machine guarding guidance resources are available from OSHA and the National Institute for Occupational Safety and Health.

John Reidy, associate editor

Reprinted in September/October in Grain Journal Issue


Related Articles:

CONVEY '20: How Using Leading Indicators Improves Workplace Safety

NGFA Update: Alliances, Regulations, and Issues Where Association Remains Focused

Find What You Need: Grain & Feed Equipment Database