Combustible gas indicators are used to...

Question 1 of 270705eccef9ebacbc34ba4d465b3

Combustible gas indicators are used to detect flammable gases or vapors in the atmosphere. As a safety feature, they are equipped with __________.

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Question 1 of 27070

Combustible gas indicators are used to detect flammable gases or vapors in the atmosphere. As a safety feature, they are equipped with __________.

🔍 Key Concepts

• Combustible gas indicators (CGIs) measure the concentration of flammable gases in air, usually as a percentage of the lower explosive limit (LEL) • Think about what could happen inside the instrument if it is drawing in a flammable gas/air mixture and there is an ignition source. • Consider what built‑in feature would stop a flame from traveling back out into the surrounding atmosphere.

💭 Think About

• If the instrument has an internal electrical or heated element, what extra protection is needed so that the instrument itself does not become the source of an explosion? • Which option directly addresses stopping flame propagation through an opening, rather than just warning, storing, or relieving pressure? • In a flammable atmosphere, which of these choices is specifically designed to prevent ignition spreading back through vents or inlets?

✅ Before You Answer

• Verify which device is specifically designed to prevent flame from passing through an opening while still allowing gas flow. • Eliminate items that mainly provide warning, storage, or over‑pressure protection, rather than stopping flame propagation. • Recall that CGIs must be safe to use in potentially explosive atmospheres, so their key safety feature must address ignition control, not just detection.