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Confined Space Ventilation | The Occupational Safety and Health Administration (OSHA) defines confined spaces as, “[spaces and openings] large enough for workers to enter and perform certain jobs,” and having, “limited or restricted means for entry or exit,” and those, “not designed for continuous occupancy.” Examples of confined spaces are pipes, basements, ducts, tunnels, attics and etc.

Working in confined spaces, the employer needs to make sure that sufficient ventilation is provided. Ventilation is a means of ensuring that the workers have access to sufficient breathable air. Any obstruction to the flow of oxygen could impact the employees health in a matter of minutes or less.

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Why We Ventilate The Confined Space

It may cause headaches, shortness of breath, dizziness, increased heart rate or restlessness. Employee safety is also at risk when the employer does not meet the ventilation requirements. Thus, to better protect them, every employer should have more knowledge about it.

Confined Space Ventilation | Zabsi

Safety and precautions

Before delving into ventilation requirements of confined space, the requirement for employers is to provide certain safety precautions as per OSHA regulations.

  • Firstly, Oxygen(O2) levels need to stay between 19.5% and 22%.
  • Secondly, gasses and flammable vapours must be kept below 10% of their explosive limit (LEL).
  • Thirdly, potentially toxic materials must stay below their personal exposure limit (PEL) levels or immediate danger to life and death (IDLH) levels if the employer using anything less than supplied air respirator protection.

5 Confined Space Ventilation requirements to follow

  1. Use the correct ventilation equipment every time when working.
  2. Make sure the amount of airflow needed is sufficient.
  3. Check for fans and blowers regularly.
  4. Ventilation equipment should not be operated in an unventilated area.
  5. Confined space ventilation chart as a guide to determine the level of ventilation required in each specific confined space.


Knowing proper setup and understanding how to ventilate a confined space correctly significantly reduces the risk of injuries and fatalities.

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