Why entering a tank without gas checks and full ventilation is dangerous.
Confined space needs a strict protocol
An emptied tank can still hold flammable vapor or low oxygen. Continuous gas monitoring, forced ventilation, and a confined-space permit must be complete before anyone enters.
The safe sequence for tank entry
Before entry
- Full drain-down, washing, and physical isolation of inlet/outlet lines (blinding)
- Forced ventilation of the interior until the air is breathable
- Gas testing for flammable vapor (LEL), oxygen, and toxic gases
- Confined-space entry permit issued and a standby attendant posted before anyone enters
Common thresholds
A typical standard is oxygen between 19.5% and 23.5% and flammable vapor below 10% of the lower explosive limit (LEL) — gas testing must be continuous, not a single reading before entry.
