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2 minute read • published in partnership with Pilz

Insight: Protection against machinery manipulation

If safeguards are manipulated, serious accidents or damage to machinery may result; the legal and financial risks are difficult to calculate. Automation company Pilz shares more about how to identify the causes and avoid manipulations.

It is not uncommon for safeguards on machinery to be manipulated by users. Movable guards and mechanical fixed guards are the most commonly affected.

There are many reasons why machine operators and users manipulate them, putting their colleagues at risk. The ability to work faster, convenience, time and performance pressure, poor ergonomics or simplification of operating modes are all possible motives. Accidents are the result – ranging from minor injuries to fatalities.

If machinery safeguards are manipulated, there is a significant risk that serious accidents or damage to machinery may occur / Picture: Getty/iStock


As an automation expert and manufacturer of safeguards, it is our objective to protect humans, the environment and assets. However, this is only possible if machinery is used in accordance with its intended purpose and safeguards are not manipulated.

How can we counteract manipulations?

First of all it’s necessary to identify the incentive for manipulation. Machinery that is not user-friendly is one incentive. The assessment scheme published by IFA (Institute for occupational health and safety of German statutory accident insurance) can be used as a guide for calculating the incentive for manipulation. It systematically shows potential weaknesses, plus options for rectifying these weaknesses.

Machine manufacturers and operators are liable for the consequences of manipulations

It is generally recommended that the protection concept is designed simultaneously with machine development. This includes:

Define needs in the requirement manual
Develop protection concept and machine function in parallel
Establish the incentive for manipulation
Optimise protection concept
Review the effectiveness of reducing the incentive for manipulation

Establish all the machine’s operating modes in the planning phase of a machine’s design and develop appropriate protection concepts. Requested changes can be accommodated at this early stage with little effort.

Where machinery is already in circulation, you should produce a situation description and cause analysis at regular intervals. Both sales and maintenance personnel can assess whether there is an incentive for manipulation or if a safeguard has actually been manipulated already.

If manipulation is identified, the motives must first be established and the safety concept improved. Simply exchange safeguards that perform the same function (e.g. swap a safety gate for a light grid if this is more appropriate). Drive controllers with integrated safety functions can also be installed.

Both the machine operator and the machine manufacturer are required to prevent the manipulation of safeguards. There are legal principles that regulate responsibilities and liability for the whole of a machine’s lifecycle.

In Europe, manipulation of safeguards is explicitly prohibited and punishable by law. The manufacturer is liable for production and manufacturing defects as well as instruction errors; the operator is liable for any potential personal injury.

Download your stop manipulation poster here
Watch the Understanding ISO 14119 – Interlock Devices webinar recording here