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Safe machinery the key to a safe workplace

Industry faces challenge to harmonise safety, productivity and user friendliness

By Frank Schrever

In accordance with state OH&S laws it is not only the machine manufacturer’s responsibility to place safe machinery on the market, but also that of the designer,
modifier, importer, supplier, and employer.

To do this and ensure compliance with the law and standards it is necessary to carry out and document a hazard analysis and risk assessment.

Properly done, this will determine whether the machine’s risks have been minimised so far as is practicable by design, or whether more risk reduction measures may be necessary.

A compliant safety concept for the respective plant or machine can then be worked out from the risk assessment.

This does require the risk assessor to have a detailed knowledge of risk controls, laws and standards to determine that the solution is not only compliant, but also affords maximum productivity and economy.

The legally defined guarding hierarchy requires that if the guard cannot be welded in place then it must be interlocked, and only if proven that these two are not “reasonably practicable” (also legally defined see VIC OH&S act) then a bolted guard may be used.

Flaps, fences, enclosures and safety gates are all used to protect operating personal from potentially hazardous processes. However just slapping these on does not necessary solve the risk control problem, especially if their use reduces productivity and operators may be motivated to bypass the safety to enable faster operation.

It’s also important to protect against potentialnemissions such as noise and dust or such things as cutting oils and flying metal swarf.

In the food industry it is necessary to satisfy hygiene requirements, which may dictate
materials and control systems which can tolerate corrosive chemicals and high pressure water on electrical control components.

To give operating personnel as much freedom as possible, lift gates and rolling shutter-like constructions have become increasingly popular alongside the classic swing gates or sliding gates. The fact that plant and machinery have become ever more compact means that the sensor technology protecting the safety gates has had to adapt accordingly. This has resulted in a wide range of version types, which meet high IP protection classes or have ATEX approval as well as having the required resistance to
cleaning agents.

Industry leaders Pilz Automation offer a wide range of high quality safety devices to maintain a safe workplace.

Machine designers and modifiers are generally responsible for selecting safety components.

They can currently choose from a wide range of safety switches, which offer various design options and operate to different principles. The challenge is to harmonise safety, productivity and user friendliness on the plant or machine.

Productivity is the first priority.

These days, non-contact safety switches are increasingly used to protect safety gates – in accordance with the risk classification – rather than mechanical tongue type safety gate switches or roller switches.

The benefits of non-contact solutions are obvious: less work required for precision
adjustment, a significantly higher service life and only one assembly required for the highest category of safety design.

Safety-related guard locking devices are used where cramped conditions mean that safety guards have to be located close to the hazardous movement, or when the machine has a lengthy run down time. In these cases, safety gates not only have to be safely monitored but securely locked as well. A mechanical guard locking device prevents the gate from being opened.

As a result, the operator is still safely protected in the event of a dangerous overrun movement.

The demands on safety-related safety gate monitoring are many and varied. A machine’s safety-related equipment must also consider the interaction between different components in a safety chain, because this is a key factor, not only in achieving the required safety level, but also for integrating the safety technology
harmoniously into the overall control system.

In this respect, complete solutions with totally compatible components, composed of sensor technology and safe control technology can enable the highest productivity, legal compliance and safety of all users.

Pilz Safe Automation
Ph: 03 9544 6300