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News Release from: Pilz Safe Automation Australia | Subject: Safety consultancy
Edited by the Engineeringtalk Editorial
Team on 12 July 2006
Manipulation of machinery safety devices
Frank Schrever of Pilz Safe Automation discusses the implications of a recent BGIA Study: "Manipulation of protective devices".
The focus on workplace safety has never been greater but injuries caused by machinery remain unacceptably high Just shy of 30,000 Australian workers were injured by machinery, plant and transport in 2004
This article was originally published on Engineeringtalk on 15 Sep 2005 at 8.00am (UK)
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Like Australia, despite world-leading low injury rates, Germany continues to battle with injuries caused by production machinery.
A new study by BG Institute for Occupational Safety (BGIA) reveals that the deliberate by-passing of safety devices has a big role to play in Germany's machinery-related incidents.
Here, we take a look at the findings of this study for lessons for Australian employers and the safety profession.
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Germany's official statistics show that 50% of all accidents can be explained by operator behaviour while 12% of accidents are attributed to technical failure.
Several questions arise.
Were there any unexpected circumstances which prompted the behaviour that caused the accident?.
Reasons for manipulations.
Often, the cause can be traced back to production machinery breakdowns, which the machine operator wanted to rectify 'without the bureaucracy' of procedures such as lock out/tag out procedures.
In many cases, accident investigations show there were no operational procedures for dealing with such breakdowns and that safety awareness among staff was very low.
It seems that - even in the eyes of staff- it's more important to achieve the production target (performance-related pay for specified quantities) than to comply with safety regulations.
Supervisors and colleagues often know about these manipulations and condone them.
In brief - What is "defeat in a simple manner".
The European standards tend to talk in terms of 'defeat in a simple manner'.
A requirement of Annex 1 of the EC Machinery Directive is that protective devices cannot easily be defeated or rendered inoperative.
In accordance with standard ISO 14119:1998 (now part of Australian Standard 4024.1) for interlocking devices, "defeat in a simple manner" means "intended operation achieved manually or with a readily available object".
This includes screws, coins, needles, keys and screw drivers, for example.
Results of the project study.
Experts estimate that 37% of protective devices are constantly or occasionally manipulated.
It is also estimated that around 25% of all industrial accidents that occur while operating machinery are a result of manipulation.
Defeat of interlocks should be minimized using one way screws, epoxy-filled fastener heads, spot-welded fasteners and parts, or riveting.
Productivity increases was the reason given by 43% of respondents for manipulating protective devices.
There is a demand for "non-disruptive safety and function concepts", which do not adversely affect either work rate or productivity, such as intelligent camera systems that can distinguish between a person and equipment.
Even so, the human factor cannot be disregarded: in many areas of companies there is no widespread safety culture dealing with this issue.
Productivity aspects certainly play a key role in this, which is why susceptibility to manipulation should be taken into account alongside productivity considerations when buying or modifying a machine.
"Economical production" versus "safety"?.
Each incident and each company is too different to be able to determine the exact cost of industrial accidents but a rough estimate of the potential consequential costs of an accident can justify preventive safety measures.
Consequential operational costs of an accident are the costs that arise as a result of an industrial accident on operations, such as: Absence of the injured person Replacement staff Loss of production and delayed delivery First aid, medical care, transportation of casualty Accident management Clearing up of material damage Loss of premiums or additional payments to the liability or property insurer Legal costs, time, fines and adverse publicity Studies show 30%-40% of the consequential costs of an accident can be avoided if the right health and safety measures have been put in place.
Conclusion.
The starting point in the prevention of accidents resulting from manipulations is the initial phase of the machine design.
Early co-ordination between the machine builder, the electrical design engineer, anyone modifying the machine and the operator is essential in order to develop efficient and effective safety solutions rather than costly and complex "band-aid" fixes with limited performance.
About the author: Frank Schrever has 29years' experience in the instrumentation and automation markets and established Pilz Safe Automation, now Australasia's leader in safe automation products and services.
Mr Schrever also sits on the AS 4024-1 review committee (SF041).
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