American Society of Mechanical Engineers (ASME) Practice Exam 2026 - Free ASME Practice Questions and Study Guide

A Scotch boiler is a specific type of fire-tube boiler characterized by its design, which includes a large shell and a series of fire tubes that contain the hot combustion gases. The requirement of a minimum of four washout plugs in this type of boiler is crucial for maintenance and safety purposes. These washout plugs allow operators to effectively clean the boiler by removing sediment and sludge that accumulates from the combustion process.

The multiple washout locations enable thorough cleaning and inspection of different sections of the boiler, ensuring that any buildup which could negatively affect performance or lead to hazardous conditions is addressed. This is particularly important because the design and operation of the Scotch boiler can lead to localized overheating if deposits are allowed to accumulate, making regular maintenance critical.

While other types of boilers may also have specific maintenance requirements, the Scotch boiler stands out due to its design and the necessity for multiple access points to ensure proper cleaning and functionality.