Warning Signs to be Aware of in Machinery and Maintenance

The old adage:

“Red sky at night sailor’s delight,

Red sky in the morning sailor take warning.”

has been around in one form or another for thousands of years (Matthew 16:2-3).  This was a well understood sign that allowed sailors to predict that a storm was coming and would allow them to prepare.  Today there are many warning signs that can help us prepare for hazards or dangers.  Some of these warning signs might include; operator manuals, noise, vibration, excessive heat, rust, cracks, and machine limits.

A piece of equipment’s operator’s manuals is often the first place one should turn to know how to use the machine and what they need to do to keep it running at its peak performance.  As an example, every car requires that the engine have multiple oil changes throughout the life of the engine.  The time between oil changes can vary drastically from one car to the next depending on make, year, and oil of the car.  With older cars requiring and oil change every 3,000 miles, and others every 15,000 miles. The specific car’s operator’s manual will instruct the owner when their car should have its oil changed and what oil to use, as well as other required maintenance steps and maintenance schedules.  Good operators manuals for your products and equipment will have the same information on periodic maintenance and things to watch for to keep it running like it did the day you bought it.

Often times a sign that a part might be reaching the end of its life is an increase in noise.  This increase can merely be that machine runs louder than it used to.  Such noise can be a sign that the bearings or other components are getting gummed up and need to be cleaned, or that the components have worn out and are reaching the end of their life.  Without this cleaning or replacement, the equipment can experience failure, including catastrophic failure resulting in equipment damage, property damage, personnel injuries, and/or death.

The increase in noise can be an intermittent sound that occurs when two or more components come into contact with each other unintentionally.  This can occur when alignment or wear has occurred in such a way that cause the equipment to come into contact with itself or that some items might be going past their intended stop point.  Such noise requires finding where the contact is occurring (signs include scratches, bent components, etc.) and determining the cause of the interference.  If these signs are ignored the equipment can become inoperable, or fail catastrophically.

Excessive motion or vibration of a piece of equipment can be a warning sign.  There could be excessive wear in the races of a rotating piece of equipment (e.g., bearing, bosses, etc.)  This excessive wear will increase with the continued operation of the equipment and can lead to the catastrophic failures mentioned above.  If wear in the races or bearings are found the situation should be resolved immediately.

Another source of excessive vibration is failure of the equipment’s isolators. Some items are mounted on dampers or isolators.  This is often to help limit the amount of vibration that occurs with an oscillating piece of equipment that is meant to have some vibration.  If the dampers or isolators begin to fail the vibrations might exceed the intended amount, and can lead to the equipment tearing itself apart.  If these warning signs are ignored catastrophic failure can be the result.

Another source of excessive vibration in an oscillating piece of equipment can occur when weight shifts in the equipment.  If components of the equipment being turned comes lose and move this can cause the equipment to vibrate in ways it was not intended to.  Imagine a washing machine with an uneven load.  When the washing machine goes to spin the uneven load, the washer starts to shake and bang around.  If this were to continue, the washer could bang into the walls, or other items around it, tear itself apart and/or eject components which could cause damage or injury.  Such unbalanced loading in equipment needs to be found immediately and resolved.

Sometimes when a piece of equipment is reaching the end of its life (whether through the normal course of operation, or poor maintenance) it can begin to generate excessive heat.  This heat can come from added friction due to wear or fouling of the equipment.  If a bearing were to get to the point where the heat becomes visible, then there is the risk of fire (https://www.redpowermagazine.com/forums/topic/129847-honey-what-does-it-mean-when-the-orange-light-is-on-the-trailer-wheel/), failure of other parts of the machine, and catastrophic failure that can result in the loss of life.  Increases in heat from a machine should not be ignored.

Rust is a sign that steel has been exposed to moisture, and is another warning sign that needs to be considered.  As steel begins to rust, it begins to flake.  These flakes pull away from the steel and allows for more moisture to get under the flakes, allowing the steel to rust and corrode even more.  If this continues, the integrity of the equipment can be compromised, and the structures initial strength will be reduced.  If rust is not treated the steel can completely falls apart, as can be seen in older cars.

Rust on equipment should be investigated, removed/repaired, and repainted depending on manufacturer’s recommendations or the results of the investigation.  If this warning sign is ignored, then rust can lead to failure of the entire piece of equipment, where it is completely inoperable, or hazardous to operate.

Rust can also be a harbinger of another warning sign, cracking.  Many pieces of equipment that support human beings (e.g. roller coasters, man lifts, etc.) will come with weld inspection protocols that will ask the inspector to look at critical areas in the equipment for signs of cracking.  These signs can include paint chipping or localized rust.  As shown below, the paint chipping and rust are next to a crack in the metal.

While the crack itself is difficult to see with the naked eye, the rust and cracked paint are clear indicators that something is happening.  After a thorough inspection it was determined that the crack went well into the tube, and would have resulted in a catastrophic failure if it was not addressed.  While not all cracks will have such blatant signs, any suspected crack needs to be investigated.  This could include mag flux testing, die penetrate testing, or some other form of crack investigation.  Ignoring such signs can lead to failure of the equipment, damage, and/or death.

Machine limits are another good source of information for avoid hazards and dangers.  Now this might seem redundant in an article about warning signs.  If we are ignoring what is written directly on the piece of equipment than we are putting ourselves and others in danger.  A good example of a machine limit is the load rating for a forklift.

This decal instructs a forklift operator on what load they can safely carry with the specific forklift and how far out from the mast the load should be.  When such warnings or instructions are ignored failure of the equipment can be expected, and result in damage, injury or death.

As in days of old, when we see a “red sky in the morning” we need to take all reasonable steps to address the hazard before us.  While this is not an exhaustive list of all warnings or signs of hazards, it is an example of items that should not be ignored.  Much like the sailors of old knew that a red sky in the morning could warn of storms in the near future, these warning signs in equipment are the red sky that warns us of oncoming storms, and that additional preparations, checks or maintenance are needed to keep us safe.

About the Author: Nathan Morrill is a licensed professional engineer (PE) and a certified safety professional (CSP).  He is an engineering project manager at Alpine Engineering and Design, Inc. and has worked on the design of projects ranging from aerial lifts to lift gates, and dump trailers to zip lines.  In addition to engineering work Mr. Morrill also provides expert witness services for patent and product liability cases.