🔍 Key Concepts

• Location and purpose of fittings mounted on the top of a boiler steam drum • Function of main steam outlets vs. safety valves on a firetube or watertube boiler • How a desuperheater connects in relation to the superheater and main steam line

💭 Think About

• Look at where the fittings labeled "P" are installed on the boiler and trace what they connect to internally—do they appear to lead steam away to the plant, or just relieve pressure? • Compare the labeling: one fitting on top is marked differently (such as for the main steam line); ask yourself how the remaining top fittings would logically be used for safe boiler operation. • Think about which component must always be located at the highest point on the steam space and open directly to the atmosphere or discharge line.

✅ Before You Answer

• Verify whether fittings "P" are connected to a discharge to atmosphere/relief line or to a service steam line feeding the ship’s systems. • Check if there is a separately labeled connection for the main steam outlet in the illustration; if so, fittings "P" must serve a different function. • Confirm that a desuperheater would normally be found in the superheater steam path, not simply as multiple identical fittings on top of the drum.