Overview
Machines and equipment are in operation without sufficient and/or proper guarding.
The concept of machine guarding is to protect people from the enormous power a machine can produce that can result in serious injury such as an amputation or even death when a body part contacts a moving part. This could be caused by entanglements, crushing, flying debris, etc. from spindles, hold downs, rollers, fan blades, and other types of rotating parts. Most of the time physical guards are used but other safety features may be used such as light curtains, interlocks, horns, sirens, two-hand controls, etc.
Machine guarding is a vast subject but in the context of a laboratory setting, the most commonly encountered situations are:
- Motor with an unguarded belt or rotating part.
- Fan blades that are unguarded (shouldn’t be able to poke a finger between the gaps).
- Laboratory-constructed equipment that has moving parts that are unguarded.
Exhibit A shows a UNL extension center’s lab-made seed sorter that was completely unguarded. Pinch points are numerous from sprockets, flywheels, chains and belts. Definitely amputation potential as it was constructed before it was guarded. Exhibit B shows the unguarded airplane-sized propeller in the wind tunnel.. The potential for injury with this rotating blade is definitely lethal due to it’s size, location and speed of the rotating blades. It was not possible to guard the blade portion without affecting the air patterns and the operation of the equipment.
In this case, a fenced cage with a padlocked door was built to restrict access to the entire area as seen in Exhibit C. The fence also protects the operators located outside the cage protection from flying debris in the area. This would be an example of an engineering and an administrative control used together. The administrative control portion is used when the researcher needs to access the area to move sensors or other equipment. Before anyone is allowed to enter the restricted area, the equipment must be shut down and locked out of service.
In almost all cases, moving parts on a piece of equipment must be guarded in one form or another. If the equipment is being serviced or retooled it must be turned off, locked out of service and de-energized before the guards are removed/disabled. If there is a concern on how a piece of equipment is guarded or being used, take a photo and ask questions on how the equipment is being used for discussion with a Senior Specialist or the EHS staff person responsible for the Lockout/Tagout program who also addresses machine guarding.