Which condition must be met for using combustible gas detectors effectively?

For an effective use of combustible gas detectors, maintaining restricted public access is crucial because it minimizes the risk of exposure to potentially dangerous environments that could lead to explosive atmospheres. When public access is restricted, it allows trained personnel to monitor the area without the distraction or risk posed by untrained individuals. This focus enhances the ability of the detection system to operate safely and accurately since it can function in an environment where only authorized personnel who understand how to respond to a gas detection alarm are present.

While constant employee presence and periodic maintenance are important for maximizing safety and operational readiness of gas detection systems, they do not address the immediate threats posed by unauthorized individuals in hazardous areas. Intermittent usage would hinder the effectiveness of the detectors, as consistent monitoring is crucial for ensuring safety. Therefore, restricting public access is essential for creating a safe working environment where gas detectors can function optimally.