Market application scope of steel-clad steel steam-insulated pipes is expanding with the vigorous development of urban centralized heating and combined heat and power generation, and the technology of thermal pipelines has been widely used domestically. The buried installation method is favored for its excellent insulation effect, high energy-saving efficiency, minimal land use without affecting urban planning, ease of installation, short construction period, long service life, and low maintenance costs. Currently, the main types of outer protective sleeves for buried steam-insulated pipes used in China are "plastic-clad steel" and "steel-clad steel." The technical route for steel-clad steel burial is based on traditional trench laying, replacing brick or concrete trenches with steel sleeves. The sliding interface of the pipeline is the interface between the pipeline support and the inner wall of the steel sleeve. Buried steam pipelines; buried; externally fixed; internally fixed. In recent years, there have been many attempts to use buried steam pipelines in northern cities. When steam pipelines cross city main roads and involve environmental beautification issues, the buried laying method can effectively solve these problems. Moreover, its fast construction progress, good insulation performance, low construction cost, and material savings have led to its increasingly widespread application. As steam buried pipelines are a new phenomenon, the national construction department has not yet formulated formal standards for detailed provisions on steam buried pipelines.

Several characteristics of steel-clad steel thermal insulation pipes from manufacturers, such as direct-burial steam pipelines, have gained increasing popularity in the heating industry as a new material due to their fast construction progress, excellent insulation performance, low construction costs, and material savings. Since there is no design specification for high-temperature steam pipelines, the insulation structures and fixing methods vary among different manufacturers. This article discusses several common types of direct-burial steam pipelines available in the market.