What is the order of parameters to test for before entering a confined space?

Before entering a confined space, the order of parameters to test for is essential for ensuring the safety of personnel. The correct sequence begins with checking the oxygen level, followed by evaluating for combustible gases, and then assessing for toxic gases.

Starting with oxygen is critical because a safe level of oxygen (typically between 19.5% and 23.5% by volume) is necessary for human respiration. If the oxygen concentration is too low, it can lead to asphyxiation or unconsciousness.

Next, testing for combustible gases is important as they pose a fire and explosion hazard if present in sufficient concentrations. Knowing the flammable levels helps determine whether the space is safe for entry and work.

Lastly, assessing for toxic gases is vital because even low concentrations of certain toxic gases can be harmful or fatal to workers. By testing for these parameters in this order, it ensures that the environment is safe before any personnel enter the confined space.

Other sequences do not prioritize oxygen first, which could lead to dangerous situations if the oxygen level is inadequate. Similarly, ignoring the order can overlook potential immediate hazards posed by combustibles before confirming a safe oxygen level.