FIELD: production of heat-insulating materials. SUBSTANCE: method involves producing first nonwoven fabric from mineral filament defining longitudinal and transverse direction extending in parallel with first nonwoven fabric of mineral filament; moving first nonwoven fabric of mineral filament in lengthwise direction; bending first nonwoven fabric transverse to longitudinal direction and in parallel with transverse direction by decelerating the displacement of first nonwoven fabric of mineral filament so as to produce loose second nonwoven fabric of mineral filament having waves including two rows of wave ridges extending in opposite directions one relative to the other and to plane of interface extending in parallel with longitudinal and transverse directions; separating two rows of wave ridges one from the other and from second nonwoven fabric along plane of interface so as to produce two rows of curved halves of coverings; providing joining of two covering halves for producing annular insulating covering from mineral filament. Insulating covering is manufactured on continuous production line. EFFECT: increased efficiency and improved heat-insulating and mechanical properties of annular covering material produced from mineral filaments. 50 cl, 23 dwg
