The users of machines assume they can use safe machinery or devices and that expectation is a global reality, a safe machine, also, avoids the manufacturer or organization which uses that to suffer lawsuits.
The safety requirements of machinery in recent years, have changed considerably due to the increasing use of the automation. In the past, the safety systems were almost always a nuisance, and then, were often not used. In contrast, today, technological innovations have enabled the integration of the safety devices in the work process, hence they are no longer an obstacle for the operator but, on the contrary, they are often useful to productivity.
The safety of machinery depends largely on the proper application of guidelines and standards. In Europe the national legal requirements are harmonized by European directives, eg the Machinery Directive 2006/42 / EC (which replaced the previous 98/37 / EC). These guidelines describe the general requirements that are described in more detail by the standards.
As for the functional safety of the electrical, electronic and programmable electronic command and control systems related to the safety of the machinery, the CELENEC committees (in particular the IEC TC 44 committee, Safety of machinery - Electrotechnical aspects) have developed the standard IEC 62061. It constitutes the variant to IEC 61508, with regard to the machinery. In fact, the IEC 62061 keeps the characteristics of IEC 61508, it simplifies the safety requirements (for both the hardware and the software) adapting them to the needs of industrial machinery.
The IEC 62061 apply to the control systems used, individually or in combination, to execute safety-related control functions of equipment (non-mobile and non-portable) ,while they are in operation, including machinery groups that operate together in a coordinated manner . It refers solely to the requirements for the functional safety, intended to reduce the risk of injury or damage to health of people in close proximity to of machinery or directly involved in the use of the same. It is limited to the risks arising directly from the dangers of the machine or group of machinery that operate together in a coordinated manner; It does not specify requirements for the performance of non-electrical control elements, which are subject to other rules (generally EN 954-1); It does not deal with electrical hazards arising from the same control apparatus.
HINTSW - T & T Systems has acquired different skills on the field of the electric, electronic and programmable electronic command and control systems , related to the safety of the machinery, among which the main ones are:
- Hazard e Risk Analysis.
- Planning of the verification and validation processes.
- Functional Safety Plan.
- Definition of the safety functions.
- Specification of safety functions requirements.
- Assignment of the SIL level for each identified security feature.
- Calculation of the average probability of dangerous failure per hour PFHD of each safety function (SRCF - Safety Related Control Function) and global security system (SRECS - Safety Related Control System).
- System development:
- Decomposition of the safety functions into functional blocks.
- Association of the subsystems to the function blocks.
- Physical composition of the subsystems (subsystem elements).
- Calculation of the maximum achievable SIL of each subsystem (SIL Claim Limit and SILCL).
- Design and development of safety software.
- Specification of the software safety requirements.
- Specification of software-based parameterization.
- Software Validation Plan with related test specifications.
- Validation and verification of the safety system (SRECS).
- Documentation for installation, use and maintenance of the SRECS.
HINTSW - T & T Systems has operated in the field of functional safety of machinery control systems taking part in several projects, including:
- Feasibility study of the safety system (SRECS) of the tower "J-Lay" t built on board of the CastorOne pipelay ship of Saipem S.p.A.