KPIs can be used within Maintenance Connection to optimise service frequencies and reduce maintenance costs. An example of this is in setting the schedules for servicing equipment which must conform to Statutory Compliance by a regulatory body.
This can include such items as Pressure Safety Valves (PSV) and Pressure Vessels. These must be inspected and maintained at regular intervals to ensure they are fit for service and do not pose a threat to people and property.Regulations for these can vary from State to State. Companies should seek advice from their local jurisdiction as the suggested options within this article may not apply to their situation.
When the initial implementation of MC is carried out, the set-up of the Modules can assist in establishing effective Reports and KPIs which will, in turn, facilitate the optimisation of the PM schedule. Logical Classifications, Failure codes and Specifications will aid in identifying recurrent problems associated with particular types of equipment or areas of operation. It will also highlight where possible over-servicing is occurring.
Let’s look at the case of PSVs. In a non-aggressive operating environment, companies will usually establish a servicing regime of approximately every two years. This will alternate between a visual inspection, looking for signs of leakage, corrosion, damage or interference and an overhaul which will require the removal, testing of the relief mechanism and replacing of corroded parts. The overhaul may be substituted with a valve exchange programme, where the existing valve is replaced with a similar pre-tested valve and the original is retained for future workshop overhaul. In most cases, the batch servicing of these valves is coordinated to lessen the down time of critical equipment and reduce labour and travel time. This schedule complies with most manufacturers’ recommendations and industry regulations. There is a considerable safety margin built into this time period and it does not take into account the variation in operating conditions.
PSVs can be found on equipment in locations ranging from covered, well-maintained and clean plant rooms to exposed, oil and gas platforms on the North-West shelf of Australia. The conditions which these valves operate under are vastly different and as such, should not be subject to the same stringent testing regimes. A plan to create a relevant preventative maintenance schedule can be established used the tools within MC. It will assist in ascertaining which is the most economical routine that should be applied while maintaining safety and complying with the Regulatory Authority requirements.
Most recommended service periods take into account the “worst-case” scenario. This results in over-servicing of equipment and unnecessary operating cost. Using the data gathered in MC, a more target-based approach can be taken to reduce maintenance costs and production equipment downtime. This can be done using the following method.
- When adding new equipment into MC, identify and classify the valves into functional types. These can be used to when creating the PM schedules.
- Establish PM schedules which groups valve inspections in logical service areas. Make sure this takes into account PSVs which should be serviced together if a major piece of machinery needs to be shut down.
- Begin with the Manufacturer’s recommended service interval unless you have a PROVEN variation to their recommendation.
- PSV inspections are often associated with pressure vessel inspections, so thought should be given to synchronise these to reduce plant shutdown.
- Create Failure codes which can identify PSV faults. This will be used when conducting reviews of reliability and recurring problems.
- Create KPIs and Reports which will identify failures and corrective work orders associated with the PSV classifications which have been created.
- Use the PSV failure report to identify any valve types or locations which have required repair before the scheduled PM period has been reached.
- Identify if these failures are due to environment conditions or simply due to an extraordinary event.
- Take a sample of the PM work orders to determine the condition of thePSVs when they have been serviced:
- Was the valve mechanism in good condition
- Was there any corrosion which needed to be treated
- Was there any sign of leakage or bypass
- Use the data gathered to determine if there is the need to reduce the service period (repeated failures of a type of PSV) or the scope to extend it (PM Work Order reports indicating minimal deterioration).
- If failures are occurring, the PM for this type of valve in a particular location may need to be altered to ensure they are serviced to reduce failures to an acceptable level. If the PM time-frame is to be altered, an assessment should be carried out to determine its impact on other equipment:
- Will this create additional plant shut downs
- Can extra visual inspection in certain areas be sufficient to identify potential failures
- Can an alternative valve or manifold arrangement be used to improve reliability
- Is there a method to reduce the impact of the working environment – covers, coatings, repositioning
- Is the frequency of failures acceptable in the given situation. Does the cost of replacement and any production loss outweigh the cost of additional maintenance
- If there are minimal signs of deterioration during the programmed maintenance, the time-frame can possibility be extended. Before this is adjusted, all consequences and benefits should be assessed:
- Does this schedule comply with the relevant Statutory body’s regulations. These departments will often approve a variation of the service period if recorded data and analysis can demonstrate the justification for it.
- Will this variation increase the danger to staff, public or equipment
- Will the possible increased risk of failure impact on the production capacity and profitability of the operation
- Does this impact on the preventative maintenance schedule of any associated equipment and create the need for additional shutdowns
- Are there any exceptions, based on location or age of equipment which need to be considered before extending the time period
Through the use of Reports, KPIs and trend graphs, periodic reviews can be undertaken to determine the results of changes made to the servicing schedules. This can be through simply software generated alerts or notifications of events which exceed set safety parameters or through periodic detailed analysis of Failure and Work Order records. Changes to operating conditions, age of equipment and service procedures will all impact on the Preventative Maintenance schedule and as such, requires an ongoing analysis and review process.
By carrying out the process of Set-up, Analysis, Optimisation and Review, the ultimate aim is to improve operational efficiency and reduce maintenance costs. Maintenance Connection can provide the tools and expertise to assist customers to achieve these goals through the Work Order, Preventative Maintenance, Report and KPIs functions of the software.