Which statement about combustible gas indicators is TRUE?

When discussing the function of combustible gas indicators, understanding their operational limitations is crucial. These devices are designed to detect the presence of combustible gases in the air; however, their effectiveness is significantly compromised in environments with low oxygen levels.

In such conditions, the combustion process itself may not occur effectively because there isn’t enough oxygen to support it, which can lead to false readings or a complete failure of the indicator to detect any gases. Therefore, a combustible gas indicator requires a certain minimum level of oxygen to accurately assess the presence of flammable gases. This inherent limitation highlights why the statement regarding their ineffectiveness in low-oxygen situations is accurate.

In contrast, indicators do not provide results regarding oxygen deficiency, cannot rely on a single air sample to assess the entire tank accurately, and are not calibrated in terms of explosion probability directly. Understanding these facts about combustible gas indicators reinforces their critical role in safety protocols when dealing with flammable materials.