Recall that the work ratio for a two-week shutdown was 37.5 per-cent. The increase in work ratio to 47 percent is a 25 percent improvement for key resources.

With 38 key mechanics working 39.5 hours each, the amount of work completed per shutdown would be nearly 1,500 shutdown hours. If 20 mechanics from other sources were borrowed, each shutdown could provide approximately 2,300 hours of task work. See figure 6-5 for another look at this shutdown.

Recall that linestops could possibly move 2,400 shutdown work hours to non-shutdown work, the annual internal shutdown work is reduced to 16,000 hours – 2,400 hours = 13,600 hours. With this strategy, four and one-half shutdowns (at 2,300 hours each = 10,350 shutdown hours) and ten maintenance linestops (at 306 hours each = 3,060 shut-down hours) would be needed to provide the approximate 13,600 shut-down hours of planned work. This plan would reduce the annual shut-down time from 28 days to about 21 days.