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Confined Spaces: Why One Gas Test is Not Enough
The air you breathe can change in a second: keep the gas detector on and with you at all times.
Why this matters
- Checking the air once before you enter is not enough to keep you safe. Gas can seep in from pipes, be released from the soil, or build up because of the work you are doing inside. If you only test the air at the start of the shift, you are walking into a trap.
- Oxygen levels can drop as you breathe, and toxic gases like H2S or methane can rise without warning. Continuous monitoring is the only way to know the air is safe every minute you are underground or inside a tank. Your life depends on that sensor stayed active.
Talking points
- The initial gas test on your permit is only a snapshot of that moment: things change.
- Keep the gas detector in the breathing zone: it must be near your mouth and nose, not left on the floor or at the entrance.
- Never turn off the gas detector or silence the alarm to save battery: if it dies, you must exit immediately.
- The standby person must monitor the readings from the outside if the device allows: communication is vital.
- If the alarm sounds or the device flashes, stop work immediately: do not stop to pick up tools, just get out.
- Be aware of 'pockets' of gas: move the monitor around if you move to a different corner of the space.
Ask the crew
- Where is the best place to clip your gas detector while you are working?
- What should you do if your gas detector battery starts blinking low?
- If the air was safe two hours ago, why do we still need the monitor on now?
Download the PDF with attendance sheet
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