Massachusetts 2nd Class Fireman's Practice Exam

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Prepare for the Massachusetts 2nd Class Fireman's Exam. Use flashcards and multiple choice questions, with explanations and hints for each. Ace your test!

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At what temperature does a fusible plug begin to melt?

  1. 212 degrees F

  2. 450 degrees F

  3. 1,000 degrees F

  4. None of the above

The correct answer is: 450 degrees F

A fusible plug is specifically designed to provide a safety mechanism in certain types of boilers and equipment by melting at a predetermined temperature. This melting action allows for the escape of steam and prevents the pressure from building to dangerous levels. The correct temperature at which a fusible plug begins to melt is typically around 450 degrees Fahrenheit. At this temperature, the material of the plug becomes soft enough to lose its structural integrity, resulting in the safety feature activating and providing protection against the risk of an explosion or other dangerous failures. The other temperatures listed do not align with the purpose or functioning of a standard fusible plug, which is designed to operate within a specific safety threshold related to steam pressure and temperature.