Mechanical Hazards and controls

The machine revolution changed human life and civilization in many aspects, particularly in terms of human working nature. It helps human productivity by utilizing minor human effort and helps workers to perform those tasks which are next to impossible for humans manually. Further, it also helps to increase precision, accuracy, and frequency in production but at the same time, the worker encounters some new type of hazard which did not exist before machines. These hazards are known as mechanical hazards and classified into eight types on the basis of their effects and nature.

Causes of mechanical hazards

There are commonly three causes when a machine's blessings convert into adversity and harm the worker. 

1. Human Error 
2. Logout/Tag-out 
3. Missing machine Guard system

Human error is the most frequent cause of the machine-related accident where worker skills, emotions, and laziness play a main role in the accidents. The second cause of the machine-related accident is lockout/tag out failure which resulted in serious accidents. The third cause of machine-related accidents is the failure of the machine guarding system. Such accidents are due to the use of substandard machines and tools. 

Mechanical Hazards 

The machine-related hazards are classified into nine machine-related hazards;

Crushing

The hazard in which a worker can be trapped between two moving parts or where one part is moving and the other part is fixed. For example Concrete Pump boom or hydraulic press. These accidents are avoidable but if occurred these are fatal most of the time. In the crush, the mechanical force can act in 360 degrees directional.

Shearing

Sharing is a hazard in which machine moving wheels with some speed tarp worker limbs particularly hand or fingers. In accidents the worker can lose his limb or fingers, moreover, the direction of force and pivot point is clockwise and anticlockwise. The lone worker particularly working at night faced such accidents. 

Cutting & Serving

Cutting & serving hazards arise from sharp edges or blades of the machine where the cutting or sewing task performs. It happens when worker body parts come in contact with moving blades. For example, the wood cutting machine where the blades cut the fingers of workers due to accidental contact. The direction of the force and human contact is 90 degrees in this hazard. 

Entanglement

Entanglement is happening due to loose clothing of the worker where a piece or part of cloth or dress of the worker is stuck in the machine and pulls the worker toward the machine with a jerk and intense force. For example, rollers in the textile industry where workers trap due to entanglement.

Stabbing or puncture

Machine with sharp moving parts includes blades, needles, or belts which move with some speed and can puncture human body parts when came in contact. For example, the simple example of stabbing or puncture hazard is sewing machine needles in industry or home which puncture fingers on the wrong contact. Or in the crushing industry the small fragments of the stones which can cause accidents. 

Abrasion or fraction

The bare parts of a machine moving with high speed is abrasion or fraction hazard. When the worker body came into contact with high speed moving part of machine abrasion or fraction. The effects of abrasion can be peeling off the epidermis or wipe off the flash from the contact surface. For example, the conveyor belt or motor belt can be a good example of an abrasion or fraction hazard.

Impact

Impact hazard is the most commonly found hazard in the heavy machine industry where giant robots are used to perform tasks. In an impact accident, a moving part of a machine hit the worker and the worker got injured. For example, a moving arm of a moving industrial robot.

Drawing or Trape

The most fatal hazard of a machine is drawing or trap where two moving parts trap the worker and drag the tarp part toward itself. Moreover, the moving parts move in an inward direction therefore once the body part is trapped it is next to impossible to drag out the struck part. In most of the accidents, the victim lost the contact body part. Spinning wheels of heavy industry are a good example of drawing and trap hazards.

High-Pressure Fluid inject

High pressures liquids or gases become the cause of injector throw hazard - these hazards cause accidents when the container of the pressurized constant is burst out. Moreover, the high-pressure fluid injection also becomes a cause of passive accidents that includes fall or impact. Boilers, hydraulic machines, and gas cylinders are examples of high-pressure fluid injects.

Controls 

Elimination is the best control for machine-related hazards and this can be done by replacing the respective machine with a more advanced and worker-friendly machine. The other options for controlling hazards, where elimination is not possible are engineering controls which are discussed in details as under;

Fixed Guard

Fixed machine guards prevent access to moveable parts of the machine with physical barriers. The main advantages of the fixed guard are it is next to the elimination of hazard and minimize the risk of machine-related accident and even if the worker competency is compromised the physical barrier block the human contact with moving parts. But, on the other hand, the fixed guard was considered to be poorly maintenance-friendly. 

Adjustable or moveable Guard

Adjustable guards are machine guarding systems that can be removed while working or some time it is auto movable which is also called self-adjustable guards. The advantages of adjustable guards are maintenance-friendly and moving parts can be oil, grease, or clean easily. But these guards don't provide 100% safeguard to the workers. 

Emergency Shutdown Button 

Some machines are equipped with emergency shutdown buttons which help workers to shut the machine if any unwanted incident happened. But these buttons are reactive, not protective, and considered as weak controls.

Highly sensitive tripping devices

Advanced technology enables machines to identify the object including the worker hand or the object under operation. The machines are equipped with tripping devices. These devices are evolving with time and effectively.

Two hands operating control

Two hand operating tool is a simple but very effective control in which the operator need full attention which ultimately lowers the risk of machine-related accidents

Personal Protective Equipment

The last resort of mechanical hazard control is personal protective equipment and in case of mechanical hazards, the PPEs are more comparably effective and easy to care for. The PPEs include gloves, safety suits, safety helmets, goggles, shoes, and complete body gear.

Training

One of the most effective controls for machine-related hazards is the skill development of workers or operators as we have mentioned in the part of the cause the human error is the most common cases of machine-related accidents therefore worker skill and capacity building is very essential.