Before anyone climbs in

A shut-down furnace looks harmless. It is cold, it is empty, the door is open. That very perception is the problem: a furnace is a confined space with one access, poor ventilation and residues from operation.

The preparation for this is regulated and well known. What is missing in practice is the link between safety preparation and technical preparation — the two happen separately, and so someone often ends up inside the furnace who is safe but does not know what to look for.

What must be settled before entry

• Permit and isolation. Fuel, gas, electricity and moving parts demonstrably isolated and secured against restarting — not switched off, isolated.
• Atmosphere. Measured, not estimated, and monitored continuously while anyone is inside. Residual gases collect in hollows and ducts, which is exactly where people crawl.
• Temperature. A wall can be hand-warm on the outside and still well above a hundred degrees inside if the insulation has done its job.
• Standby attendant and escape route. One person outside, visual or voice contact, a clear way out — including if the lighting fails.
• Structural stability. Remove loose parts in the arch and roof before entry. Whatever comes down during the inspection comes down on somebody.

The technical preparation that belongs with it just as much

Whoever goes in has limited time and limited light. An inspection without a plan becomes a photo series; an inspection with a plan becomes a finding.

• Take the documents from the last overhaul with you rather than relying on memory. Same place, same dimension, same angle for the photograph.
• Decide beforehand which measurements will be taken — residual wall thickness at defined points instead of wherever there happens to be room.
• Take marking material with you. What is decided inside the furnace is marked inside the furnace; what is decided outside, nobody finds again.
• Allow time for the way out. The last minutes are the ones in which tools get left behind.

Why these belong together

A well-prepared inspection takes less time. Someone who knows where to go is out again sooner — and that is at the same time the most effective safety measure, because every minute in a confined space carries a risk that cannot be organised away.

That is why we treat safety preparation and the inspection plan as one procedure with one signature, not as two lists with two people responsible.

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