According to Zhao Honghan, member of the China Association for Composite Materials Science and Technology Development and Advisory Committee, insulation materials for construction can be roughly divided into inorganic and organic categories. Commonly used inorganic exterior wall thermal insulation materials include rock wool, perlite, foamed cement (concrete), foam glass and vitreous microbeads. Although they have good fireproof performance, due to the high thermal conductivity, the use of thickness is inevitable. Increase, increase construction load and construction costs. Organic exterior wall thermal insulation materials include polystyrene foam (PS, EPS, XPS Type II), polyurethane foam (PU) and phenolic foam (PF), etc. It has the advantages of low density, low thermal conductivity, and easy construction. EPS and XPS are Class B2 (combustible). When heated above 80°C, melt softening, shrinkage and dripping occur. After the fire, thick smoke rolls and produces toxic gas. The PU combustion level is also B2. Although the softening temperature is slightly higher (110°C) and there is no dripping phenomenon, the smoke poison gas generated after the fire is a great hazard.

In the 1980s, foreign scientists researched phenolic resins and their products and found that they had outstanding flame-retardant, smoke-free, and non-toxic properties (abbreviated as FST characteristics). The phenolic foams produced were more flame-retardant than polyphenylenes. Dilute foam and polyurethane foam are better. The PF plate with a thickness of only 30 mm was subjected to a flame spray at 1700°C for 10 minutes. Only the surface was slightly charred and burned. It neither ignited nor emitted smoke or toxic gas.

It is understood that since the 90s of last century, phenolic composites including PF have been greatly developed. They have first been valued by the British and American military, and have been used in the field of aerospace and defense military industry. Later, PF was also used in ships, railway stations, oil wells and other places where fire protection requirements were strict, and gradually pushed to public and civil buildings such as hospitals, sports facilities and building housing. Due to its low thermal conductivity, PF is approximately twice as energy-efficient as conventional insulation materials such as rock wool, glass wool and expanded perlite. It is recognized that its energy-saving insulation performance ranks first in all insulation materials, and some people call it the "King of insulation" or the third generation of insulation materials. For example, if the thickness of the expanded perlite insulation layer is 60mm, PF only needs 25mm to achieve the same insulation effect.