Coast Guard Exams
Question 20Steam Plants - 1st Asst/Chief70% to pass

According to the illustration of a typical boiler furnace rear wall, which item number would best represent "insulating block"? Illustration SG-0003

Diagram for question 20
AI Explanation
The correct answer is D. According to the illustration SG-0003, item number 7 represents the "insulating block" in the typical boiler furnace rear wall. Insulating blocks are used to line the interior of the furnace to provide thermal insulation and protect the outer walls from the high temperatures within the boiler. The other answer choices are incorrect because: A) Item 3 represents the "burner", which is a different component of the boiler furnace. B) Item 1 represents the "boiler shell", which is the outer casing of the boiler, not the insulating material. C) Item 2 represents the "refractory", which is a different type of insulating material used in the furnace.