In the last article in this series, we started the discussion on some listed facility maintenance strategies. This article is the continuation of the discussion on the remaining Maintenace strategies in our list.
Risk-Based Inspection (RBI)
Just as the name signifies, this form of maintenance strategy is used to select or prioritize equipment for inspection based on the associated risk of failure.
The risks of equipment failures are analyzed in terms impact/consequence of failure to personnel, environment, the business, and the likelihood of the failure happening. The outcome of this analysis is a list of the equipment ranked in order of magnitude of the consequence of failures; that is, the equipment whose failure has the greatest impact to the personnel/business, or the environment comes top in the list. This list is used to prioritize the selection of the equipment for maintenance.
The risk-based inspection/maintenance approach maximizes the use of resources by focusing of equipment whose failures pose greater risks to the business.
In the manufacturing or production operations, the risk-based inspection is deployed on storage and pressurized vessels and other critical equipment subject to regulatory requirements.
The risk-based maintenance strategy offers the following advantages:
- Reduce the risk of equipment failures
- Enables cost efficient use of maintenance resources
- Enables identification of risks associated with equipment failures
This form of maintenance is an improved form of condition-based maintenance that deploys data analysis tools. This involves use of historic and real time data gathered while operating the equipment to anticipate or predict failures. In most cases, with continuous advancement in technology, the data analysis tools can predict how much time is left before the imminent failure of the equipment and send a warning signal to the responsible persons.
The early warning allows the responsible person to prepare for the fault repair by ensuring all relevant materials and personnel are available before shutting down the equipment for repairs.
Advantages of predictive maintenance include the following:
- Enables efficient operation of the equipment by avoiding frequent shutdowns for maintenance interventions.
- Minimize operation hours lost to maintenance or reduction in equipment down time.
- Reduce the amount spent on spare parts and supplies.
- Minimize the amount spent on equipment maintenance.
Disadvantages of the predictive maintenance include:
- High set up cost
- Requires specialized skills
Corrective maintenance, as the name implies, is the repair or restoration activities carried out on a faulty equipment.
Sometimes, equipment can fail without warning due to wrong operation, impact of external force, or a premature failure of a component with manufacturing defects.
To reduce the down time from unplanned equipment breakdowns and their associated impact to the business, the following activities should be carried out:
- Identify the equipment that are crucial to smooth operation of the business.
- Identify the critical spares without which the equipment will note operate.
- Estimate the likelihood of sudden failure of the critical equipment
- Determine the optimum number of spare parts that should be stocked to enable quick response to sudden failures.
- Set up spare parts management system
- Set up regular inspection of the spare parts to ensure they are not damaged while on the shelf.
To reduce interruption to operations from sudden loss of critical equipment, most design philosophies for critical equipment involve provision of spare equipment that is started when the main equipment fails.
Provision of adequate training and tools for the workers reduces the frequency of unplanned operations shutdown due to faulty equipment, thereby contributing to maximizing production and profit for the business.