Mechanical hazards: a basic tutorial in machine safety

06 October 2010

In the machine-intensive manufacturing industry, employees must be protected against machine-related injuries. Choosing the right method for protecting people from the hazard, let alone choosing the right product can be a daunting task. Chris Aulton offers an outline tutorial to guide you through some of the basic steps you need to take on your path to a safer working environment

There are very sound reasons why safety in the manufacturing sector matters. Good safety policy and safety practice benefit workers, manufacturers and employers by reducing lost working days due to injury; increasing productivity and worker morale; reducing liability for employers, and demonstrating the latters’ compliance with safety standards before the appropriate regulatory agencies.

All machines and safeguarding devices shipped to and traded between EU countries must meet essential health and safety standards. Compliance with these standards is mandated by the EU and the standards are defined within the EU’s Machinery Directive.

Where are safeguards needed?
Occupational hazards can be either mechanical or non-mechanical. For the purposes of this tutorial, we will address only those hazards that are mechanical in origin. Non-mechanical hazards include electrical power sources, noise, ergonomic hazards and hazardous or toxic substances.

Mechanical hazards are any machine part, function or process which may cause harm. These typically occur in three areas:

 Point of operation: the worker’s operating position in relation to the machine
 Power transmission: parts of the machine that transmit power to the parts doing the work
 Other moving parts: all parts of the machine that move when the machine is working

Safeguarding methods include any practices or procedures that implement the safeguarding requirements. They may be subject to industry-specific standards, regulations or specifications. There are a number of practices to consider, including performing a risk assessment of the workplace. Others involve the elimination of potential hazards at the machine design stage and using specialised circuitry for safety system controls.

Where procedures are concerned, a manufacturer must implement a safety programme, train and subsequently supervise employees engaged in the manufacturing operations, and make use of written procedures that describe how to perform a manufacturing task.

Risk assessment
Risk assessment is an established process, which can be used to evaluate the operation of the machine and the tasks the operators must perform, as well as the associated hazards. For machine safety, risk assessment is used to identify, document and eliminate or reduce hazards in a particular machine or process. When conducting a risk assessment identify the task and the associated hazard; assess the potential to cause injury, as well as the severity of injury, and then take steps to reduce the risk.

Of course, for the purposes of this short article, the above is an oversimplification of the procedure, and the writer urges readers to refer to the standards document ISO 14121 (EN 1050), Principles of Risk Assessment. ISO 14121 (EN 1050) uses additional standards, such as IEC 13849-1 (EN 954-1), to outline the risk assessment process and to specify the means to reduce risk.

Once the risk assessment has been conducted and analysed, there are a number of measures that can be taken to protect the workforce and maintenance staff. These include provision of any apparatus, device, clothing or personal protective equipment that can reduce risk of harm, including physical guards or safeguarding devices, complementary protective equipment and protective clothing and equipment.

The foregoing has necessarily been simplified for the sake of brevity. Readers can find greater detail here.

Chris Aulton is a machine safety specialist