Market application range of steel-clad steel steam-insulated pipes is expanding with the vigorous development of urban centralized heating and combined heat and power generation. The technology of thermal pipelines has been widely used domestically. The buried laying method is favored for its excellent thermal insulation effect, high energy-saving efficiency, minimal land occupation without affecting urban planning, easy 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 our country are "plastic-clad steel" and "steel-clad steel." The technical route for steel-clad steel burial is based on the 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 urban main roads and involve issues related to environmental beautification, the buried laying method can effectively solve these problems. Moreover, due to its fast construction progress, good thermal insulation performance, low construction cost, and material saving characteristics, it has been increasingly widely used. As steam buried pipelines are a new phenomenon, the national construction department has not yet formulated formal standards for detailed regulations on steam buried pipelines.

Steel-clad steel-insulated pipe manufacturers offer direct-burial steam pipelines with several features. As a new material in the heating industry, direct-burial steam pipelines have gained wider application due to their fast construction progress, excellent insulation performance, low construction cost, 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 features of direct-burial steam pipelines available on the market.