726 Introduction to Machine Guarding

Design Requirements

Safeguards are critical in ensuring worker safety by preventing injuries from mechanical hazards in industrial and manufacturing environments.

To be effective, safeguards are designed to address the risks posed by dangerous moving parts, falling objects, and improper safeguard design, ensuring a safe and productive workplace.

The following safeguards meet a set of minimum general design and construction requirements that prioritize worker protection, durability, and operational efficiency.

• Prevent Contact: The primary function of a safeguard is to prevent hands, arms, or any other part of a worker’s body from coming into contact with dangerous moving parts, such as rotating gears, cutting blades, or conveyor belts. A robust safeguarding system eliminates the possibility of the operator or other workers placing any part of their body near hazardous areas during machine operation. For example, a barrier guard on a lathe or a light curtain on a press can physically or electronically block access to dangerous zones, ensuring no accidental contact occurs.

• Protect from Falling Objects: Safeguards should prevent objects, such as tools, debris, or workpieces, from falling into moving parts of a machine. A dropped tool in a cycling machine could become a projectile, posing a significant risk of injury to workers. For instance, a protective mesh or cover over an open machine area can prevent small items from entering hazardous zones, reducing the likelihood of dangerous incidents.
• Create No New Hazards: An effective safeguard must not introduce new risks, such as shear points, jagged edges, or rough surfaces that could cause cuts, lacerations, or other injuries. For example, the edges of guards should be rolled, smoothed, or bolted in a way that eliminates sharp or protruding surfaces. Poorly designed safeguards that create pinch points or exposed edges defeat their purpose and compromise worker safety.
• Create No Interference: Safeguards should be designed to minimize interference with a worker’s ability to perform their tasks efficiently and comfortably. If a safeguard is cumbersome or impedes workflow, workers may be tempted to bypass or disable it, undermining safety efforts. Well-designed safeguards, such as transparent barriers or interlocked gates, allow workers to operate machines without unnecessary obstacles while maintaining protection, ultimately enhancing both safety and productivity.
• Allow Safe Lubrication: Whenever possible, safeguards should enable maintenance tasks, such as lubrication, to be performed without requiring their removal. This reduces the need for workers to access hazardous areas. For example, oil reservoirs can be located outside the guard, with a line or channel leading to the lubrication point. This design minimizes exposure to moving parts during routine maintenance, ensuring both safety and operational efficiency.

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