Membrane Wall Construction

This figure illustrates key components of a typical furnace wall.

A: Membrane bar (to connect two adjacent water tubes)

B: Wall tube

C: Insulation (to keep the heat inside the surface, also to keep the outer region cool enough for operator functions).

D: Metal lagging (to protect the insulation and other wall components).

Graphic Source: Steam - Its Generation and Use. Babcock and Wilcox