# IoT-Aware Architecture to Guarantee Safety of Maintenance Operators in Industrial Plants
## 2 Industrial Regulation  
The most critical factor to be addressed for guaranteeing workers' safety is the reasonably foreseeable misuse of machineries and tools as defined in MD 2006/42/CEE, annex I, Definition 1.1.1, that shall be covered in all the machines sold and installed in EU: with the term'reasonably foreseeable misuse' we intend the use of machineries in a way that was not foreseen during its construction and, therefore, not reported in the manual, but which may be predicted from readily predictable human behavior. Same similar regulations are not only foreseen by the EU, in fact, they are also present in almost every country of the world due to their importance.  
Based on the literature, it is difficult to define in practice the \"predictable human behaviors\" but at least some \"dangerous\" behaviors are defined in ISO 12100:2010 [8] that is the type A standard for the risk reduction in machine directive.  
The ISO 12100:2010 standard gives the following examples of the kinds of misuses or readily predictable human behaviors to be taken into account: (a) loss of control of the machine by the operator; (b) reflex behavior of a person in case of malfunction, accidents or failure during the common use of the machinery; (c) behaviors resulting from lack of concentration or carelessness; (d) behavior resulting from adopting the line of least resistance in carrying out a task (e.g., a given machinery is designed with redundant safety devices and, as a consequence, the worker removes/disables the safety devices to work faster thinking that they are not important); (e) behavior resulting from pressures from the bosses to keep the machinery running in all circumstances; (f) the behavior of specific kind of people such as children. All these behaviors can be partially or fully foreseen during the design of machineries, however, if the machine is off or in maintenance mode there is no way to act with the proper countermeasures.  
Moreover, as already anticipated, during maintenance operations various third-party workers are usually responsible for the maintenance activities, but they may be not sufficiently aware of the system or the machinery they are maintaining. Therefore, in normal conditions, such operators need special training for maintenance on the particular machinery, while, if a system like the one we are proposing, can guide them throughout all the operations, the training can have a lower impact on the preparatory activities (and therefore on the funds spent by the company).  
An alternative to an automatic monitoring and acting system is to have a tutor per each operator, that is a second dedicated worker that follows step-by-step the third-party maintainer. Such a tutor should be an expert that is completely aware of the control station of the specific machinery under maintenance. However, such a solution may result in the exploitation of modified maintenance procedures that are not in line with the instructions designed by the machine builder (e.g., typically, the presence of more than one operator is not allowed by the machine builder, especially for large machinery).  
Typically, those problems are managed with LockOut/TagOut (LOTO) procedures [9], some safety procedures used to ensure that dangerous equipment is properly shut off and not able to be started up again prior to the completion of maintenance or repair work. The application of these procedures usually results in the segmentation of the working area into different \"LOTO points\" in which the operators are asked to de-energize relevant devices and lock energy sources with real locks and keys that can be removed only by maintenance workers; however, such solutions may introduce latency in the execution of the procedures and/or further effort in preparing operators.