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2.3 Strategy for Risk Reduction
The U.S. Code of Federal Regulations, Title 29, Part 1910, Subpart 0 requires that with the construction of machinery risks must be analyzed and, where required, protective devices must be provided to protect the operator.
Technical Report ANSI B11.TR3:2000 includes proposals for assessing, analyzing and reducing risks on tool-making machines.
OSHA/ANSI provides the following hierarchical procedure for risk reduction:
Identification and analysis of the risk (see ANSI B11.TR3:2000)
Removal of the risk with constructive measures
Reduction of the risk with technical protective devices
Warning signals and warning information
Personal protective equipment for the operating personnel
Operator training
The international standard, EN/ISO 12100-1 Safety of machinery – Basic concepts, general principles for design is similarly structured. It provides detailed assistance with the identification of hazards, describes the risks to be considered by the designer, contains design principles and a method for safe construction and risk minimization. EN ISO 14121 Safety of machinery – Principles of risk assessment describes an iterative method for risk analysis, risk assessment and risk minimization to achieve the required machine safety. Existing machine-specific standards, such as type C EN standards, for example, must be considered with priority.
Iterative process for risk reduction in accordance with EN ISO 12100-1:
(source: EN ISO 12100-1)
EN ISO 12100-1 recommends that the machine designer use the following step-by-step procedure for risk reduction
Specification of the limits and proper use of the machine
Identification of possible hazards and hazardous situations
Estimation of the risk of each identified hazard and each hazardous situation and parallel consideration of the foreseeable malpractice or faulty operation by operating personnel
Evaluation of each individual risk and decision on whether a risk reduction is required or not
Attempts to remove or reduce the risk with constructive measures. If this does not work then:
Reduction of the risk with the use of protective devices (guards, such as hard guards or covers, or electro-sensitive protective equipment, such as Safety Light Curtains, for example)
Informing and warning machine operators about the remaining risks of the machine by using warning notes and plates on the machine and in the operating instructions
The first four steps describe the risk analysis and risk assessment. EN ISO 14121 contains detailed requirements for this. It is important that the risk analysis and risk assessment be carried out methodically and that it be comprehensibly documented.
In addition to these protective measures selected by the machine designer/constructor, further protective measures may also be required by the operating company or machine operator to reduce the remaining risk. This may be, for example:
Organizational measures (e.g. safe work processes, regular inspections, etc.)
