Interaction between technical system reliability and safety

Príspevok sa zaoberá v súčasnosti veľmi aktuálnymi vzťahmi rozhodujúcich parametrov kvality výrobku (technického systému), teda vzťahmi medzi jeho spoľahlivosťou a bezpečnosťou. V príspevku sú uvedené definície pojmov kvality, medzi spoľahlivosti a bezpečnosti a sú analyzované ich vzťahy pomocou aparátu množinového počtu a počtu pravdepodobnosti. Z úvahy uvedenej v príspevku jednoznačne vyplýva, že za rozhodujúci parameter kvality výrobku (technického systému) môžeme považovať je jeho bezpečnosť, to konštatovanie potvrdil v príspevku uvedený experiment s tvárniacimi strojmi a je potvrdené aj platnou legislativou, teda zákonmi, vyhláškami a normami z oblasti kvality a bezpečnosti.The contribution deals with very topical parameters of product (technical system) quality, i.e. its reliability and safety. On the basic of analysis of the basic conceptual apparatus in reliability and safety, it analyses the interaction of three basic subsystems of safety and the influence of reliabilities on system quality. Through an undesirable event (failure) in function it tries to define system hazardousness by means of multiple calculus and schemes to determine conditions under which such an event may appear. The autor analyses conditions for failure occurence (health damage, or injury) and the decesive "merit" of a man in the occurrence of this failure. It follows from this consideration unambiguously that if a product is to be of high quality also from the point of view of safety, its compliance with requirements of safety legislation is not sufficient; safety devices or their functions must be sufficiently reliable as well. The author verifies theoretical considerations by experiment conducted on a group of forming machines and presents an interesting parameter of system safety, i.e. the probability of injury occurrence, P(u). On the basis of performed observation of reliability of the operation of the given group of machines, the author also presents the probable behaviour of failure rate of function groups participating in system safety. From the consideration given in the contribution it follows unambiguously that as a decisive parameter of product (technical system) quality its safety can be taken; this was confirmed by the experiment carried out by the author on the selected group of hazardous technical systems (forming machines), which is described briefly in the contribution