The six-month window: what a postponed maintenance interval costs

Two cases from practice, one and the same cause. In the first, a repair costing around 5,000 euros was postponed and the care spraying that was due was skipped. Six months later, the same spot cost around 80,000 euros. In the second, a customer went a full year without maintaining his aluminium furnace — the repair ended up above 100,000 euros, and the charging capacity had dropped significantly in the meantime. In neither case did anything fail that was not foreseeable.

Why six months and not twelve

• Slagging is not an event but a build-up. It grows steadily — and beyond a certain thickness it can no longer be cleaned off, only removed together with the lining.
• For around six months, the build-up remains mechanically removable. After that it grows into the lining, and a cleaning job turns into a relining job.
• Small defects travel. An open joint closed early is an hour's work. The same joint after six months of infiltration is a zone.
• A finding needs comparative values. Whoever looks inside twice a year recognises change. Whoever looks inside once a year sees only a condition.

What belongs in a maintenance interval

• Cold inspection with visual examination and documentation of the change since the last visit
• Complete cleaning before the build-up grows into the lining
• Care spraying on a clean substrate as a protective layer against renewed build-up
• Immediate treatment of small defects instead of pushing them into the next shutdown

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