Certified Healthcare Constructor (CHC) Practice Exam

Before an employee enters a permit-required confined space, which atmosphere should be tested with a calibrated direct-reading instrument?

1. Carbon dioxide levels

2. Oxygen content and potential toxic air contaminants

3. Temperature and humidity levels

4. Noise levels and vibrations

The correct answer is: Oxygen content and potential toxic air contaminants

Before an employee enters a permit-required confined space, it is crucial to test the atmosphere for oxygen content and potential toxic air contaminants. This is because the safety and health of workers are significantly impacted by the conditions within the space. The oxygen content must be within a safe range, typically between 19.5% and 23.5%, as too little oxygen can lead to suffocation, while too much can create a fire hazard. Additionally, determining the presence of toxic air contaminants is essential for preventing health risks associated with exposure to harmful gases and vapors. A variety of chemicals can be present in these confined spaces, including but not limited to carbon monoxide, hydrogen sulfide, and volatile solvents, which can pose serious risks if not monitored properly. Testing temperature and humidity levels, as well as noise levels and vibrations, are important for maintaining overall workplace safety, but they do not directly correlate with the immediate atmospheric hazards that can cause severe health issues or be life-threatening in confined spaces. Therefore, the focus on oxygen and toxic air contaminants is the key aspect to ensure a safe working environment before any entry is permitted.