Bluefield has recently participated in maintenance strategy development and improvement projects with several different clients. Discussions regarding the optimal frequency have been a hot topic of conversation. So, we threw the following question out to our most experienced maintenance professionals:
In your experience, what are the pros & cons of a 48-Week maintenance interval as opposed to a 52-Week maintenance interval?
The only reason I know for (a 48-Week interval) is so that the interval can be divided by 12 and quarters more easily. I do not see any real benefit in adopting 48-Week vs 52-Week unless there is some system issue like in SAP that makes it simpler to implement.
Gerard introduces the Bluefield webRE service here.
Stefan Van Der Linde
Logistics/simplicity is the main driver for a 48-Week cycle, especially from a maintenance plan suppression hierarchy in SAP. 4 weeks roll up into 12 weeks, 24 weeks and 48 weeks nicely which roughly translates to monthly, 3 monthly, 6 monthly, 12 monthly, etc. It also aligns with crew rosters which are usually based on a 14-day cycle (7/7, 8/6, etc). This does not hold true for a 52-week year.
52-Week cycles are advantageous if you want services to occur at a consistent time of the year (to avoid holiday periods etc). A client I have dealt with have gone down this road with 13-week shutdowns (4 over a 52-week period) for this reason.
Another reason for a 48-Week cycle may be due to some "tolerance" built into statutory/critical tasks. If a task is required to be done annually to meet an obligation than a 48-Week frequency gives you some grace (I personally find this a fairly weak reason but have seen it used this way).
The main issue is suppression in the Computerised Maintenance Management System (CMMS). 48-Week works for a 4 week month so if you have a strategy that is 1 or 2 week suppressed by a 4 week (1 month) suppressed by a 12 week (3 month) suppressed by a yearly then you need a 48 week year. this can also work well for planning. If the strategy is just 3, 6, 12 months a 13, 26, 52-Week cycle works better. If possible, the 52-Week cycle is better as there is one less execution a year - saving downtime and money. In response to Gerard’s comment this is not SAP specific. All CMMS have this issue.
48-Week will give you much more flexibility with (1, 2, 3, 4, 6, 8, 12, 16, 24, 48) weekly suppression/hierarchical strategy options whilst 52-Week is better suited to monthly suppression/hierarchical strategies as fewer options with (13, 26, 52).