Category: Safety & quality
Prepared by Eng. Ahmed Fathy, Projects Manager ·
Definition
A confined space is not designed for continuous work and has limited entry and exit, such as tanks, manholes, septic pits, tunnels and valve chambers, where toxic or flammable gases can build up or oxygen can fall below the safe level (19.5%).
Why it matters on a project
Confined space incidents often kill more than one person, because rescuers go in unprotected. Entry needs a permit, gas testing, an attendant outside and a rescue plan.
Measurement and pricing
Within safety costs: gas detectors, forced ventilation, rescue equipment and training.
Common mistake
Going in to rescue a worker who collapsed in a confined space without breathing apparatus, so the rescuer becomes a second victim.
Frequently asked questions
What oxygen level is safe?
Between 19.5% and 23.5%, with flammable and toxic gases measured before and during entry.
Is opening the cover enough ventilation?
No, it needs forced ventilation and continuous gas monitoring.
Related terms
- Permit to workWritten authorisation for hazardous work (hot work, work at height, confined spaces) under set conditions.
- Risk assessmentIdentifying hazards in each activity, estimating likelihood and severity and setting controls before work starts.
- PPEHelmet, high-visibility vest, safety boots, glasses, gloves and harness as the activity requires.
- Toolbox talkA short pre-work briefing on the day's task hazards.
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