Reliability, maintainability, and availability methodology based on statistical approach for cooling systems design modification and maintenance

Abstract

ABSTRACT This study presents a described methodology for reliability analysis, maintenance options, and system availability in all its steps and is graphically presented via a flowchart. The methodology was verified on an example of a cooling plant in the pharmaceutical industry. All the results are presented in diagram and tabular form. For this purpose, two subsystems were selected, and the respective analysis with the results was presented through all the described steps. The methodology is iterative in essence, which means that the procedure sometimes has to be repeated several times to obtain satisfactory results. It is based on a statistical approach; the calculation of individual parameters regarding functions in each step of the methodology was done by applying the Weibull and lognormal distribution. According to the obtained parameter β from the reliability analysis, both observed subsystems were slightly larger than 1, and showed slow equipment aging in the plant. The maintainability analysis for function M(t) also showed that the components of the power subsystem require a shorter time to replace the faulty or worn-out part rather than with the hydraulic cooling subsystem. The value of the parameter σ is relatively low, which means that a little dispersion exists around the mean value of failure numbers.