Tab. 1
Risk analysis tools used for maintenance
| Risk Tool | Description | sample publications on the issue |
|---|---|---|
| ETA | Event Tree Analysis — a method for describing the consequences of the superior event, illustrating the progression of events from the initial event to the final event, with particular emphasis on the moments that are decisive for the condition of the facility (installation). It is the primary method of creating an object model for threat analysis | Ahmadi et al., 2008; Mareş et al., 2017 |
| FTA | Fault Tree Analysis — a qualitative method of risk analysis using the structure of logical trees, allowing for modelling the course of a failure and then its analysis. An FTA diagram illustrates causes, the result of which are referred to as uncertain events or risk | Gharahasanlou et al., 2014; Vaurio, 2010 |
| FMEA | Failure Modes Effects Analysis — a method that consists of analytically determining the cause-and-effect relationships of potential product defects and considering the criticality (risk) factor in the analysis. Its aim is to consistently and systematically identify potential product/process defects, and then eliminate them or minimise the related risk | Sutrisno et al., 2015; Onodera & Katsushige, 1997; Braaksma et al., 2013; Mikołajczyk, 2013; Mańka, 2015; Ennouri, 2015 |
| HAZOP | Hazard and Operability Studies, in other words, the analysis of threats and operational capabilities, is based on the PN-IEC 61882 standard. It is often used in the design of new facilities and installations, modernisation of facilities, installations or processes | Hu et al., 2012; Crawley &Tyler, 2015 |
| HIRA | Hazard Identification and Risk Assessment — risk assessment tool that can be used to assess which hazards pose the greatest risk in terms of how likely they are to occur and how great their potential impact may be | Purohit et al., 2018; Liberti et al., 2015 |
| GOFA | Goal-Oriented Failure — analysis and a hazard identification technique that uses selective features from Failure Mode and Effects Analysis (FMEA) and Fault Tree Analysis (FTA) to identify the causes of failure of a specific target | Yi et al., 2017; Yi et al., 2016 |
| RBI | Risk-Based Inspection — determining the scope and methods of testing, allowing to determine the risk associated with the operation of technical devices, based on the results of quantitative risk analysis | Arunraj & Maiti, 2007; Khan et al., 2004; Khan & Haddara, 2003 |
| RCM | Reliability-Centred Maintenance — determining the necessary maintenance activities in the operational efficiency of the machine or device, considering the conditions of use | Hauge et al., 2001; Braglia et al., 2019 |
Tab. 2
List of the frequency and duration of emergency downtime at the enterprise
| Equipment | Units of equipment | Code of equipment | Number of failures ni in the analysed period | Number of failures per equipment | Total time ti of damage removal [h] | Time ti of damage removal for single equipment [h] |
|---|---|---|---|---|---|---|
| horizontal tank | 7 | hori | 35 | 5 | 70 | 2 |
| submersible pump | 20 | subm | 40 | 2 | 40 | 1 |
| washing station | 2 | wash | 8 | 4 | 24 | 3 |
| condensing unit | 1 | cond | 5 | 5 | 15 | 3 |
| water boiler | 1 | wate-b | 5 | 5 | 10 | 2 |
| shrink wrapping machine | 1 | shri | 3 | 3 | 9 | 3 |
| pneumatic pump for cheese | 1 | pneu | 3 | 3 | 9 | 3 |
| centrifuge LWG-47 | 1 | cent | 3 | 3 | 9 | 3 |
| pneumatic press of cheeses | 1 | pneu1 | 4 | 4 | 8 | 2 |
| milk collection station | 1 | milk | 4 | 4 | 8 | 2 |
| cheese cauldron | 1 | chee-c | 3 | 3 | 6 | 2 |
| vacuum packing machine | 1 | vacu | 3 | 3 | 6 | 2 |
| cheese slurry pump | 1 | chee-s | 3 | 3 | 6 | 2 |
| hot water pump | 3 | hot | 3 | 1 | 6 | 2 |
| water cooler | 1 | wate-c | 2 | 2 | 6 | 3 |
| pasteuriser - milk - cream | 1 | past | 4 | 4 | 4 | 1 |
| centrifugal pump | 1 | centp | 2 | 2 | 2 | 1 |
| screw compressor | 1 | scre | 1 | 1 | 2 | 2 |
| elevator | 1 | elev | 1 | 1 | 1 | 1 |
| together | 132 | 58 | 241 | 40 |
Fig. 1
Result of the Pareto analysis for the “repair time” criterion in the V1 variant
Fig. 2
Result of the Pareto analysis for the “number of failures” criterion in variant V1
Fig. 3
Result of the Pareto analysis for the “repair time” criterion in the V2 variant
Fig. 4
Result of the Pareto analysis for the “number of failures” criterion in the V2 variant
Fig. 5
Tested equipment and the “number of failures — failure recovery time” (V2) system
Fig. 6
Tested equipment and the “number of failures — failure recovery time” (V1) system
Fig. 7
Risk matrix for the tested devices (V2)
Fig. 8
Risk matrix for the tested devices (V1)
Tab. 3
Summary of the analysis results for variant V1
| Category | Equipment qualification in aspect (V1) | |||
|---|---|---|---|---|
| single-criteria Pareto analysis | two-criteria Pareto analysis | risk analysis | ||
| by repair time | by number of damage incidents | |||
| A | washing station, condensing unit, shrink wrapping machine, pneumatic press of cheeses, centrifuge LWG-47, water cooler, horizontal tank, water boiler, pneumatic pump for cheese, milk collection station, cheese cauldron, vacuum packing machine, cheese cauldron | horizontal tank, condensing unit, water boiler, washing station, pneumatic press of cheeses, shrink wrapping machine, pneumatic pump for cheese, centrifuge LWG-47, cheese cauldron, vacuum packing machine | shrink wrapping machine, centrifuge LWG-47, pneumatic press of cheeses, washing station, condensing unit, cheese slurry pump, cheese cauldron, vacuum packing machine, pneumatic pump for cheese, milk collection station, water boiler, horizontal tank | pasteuriser - milk – cream, pneumatic pump for cheese, washing station, milk collection station, condensing unit, horizontal tank, water boiler, |
| number of devices | 13 | 10 | 12 | 7 |
Tab. 4
Summary of the analysis results for variant V2
| Category | Equipment qualification in aspect (V1) | |||
|---|---|---|---|---|
| single-criteria Pareto analysis | two-criteria Pareto analysis | risk analysis | ||
| by repair time | by number of damage incidents | |||
| A | horizontal tank, submersible pump, washing station, condensing unit, water boiler, shrink wrapping machine, pneumatic pump for cheese, centrifuge LWG-47 | submersible pump, horizontal tank, washing station, condensing unit, water boiler, pneumatic pump for cheese, milk collection station, pasteuriser - milk - cream | horizontal tank, submersible pump, washing station | horizontal tank, submersible pump |
| number of devices | 8 | 8 | 3 | 2 |