CSLB C-46 Solar ContractorSafetyMedium
A solar technician is working in a confined space, such as an underground utility vault, to connect a new solar array to the grid. Prior to entry, the atmosphere was tested and found to be oxygen deficient. What is the most appropriate next step before allowing entry?
- AUse an N95 respirator for entry.
- BVentilate the space to achieve safe atmospheric conditions.
- CEnter quickly to minimize exposure time.
- DPerform a secondary test with a different gas monitor.
Show answer & explanationAnswer & explanation
Correct answer: B. Ventilate the space to achieve safe atmospheric conditions.
An oxygen-deficient atmosphere is immediately dangerous to life or health (IDLH). Ventilation is required to bring the oxygen level to a safe range (19.5% to 23.5%) before entry. Respirators alone are insufficient for IDLH atmospheres unless specifically rated for self-contained breathing apparatus (SCBA) and used as part of a comprehensive confined space program.
Why the other options are wrong
- A. An N95 respirator filters particulates, but does not provide oxygen or protect against oxygen deficiency.
- C. Entering an oxygen-deficient space is extremely dangerous and can lead to unconsciousness or death.
- D. While a secondary test might be useful for verification, the primary action for an oxygen-deficient atmosphere is to correct the condition through ventilation, not just re-test.
Confined Space Oxygen Deficiency
An oxygen-deficient atmosphere in a confined space (below 19.5% oxygen) is an Immediately Dangerous to Life or Health (IDLH) condition requiring ventilation before entry.
- Normal oxygen range: 19.5% - 23.5%.
- Oxygen deficiency can cause unconsciousness, death.
- Ventilation is the primary control method.
- Respirators (other than SCBA) are ineffective for oxygen deficiency.
Memory trick: Low O2, ventilate anew, before you go through.