Case Studies in Maintenance and Reliability: A Wealth of Best Practices. V. Narayan
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Figure 7.1 Excavation & Refilling—Relative Costs
Insulation
Removal of cladding (galvanized iron or aluminum sheeting) and rock wool insulation over a length of 30 meters of a 6” and a 12” pipe, lying next to each other, in a pipe bridge of approximately 6 meter height. The lagging and rock wool insulation are in good condition and can be put back after inspection of the pipe. Scaffolding and grit blasting or power brushing are excluded from the contract. See results in Figure 7.2.
Figure 7.2 Insulation Removal and Replacement—Relative Costs
Scaffolding
Erect and, after use, remove tubular scaffolding for the above-mentioned example (insulation work on a pipe bridge) to the local safety requirements. See results in Figure 7.3.
Grit Blasting
The 6-inch pipe mentioned in the example for insulation needs to be grit blasted to SA 2.5. Estimate man hours. See the results in Figure 7.4.
Figure 7.3 Scaffolding—Relative Costs
Figure 7.4 Grit Blasting—Relative Costs
Spading/Despading
As part of a job, spades have to be placed to isolate a vessel. For this purpose, 4 nos. 8” 300#, 4 nos. 6” 300#, and 6 nos. 2” 150# spades have to be installed in the existing line work. Estimate man hours required per spade of each size, including cleaning the flange faces, placing new gaskets, placing new stud bolts, and de-spading after the job is completed. See results in Figure 7.5.
Figure 7.5 Spading/Despading Pipes—Relative Costs
Figure 7.6 Welding 4”, 6,” and 10” Pipes—Relative Costs
Welding
A few lines in the pipe bridge mentioned in the examples above need to be renewed; each has a length of approximately 30 meters. These pipes are 4”, 6”, and 10” in size; all are schedule 80 carbon steel. Safe-to-work preparations, scaffolding, and insulation work are done by others. Please estimate man-hours per completed weld of each size, including joint preparation, grinding, alignment, and welding. See results in Figure 7.6.
Valve Gland Packing Renewal
During a shutdown, various types of gate valves need to be repacked (all old packing rings to be removed from the stuffing box and renewed). The total number of valves to be repacked is approximately 40 pcs of sizes 4, 6, and 8 inch. Estimate the man-hours required per piece of each size. See results in Figure 7.7.
Figure 7.7 Valve Gland Packing—Relative Costs
This kind of benchmarking proved quite simple to carry out. It proved useful in checking contract prices and in preparing estimates prior to inviting competitive bids.
7.6 Lessons Learned
1.Although competitive bidding is a safeguard against overpricing, it fails when contractors form alliances.
2.All norms should be reviewed regularly and updated if necessary.
3.An outside pair of eyes can reveal weaknesses in your systems, which you yourself are too close to observe.
4.Benchmarking is a powerful tool for assessing comparative performance.
7.7 Principles
Without in-house capability for making realistic estimates, there is no way of knowing whether you get value for money from your contractors.
Externally-enforced maintenance cost reductions can hurt the long-term viability of the company, cutting away some flesh and bone along with the fat. Internal audits of current practices can help identify out-dated procedures that add costs without adding value. Some of these practices may have started off as well-intentioned streamlining exercises, to improve efficiency of repetitive work. Periodic audits will demonstrate that controls are constantly reviewed, and thus minimize external pressures.
Benchmarking is about being humble enough to admit that someone else is better at something than you; and wise enough to try to learn how to match and even surpass them at it.
American Productivity and Quality Center.
Author: Jim Wardhaugh
Location: 2.3.3 Corporate Technical Headquarters
8.1 Background
Our little group was providing a benchmarking and consultancy service to our own facilities and to a few others with whom we had technical support agreements. These sites were scattered around the world. They operated in different geographical areas, under different government regulatory regimes. They were of different ages and sizes; they used different feed-stocks to make different portfolios of products. Our task was to scrutinize data from these locations, identify those whose performance could be improved, and arrange to help those who needed it.
8.2 Company Performance Analysis Methodology
We had a systematic methodology for capturing performance data from the sites. There were structured questionnaires asking for relevant data. These were backed up by copious notes explaining in detail the methodology, terminology, and definitions. Some returns were required every quarter while the rest were required annually. Each client location would then send the requested data, which was checked rigorously for any apparent errors. The data was used by a number of different groups in the head office, each looking at different aspects of performance. Our group looked at aspects of maintenance performance.
We did not want to ask a site for data that it was already sending to the head office in any report. So we took great pains to extract data from a variety of sources. In this way, the input effort by the sites was minimized and little additional information was needed from them.
When satisfied that all the data looked sensible we massaged the data to identify the performance of each site (or a facility on that site) in a number of ways. The main performance features published for each site were:
For each of the major plants on site [e.g., Crude Distillation Unit (CDU), Catalytic Cracker (CCU), Hydro-cracker (HCU), Reformer (PFU), Thermal Cracker (TCU/VBU)]:
•Downtime averaged over the turnaround cycle (whether 3, 4, or 5 years). This smoothed out the effect of major turnarounds (also called shutdowns)
For the whole site:
•Maintenance cost, averaged over the turnaround cycle, as a percentage of replacement value
•Maintenance cost,