## 1 Introduction
In regard to this development and trends not only in Europe but all over the world, machinery safety appears as a field that is still not sufficiently solved and further development supported by new regulations and harmonized standards is expected. The condition of machinery, the methods for performing activities, and the environment in which the machine is located are the basic factors that can influence the occurrence of hazardous events. Although the unified EU market expects the observance of the actual rules for machinery construction, it is, however, mainly the organizations that have out-of-date machinery and make changes to the machinery without adequate consideration of the basic requirements of the Machinery Directive [13]. The next issue is the education and training of technical workers/designers who have no knowledge of the principles and requirements for safe designing [14; 15; 16]. Some industry studies have identified up to 50% of the root causes of serious industry accidents come from mistakes caused by machinery designs [17]. A risk assessment performed early in the stage of the machine's design is an essential requirement for safe machinery construction, so that the residual risks are at the lowest possible level. Although modernization of old machinery provides higher effectivity and enables a significant increase in productivity by means of new automated functions, this will only happen when the right principles of safe design are used [18]. Modernization may also be performed to increase reliability and safety, meet environmental requirements, and for maintenance improvement purposes. When implementing new safety principles into old machinery, the knowledge and implementation of logical steps of risk assessment are necessary, targeting risk reduction in both an effective and efficient way. Consideration of all activities related to the machine's operation throughout its entire life cycle (pursuant to ISO 12100 [19]) is mainly related to an intended use assessment as well as to reasonably foreseeing any misuse, however, the actual trend also requires consideration of every kind of intentional violation, which can affect the integrated machinery's safety system (e.g., applied pursuant to the ISO 13849-1 requirements) [20]. This article contributes to the analysis of current methods and requirements for safe machinery construction. It describes a methodology of assessment of safety conditions and the efficiency of measures implemented throughout the machine's life cycle. It stems from the fact that the machine's condition and its operation changes during its life cycle, which is not always considered in safety management practice. For this reason, the foundation of the methodology is risk assessment, as a tool to determine the level of machine safety in any operation. This risk assessment was performed in accordance with the principles described in the harmonized standard ISO 12100:2010 within a particular production plant (using their internal risk matrix for risk evaluation). In the past, risk reduction measures had already been implemented on the machines (either by the manager or operator depending on the machine's age and/or requirements of the operation itself), these measures and the machine's state were assessed by experts in the field of safety by means of a questionnaire (19 criteria) stemming from the requirements of the directives (Directive 2009/104/EC but mainly Directive 2006/42/EC). The objective of the proposed methodology was to create relevant indicators that would make it possible to evaluate whether the implemented risk reduction measures were efficient. In applying the methodology in practice on 60 machines (three operations-plants), it provides instructions on how to assess the fulfillment of the regulatory requirements and implement the right procedures to meet the requirements for safe machinery operations while meeting the business objectives of the organization.