Some Problems When Preparing for Maintenance

Within a typical world-class industrial commodity chemical company the annual cost of maintenance is 3 to 6 percent of the asset replacement costs. A number of significant maintenance activities require very little interruption of continuously operating chemical plants. Everyday maintenance activities that may be accomplished on a routine basis include repairs to a spare pump or spare compressor after it has been properly isolated and cleared of fluids, and overhaul of a fully spared filter or painting. 

However, other preparations for maintenance activity that seem innocent can jeopardize or ruin equipment and result in injury. Trevor Kletz has often discussed problems of preparation of maintenance. Recently, Kletz wrote  

Maintenance is a major source of accidents, not so much the maintenance in itself but the preparation of equipment for maintenance. Sometimes the procedures are inadequate sometimes the procedures are satisfactory but not followed. In particular  

This chapter covers examples of system modifications made to prepare for maintenance. Each unwise modification created equipment damage. These incidents were simple changes intended to isolate, protect, clean, or clear equipment, and the methods chosen created problems. In some cases equipment was subjected to partial vacuum or positive pressure beyond the tolerable design limits. 

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