Change Control

By involving the process technologist and operations in the design of the new dampers, potential problems were identified in time. Rigging activities inside the duct would be quite demanding, so we took advice from the rigging foreman in sequencing the work. We applied the normal change control procedures to obtain approvals.


The new design of dampers performed satisfactorily, allowing operators to control the draft efficiently. Contrary to the experience with the old design, the dampers worked right through to the next planned shutdown. Repair of dampers was no longer an item on the shutdown work list. The cost of fabricating and installing two sets of new dampers was less than 30% of the cost of one set of original dampers. During the subsequent shutdown, inspection showed that the dampers were in good condition without any sagging. The bearings were also undamaged and did not need replacement.


1. The cause of damper failure had to be established before attempting a solution. Once this was done, innovative solutions were required

  • 2. Problems that have remained unsolved for many years offer interesting challenges.
  • 3. The change control process was speeded up by working closely with operations and the process technologist.


No amount of maintenance can cure an inherently poor design. Some reliability problems will require redesign.

Solving problems that affect operability brings credibility to maintainers.

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