Maintenance management 1 Maintenance Management Loop 2 FMEAFMECA

Maintenance management 1

Maintenance Management Loop 2

FMEA/FMECA n Failure Mode, (Criticality) and Effects Analysis n A Failure Mode and Effects Analysis is often the first step in a systems reliability study n It involves reviewing as many components, assemblies and subsystems as possible to identify possible failure modes and the causes and effects of such failures n For each component, the failure modes and their resulting effects on the rest of the system are written onto a specific FMCEA form n FMECA is an important element of RCM 3

Maintenance and inspection types and intervals n The main objective of this step is to determine the type and frequencies of maintenance and inspection tasks n In principle each failure mode/failure cause in the FMECA should be combated by a maintenance task n The RCM logic of an RCM analysis will be a starting point for identifying relevant maintenance tasks n To determine optimal frequencies of maintenance tasks it is usually required to establish a cost model to optimize 4

Grouping of maintenance and inspection work n When the maintenance tasks are identified, and frequencies set it will usually be natural to group these activities into maintenance packages, each package describing what to do, and when to do it n It is a challenge to establish such an optimal grouping strategy n Why grouping n Save “set-up” cost n Convenience 5

Maintenance and inspection plan n A maintenance program shall be established, which includes written procedures for maintaining, testing, and repairing the various components n Such a program is often implemented by a computerized maintenance management system (CMMS) n A main task of the CMMS is to manage all work orders for preventive maintenance 6

Failures need corrective maintenance n Failures represent technical component failures (e. g. rail breakage, defect breaks etc), and deviations (e. g. geometrical deviations of the track) n Failures and deviations require repair, overhaul etc n Typically a work order for corrective maintenance (CM) is issued n The CMMS will also manage these work orders 7

Reporting of result from maintenance and inspection n All maintenance work (functional testing, preventive maintenance, and corrective maintenance) shall be reported into an electronic maintenance database n The information to report depends on the type of maintenance work n Important information to report n n n Exact description of failed/maintained unit Failure mode (CM) Component state (PM) Failure cause (CM) Effect of failure (CM) Direct cost of maintenance action 8

Database n The database used in the maintenance management loop is a conceptual term n A RAMS database may be realized as a part of the CMMS n It is essential that the database system contains necessary information for a proper data analysis 9

Data analysis and improvement analysis n A proper failure cause analysis (FCA), or root cause analysis (RCA) n Investigation into the failure reports to identify common cause problems (CCF) n Updated reliability data that was used in quantitative risk analyses/maintenance optimization models n Verification of assumption related to safety critical functions/safety barriers 10

Restrictions n When maintenance comes out of control (large backlog) it is important to initiate operational restrictions n Closing a railway line n Reducing speed n Stop production n Use of compensating measures n Restrictions will also be necessary when the system integrity is threatened by weather conditions such as rain, frost, snow, high temperature etc. 11

Exercise n What is meant by “the maintenance management loop is NOT closed” 12