|User|
Dealing with defeating of safeguards within the company
Immediate measures
If the user has determined that the safeguard of a machine in his company is being or has been defeated, action must be taken. As an immediate measure, the machine must be restored to its original, safestate at the next available opportunity. If this is not possible immediately, the machine must be signed unsafe and safety must be ensured by accompanying measures until it can be restored to its original state.
As a rule, however, restoring the machine to its original state is only a temporary solution. To prevent safeguards on the machine from being defeated in the long term, the causes must be analysed and eliminated.
Where a greater incentive to defeat safeguards has been identified on a machine, i.e. defeating is foreseeable, the following procedure can also be applied.
Description of the situation
The situation encountered must first be documented. The following circumstances of defeating of a safeguard are to be noted:
- On which machine
- In which operating mode
- Which safeguard (e.g. guard switch)
- For what task (e.g. troubleshooting)/li>
- By what means (e.g. by use of a substitute actuator, bypassing of a contact)
- Performed by whom (e.g. maintenance personnel)
This information is required for the causes of defeating to be determined. It can also be determined whether an incentive exists to defeat safeguards on other machines presenting a similar scenario.
Constructive discussion
The next step is to determine and analyse the reasons why a safeguard was defeated. As in other situations in which the incentive to defeat a safeguard on a machine is evaluated, the persons familiar with the machine and those charged with ensuring operational safety must both be involved. Specifically, these persons are:
- Person who defeated the safeguard
- Operating, setup and maintenance personnel
- OSH professional
- Superior in charge
An atmosphere free of reproach and geared towards finding a solution is very important for constructive discussion, since it is rare for safeguards to be defeated with malicious intent or because of a willingness on the part of employees to take risks; rather, their intention is to help the company by speeding up processes or minimizing down times.
Ignorance as a cause
People defeating safeguards, or knowingly working on machinery on which they have been defeated, are often unaware of the resulting risks. A lack of risk awareness or ignorance of correct use of the machine are clear signs that the operating personnel have not been adequately instructed in operation and safety of the machine. This is a leadership and training issue. The sections Instruction of employees, Operation and organization and Leadership responsibility provide information on appropriate organizational measures for counteracting the defeating of safeguards.
Essential questions
Before attempting to identify the incentive leading to a safeguard being defeated, first answer the following questions:
- (1) Is the task for which the safeguard was defeated intended to be carried out in the operating mode that was selected?
Information on operating modes and tasks for which they are intended can be found in the manufacturer’s operating instructions. Comprehensive operating instructions should describe the tasks for which each operating mode is intended.
If a different operating mode is intended for the task in question, consider why this operating mode was not used. The reason may be that the person defeating the safeguard was not sufficiently qualified for the task.
If the task is not intended to be performed at all (in any operating mode), the machine’s safety concept is clearly deficient and not suitable for the task. In this case, contact the manufacturer of the machine to discuss the problem and adapt the machine’s safety concept.
- (2) Can the task be performed on the machine without a safeguard being defeated?
If the answer to this question is “no”, the machine’s safety concept is deficient. In this case, contact the manufacturer of the machine to discuss the problem and adapt the machine’s safety concept.
If both questions are answered with a “yes”, it must be investigated whether other reasons provide an incentive to defeat safeguards on the machine.
Incentives for defeating safeguards
Various aspects play a role in determining the incentives to defeat safeguards. Firstly, the possibility must be considered that the safeguard presents an obstruction during processing tasks. At the same time, the need for operating personnel to monitor the machine or intervene in the process in certain situations must also be considered.
To facilitate identification of potential incentives for the defeating of safeguards, we recommend the following method:
- List all foreseeable tasks on the machine
- For the safeguard under consideration, consider whether incentives exist for it to be defeated during a task
The following are among the incentives most frequently stated:
- Time saving
- Higher productivity
- Fewer work steps
- Less effort required
- Better process monitoring
- The safeguard is a hindrance to setup of the machine
- The safeguard obstructs the process
- Changing the operating mode is simplified
- Access is facilitated for troubleshooting/cleaning
Adaptation of the safety concept
When an incentive to defeat a safeguard is detected, the reason is usually that the machine’s safety concept impairs its operation in some way. In this case, the safety concept must be adapted. The manufacturer should be consulted here, particularly if the machine is still in its original state and has not been modified by the user since it was procured. In addition to the manufacturer, the responsible accident insurance institution is also able to provide assistance.
Measures should be taken in the following order wherever possible:
Measures that reduce the incentive to defeat safeguards on the machine and thus make defeating unnecessary. This could for example be the introduction of a new operating mode.
Measures that do not reduce the incentive to defeat safeguards, but make it more difficult, or detect that it has taken place.
Interlocking guards, in particular, can be made more difficult to defeat, for example by the installation of position switches in a shrouded location or the use of position switches with high coding level.
Defeated safeguards can be detected, for example by plausibility monitoring.
Examples of these measures can be found in the design examples and in tuition module 4.
Substantial modification
A modification of a machine always raises the question as to whether it constitutes a substantial modification that would make the user of the machine its manufacturer, with all associated legal implications. The question of what constitutes a substantial modification may temper the user’s willingness to have the modification performed, leading to continued use of an unsafe machine, despite the user knowing better. However, when performed solely for the purpose of increasing a machine’s safety level, a modification does not usually constitute a substantial modification.
Special duty of care
When a machine is modified, the solution implemented must lead to a permanent increase in safety. Particular care must therefore be taken during planning, documentation and implementation of the measure. Reciprocal impact upon neighbouring work areas and work equipment in use must be considered. Machine operating personnel must be adequately informed of the changes and trained in the new operating procedures. To ensure that the measures implemented are effective, checks and consultations of the operating personnel must be performed periodically. After a specified interval, check whether the machine still presents an incentive to defeat safeguards. If so, the procedure described here should be repeated.
